DANYLO HALYTSKY
NATIONAL MEDICAL UNIVERSITY OF LVIV
DEPARTMENT OF THERAPEUTIC DENTISTRY
METHODOLOGICAL GUIDE
for practical classes
„Preclinical course of Therapeutic Dentistry”
(IV semester)
for the 2-nd year students
Part I
Lviv-2012
The methodological guide worked out by: M. Hysyk,
O. Ripetska, Yu. Riznyk
Edited by prof. V. Zubachyk
Accountable for an issue  first vice-rector of
scientific and academicl work, professor, Corresponding
Member of the Academy of Medical Sciences of Ukraine, M.R.
Gzhegotskiy.
Reviewers: associate professor of department of
Surgical dentistry N. Krupnik,
associate professor of department of
Pediatric dentistry N. Chukhraj
Methodological guide for students in Therapeutic
dentistry (III semester) was discussed and approved on the
sitting of the department of Therapeutic dentistry (record of
proceedings №15, dated from 11, May, 2010) and approved on
the meeting of Methodological committee in dentistry
disciplines on June 22, 2010, protocol № 3.
Computer printing: Oksana Zamoiyska
2
CONTENT OF THE COURSE
Page
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Plan of the discipline „Preclinical course of
Therapeutic Dentistry” according to the creditmodule system of the organization of studies
(CMSO) ..............................................................
Types of self-education work for students...........
Types of individual work for students..................
The structure of discipline „Preclinical cause of
Therapeutic Dentistry” estimation of grades for
current educational activity (converting of
traditional marks into marks, estimation in grates
for implementation of individual tasks) ………...
Introduction …………………………………….
Practical lesson 21 Filling materials.
Classification. Main demands. Temporary filling
materials. Composition, properties, and use
indications ………………………………………
Practical lesson 22. Bases and liners.
Composition, structure, properties, and use
indications ………………………………………
Practical lesson 23. Permanent filling materials.
Classification. Physical-chemical properties of
cements. Indications for use ……………………
Practical lesson 24. Glass-ionomer cement.
Characteristic. Indications. Peculiarities of
practical use …………………………………….
Practical lesson 25. Amalgam. Physicalchemical properties. Methods of preparation and
filling with amalgams ………………………….
Practical lesson 26. Composites resins.
Classification. Composition. Characteristic.
3
5
8
9
10
12
14
19
26
32
41
12.
13.
14.
15.
16.
17.
Indications for use. Filling materials of the main
manufactures ……………………………………
Practical lesson 27. Adhesive systems for
enamel and dentin ………………………………
Practical lesson 28. Self-curing resin
composites. Properties, indications for use,
peculiarities of treatment ……………………….
Practical lesson 29. Light-curing resin
composites. Properties, indications for use,
peculiarities of treatment. Compomers …………
Practical lesson 30. Filling of the caries cavity
of the I and V classes according to Black
classification. Substantiation of the choice of the
filling material ………………………………….
Practical lesson 31. Filling of the caries cavity
of the II class according to Black classification.
Substantiation of the choice of the filling
material …………………………………………
Practical lesson 32. Filling of the caries cavity
of the III and IV classes according to Black
classification ……………………………………
4
50
61
70
74
85
97
103
Plans of practical lessons, out of class work and individual
work in discipline „Preclinical course of Therapeutic
Dentistry” for 2-rd year
English-medium students (4th term)
Credit-Module System
PRACTICAL LESSONS
Module 2: Filling materials and Endodontics 2,2 credits
(66 hours)
№
21
22
23
24
Topic
Pract. Out of Individual
lessons class
work
work
Filling
materials.
2
1
Classification.
Main
demands.
Temporary
filling
materials.
Composition,
properties, and use
indications.
Review of
Bases
and
liners.
2
1
scientific
Composition, structure,
and
properties, and use
professional
indications.
literature,
Permanent
filling
2
1
preparation
materials.
of the
Classification. Physicalwritten work
chemical properties of
and carrying
cements. Indications for
on scientific
use.
investigation
Glass-ionomer cement.
2
1
Types,
properties,
indications for use,
peculiarities of the
5
25
26
27
28
29
30
31
filling procedure.
Amalgam.
Physicalchemical
properties.
Methods of preparation
and
filling
with
amalgams.
Composites
resins.
Classification.
Composition.
Characteristic.
Indications for use.
Filling materials of the
main manufactures.
Adhesive systems for
enamel and dentin.
Self-curing
resin
composites. Properties,
indications for use,
peculiarities
of
treatment.
Light-curing
resin
composites. Properties,
indications for use,
peculiarities
of
treatment. Compomers.
Filling of the caries
cavity of the I and V
classes according to
Black
classification.
Substantiation of the
choice of the filling
material.
Filling of the caries
cavity of the II class
6
2
1
2
1
2
1
2
1
2
1
2
1
2
1
32
33
34
35
36
37
according to Black
classification.
Substantiation of the
choice of the filling
material.
Filling of the caries
cavity of the III and IV
classes according to
Black classification.
Endodontics.
Topographical anatomy
of permanent teeth
cavities and root canals.
Technique of tooth
cavity
opening.
Medications for pulp
devitalization.
Local
anesthesia.
Endodontic instruments.
Classification. Types.
Indications for use.
Work with endodontic
instruments. The use of
medications
for
cleaning of the root
canal.
Methods
of
cleaning and widening
of root canals.
Root
canal
filling
materials.
Classification.
Main
demands.
Partially
hardening
sillers.
Composition.
7
2
1
2
1
2
1
2
1
2
1
2
1
38
39
40
Characteristic.
Indications for use.
Filling of the root
canals with partially
hardening
and
hardening sealers and
fillers.
Methods of fillings of
the
root
canals.
Mistakes
and
complications
during
endodontic
manipulations,
their
reasons and ways of
removal.
Summary control 2.
Summary hours
2
1
2
1
2
40
2
22
TYPES OF SELF-EDUCATION WORK FOR STUDENTS
(22 hours)
№
Topic
Hours
1.
Preparation for the practical
lessons  theoretical part.
Individual work with the topics
not included to the practical
lessons:
- Anatomical-physiological
peculiarities of some parts of
oral mucosa.
- Pit and Fissure sealants.
Composition.
Characteristic.
15
2.
8
1
1
Type of
control
Control at
practical
lessons
3.
Indications for use.
- Compomers.
Composition.
Characteristic. Indications for
use.
- Topographical anatomy of
permanent teeth cavities and root
canals.
(Horizontal
section.
Drawing)
- Topographical anatomy of
permanent teeth cavities and root
canals. (Vertical section. Drawing)
Preparation for the summary
module control
1
1
1
2
Summary
module
control
TYPES OF INDIVIDUAL WORK FOR STUDENTS
№
Topic
Points
1.
Ormokers. Composition. Characteristic.
Advantages and disadvantages.
Giomers. New generation of hybrid of
light-curing
resin
composites
and
glassionomer cements.
Silorans – improved nanocomposites.
2
2.
3.
9
2
2
THE STRUCTURE OF DISCIPLINE „PRECLINICAL COURSE OF THERAPEUTIC
DENTISTRY”, MARKS FOR CURRENT EDUCATIONAL ACTIVITY (THE
CONVERTATION OF TRADITIONAL ESTIMATIONS IN MARKS, ESTIMATION IN
GRADES FOR IMPLEMENTATION OF INDIVIDUAL TASKS)
module, numder of
educational hours,
numder of credits,
ECTS
Distribution
of practical
classes
Convertation of
traditional marks into
grades
Traditional marks
Module 1. Structure of
teeth and preparation of
carious cavities  69
hours, 2,3 credits
Practical
classes
(in all 19)
„5”
„4”
„3”
„2”
6
4
3
0
Grades
for the
implemen
tation of
the ISRS
Number of
grades for
current
educational
activity of
students
Number of
grades for final
module control
6
max
6,19=114
min
3,19=57
max
80
min
40
Students which collected 57 marks are admitted to final module control. For individual work 6 marks are added
Module
2.
Filling
Practical
6
4
3
0
6
max
max
materials
and
classes
114
80
(in
all
19)
min
min
endodontics  66 hours,
57
40
2,2 credits
Students who reseived 57 grades are admitted to final module control. For individual work 5 marks are added.
10
The convertation of estimations in rating scale into the
scale of progress in studies ECTS
Estimation Statistical index
of ECTS
Description
The best 10%
Next
followings 25%
Next
followings 30%
Next
followings 25%
The last 10%
Repeated
handing over
Obligatory
repeated course
of studies
Exellent
Very good
Limits of
estimations
of ECTS
191-200
166-190
Good
136-165
Satisfactory
111-135
Acceptably
Unsatisfactory
101-110
A
B
C
D
E
Fx
F
Unsatisfactory,
with the
repeated
course of
studies
11
Introduction
The curricula for students of dental faculties of higher
medical establishments of Ukraine of the III-rd and IV-th
levels of accreditation contains the course of preclinical
therapeutic dentistry which tought during in the III-rd and IVth semesters. On the basis of typical curriculum, educational
qualification (EQD) and educational professional programs
(EPP) of training of specialists, experimental curriculum and in
accordans with principles of ECTS (European credit-transfer
systems) and the order dated from 31.01.2005 № 52 approved
by Ministry of Health Care of Ukraine, current educational
programme has been developed by co-workers of the
departments of Therapeutic dentistry.
Preclinical course during the 2-nd year of studies
provides thorough and profound preceding education of
students, mastering of obligatory manual skills, on phantoms,
which are extremely important for the future independent work
in the clinic of therapeutic dentistry.
Initial level of knowledges of students on the III-rd and
IV-th semesters foresees knowledge of fundamental medical
disciplines.
The educational process is carried out according to the
credit-module system in accordance with the requirements of
Bolon’ process.
The specific aim of study of the module 1 „Structure of
teeth and preparation of carious cavities” envisages the
thorough study of substantial modules „Anatomico-histological
and clinico-topographical peculiarities of structure of teeth”
and „Preparation of carious cavities”.
Substantial module 1 „Anatomico-histological and
clinico-topographical peculiarities of tooth structure ” includes:
- analysis of histological structure and chemical
composition of hard tissues of tooth (the dentine, the
12
cement) and the pulp, anatomico-histological and
physiological structural features of separate areas of
oral mucosa;
- interpretation of age changes, the influence of the
function of salivary glands and the quality of saliva
on the condition of hard tissues of the tooth;
- analysis of clinico-anatomical features of different
groups of teeth;
- explanation of the role of the structure and signs of
teeth in the determination of their belonging to one
or another group, side, upper or lower jaws.
A 2 „Preparation of carious cavities” foresees:
- analysis of dental instruments;
- effective sterilization;
- the classification of carious cavities according to
Black classification;
- the interpretation of the necessity to follow rules of
the mode and stages of the preparation of carious
cavities;
- the explanation of peculiarities of preparation of
carious cavities according to Black classification;
- an analysis of indications to the application of
different methods of preparation (classical, M.I.therapy, ART-therapy, tunnel preparation) of carious
cavities.
The methodological guide contains short description of
themes for each lesson, the list of control questions to evaluate
every students’ knowledge of presented material, tests and
situational tasks. At the end of every topic the list of
recommended literature is presented, which will help students
to prepare for their practical classes.
13
Practical lesson No 21
Theme: Filling materials. Classification. Main demands.
Temporary filling materials. Composition, properties,
and use indications.
Short description of a theme
Classification of dental filling materials
Dental filling materials according to their purpose can
be divided as follows:
- for temporary filling,
- for permanent filling,
- subbase and base materials,
- endodontic materials.
Temporary filling materials are used for 1-2 weeks (up
to one month). Artificial dentinum (zinc sulfate cement) is
most common. The powder consists of zinc sulfate and zinc
oxide in the ratio 3:1 and 5-10% of kaoline. The powder is
mixed with water on the rough side of the glass by metal
spatulas. At first the powder is given in the amount able to
absorb all the water and then the powder is added by small
portions to achieve an optimal consistence. The prepared
mixture is taken to the cavity in on portion and condensed by
cotton pellet and shaped by one of the filling instruments.
Temporary filling has low mechanical steadiness to grinding.
Dentin – paste is also used (it is dentinum mixed with
vegetable oil). The paste becomes firm in 2-3 hours at body
temperature.
Zinc mixed with eugenol can be used as the temporary
filling.
Materials for temporary filling: timodentinum (Poland),
multidentinum (red powder – for devitalized teeth, white
14
powder – during caries treatment, yellow antiseptic dentin –
during endodontic procedures).
Septodont (France) produces Cimpat for temporary
filling: red powder (used after application of devitalizing
agents) and white powder.
Voco produces light curing material for temporary
filling – Provicol.
There are different names of dentin-pastes also,
according to producent: Cimpat – Septodont (England).
Demands to the permanent filling materials
a. Tooth filling materials should be:
- non-irritant to the pulp and gingival;
- of low systemic toxicity;
- cariostatic.
b. Ideally there should be bonding between filling and
enamel and dentine, and marginal leakage should not occur.
c. Not dissolve or erode in saliva or in fluids taken into
the mouth. Low water absorption is also important.
d. Mechanical properties should be adequate to
withstand the forces of mastication, and should be similar to
those of enamel and dentine in respect of modulus of elasticity
and strength. Good abrasion resistance to dentifrices and
constituencies of food is also important. Restorations of
posterior teeth are particularly subject to conditions of abrasive
wear.
e. Good aesthetic properties are required, particularly
for fillings in anterior teeth. Thus the restoration should ideally
match the tooth in:
- colour;
- translucency;
- refractive index.
Over a period of time there should be no staining or
discoloration.
f. Thermal properties:
15
- coefficient of thermal expansion should be similar to
that of enamel and dentine;
- low thermal diffusivity.
g. Other properties:
- minimal dimensional changes on setting;
- ability to retain a smooth surface;
- adequate working time;
- radio-opacity, to enable;
- detection of secondary caries;
- identification of overhanging ledges;
- detection of incompletely fille cavities due to trapped
air.
Control questions to practical lesson
1. What are the main groups of dental materials?
2. What temporary filling materials are used in dentistry?
3. What is the purpose of using temporary filling materials in
dentistry?
4. Describe the composition of the artificial dentin, used as
temporary filling material.
5. What are the main demands to the permanent filling
materials?
6. Innumerate the propeties which should possess an ideal
dental material for permanent filling.
Situation tasks and test control
1. The powder of temporary filling material (Dentin) consists
of:
A. Zinc sulfate and zinc oxide
B. Zinc sulfate and eugenol
16
C. Zinc oxide and eugenol
D. Zinc sulfate and kaolin
E. Zinc sulfate, zinc oxide and kaolin
2. The powder of Artificial dentin is mixed with water in the
ratio
A. 2:2
B. 2:1
C. 1:1
D. 1:2
E. 3:1
3. The time of hardening for Dentin paste as a temporary filling
is:
A. 8 min.
B. 2-3 hours
C. 1 hour
D. 40 min.
E. 25 min.
4. The time of hardening for Artificial dentin as a temporary
filling is:
A. 8 min
B. 25 min
C. 40 min
D. 1 hour
E. 2-3 hours
5. What liquid should be used for mixing of the powder of the
Artificial dentin?
A. Polyacrylic acid
B. Orthophosphoric acid.
C. Methylmethacrylate
D. Eugenol.
17
E. Distilled water
6. Which of the enumerated materials can be used as temporary
fillings:
A. Silico-phosphate, composite
B. Compomers
C. Zinc-eugenol cements
D. Silicate cements
E. All cements
7. With what instrument it is recommended to install the
temporary filling into the tooth cavity
A. Spatula.
B. Excavator
C. Tweezers
D. Instruments for cavity filling
E. Elevator
8. With what instrument it is recommended to remove the
temporary filling from the tooth cavity
A. Probe
B. Excavator
C. Tweezers
D. Elevator
E. Dental drill in a turbo handpiece
9. What are the two compounds of the Zinc which form the
structure of the Artifitial dentin?
A. Oxide and Sulfate
B. Fluorine and Oxide
C. Cloride and Nitrate
D. Fluorine and Sulfate
E. Fluorine and Sulfate
18
10. Which one of the mentioned demands to permanent filling
is absent in modern composites?
A. Good aesthetic properties
B. Translucency
C. Non-irritant to the pulp
D. Low systemic toxicity
E. Radio-opacity
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
Practical lesson No 22
Theme: Bases and liners. Composition, structure, properties,
and use indications.
19
Short description of a theme
Base materials and subbase materials
Subbase materials have therapeutic effect on the pulp.
In the case of deep cavities even very economical tissue cutting
leads to the traumatization of odontoblasts sprouts which
influences the pulp of the tooth. During the preparation in deep
cavities one can observe direct influence of microorganisms
and products of their metabolism on the pulp, thereby existing
a possibility of pH lowering in the dentinum layer near the
pulp.
Subbase materials have an antiseptic properties and
anti-inflammatory effect on the pulp, they stimulate
odontoblasts to produce mineralized dentinum (so called
substantional dentine or tertiary dentine).
The majority of used subbase materials include calcium
hydroxide (Ca(OH)2). They have alkaline pH>12 and thus
lowered pH in the cavity and normalize pulp blood circulation.
Subbase materials do not possess adhesion properties to
dentinum, that’s why it should be layed over in very thin
amount and should not cover the whole bottom of the cavity. It
is enough to put small amount (one drop of the material) with
the help of dental probe on the nearest point to the pulp.
Subbase materials must be covered by the base
materials.
There are different forms of production of subbase
materials:
7. Hydrosolutions (Hypocal, Calxyl (They are
prepared from the powder of Ca Hydrooxide (some
have also K, Na, NaHCO3) and water. Radioopague
substances (for example hydroxide of Titanium) are
added to them;
8. Varnishers for cavity treatment with Ca(OH)2
(Hydroxyline, Tubulitec Alcaliner);
20
9. Oil containing substsnces with Ca(OH)2 (Gangraena
Merz);
10. Cements (Dycal, Kerr-Life). These are acids
connected with Ca(OH)2. One of the substances is
sulicilate ether which forms the chelate complex
with Ca Hydrooxide and Ca salicilate.
Cement subbases can have additional substances
(ethyltoluol sulfonamide) and dyes. These cements are pastelike and harden after mixing. Cement subbases cannot be used
instead of base cements (they are too mild and can dissolve
under the filling).
One of the examples of combination of Ca(OH)2 in the
base is Cp-Cap (Ca salicilate cement combined with the Zinc
oxide cement).
Demands to the base materials
1. to protect the pulp from chemical, thermal and microbe
influences
2. to cover all the walls of the cavity directed to the pulp
3. to be biocompatible with tooth tissues
4. to be strong in the molar teeth
5. to be of minimal solubility in oral liquid
6. in the case of using materials, raising the adhesion of
composites, base ought to be acid stable and not contain
eugenol.
All the materials containing Ca(OH)2 cannot be used as
base materials.
Base materials are divided into two main groups
varnishers/lines
cements
21
Varnishers in dentistry are resins dissolved in organic
solvents.
After the varnish is put into the cavity the solvent
evaporates and the resin remains. Liners have treatment
supplements (Ca(OH)2, ZnO etc.). They are used only in
shallow and small cavities. It is important that organic solvents
of the liners are not compatible with the pulp (examples:
Cavity-Liner, Copalite).
Control questions to practical lesson
1.
2.
3.
4.
Whar is the purpose of the subbases use in dentistry?
What subbase materials are applied in carious cavities?
What are the main properties of subbase materials?
Enumerate the demands to base materials.
Situation tasks and test control
1. Pulpal SENSITIVITY is caused primarily by:
A. Vibration from cavity preparation
B. Thermal trauma
C. Electrical trauma
D. All of answers are correct
E. Chemical irritation from bacteria
2. CHRONIC INFLAMMATION is caused primarily by:
A. Mechanical inflammation
B. Microleakage of endotoxins
C. Thermal trauma
D. All of the metioned factors
E. Chemical irritation from dental materials
22
3. The DENTIN SMEAR LAYER increases:
A. Chemical adhesion for varnishes
B. Mechanical adhesion for liners
C. Coverage of tubule openings
D. Thermal insulation for the pulp
E. Formation of reparative dentin
4. What is the THICKNESS of thermal insulation required
for pulpal protection?
A. 1000-2000 mm (1.000-2.000 mm)
B. 10-50 mm (0.010-0.050 mm)
C. 50-200 mm (0.050-0.100 mm)
D. 200-1000 mm (0.200-0.500 mm)
E. 2-5 mm (0.002-0.005 mm)
5. DYCAL is classified as a:
A. Solution liner
B. Suspension liner
C. Cement liner
D. Cement base
E. Cement filling material
6. Dental materials that are designed as PULPAL
MEDICAMENTS contain:
A. Calcium hydroxide or Eugenol
B. Calcium phosphate or Eugenol
C. Calcium hydroxide or Methyl Salicylate
D. Zinc oxide or Eugenol
E. Calcium hydroxide or Zinc Oxide
7. The pH of concentrated CALCIUM HYDROXIDE
solutions is:
A. pH = 1-3
B. pH = 3-5
C. pH = 5-7
23
D. pH = 7-9
E. pH = 9-11
8. Which intraoral component is required to start the
setting of DYCAL?
A. Ca ions from tooth structure
B. Higher temperatures of the intraoral tissues
C. Denatured proteins in the smear layer
D. Monovalent ions from saliva
E. Moisture for calcium hydroxide dissociation
9. What is the key IONIC species for the setting of DYCAL
and LIFE?
A. Zn++
B. Ca++
C. Sn++
D. K+
E. Na+
10. Indirect pulp capping is conducted as follows:
A. After the placement of on adhesive layer
B. Before indirect capping procedure the pulp should be
covered with isolation base
C. The subbase is put on the dentin in the bottom of the cavity
D. The medication is put directly on the pulp
E. The subbase is put on the second visit
11. Which of the below mentioned materials belong to the
group of medicinal subbases:
A. Zinc phosphate cement
B. All answers are wrong
C. Silicate cements
D. Silicophosphate cements
E. Dycal
24
12. During the treatment of deep caries non-hardening subbase
of Ca hydroxide was used. What is the next stage of treatment?
A. Placement of the temporary filling
B. Placement of the permanent composite filling
C. Permanent of the glass-ionomer filling
D. Etching of the caries cavity
E. Etching, bonding, placement of composite filling
13. The liquid of zinc phosphate cement consists of:
A. 37% ortophosphoric acid
B. Acrylic acid
C. Distilled water
D. Aqueous solution of ortophosphoric acid (52-56% of mass)
and supplements (zinc, aluminum)
E. 10-50% of polyacrylicaud
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. Seltzer and Bender’s. Dental pulp // Quintessence
Publishing, 2002.
5. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
25
Practical lesson No 23
Theme: Permanent filling materials. Classification. Physicalchemical properties of cements. Indications for use.
Short description of a theme
Cements
These materials are powders connected with water or
aqueous solutions.
Cements are divided in:
- Zinc-phosphate cements;
- Silicate cements;
- Glassionomer cements;
- Carboxilate cements;
- Zinc-oxide eugenol cements.
Zinc-phosphate cements are used as base materials for
filling of deciduous teeth and for fixation of the crowns. They
stand considerable loads, and poorly dissolve in the saliva.
They provoke pulp reaction which is reversible. The pH
of the cements after mixing is acid tending to be neutral in
some hours. If the consistency of the cementum is more liquid,
neutralization will take more time, which means more irritation
to the pulp. Protection of the pulp in deep cavities is achieved
by subbases.
The powder of the zinc-phosphate cement consists of:
zinc-oxide – 80-90% and supplementaries mostly MgO up to
10% – it makes the cement more durable. Also silicium oxide
and other oxides are used.
Liquid of the cement consists of the aqueous solution of
ortophosphoric acid (52-56% of mass) and supplements (zinc,
aluminium), the rest is water.
26
Cement is mixed on a slightly cooled glass, to decrease
the amount of heat discharged during the reaction. The powder
is always added to the liquid (not vice versa) by small portions
to achieve the necessary consistency.
After taking the powder and liquid, bottles must be
closed immediately to protect the acid from moisture
absorption. When the powder is opened it absorbs carbon
dioxide (CO2) from the air and during mixing gasses are
educed which leads to the porous structure of the cement.
The reaction of hardening is exotermic. The time of
hardening is 5-9 minutes. The shrinkage is 0,03-0,06% in 7
days in humid medium.
Heat-conductability is the same (close to) the dentin,
thus the cement doesn’t protect the pulp from thermal irritation.
Silicate cements differ from zinc-phosphate mainly by
the composition of the powder, which include SiO2 (up to
47%) and Al2O3 (up to 35%). These cements are rarely used
because of bad adhesion and pulp irritating effect.
The powder of zinc-oxide eugenol cements consist of
ZnO and different Zn-compounds, the liquid is eugenol.
Mostly these cements are used for temporary fillings.
The cement hardens quickly in oral cavity (at body
temperature).
Zn-eugenol cements cannot be used with composites,
because eugenol effects resins polymerization. Zn-eugenol
cements have bacteriocide effect. Being derivate of phenol,
eugenol can cause allergic reactions.
Zn-eugenol cement cannot be used as direct pulp
covering, it can provoke the exacerbation of the pulpitis.
Carboxylate cements. Their composition is similar to
those of Zn-eugenol cements. Liquid in 40-50% consists of
polyacrylic acid. They are more viscous (sticky) than
phosphoric acids and more compatible with the pulp and form
chemical bonding with tooth hard tissues. But these cements
27
have greater shrinkage and are less durable (stable). The
solubility of carboxylate cements is the same as that of Zn
phosphate cements.
These cements cannot be used in tooth areas which are
exposed to great pressure.
Control questions to practical lesson
1. What groups of cements do you know?
2. What is the composition of zinc-phosphate cement?
3. What is the main difference between zinc-phosphate and
silicate cements?
4. Enumerate the properties of Zn-eugenol cements.
5. What are the advantages of Carboxylate cement being
compared with zinc-phosphate cements.
6. Why is fluoride release so important in a cement?
7. What is the difference in function between a cement liner
and a cement base?
8. Why are polymer cements recommended for use with
CAD/CAM inla\-s with poor marsrinal fits?
9. What is the minimum compressive strength required of a
dental cement for adequate retention of restorations?
10. How does the solubility of phosphate cements in citric or
lactic acid compare with their solubility in water? What are
adhesive resin cements?
11. What agents accelerate the setting of zinc oxide— eugenol
cements?
12. Why do zinc oxide-eugenol cements have a high solubility?
13. What materials can be added to zinc oxide-eugenol cements
to improve their strength?
14. What effects do zinc oxide-eugenol cements have on resin
restorative materials?
15. How does the composition of EBA cements differ from that
28
of zinc oxide-eugenol cements?
16. WTiat factors affect the setting reaction of polycar-boxylate
cements?
17. Give possible reasons for the minimal effect of
polycarboxylate cements on pulp.
18. What are important considerations in manipulating
polycarboxylate cements?
19. Define the two types of polymer-based cement.
20. What are the principal disadvantages of polymer-based
cement?
Situation tasks and test control
1. What properties of alumosilicate cements limitate their use
in carious cavities of II-nd an IV-th classes?
A. Instability to abrasion
B. Chemical solubility
C. Instability in colour
D. Thermal expansion
E. Thermal conductivity
2. The main difference between Zinc phosphate and
Polycarboxilate cements is:
A. Composition of the powder
B. Composition of the liquid
C. Indications for use
D. Colour
E. Thermal conductivity
3. What cement from the below mentioned can be used for
filling of the deciduous tooth witout isolation with a base
material?
A. Silicate cement
29
B. Polycarboxilate cement
C. Silicophosphate cement
D. Silicate and Silicophosphate cements
E. Polycarboxilate and Silicate cements
4. What are indications for use for the Zinc-phosphate
cements?
A. Fixation of the intracanal metal posts
B. Root canals filling
C. All varients are correct
D. Fixation of the crowns
E. As a base material
5. During the treatrment of profound caries Zinc-Oxide
eugenol base has been used. Which of the innumerated
materials can be fixed over this base?
A. Composite resin
B. Light-cured Composite resin
C. Microhybrid Composites
D. Cements for permanent filling
E. All answers are correct
6. During the process of mixing of Zinc-phosphate cement it
tends to be too hard. The operator add one drop of liquid to
achieve proper consistency. Was it correct?
A. The operator needs to mix a new portion of cement in
proper ratio of liquid and powder
B. Yes
C. More liquid is needed
D. It depends of achieved consistency
E. It is necessary to place the mixed cement into the cavity
without adding the liquid
30
7. Silicate cements differ from Zinc-phosphate mainly by the
composition of:
A. Supplements
B. Heat-conductability
C. Liquid
D. Powder
E. All answers are correct
8. The main difference between Carboxylate cements and Zneugenol cements is:
A. Composition of the powder
B. Composition of the liquid
C. Shrinkage
D. Solubility
E. Thermal conductivity
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
31
Practical lesson No 24
Theme: Glass-ionomer cement. Characteristic. Indications.
Peculiarities of practical use.
Short description of a theme
Fluorine-containing aluminosilicate glasses are of
particular interest.
These cements contain an ion-leachable glass which can
react with a water-soluble polymer acid to yield a cement.
They are used not only as base materials but also as
filling materials.
As cement liquid can be used:
1) polycarbonic acids (polymers of alkenic acid), for
example polyacrilic acids and their copolymers with
itaconic and maleinic acids;
2) distilled water.
Powder of Glass-ionomer cements includes of Ca-Alsilicat glass with inclusions of crystallized, saturated with
Calcium-fluorine drops.
Generic formula can be as follows:
SiO2-ZnO2-TiO2-Al2O3-AlF3-LaF3-CaF2-NaF-AlPO4Ca3PO4.
After filling with glass-ionomer it releases fluorine for a
long period of time (it ensures carious-static effect in the
border line between the walls of the cavity and the filling
materials).
It is important to protect glass-ionomer filling from
dehydratation and humidity (it is achieved by varnishers after
filling). Glass-ionomer cements can not be well polished
(because of the connection of mild polycarboxylic gel and hard
silicat glass). Optimal surface of the filling is achieved with the
32
use of matrixes. After the end of hardening (24 hours)
processing is made with fine grinded diamond burnishers and
disks covered with aluminium oxides.
What is very important about glass-ionomer cements –
is their ability to form chemical bonding with tooth hard
tissues. There exist ionic and covalent connections among
carboxylic groups of polyacrylic acid and inorganic
components of enamel and dentine. Resin-enamel connection is
6 times stronger than the connection of glass-ionomer cement –
enamel. To take the connection better dentin surface can be
conditioned with 25% polyacrylic acid. Not having enough
mechanical stableness and aesthetics, glass-ionomer cements
can not be used in class II and IV cavities.
Classification and applications
Three types of cement, glass-ionomer should be
distinguished:
a. Type I, luting cements. These are fine grain materials
with low film thickness when set (Aquacem (Dentsply), Fuj
Fuj Ortho (GC), Sen-Fix (Sendentel), Aqua Meron, lonofix
(Voco), Ketac Cem (ESPE).
b. Type II, restorative materials (Chemfil Superior
(Dentsply), Fuji (GC), Ketac Molar (ESPE), Ionofil Molar
(Voco), Sen-Fill, Sen-Fill Ague (Sendental), Ionofil, Aqua
Ionofil (Voco). Examples of applications include:
- abrasion and erosion cavities;
- restoration of deciduous teeth;
- restoration of Class III and V carious lesions;
- repairing defective margins in restorations.
c. Type III, lining materials (Gem Base (DCL), BaseLine (Dentsply), Lining Cement (GC), Sen-Line (Sedental),
Shofu-Base Cement, Shofu Liner Cement (Shofu), Viva-Glass
Liner (Vivadent), lonobond, Aqua lonobond (Voco), Ketac
Bond (ESPE) and fissure sealants, for:
33
- sealing occlusal fissures;
- cavity lining, particularly if cariostatic action is
required;
- as a lining under composite filling materials; one such
technique involves etching the cement as well as the tooth
enamel, so that micromechanical bonding between composite
and cement is achieved.
Because of their nature, glass polyalkenoate cements
are contraindicated for:
- amalgam replacements;
- class IV restorations;
- replacement of lost cups areas.
a.
b.
c.
d.
e.
f.
g.
Manipulation
Mix the cement at the correct ratio – this is of critical
importance for Type II cements.
Rapid mixing is required, ideally by mechanical mixing, or
by the use of a refrigerated glass slab.
Moisture isolation of the tooth is desirable.
A surface conditioner should be applied to dentine.
Pulpal protection by a calcium hydroxide cement is
important if the dentin over the pulp chamber is less than
0,5 mm thick.
Protection of the freshly set cement from moisture by
application of, for example, a varnish is important.
After polishing, varnish should be re-applied.
Light activated cements
Recently, materials have become available, the setting
of which is activated by the application of visible light, using
the same light system as designed for composite resins.
Essentially, two setting reactions occur:
34
-
-
further polymerization of the poly(alkenoic acid)
which, in these products, contains polymerisable
double bonds;
the conventional acid-base reaction.
Control questions to practical lesson
1. What is the source of fluoride in a glass-ionomer cement?
2. What are resin-modified glass ionomers?
3. What are the advantages of light curing glass-ionomer
cements?
4. What are the major advantages of glass-ionomer cements?
Situation tasks and test control
1. What is the POWDER component in GICs (traditional glass
ionomers)?
A. Zinc oxide
B. Silica
C. Lithium aluminosilicate
D. Aluminosilicate glass
E. Alumina
2. What is the LIQUID component in GICs (traditional glass
ionomers)?
A. Polyacrylic acid
B. Polymethacrylic acid
C. Polymethyl methacrylate
D. BIS-GMA polymer
E. Phosphoric acid
35
3. Which one of the following has NOT been used as part of
the GIC liquid composition?
A. Acrylic acid
B. Tartaric acid
C. Maleic acid
D. Citric acid
E. Itaconic acid
4. How is F ion released from a cured GIC?
A. Intraoral fluids dissolve it out of the glass particles
B. CaF2 salts dissolve and release the fluoride
C. Fluoride ions in the matrix are released
D. Sodium fluoride salts release the fluoride
E. Acid in the oral environment dissolves the residual glass
5. What causes the initial setting reaction in a GIC?
A. Release of fluoride ions from the aluminosilicate glass
B. Crosslinking of polyacrylic acid polymer chains by
aluminum ions
C. Loss of water from the matrix phase
D. Crystallization of the dissolved salts from the powder
particles
E. Crosslinking of polyacrylic acid polymer chains by calcium
ions
6. What causes the final setting reaction of in a GIC?
A. Release of fluoride ions from the aluminosilicate glass
B. Crosslinking of polyacrylic acid polymer chains by calcium
ions
C. Crosslinking of polyacrylic acid polymer chains by
aluminum ions
D. Loss of water from the matrix phase
E. Crystallization of the dissolved salts from the powder
particles
36
7. What produces chemical adhesion to tooth structure for a
GIC?
A. Chelation of polyacrylic acid with calcium ions
B. Chelation of polyacrylic acid with aluminum ions
C. Reactions of the fluoride ions with hydroxyapatite
D. Precipitation of calcium phosphate from the dissolved
powder
E. Precipitation of calcium oxide
8. Contaminated or overly wet tooth surfaces interfere with the:
A. Adaptation of the cement for chemical bonding
B. Initial setting reaction
C. Final setting reaction
D. Release of fluoride ion
E. Color of the final cement
9. Which one of the following is key during the first 24 hours
for conventional GIs?
A. Protection against contact with moisture
B. Protection against intraoral acid contact
C. Protection from ultraviolet radiation
D. Protection against salivary protein contact
E. Protection against fluoride release
10. What is the time of maximum fluoride release RATE out of
the cement?
A. During the first few minutes
B. During the first 24 hours
C. During the first month
D. During the first year
E. After the first year
37
11. Which one of the following is NOT a major use for glass
ionomers?
A. Class V filling material
B. Liner
C. Base
D. Cement
E. Tunnel preparations
12. Which application takes best advantage of chemical
adhesion of glass ionomers?
A. Class V filling material
B. Liner
C. Base
D. Cement
E. Tunnel preparations
13. Which application takes best advantage of the fluoride
release of glass ionomers?
A. Liner
B. Base
C. Root caries restorations
D. Retrograde filling material
E. Core
14. Which one of the following has the most influence on the
final mechanical and chemical properties of conventional GI
cements?
A. Fluoride content of the aluminosilicate glass
B. Mixing technique
C. Powder-to-liquid ratio
D. Acidity of the mixture
E. Reaction exotherm
38
15. What is the mechanism of reinforcement of metal-modified
GIs?
A. Addition of stronger powder particles
B. Addition of particles which can be chelated by matrix
C. Addition of particles which can dissolve and affect reaction
D. Addition of particle that accelerate fluoride release
E. Addition of insoluble particles
16. What is the major difference between chemically-cured and
light-cured (LC) GIs?
A. LC produces second matrix
B. LC version has no acid-base reaction
C. LC versions accelerate release of F from aluminosilicate
glass
D. LC eliminates all moisture sensitivity of material
E. LC version increases adhesion to tooth structure
17. Which one of the following is not part of a "multiplecuring" GI system?
A. Ca++ ion crosslinking of acid-functional polymer chains
B. Al+++ ion replacement of Ca++ crosslinking
C. Visible light polymerization of matrix monomers into
polymer
D. Chemical curing of matrix monomers into polymer
E. F ion crosslinking of polymer chains
18. Which one of the following materials is a traditional glass
ionomer cement?
A. Vitremer cement
B. Fuji II
C. Advance
D. Dyract
E. Ketac-Cem
39
19. What is the term used for glass ionomers that are very
similar to composites?
A. Hybrid ionomers
B. Compomers
C. Hybrid composites
D. Giomers
E. Glass ionomer modified composites
20. ART is the acronym for which of the following?
A. Advanced Resistance Technique
B. Atraumatic Restorative Technique
C. Advanced Restoration Therapy
D. Assisted Re-Enameling Technology
E. Archive of Restoration Technologies
21. What is the primary goal of ART?
A. Prevention and treatment of dental caries with minimal
instrumentation
B. Delivery of F from restorations for patients at high risk to
dental caries
C. Relief of patient pain
D. Alternative to dental amalgam restorations
E. Inexpensive dentistry
22. Which of the following re-charging sources is the most
effective?
A. Topical fluoride treatments
B. Daily fluoride mouth rinses
C. Fluoride-containing toothpastes
D. Ice tea
E. Fluoride supplements
40
23. How long does re-charging of glass ionomer materials
effect F-release?
A. 1-2 minutes
B. 1 -2 days
C. 1 -2 weeks
D. 1-2 months
E. 1 -2 years
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
Practical lesson No 25
Theme: Amalgam. Physical-chemical properties. Methods of
preparation and filling with amalgams.
41
Short description of a theme
Definition: an amalgam is an alloy of mercury with
another metal or metals. Mercury is a liquid at room
tempetature; its freezing point is – 39oC. It can readily undergo
amalgamation reactions with metals such as silver, tin and
copper to give a set material.
Alloys for the preparation of dental amalgam may be
broadly classified into two types:
- сonventional alloys, containing less than 6% copper
– the chemical formulation of these materials has
been very little changed over the years (Quicalloy,
Standalloy, Stabil B);
- сopper enriched alloys, which have become
available since the 1970s (sometimes referred to as
„Higher copper”alloys).
Conventional alloys contain the following principal
constituents:
- Silver – 67-74%4
- Copper – 0-6%;
- Tin – 25-27%;
- Zinc – 0-2%.
Copper enriched alloys are of the following types:
a. Blended alloys, sometimes referred to as „dispersion
modified” alloys; these contain two parts by weight of
conventional composition lathe cut particles plus one part by
weight of spheres of a slver-copper alloy (70% Ag + 30% Cu,
approximately). Representatives: Dispersalloy, Luxalloy,
Amalcap plus. The overall composition is approximately:
- Silver – 69%,
- Copper – 13%,
- Tin – 17%,
- Zinc – 1%.
42
b. Single composition alloys: a number of different
types are available, including:
Ternary alloys in spherical form, either:
- Silver 60%, Tin 25%, Copper 15% (Representatives:
Oralloy, Dispersalloy)
or
- Silver 40%, Tin 30%, Copper 30% (Representatives:
Duralloy, Vivalloy, Sybralloy, Valiant).
An alloya similar to the first of those detailed above, but
containing particles in spheroidal form – that is, that particles
are not perfectly spherical.
Quaternary alloys in spheroidal form, containing:
- Silver 59%, Copper 13%, Tin 24%, Indium 4%.
c. Alloys which are the reverse of type (a) above are
available in some countries. That is, they contain 2 parts by
weight of spheres of 60% Ag, 25% Sn and 15% Cu, plus 1
parts by weight of conventional alloy. This latter component
may be either as spherical or fine grain lathe cut particles.
Control questions to practical lesson
1. Are dental amalgams a health hazard?
2. Why is dental amalgam so popular, even though it is not
esthetic?
3. What are the advantages and disadvantages of using a
bonding agent with amalgam restorations?
4. How does copper affect the set microstructure of amalgam?
5. How can the working time of amalgam be controlled?
6. Should a zinc-free amalgam be used?
7. Can some amalgams be finished the same day they are
placed?
8. Why are spherical amalgams difficult to condense?
9. Does creep predict marginal fracture?
43
10. Why are seal/bond amalgam restorations of particular
interest?
11. How safe are amalgams?
Situation tasks and test control
1. Dental amalgam is DEFINED as:
A. A mixture of mercury with any metal
B. A mixture of mercury with silver
C. A mixture of mercury with silver and tin
D. A mixture of mercury with any zinc alloy
E. The alloy for mixing with mercury
2. How much MERCURY (by weight) is in a modern set dental
amalgam?
A. >60%
B. 55-60%
C. 50-55%
D. 45-50%
E. 40-45%
3. What is the COPPER CONTENT in LOW COPPER dental
amalgam alloys?
A. 0 - 5%
B. 5 -12%
C. 12-30%
D. 30-38%
E. 38-50%
4. What COMPONENTS are typical in LOW COPPER dental
amalgam alloy?
A. Ag-Sn
B. Ag-Sn-(Cu)-(Zn)
C. Sn-Cu-Zn
D. Ag-Sn-Cu-(Zn)
44
E. Ag-Sn-Cu-Zn
5. What COMPONENTS are typical of HIGH COPPER dental
amalgam alloy?
A. Ag-Sn-Cu
B. Ag-Sn-Cu-(Zn)
C. Ag-Sn-Zn
D. Ag-Sn
E. Sn-Cu-Zn
6. Which one of the following terms is NOT synonymous with
the rest in the list?
A. Comminuted particles
B. Filings
C. Lathe-cut particles
D. Irregular particles
E. Spherical particles
7. COMMINUTION is:
A. Milling or filing an ingot into powder particles
B. Heat treatment to control the setting reaction of powder
particles
C. Decreasing the mercury content of an amalgam
D. Eliminating the copper content of an amalgam alloy
E. Elimination of the tarnish on an amalgam restoration
8. Which one of the following is NOT a standard method of
classification for dental amalgams?
A. Particle Shape
B. Copper Content
C. Mercury Content
D. Number of Powder Particles
E. Zinc Content
45
9. NEW TRUE DENTALLOY dental amalgam alloy is
made as what type of powder?
A. Irregular
B. Irregular + Irregular
C. Irregular + Spherical
D. Spherical + Spherical
E. Spherical
10. What is the reason Zn is used in a dental amalgam
alloy?
A. Oxygen scavenger in production
B. Reducing mercury vapor release from the set restoration
C. Improved hardness
D. Controlling the setting reaction
E. Prevent tarnishing
11. What is the reason Sn is included in a dental amalgam
alloy?
A. Corrosion protection
B. Improved ductility
C. Prevent tarnishing
D. Particle dissolution during reaction
E. Increased tensile strength
12. What is the reason Cu is included in a dental amalgam
alloy?
A. Corrosion protection
B. Increased ductility
C. Prevention of tarnishing
D. Reduction in amalgamation speed
E. Improved condensability
13. The SETTING REACTION of dental amalgam
proceeds primarily by:
A. Dissolution of the entire alloy particle into mercury
B. Dissolution of the Cu from the particles into mercury
C. Mercury reaction with Ag on or in the alloy particle
D. Formation of Zn-Hg crystals
46
E. Precipitation of Sn-Hg crystals
14. What is the ABBREVIATION for the Sn-Hg phase?
A. Gamma (= Y)
B. Gamma-1 (= YI)
C. Gamma-2 (= Y2)
D. Beta (= p)
E. Epsilon (= s)
15. Which phase in a set dental amalgam contains most of
the MERCURY?
A. Gamma (= Y)
B. Gamma-1 (= YI)
C. Gamma-2 (= Y2)
D. Eta (= n)
E. Epsilon (= s)
16. Which one of the following variables does NOT
influence the amount of DIMENSIONAL CHANGE during
setting of dental amalgams?
A. Alloy particle size or shape
B. Hg/alloy ratio
C. Trituration time
D. Condensation method
E. Burnishing technique
17. What does the batch (or lot) number code of "040501"
on an amalgam alloy mean?
A. It was produced on January 5, 2004
B. It was shipped on January 5, 2004
C. It is no longer acceptable after January 5, 2004
D. That it contains 4Sn-5Cu-1Zn in the alloy
E. That it should not be used before January 5, 2004
47
18. A PROPERLY TRITURATED dental amalgam
mixture should look like a:
A. Grainy, dull mass
B. Coherent, smooth mass
C. Grainy, wet mixture
D. Fibrous, dull mass
E. Fibrous, shiny mass
19. Which one of the following produces the MOST
mercury-rich matrix removal?
A. Condensation late in the working time
B. Use of the largest condenser tip
C. Use of the most load during condensation
D. Non-overlapping condensing strokes
E. Burnishing
20. What is the effectiveness for HIGH COPPER dental
amalgams?
A. 1-2 years
B. 4-5 years
C. 8-12 years
D. 20-25 years
E. 30-50 years
21. Which one of the following mechanisms of FAILURE is
most common for LOW COPPER dental amalgam?
A. Excessive tarnish
B. Bulk fracture
C. Intergranular corrosion of the occlusal surface
D. Dental caries
E. Marginal fracture
22. Which one of the following mechanisms of FAILURE is
most common for HIGH COPPER dental amalgam?
A. Excessive tarnish
48
B. Bulk fracture
C. Intergranular corrosion of the occlusal surface
D. Enamel wall fracture from thermal expansion stresses
E. Marginal fracture
23. MARGINAL FRACTURE of dental amalgam is NOT
associated with this property.
A. Compressive strength
B. Creep
C. Mercury content
D. Electrochemical properties
E. Thermal conductivity
24. Which one of the following does NOT affect the strength of
dental amalgam?
A. Time between trituration and condensation
B. Mercury content
C. Zinc content
D. Condensation effectiveness
E. Porosity
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
49
Practical lesson No 26
Theme: Composites resins. Classification. Composition.
Characteristic. Indications for use. Filling materials
of the main manufactures.
Short description of a theme
Composites resins were introduced by Bowen (1962)
for the first time. Bowen developed a BIS-GMA composite
resin. A high percentage of an inter filler was dispersed in the
resin to produce higher strength and lower coefficients of
thermal expansion.
Contemporary composite resins consist of three main
components:
1. Organic matrix.
2. Dispers phase (Filler).
3. Connecting phase (copolymers).
1. Organic matrix.
Composite matrix in soft state consists of monomers,
initiators, stabilizators, dyes and pigments and other
supplements.
As monomers polyfunctional metacrylates with
simplified formula MA-R-MA are used. MA – are the residual
complex ethers of metacrylic acid. R – intermediate link which
can be formed by aliphatic lines, uretanprepolymers, aromatic
rings and polyethers.
50
Molecules of resin’s matrix have minimal toxic effects,
are colour stable, have good physical characteristics.
Initiators – are matrix components, which by chemical
or physical activators dissociate to active radicals which react
with double links of monomers.
These reactions result in the production of polymer
lines.
The activity of initiators is the decisive factor in the
material’s hardening. (The degree of polymerization). The
higher is the polymerization degree, the higher will be
mechanical and physical characteristics of matrix. Initiators
also influence composite colour. Stabilizators (inhibitors) –
sterine phenols prevent premature polymerization.
2. Connecting phase (colorymer).
Connection of the filler and the matrix depends on the
silanization of the filler. As silanization agent 3 metacryloloxipropyl-trimetoxisilan is used. During the polymerization not
all double links of resins are involved. Residual double links
form 45%. This indicates the presence of residuum monomer.
In matrix there are also some other products which partially do
not react. They may be toxic for pulp. Shrinkage after
polymerization of the used composites is 1,7-6% in mass. It
can lead to the existence of tensions inside the resin and
appearing of cracks on the surface of filling.
3. Dispers phase.
To make resin matrix more stable mechanically and
physically inorganic fillers are added. They are quarts,
ceramics, silicon dioxide (SiO2).
Classification of composite resins is based on the type
and size of fillers being used.
Macrofillers (quartz, glass, ceramics) the mean size of
particles is 1-100 mcm the meddle size of particles 1,5-5 mcm.
The size of particles is larger than the length of light waves
(they are seen by the eye). Fillers particle fall out of matrix
51
because of different hardness. After polishing the surface
becomes rough. These materials do not need polishing. They
have low stability to grinding („Concise”, „Valux” (3M),
„Estilux”).
Composite resins with microfillers.
Size of particles is less than 1 mcm. They contain
highdispersible silicic acid (silicon oxide) with particles 0,007
mcm to 0,04 mcm. All particles are spherical. The general
quantity of filler can be 70-80% on the average 50%. These
materials are polished well and have surface luster. Diameter of
particles is less than the length of light waves. These
composites are more stable to grinding. But polymerization
shrinrage is large, hardness (in Vikers units) and elasticity is
less than in order composites. They are not appropriate for
filling cavities class I, II, IV. („Silux Plus” (3M),
„Helioprogress”, „Heliomolar” (Vivadent)).
To unit positive properties of abovementioned two
groups of composite resins hydrid composite resins were
introduced. These resins have at an average 85-90% (by mass)
macroparticles and 10-15% microparticles. General contents of
filler particles is 85%. Finegrinded hydride composite resins
contain macrofillers with diameter less than 2 mcm. They are
good in polishing. These composite resins are used in filling
the cavities of all classes (I, II, III, IV, V).
Hydrid composites can be devided into composites with
particles 0,04-4 mcm – (Brilliant (Coltene), Herculite XR
(Kerr), Degufill H (Degussa) with high esthetic properties
which are recommended for front teeth reconstruction and
composites (P-10, P-50 (3M), Polofil Molar (Voco) with
particles 0,04-50 mcm with 87,5% of filler. They are strong but
less esthetic. For filling cavities class I and II.
Modern hydrid composits can be called microhybrid
and are used in filling a;; classes of cavities. Average size of
particles in this composites are 0,7-0,9 mcm.
52
Herulite RV, Prodygy (Kerr)
Tetric (Vivadent)
Brilliant Esthetic Line (Coltene)
Polofil Supra (Voco)
Solitaire (Kulzer0
Charisma (Kulzer)
Flow line composites:
Revolution (Kerr)
Durafill (Flow)
Flow line composites are poorly filled what allows to
put them without condensation (the average size of particles is
less than 1 mcm) with filler less than 60%.
Control questions to practical lesson
1. Describe the composition ofcomposite resins.
2. How are composite resins classified according to the size of
inorganic filler?
3. Enumerate the representatives of microhybrid composite
resins.
4. What is the general composition of resin composite
restorative materials?
5. How have composites overcome many of the problems of
unfilled resin restorative materials?
6. How well are composite materials competing against dental
amalgam?
7. Although microfilled composite materials have inferior
mechanical properties, they continue to be widely used.
Why?
8. What is the general composition of resin composite
restorative materials?
9. What are the applications for resin composite restorative
materials?
53
10. How long do composite restorations last?
11. What are the advantages of fine-particle composites?
12. What are the advantages of microfilled composites?
13. What is a hybrid, or blend, composite?
14. What is polymerization shrinkage, and why is it a problem?
15. Which restorative materials release fluoride? List them in
order of amount released.
16. What is the material of choice for cervical restorations?
Situation tasks and test control
1. Which ONE of the following is NOT a reason for utilizing
composite technology in dentistry?
A. Metal, ceramic, or polymer alone does not have the correct
properties to replace tooth structure
B. In situ molding requires a fluid phase for flow
C. In situ adhesion requires a fluid phase for physical and/or
chemical bonding
D. In situ setting avoids built in mechanical stresses
2. The major shortcoming of the rule-of-mixtures is that it
accounts for only ONE of the following factors, which is:
A. Arrangement factors
B. Bonding factors
C. Composition factors
D. Defect factors
3. Which ONE of the following is NOT a stage in chain reaction
polymerization?
A. Activation
B. Initiation
C. Configuration
D. Propagation
E. Termination
4. Which ONE of the following species is comparatively high
concentration in the average composite composition?
54
A. Colorants
B. Initiator
C. Accelerator
D. UV stabilizer
E. Low MW monomer
5. Which of the following is FALSE about chain reaction
polymerization reactions during the setting of composite
materials?
A. Fast
B. Involves double bonds
C. Endothermic
D. Requires initiation
E. Involves acrylic monomers
6. The BIS-GMA monomer unit is:
A. Mono-functional
B. Di-functional
C. Tri-functional
D. Tetra-functional
E. Penta-functional
7. The reactive end groups of BIS-GMA monomer are most
similar to which ONE of the following structures?
A. Bisphenol-A
B. Methyl methacrylate
C. Benzoyl peroxide
D. Methyl acrylate
E. Urethane
8. All of the following are true about BIS-GMA monomer,
EXCEPT:
A. Includes a Bisphenol-A nucleus in the backbone
B. Is high viscosity
C. Is highly volatile
D. Is called Bowen's resin
E. Is impossible to purify by crystallization
9. Which of the following is not present in an auto-polymerizing
dental composite?
55
A. BIS-GMA
B. BPO
C. DHPT
D. Silane
E. PMMA
10. For silane coupling agents to effectively bond filler particles
to matrices, which chemical species must be present on the filler
particle surfaces?
A. Si-O
B. Zn-O
C. Ba-O
D. Zr-O
E. H2O
11. Which of the following does not impact the viscosity of a
unset composite?
A. Volume fraction of filler
B. Viscosity of the resin
C. Surface area-to-volume ratio of the filler
D. Benzoyl peroxide concentration
12. Which ONE of the following potential fillers can NOT be
silanated?
A. Quartz
B. Aluminosilicate glass
C. Lithium aluminosilicate glass
D. Silica
E. Barium sulfate
13. Which one of the following is NOT a category of dental
composites?
A. Packables
B. Flowables
C. Nanocomposites
D. Microfills
E. A R T
56
14. What types of fillers are mixed together in standard hybrid
composites?
A. Midifiller and Minifiller
B. Minifiller and Microfiller
C. Microfiller and Nanofiller
D. Midifiller and Microfiller
E. Minifiller and Nanofiller
15. What types of fillers are mixed together in mini-hybrid
composites?
A. Midifiller and Minifiller
B. Minifiller and Microfiller
C. Microfiller and Nanofiller
D. Midifiller and Microfiller
E. Minifiller and Nanofiller
16. What types of fillers are mixed together in nano-hybrid
composites?
A. Microfiller and Nanofiller
B. Minifiller and Nanofiller
C. Microfiller and Nano-clusters
D. Microfiller and Nanomers
E. Nanomers, Nanoclusters, and Midifiller
17. Which one of the following is not a true statement about
biofilms?
A. The base layer involves cells attached by a polysaccharide
coating.
B. Biofilms have extensive channels among mushroom plumes
of cells.
C. Biofilms can migrate across a surface to relocate the entire
film.
D. Cells in biofilms easy destroyed by standard antibiotics.
E. Biofilms are found universally in moist environments
regardless of bacterial cell type.
57
18. Which one of the following statements characterizes
second generation flowable composites?
A. Much better flow than first generation products.
B. All products are almost the same strength as standard hybrid
composites.
C. Much greater depth of cure than regular composites.
D. Do not adapt well to bonded dentin surfaces.
E. Are more difficult to cure with visible light than other
composites.
19. What is the reason for applying several coats of primers,
self-etching primers, or self-etching adhesives during bonding
procedures?
A. Insure adequate film formation after solvent loss
B. Increase the strength of the bonding layer
C. Increase the water resistance of the cured film
D. Increase the fatigue resistance of the adhesive
E. To minimize oxygen inhibition during VL curing
20. What is the typical solvent level range for dentin bonding
systems?
A. 10-30%
B. 20-50%
C. 45-50%
D. 55-60%
E. 60-90%
21. What is the hybrid layer?
A. Zone of collagen surrounded by resin within intertubular
dentin
B. A layer of resin in which there is a combination of filler
particle sizes
C. A double layer produced by primer and then bonding agent
D. Resin that has mixed with dentinal fluid and filled the
tubules
E. Any resin layer that includes HEMA in the composition
58
22. What is the third major category of variables affecting
visible light curing in addition to "curing equipment factors"
and "procedural factors"?
A. Restoration factors
B. Patient factors
C. Intraoral location factors
D. Oral hygiene factors
E. Surface contamination factors
23. What is the active absorber of visible light in a dental
composite that initiates polymerization?
A. BIS-GMA
B. Glass filler
C. Silane coupling agent
D. Camphoroquinone
E. Hydroquinone
24. What is the minimum output expected for standard QTH
visible light curing units?
A. 100 mW/cm2
B. 200 mW/cm2
C. 300 mW/cm2
D. 400 mW/cm2
E. 600 mW/cm2
25. What is the standard operating output for many QTH
visible light curing units?
A. 100 mW/cm2
B. 300 mW/cm2
C. 600 mW/cm2
D. 1000 mW/cm2
E. 1500 mW/cm2
26. What is the standard output for third-generation LED
visible light curing units?
A. 100 mW/cm2
59
B. 200 mW/cm2
C. 300 mW/cm2
D. 600 mW/cm2
E. 800-1000 mW/cm2
27. What happens to the visible light generated by QTH units
that is not the correct wavelength to be absorbed by CQ?
A. Passes completely through restorative material
B. Scattered by the glass filler particles into adjacent tooth
structure
C. Absorbed and converted into heat
D. Reflected by the surface of the restoration as light
E. Absorbed and re-emitted as infrared light
28. What is the largest volume of glass ionomer sold in the
world today?
A. Giomer
B. Compomer
C. Resin-modified glass ionomer
D. Conventional glass ionomer
E. Resin-reinforced glass ionomer for ART technique
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
60
Practical lesson No 27
Theme: Adhesive systems for enamel and dentin.
Short description of a theme
Enamel conditioning (enamel etching). Composite
resins do not form chemical connection with teeth hard tissues.
Polimerizational shrinkage takes place after the hardening of
the material what leads to the decrease of filling’s volume. As a
result fissure between the filing and tooth wall appears. And
this is a precondition (prerequisite) for retaining of
microorganism, discoloration of filling’s margins and
secondary caries origin. To achieve better filling-enamel
connection, before insertion of filling enamel surface has to be
conditioned (for the first time recommended in 1955).
Stages of enamel conditioning:
- сleaning of the enamel by prophylactic paste in
order to remove organic remnants;
- enamel beveling;
- protection of the operative field from the saliva;
- etching procedure by 37% phosphoric acid (30 sec);
- washing out of the acid and drying the surface (it
looks white without the lustre).
Dentin conditioning. Chemical and structural
composition of dentine (dentinal tubules with fluid organic
components and smear layer) excludes micromechanical
adhesion with hydrophobic composites.
61
Special agents have been elaborated to connect dentin
and composite resins. Chemical link is achieved (due to this
agents) with organic and inorganic dentine components.
Before agents (primer) is put to dentinal surface the
latter is etched with acids. It may be citric (10%), phosphoric
(10-40%), polyacrilic acids. Primers usually includes
hydrophilic monomers soluble in water and other solvents
(acetone, alcohol). Supplementary primer solutions can include
maleinic acid and glutaraldehyd. They from intermediate layer
between wet dentin surface or smear layer and composite.
3 Different types of composite-dentin links are know:
I. Smear layer is only modifiered by the primer and not
removed. Representative: „Pertac universal Bond” (ESPE),
„ALL-Bond-2” (Bisco).
II. Smear layer is partially removed.
Maleinic acid is used in concentration 2,5-4% of mass.
After the partial dissolution of smear layer hydrophilic
monomers of primer penetrates dentinal canals, forming
retentional connections. As a result hydrid layer is formed were
molecules of primer are bound up with precipitated smear
layer. Representation: „XR-Bond” (Kerr).
III. Smear layer is completely removed and
simultaneously demineralization of intertubular and peritubular
dentin is taking place. Ortophosphoric acid (20% or 37%) is
used in dentine etching in this case.
Representatives: „All-Bond”, „All-Etch” (Bisco)
Dentadhesive (Kultzer), Scotchbond-2 (3M), Syntac
(Vivadent).
There are several generations of dentin adhesive
system, the I generation of adhesives bonds dentine and acrylic
materials (Cosmic Bond (De Tray). Adhesive forces were 1-3
Mpa. II generation of adhesives – provided connection of
dentinal Ca with chlor-phosphate groups and increased
adhesive forces 3 times as much as those of the I generation.
62
In the III generation of adhesives alumosilicates, 4
META, HEMA etc. are used as active groups (Amalgobond
(Parkel USA), Clearfilphoto Bond (Kuraray), Gluma (Bayer),
Scotchbond-2 (3M). Adhesive forces (were 12-18 Mpa).
Adhesives of the forth generation are widely used in
modern techniques. They produce a wide hydrid zone,
penetrating deep into dentinal tubules. They include PENTA,
which has hydrophobic and hydrophilic molecules. It allows
active connection with Ca ions of enamel and dentin as well as
with collagen – organic part of dentin.
This dual chemical connection in addition to
micromechanical connection produces connection with dentin
adhesive forces being of 25-27 Mpa.
Adhesive of the IV generation except PENTA include
other dymethacrelates TEDMA, UDMA, HEMA. To increase
absorption of primers into dentinal tubules acetone, etanol and
other dissolvents have been added to them. Adhesive of the
forth generation are more elastic and include fluor to decrease
tooth sensibility.
Representative: „Dentadhesive” (Kultzer), „Pro Bond”
(Dentsply), „Scotchbond MP Plus” (3M), „Syntac” (Vivadent),
„Optibond” (Kerr), „Art Bond” (Coltene Whaledent).
The fifth generation of adhesives are composed to
simplify the 3-stage procedure of bonding (etching, primer and
bond application).
They unite the properties of primer and bond in one
solution.
Representatives: „One-Step” (Bisco), „Prime & Bond
2,0”, „Prime & Bond 2,1” (Dentsply), „Single Bond” (3M),
„Optibond Solo” (Kerr), „Gluma bond” (Kultzer). The
adhesive forces in the adhesives of the V generation are 27-31
MPa.
It is important when using this systems not to overdried
dentinal surface, which leads to the collapsing of collagen
63
fibers and deterioration of the adhesive’s penetration deep into
dentinal tubules.
One of the newest representative of the V generation
adhesives is the system Promt L Pop (ESPE). Its three
ingredients are connected just before usage and obtained
substance is easily applied to the prepared tooth surface by
special applicator.
Control questions to practical lesson
1. What is the aim of enamel etching?
2. Enumerate the stages of enamel conditioning.
3. Why is the connection of dentin and composite resins
difficult?
4. What types of composite-dentin connection are known?
5. Describe the advantages of dental adhesives of the 4-th and
5-th generations.
6. Named the representatives of dental adhesives of the 4-th
and 5-th generations.
7. Why is wetting by an adhesive so important for bonding to
tooth structure or any other material:
8. Why is the strength of enamel and dentin a limiting factor
in the adhesive bond strength?
9. What is the essential role that hydrophilic primer coupling
agents play in the formation of the hybrid layer?
10. How could the geometry of a restoration affect the final
bond strength to tooth structure?
11. Miy does surface tension exist in liquids?
12. How does wetting affect capillary' penetration of a liquid?
13. How do absorption and adsorption differ?
14. Name three colloidal systems of importance to dental
materials.
15. Which properties affect the penetration rate of liquids into
64
capillaries?
16. In terms of innovation, would the bonding of restorative
materials to dentin by etching and forming a hybrid layer
be classified as a major, medium, or minor product
improvement?
Situation tasks and test control
1. The principal goal(s) of bonding are:
A. Sealing and retention
B. Esthetics and reduction of postoperative sensitivity
C. Retention and reduction of tooth flexure
D. Strengthening teeth and esthetics
E. Sealing and thermal insulation
2. Which one of the following applications does NOT involve
an adhesive joint?
A. Enamel bonding system
B. Pit-and-fissure sealant
C. Dentin bonding system
D. Amalgam bonding system
E. Composite cement
3. Which one of the following applications does NOT involve
an adhesive joint?
A. Dentin bonding system
B. Composite resin cement
C. Surface sealant
D. Amalgam bonding system
E. Orthodontic bonding system
65
4. Which ONE of the following is NOT a major requirement
for development of good adhesion?
A. Clean adherend
B. Calcium ions present for bonding
C. Good wetting
D. Intimate adaptation
E. Good curing
5. Dentin bonding systems involve which of the following
exclusive joint components?
A. Adhesive only
B. Adherend only
C. Adhesive/adherend
D. Adhesive/adherend/adhesive
E. Adherend/adhesive/adherend
6. What is the typical shear bond strength range for enamel
bonding systems?
A. 2-6 MPa
B. 6-12 MPa
C. 12-18 MPa
D. 10-22 MPa
E. 22-35 MPa
7. What is the typical shear bond strength range for newer
dentin bonding systems?
A. 2-6 MPa
B. 6-12 MPa
C. 12-18 MPa
D. 18-22 MPa
E. 22-35 MPa
66
8. Which category of factors is most important in determining
clinical performance?
A. Operator factors
B. Tooth factors
C. Location factors
D. Materials factors
E. Patient factors
9. Which of the following correctly describes the shape of
hydroxyapatite crystals?
A. Cylindrical
B. Parallelopipeds
C. Dodecahedrons
D. Hexagonal rods
E. Keyhole shaped tubes
10. At which location in enamel is the density of enamel
crystals the lowest?
A. Prismless enamel
B. DEJ
C. Center of enamel prisms
D. Edges of enamel prisms
E. Facial enamel
11. Which of the following is not a conditioner?
A. Phosphoric acid
B. EDTA
C. Maleic acid
D. Citric acid
E. BIS-GMA
12. What is the principal mechanism for enamel bonding?
A. Physical bonding
B. Primary chemical bonding
67
C. Hydrogen bonding
D. Micro-mechanical bonding
E. Incoherent bonding
13. In normal dentin, how far does an odontoblastic process
extend from the cell?
A. 10-20 |im
B. 0.5 mm
C. Most of the way to the DEJ
D. Half way to the DEJ
E. 1 mm
14. What is the typical volume of dentin occupied by dentinal
tubules in the outer third of dentin?
A. 50%
B. 40%
C. 25%
D. 14%
E. 5%
15. What is the principal mechanical for dentin bonding?
A. Physical bonding
B. Primary chemical bonding
C. Hydrogen bonding
D. Micro-mechanical bonding
E. Chelation bonding
16. Which one of the following is most important event for
dentin bonding?
A. Smear layer removal
B. Smear plug removal
C. Peritubular dentin decalcification
D. Intertubular dentin decalcification
E. Collagen denaturation
68
17. What is the hybrid zone?
A. Decalcified peritubular dentin
B. Embedded smear layer
C. Embedded smear plugs
D. Bonding agent/ composite interface
E. Embedded smear layer and intertubular dentin
18. Which of the following products was the first to represent a
1-component DBS?
A. Prompt L-Pop
B. SingleBond
C. Optibond Solo
D. One-step
E. Clearfil Liner Bond
19. When a ceramic inlay is bonded, which of the following
interfaces does NOT involve chemical bonding as part of the
joint?
A. Enamel/Bonding Agent
B. Bonding Agent/Composite Cement
C. Composite Cement/Coupling agent
D. Coupling Agent/Ceramic
20. When a ceramic inlay is bonded, which of the following do
NOT involve micro- mechanical bonding in the joint?
A. Enamel/Bonding Agent
B. Dentin/Bonding Agent
C. Bonding Agent/Composite Cement
D. Composite Cement/Ceramic
Reference literature
69
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
Practical lesson No 28
Theme: Self-curing composite resins. Properties, indications
for use, peculiarities of treatment.
Short description of a theme
Self-curing composites are the composites in which
reaction of polymerization is initiated by chemical substance –
benzoil peroxide-amine. All of the composites of the type
consist of two parts: paste-paste, paste-liquid, powder-liquid.
These composites as compared to modern light-curing
composite resins are characterized by:
- quick wearing, which depends on the inner porosity
and degree of polymerization;
- tendensy to colour change (grayish, yellowish
shade), which depends on the presents of activator –
benzoil peroxide-amine, being sensible to UV
70
radiation;
- corrosion in some spots of the filling.
Polimerization self-curing composite resins takes part
simultanuosly throug all the volume of the material. Shrinkage
of the composites is directed to the centre of the filling.
The exemple of self-curing composite resins are:
„Evicrol” Spofa-Dental, „Consice” 3M ESPE, „Charisma PPF”
Heraeus Kulzer, etc.
Control questions to practical lesson
1. Classify composite resins according to the type of
polymerization.
2. What are the main demands to composite resins as filling
materials?
3. What are the drawbacks of self-curing composites when
compared to light-cured composites.
4. Is there a necessity to use base materials with self-cured
composites.
5. Describe the procedure of filling the carious cavities class
I-V with self-cured composite resins.
6. What are the pecularities of polishing of self-cured
composite resins.
7. Innumerate some representatives of self-cured composite
resins.
Situation tasks and test control
1. What is the main difference between self-cured and lightcured composite resins?
А. The type of filler
В. The type of catalyst
С. The type of polymer
D. The type of monomers
71
Е. The size of filler particles
2. It is indicated in the instructions for use that composite
material Degufill (Degussa) has the size of filler particles 0,4
mcm. To what group of composites belongs this material?
А. Light-cured composites
В. Microfillers
С. Hybrid
D. Macrofillers
Е. Flowable composites
3. What classes of carious cavities (according to Black’s
classification) can be recommended to be filled with Degufill
composite resin with size of filler particles 0,4 mcm.
А. I-II classes
В. III, IV classes
С. II-III-IV classes
D. III, I, V classes without masticatory load
Е. All classes
4. In what time after filling the cavity it is recommended to
polish self-cured composite?
А. In 8-12 minutes after hardening
В. Immediately after hardening
С. In 2-3 hours after hardening
D. In 24-38 hours after hardening
Е. The polishing is not needed
5. Macrofill composites are characterized by great strength, but
have not appropriate esthetic properties. What is the reason for
low esthetic properties of macrfill composites?
А. Inadequate colour shade spectrum
В. Low colour stability
С. Low colour transparency
72
D. Excessive transparency
Е. They can’t be polished
6. Carious cavity of 37 tooth (chronic medium caries) was
filled with self-cured composite. What should be the next stage
after preparation of caries cavity?
А. Placement of the treatment base
В. Placement of connecting agent
С. Etching of the cavity
D. Cleaning of the cavity
Е. Placement of the base materials
7. What pastes are used for cleaning of hard tissues before
filling the cavity?
А. Pastes without fluorine
В. Pastes containing Ca and F
С. Fluoride-containing tooth-pastes
D. Ca-containing tooth pastes
Е. Polishing pastes without Ca
8. The selection of the colour of future restoration is choosen:
А. In natural illumination and wet surface of the tooth
В. Artificial illumination and dry surface of the tooth
С. In natural illumination
D. In artificial illumination
Е. Tooth should be isolated by rubber dam
9. What drills are used for polishing of composite fillings?
А. Carbide drills
В. Coarse diamomd drills
С. Diamond drills with medium grains
D. Diamond drills with small grains, carbide drills with 32
blades
Е. Carbide drills with 6 blades
73
10. What substance is used for etching of tooth surface before
composite filling?
А. Polyacrylic acid
В. Ortophosphoric acid
С. Citric acid
D. Sulphuric acid
Е. Hydrochloride acid
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
Practical lesson No 29
Theme: Light-curing resin composites. Properties, indications
for use, peculiarities of treatment. Compomers.
Short description of a theme
Polymerization of composites may be achieved by
74
chemical means (self-cure) or by visible-light activation. Dual
cure is a combination of light and chemical curing. In
chemically activated systems, an organic peroxide initiator (or
catalyst), upon reacting with a tertian' amine accelerator,
produces free radicals that attack the double bonds of oligomer
molecules and begin the process of addition polymerization.
Initiation of polymerization in light-activated systems depends
on the scission of the initiator molecule, often
camphoroquinone, by visible light of appropriate wavelength.
In the presence of an aliphatic amine accelerator, free radicals
are produced and polymerization begins. For both systems, the
following general reaction occurs:
Dimethacrylate + Initiator (peroxide or diketone + blue
light) + Accelerator (amine) + Silane-treated particles
→Dental composite
Since dimethacrylate oligomers as well as
dimethacrylate diluent monomers have reactive double bonds
at each end of the molecules, polymerization results in a highly
cross-linked polymer.
Today's composites designed for restorative applications are
supplied as single pastes in opaque, disposable syringes or in
color-coded compules for use with a syringe. Light-activated
composites are currently the most widely used systems
available.
Commercially available curing units transmit light from
a halogen lamp to the tooth surface by way of a curved quartz
rod, a liquid-filled transmission tube, or a bundle of flexible
quartz fibers attached to a fiberoptic handpiece. Ultraviolet
light is generally filtered out at the light source.
The initiator present in most photocuring monomers is
camphorquinone. To initiate polymerization, curing lights must
emit light within this spectrum, which is in the blue range.
75
Filtered halogen lights produce a broad range of wavelengths
within the camphorquinone spectrum and are the standard.
Other lights that have higher intensities for faster
polymerization have been introduced. These include plasma arc
lamps (PAC) and argon laser lights. Although more intense,
not all PAC and laser lights have the broad spectrum of the
halogen lamps. It is important to match the spectrum of a PAC
light to the product being used. The PA 430 has been found to
be more effective for certain resin products. Lasers are still in
the development stage due to their narrow spectrum.
Halogen curing lights are available with continuous
operation and programmed cycles. One program is called a
stepping function, which cycles the light on and off to reduce
possible overheating of the tooth.
As with ultraviolet light used in early curing units, blue
light has the potential to cause retinal damage. Protective
eyewear during operation of curing units is also available and
recommended.
The setting time and the depth of cure of light-initiated
materials depend on the intensity and penetration of the light
beam. Polymerization is approximately 75% complete at 10
minutes after exposure to blue light, and curing continues for a
period of at least 24 hours. At 24 hours, up to 30% of double
bonds still remain unreacted.
Polymerization in both chemically and light-activated
composites is incomplete. Degrees of conversion are reported
to be in the range of 60% to 75%. The number of unreacted
double bonds at 24 hours is higher in light-activated than in
chemically activated systems and results from a number of
factors affecting depth of cure.
Light intensity at the surface and time of exposure are
critical. The tip of the light source should be held within 3 to 4
mm of the surface in order to cure a light shade of material to a
depth of 2.0 to 2.5 mm using a standard exposure time of 40
76
seconds. A longer exposure time will increase the degree of
polymerization at all depths and is a necessity when using
darker shades or more opaque materials. A reduction in
thickness of the increment to be cured is a more reliable way of
achieving polymerization than is an increase in exposure time.
In addition, hardness of the top surface of a cured restoration is
not a good indication of the extent of polymerization at the
bottom surface.
Depth of cure is also influenced by the wavelength of
light and the concentration of the activator-initiator system.
The refractive indices of the resin and filler, as well as the size,
shape, and number of filler particles, are important to the
dispersion of the light beam. The small, highly numerous
colloidal-sized particles of mi-crofilled composites scatter
incident light very efficiently, necessitating a longer exposure
time to obtain adequate polymerization.
Chemically activated systems are considered to have an
infinite depth of cure.
Manipulation. Placement.
Eugenol inhibits the polymerization of resin composites. Therefore, liners, bases, and interim restorations
containing eugenol are not recommended. The use of cavity
varnish is not recommended under composite restorations,
because monomers present in the composite may solubilize and
disrupt the integrity of the varnish film. Also, varnish will
prevent bonding.
Following cavity preparation and prior to placement of
the composite, a sealing procedure of some type is indicated. If
any dentin bonding agent is to be used, the use of a rubber dam
is indicated because moisture in exhaled air may interfere with
bonding. The dentin is first conditioned according to the
manufacturer's directions. Deep preparations may require the
placement of a glass-ionomer or resin-modified glass-ionomer
liner or base over the dentin. Very deep cavities require pulpal
77
protection in the form of a thin layer of a calcium hydroxide
product on the dentin over the pulp.
Enamel and dentin are treated strictly according to
manufacturer's directions depending on the bonding agent used.
Generally, enamel and dentin are etched for 15 seconds using a
35% to 50% phosphoric acid solution or acid gel. Highviscosity gel etchants have the advantage of ease of control of
the application to enamel walls. The preparation is thoroughly
washed with water for at least 15 seconds to remove all
residue. The surface is gently air-dried, at which point the
enamel should have an opaque, white appearance. Any
contamination by saliva after this step requires re-etching to
clean the surface thoroughly.
A dentin bonding agent is applied to the clean enamel
and dentin according to the manufacturer's directions. The
bonding resin should be air-blown gently to ensure a thin film
application. Dentin bonding agents work as well on enamel as
do enamel bonding agents. While components of bonding
systems should not be interchanged, any composite can be used
with most bonding agents.
A transparent matrix band is sometimes placed for the
purpose of contouring the restoration. The composite is best
placed in small layers to minimize polymerization shrinkage.
Shrinkage per layer placed is less if the tooth-composite
bonding area per layer thickness is large. Each layer should be
light cured for at least 40 seconds. After curing, a tackv, airinhibited layer is present, through which the subsequent layer
bonds.
Microfilled composites require longer exposure times
than do fine-particle composites because their colloidal-sized
filler particles scatter blue light more efficiently.
Finishing.
Composites are finished and polished in order to
establish a functional occlusal relationship and a contour that is
78
physiologically in harmony with supporting tissues. In
addition, proper contour and high gloss give the restoration the
appearance of a natural tooth structure. Early composites had
large, hard quartz particles. Polishing preferentially removed
the resin matrix, leaving filler particles exposed and giving the
surface a dull appearance. In addition, quartz has a hardness
about 2.5 times that of enamel and is difficult to polish
compared to glasses, which have hardness characteristics
similar to that of enamel.
Particles smaller than about 0.05 pm cannot be detected
visually and allow polishing to a high luster. Fine-particle
composites have no microfilled particles, are considered to be
only semipolishable, and tend to have a rather opaque
appearance. The colloidal-sized filler particles of microfilled
materials scatter light efficiently, giving these restorations a
pleasing esthetic appearance. Hybrid composites are
polishable, but are not as translucent as microfilled composites.
Control questions to practical lesson
1. What substance is used to initiate the polymerization in
light-activated composites?
2. On what distance it is necessary to hold the light source
from the surface to cure a light shade of material?
3. What is a standard exposure time for hardening of the
composite resin?
4. To what depth usually the composite is cured by a standard
exposure time?
5. What is the composition of light-curing composites?
6. Enumerate the types of light-curing composites?
7. Describe the process of filling cavity with light-curing
composites.
79
Situation tasks and test control
1. The three major components of composite restorative
materials are:
A. Resin -- Silane -- Filler
B. Silane -- Filler -- Bonding System
C. Bonding System -- Filler -- Acrylic Resin
D. Acid Etchant -- Bonding Agent -- Acrylic Resin
E. Acid Etchant -- Bonding Agent -- Filler
2. What is the role of silane in composite?
A. Coupling agent
B. Bonding agent
C. Conditioning agent
D. Acid etchant
E. Polishing agent
3. Which ONE of the following is NOT a component of
bonding agents used with composite restorations?
A. Initiator
B. Inhibitor
C. Reinforcing filler
D. Low MW monomer
E. BIS-GMA
4. Which ONE of the following methods is NOT used to
categorize composite restorations?
A. Weight percent filler level
B. Volume percent filler level
C. Method of matrix activation
D. Filler particle size (or distribution)
E. Composite shade
80
5. Earlier generations of composites (macrofills) contained
which ONE of the following volume percent levels of filler?
A. 30 v/o
B. 40 v/o
C. 50 v/o
D. 60 v/o
E. 70 v/o
6. Which ONE of the following products contains the MOST
filler?
A. Macrofill Composites
B. Pit-and-Fissure Sealants
C. Microfill Composites
D. Heterogeneous Microfills
E. Hybrid Composites
7. Which ONE of the following products contains ONLY very
small filler particles?
A. Macrofill Composites
B. Midifill Composites
C. Minifill Composites
D. Microfill Composites
E. Hybrid Composites
8. Which one of the following systems is currently NOT used
for curing composites?
A. Ultraviolet-light curing
B. Visible-light curing
C. Chemical curing
D. Dual curing
E. Very high intensity light curing
81
9. Which one of the following acids is generally recommended
for etching?
A. Maleic acid
B. Polyacrylic acid
C. Tartaric acid
D. Phosphoric acid
E. EDTA
10. In which of the following categories is dentin bonding of
critical importance?
A. Class III and IV restorations
B. Class V and Erosion-Abrasion Restorations
C. Class I and II restorations
11. Which ONE of the following does not affect the depth-ofcure of double bonds in composites?
A. Method of activation
B. Incremental addition
C. Post-curing
D. Composite Color
E. Finishing Procedure
12. What is the reason for choosing a self-curing (or dual
curing) composite rather than light-curing one?
A. Large size of the restoration
B. Poor access for the curing light
C. High level of filler content
D. Type of filler in the composite
E. Ease of finishing
13. What is the minimum acceptable level for visible curing
light outputs?
A. 50 mW/cm2
82
B. 150 mW/cm2
C. 300 mW/cm2
D. 550 mW/cm2
E. 1500 mW/cm2
14. Which one of the following materials is not a retarders or
inhibitors of chain reaction polymerization?
A. Eugenol
B. Calcium Hydroxide
C. Water
D. Air
E. Hydroquinone
15. Which ONE of the following materials should not be used
as a base or liner below a composite resin restoration?
A. Zinc Oxide Eugenol Cement
B. Calcium Hydroxide Cement
C. Zinc Phosphate Cement
D. EBA Modified ZOE Cement
E. Polycarboxylate Cement
16. What is the main reason for avoiding the use of green
stones, white stones, or coarse diamond burs for finishing a
composite?
A. Heat generation
B. Battering of enamel margins
C. Poor abrasivity
D. Scratch width
E. Discoloration of the composite
17. What range of scratches would be considered FINE
finishing?
A. 100-1000 μm
B. 10-100 μm
83
C. 1 -10 μm
D. 0.1-1 μm
E. 0.01-0.1 μm
18. Which ONE of the following "finishing" procedures
produces the smoothest surface on a composite?
A. Talc
B. Soflex discs
C. Finishing strips
D. Fine diamonds
E. Carbide burs
19. Which ONE of the following "finishing" procedures
produces the smoothest surface on a composite?
A. Talc
B. Finishing strips
C. Diamond finishing burs
D. Carbide burs
E. Diamond finishing pastes
20. What is the primary problem resulting from polymerization
shrinkage?
A. Marginal gap formation and microleakage/staining
B. Separation of the filler and matrix phases
C. Markedly increased water absorption
D. More rapid occlusal wear
E. Matrix discoloration
21. What is the typical level of polymerization shrinkage for
most dental composites?
A. < 0.25 %
B. 0.25-2.0%
C. 2.5-4.0 %
D. 6.0-10 %
84
E. 10-12 %
22. What is depth-of-cure possible for an A2 shade of hybrid
composite ?
A. 5-10 mm
B. 4-5 mm
C. 2-3 mm
D. 1-2 mm
E. 1 mm
23. What do dental composites produce when they undergo
superficial decomposition over long times?
A. Monomers
B. Formaldehyde and water
C. Acrylic acid
D. Bisphenol-A
E. Oligomers
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
85
Practical lesson No 30
Theme: Filling of the caries cavity of the I and V classes
according to Black classification. Substantiation of
the choice of the filling material.
Short description of a theme
The indication for an initial Class I amalgam restoration
is carious tooth structure in the occlusal surface (or in facial or
lingual pits in posterior teeth) detected clinically and with bitewing radiographs. The objectives of treatment are eliminate
caries lesions, to remove any enamel that has been undermined
by the caries process, to preserve as much sound tooth structure
as possible, and to create a strong restoration that mimics the
original sound tooth structure and allows little or no marginal
leakage. Traditionally, in Class I amalgam preparation,
occlusal fissures, or at least those in the developmental
grooves, have been included in the preparation, even when
caries has not extended throughout the fissures. Additionally,
extension of cavity preparations through grooves in which
there are no fissures is contraindicated.
The preparation is widened to give access to all carious
dentin and to remove any enamel not supported by sound
dentin. The preparation should be widened only enough to
obtain enamel margins supported by sound dentin.
Although the outline form should not contain sharp
angles, sound tooth structure should not be removed simply to
obtain wide, smooth curves in the outline form. The outline
form should be smooth to facilitate the uncovering of the
margins during carving of amalgam.
86
That is, the margins of the preparation should not be
jagged or rough, because it is difficult for the dentist to know
whether a restoration margin appears to be irregular because
the enamel margin is rough or because amalgam extends post
the margins onto the surface of the tooth (overextended
amalgam or amalgam flash). When replacing a defective
restoration or a restoration associated with a recurrent caries
lesion, the outline form will be determined by several factors.
First, the outline form of the old restoration will have a major
influence. Also, the outline form may have to be extended
because of additional pathosis. Finally, the resistance form for
the tooth structure or restoration may have to be improved, and
that will affect the outline form.
To provide retention form for the amalgam, opposing
walls of Class I osslusal restorations should be parallel to each
other or shoul converge occlusally. Enamel rods in most areas
of the occlusal surface are directed roughly parallel to the long
axis of the tooth, a factor that should be considered when the
angulation of the margin of the amalgam preparation is
designed. To enhance their ability to resist fracture, enamel
margins should be prepared at a 90-degree or more obtuse
angle; enamel margins of less than 90 degrees are much more
subject to fracture. Occlusal amalgam restorations should have
an occlusogingival thickness of at least 1.5 mm, and preferably
2.0 mm, to resist fracture during function.
Placement of amalgam.
The technique for amalgam placement is basically the
same regardless of the type or classification of the preparation.
Amalgam is mixed, carried to the cavity preparation, and
condensed into the preparation so that voids are eliminated and
all areas of the preparation are filled. The amalgam is then
carved to reproduse the portion of the tooth that is missing.
Spherical alloys produce an amalgam that requires a lower
mercury-alloy ratio and less condensation force. However, the
87
direction of the condensing force is extremely important for
spherical amalgams. They do not adapt to the cavity walls as
well as lathe-cut or admixture amalgams. Sperical amalgams
are said to be less condensable, and lateral condensation is
even more important when spherical amalgams are used than
when conventional or admixture amalgams are used. The
spherical materials generally have a shorter working time and
demonstrate a faster set than the admixtures.
Class V lesions are those carious and noncarious defects
found in the gingival third of facial and lingual tooth surfaces.
Class V carious lesions are produced by bacterial plaque
attaching to the surface of teeth and producing
demineralization. But the etiology of noncarious class V
lesions, estimated to occur in 31% to 6% of the population, is
both unclear and controversial. Certainly erosion and abrasion
play a part in the formation of some class 5, or cervical lesions,
but the role of occlusion, and the formation of defects called
abfraction lesions, is less clear.
Due to the physical properties of tooth structure and
restorative materials, long-term retention of the restoration
presents a unique challenge.
For any class V restoration, the extend of the restoration
should be determined by the extent of the lesion. With carious
lesions, all demineralized tooth structure should be removed.
Some lesions can be treated without cavity preparation, and
others require preparation to obtain adequate retention of the
restoration.
When adhesive restorative material
are used,
unsupported enamel should be removed to prevent the potential
fracture of weaking enamel margins during or after restoration
placement. Many techniques and materials have been
developed in an attempt to obtain long-term retention for
esthetic materials placed in cervical location. Polymerization
shrinkage can cause resin composite to pull away from the
88
tooth restoration interface, leaving an open margin and
pathway for microleakage occur. For moderate-size to large
restorations, incremental resin composite placement is
recommended to decrease the effects of polymerization
shrinkage. Frequently, the lesion extends onto the root surface,
where no enamel is available for bonding. If bonded
restorations are placed with no mechanical , undercut retention
and the bonding system is relied on to provide all retention, the
opportunity for microleakage at the gingival margin increases.
Beveling the gingival margin that ends on cementum may
increase microleakage. This microleakage can result in the
initiation of caries under the restoration, sensitivity,
discoloration, or loss of the restoration. It is this microleakage
that has spurred the development of new materials and
techniques for Class v restorations.
Flowable resin composites have reduced filler particle
loading, a lower elastic modulus, and lower fracture toughness
relative to traditional resin composites, but their resistance to
abrasion compares favorably to hybrid composites. They are
often used in Class 5 restorations, and it is thought that, like
microfilled resin composites, as the tooth flexes, the less rigid
restoration will be more able to accommodate the cavity shape
change, and therefore be more difficult to dislodge. After
cleansing the tooth surface with pumice, a dentin bonding
system is used and light polymerized, and a light- cured
flowable resin composite is placed into a defect. The technique
is quite simple and the restorations can be highly esthetic, but
the material has been available for only a short time, and longtime clinical studies to support the use of flowable composites
are not available yet.
Glass ionomer has been used successfully in class 5
restorations for many years. The preparation for glass-ionomer
restoration is essentially the same as that for resin composite.
Tooth structure should be conserved as much as possible. The
89
need for mechanical retention is somewhat controversial.
Theoretically, the compatibility between coefficients of
thermal expansion of tooth structure and traditional GiC should
obviate the need for mechanical retention. However, because of
tooth flexure and the relatively low bond strength of traditional
glass ionomer to dentin, mechanical retention should be
considered. Cavosurface bevels are not recommended for the
preparation because glass ionomer is a brittle material that
requires bulk. Autocured glass-ionomer materials can be placed
into the preparation in one increment until it is slightly
overfilled. A precontoured cervical matrix is then placed over
the material, and the excess material is allowed to extrude out
the sides. The matrix is left in place until the material is set.
Autocured glass-ionomer cements are inherently rough
materials that do not polish well and require protection from
water contamination and desiccation for 7 to 10 minutes after
placement to preserve strength and tranclucency. After removal
of the matrix, the restoration can be contoured with a scalpel
blade, carbide or diamond burs, or discs. The finishing
procedure should be performed with water or with the surface
of the restoration coated with unfilled resin to provide
lubrication and prevent desiccation.
Control questions to practical lesson
1. What for is rubber dam needed and used?
2. What kind of matrix system you have to use in Class V
treatment?
3. What kind of resin composites you have to use in Class V
restoration?
4. What kind of resin composites you have to use in Class I
restoration?
5. What kind of cement you may use in Class I restoration?
90
6. What kind of cement you may use in Class V restoration?
7. What material can be used as treatment liner?
8. What material type can be used as liner?
9. What for is etching needed?
10. What for is bonding needed?
11. What for is finishing and polishing needed?
12. What is the shrinkage stress?
13. What is for finishing and polishing can be used?
14. What is the polymerization shrinkage?
Situation tasks and test control
1. What materials of the below mentioned are recommended
for filling of class V carious cavities:
A. Self-cured composites
B. Light-cured composites
C. Glass-ionimer cements
D. Amalgams
E. All of the above mentioned
2. What materials of the below mentioned are recommended
fpr filling of class I carious cavities?
A. Microfill composites
B. Microhybrid composites
C. Zn-phosphate cement
D. Sylicate cement
E. ZnO-eugenol cement
3. In the indication for use of the composite it is written that the
size of particle is less than 0,04 mcm. In what classes of
cavities it can be used?
A. I-II classes
B. III-II classes
91
C. V-I-II classes
D. III-V classes
E. III-V classes
4. During the filling of carious cavity class I what is the proper
seguence of stages:
A. rubber dam isolation, etching, bonding, filling
B. etching, rubber dam isolation, bonding, filling
C. rubber dam isolation, etching, placement of the bose,
bonding, filling
D. etching, rubber dam isolation, placement of the bose,
bonding, filling
E. etching, bonding, filling
5. What type of drills is used for final preparation of the
filling?
A. Diamomnd and carbide drills
B. Fine grinded and carbide drills
C. Medium grinded diamond drills
D. 6-blanded carbide drills
E. Course and medium diamond drills
6. The final stage of filling procedure is polishing of the filling.
In what time it can be conducted after the placement of the
filling of self-curing composite?
A. Just after the placement of the filling
B. In 8-12 minutes after the placement of the filling
C. In 2-3 hours after filling
D. In 24-38 hours after filling
E. Final polishing is not needed
7. During which stage of treatment the operator should choose
the colours of future filling?
A. After the preparation of carious cavity
92
B. Before the preparation
C. After the placement of isolation base
D. After bonding procedure
E. After the etching procedure
8. Step by step restoration technigue ebsure:
A. Compensation of the occlusal loading
B. Before fixation of the filling
C. Esthetic restoration
D. A+C
E. All answer are wrong
9. What type of composite is recommended for Class V usage?
A. Macrofilled
B. Microfilled
C. Minifilled
D. Nanohybrid
E. Any correct answer
10. What type of composite is recommended for Class V
usage?
A. Macrofilled
B. Microfilled
C. Minifilled
D. Microhybrid
E. Any correct answer
11. What type of filling material is recommended for Class V
usage?
A. Amalgam
B. Zink-phosphate cement
C. ZOE cement
D. Polycarboxylate cement
E. No correct answer
93
12. What type of filling material is recommended for Class V
usage?
A. Zink-phosphate cement
B. ZOE cement
C. Compomer
D. Polycarboxylate cement
E. No correct answer
13. What type of filling material is recommended for Class I
usage?
A. Amalgam
B. Zink-phosphate cement
C. ZOE cement
D. Polycarboxylate cement
E. Any correct answer
14. What types of polishing accessories are recommended for
Class I restoration?
A. abrasive disk
B. abrasive band
C. rubber cups
D. rubber disks
E. abrasive disk, rubber cups and polishing rubber disks
15. What type of polishing accessories is recommended for
Class V usage?
A. abrasive disk
B. abrasive band
C. rubber cups
D. rubber disks
E. abrasive disk, rubber cups and polishing rubber disks
16. What thickness of microhybrid composite layer is
recommended for curing in modern Composites?
94
A.
B.
C.
D.
E.
Not more than 1 mm
Not more than 3 mm
5 mm
Not more than 2 mm
No correct answer
17. What isolation accessories are recommended for Class I
restorations?
A. Rubber dam
B. Cotton balls
C. Cords
D. All of the answers are correct
18. How long the 37% phosphoric acid should stay on the
enamel surface for Class I composite restoration according to
total-etch method?
A. 10 sec
B. 30 sec
C. 15 sec
D. 20 sec
E. 25 sec
19. How long the 37% phosphoric acid should stay on the
dentin surface of Class I composite restoration according to
total-etch method?
A. 10 sec
B. 20 sec
C. 15 sec
D. 25 sec
E. 30 sec
20. The modern nanohybrid composite adhesive systems are
recommended to polymerize for:
A. 10 sec
95
B.
C.
D.
E.
5 sec
20 sec
40 sec
Any correct answer
21. What thickness of „Life” (Kerr) treatment liner is
recommended?
A. Not more than 1.0 mm
B. 1.5 mm
C. 0.5 mm
D. Not less than 2.0 mm
E. Any correct answer
22. What thickness of GIC layer according to the sandwichtechnique in Class I amalgam restoration is recommended?
A. mm
B. 0.5 mm
C. Reach the EDJ
D. Any correct answer
23. What thickness of GIC layer according to the sandwichtechnique in Class I composite restoration is recommended?
A. mm
B. 0.5 mm
C. Reach the EDJ
D. Not less than 1.0 mm
E. Any correct answer
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
96
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
Practical lesson No 31
Theme: Filling of the caries cavity of the II class according to
Black classification. Substantiation of the choice of
the filling material.
Short description of a theme
An initial Class II restoration is usually placed a carious
lesion is present on proximal surface of a molar or premolar.
During removal of carious dentin, the demineralized
dentin in the periphery of the preparation (at or near DEJ)
should be removed and the outline form should be extended to
ensure that the enamel at the margins of the preparation is
supported by sound dentin. Carious dentin should be removed
with the largest round bur that will fit into the area. After the
periphery of the preparation is clear of demineralized tooth
structure, the carious dentin near the pulp should be removed.
The bur should be rotated very slowly in a low-speed
handpiece4; the rotation rotation should be so slow that the
individual blades of the bur can be seen as it rotates. The
blades of the slowly rotating bur are like multiple spoon
excavator blades, but the depth that a blade can penetrate into
the carious dentin is limited by the edge angle of the bur and by
97
the depth of each bur blade toward the center of the bur, so the
bur will remove only a limited depth of carious dentin during
each rotation. During removal of deep carious dentin, this
procedure is less likely to result in a pulpal exposure than is the
use of a spoon excavator. After the shape of the preparation is
roughed out with a bur, hand instruments, such as margin
trimmer, may be used to fracture the shell of enamel, to shape
the facial, lingual, and gingival walls and margins, and to
scrape away any fragile enamel from the margins. The facial
and lingual walls of a Class II slot preparation should converge
slightly toward the occlusal surface to provide retention form
for the restoration. To provide resistance form for the Class II
amalgam restoration, the proximal preparation should have a
mesiodistal dimension of about 1.5 mm or more. If there is
sound dentin supporting occlusal enamel in the fossa adjacent
to the marginal ridge, that dentin and enamel should be left
intact. If the carious lesion extends from the proximal DEJ
deeper into dentin, the demineralized dentin should be removed
completely, especially in the areas near the DEJ, and sound
dentin should be left in place. The gingival floor of the
proximal preparation may be flat and approximately
perpendicular to the long axis of the tooth, or it may be curved
faciolingually, as determined by the extent and configuration of
the carious lesion that necessitated the restoration. The location
of the gingival floor, therefore, should be determined by the
gingival extent of the carious lesion and\or by the level
necessary to provide separation of the gingival margin from the
adjacent tooth. The gingival wall, like the facial and lingual
walls of the proximal preparation, should form an angle of
proximately 90 degrees with the surface of the tooth.
Convergence toward the occlusaal surface of the facial and
lingual walls of the proximal slot preparation gives retention
form to the restoration to keep it from dislodging occlusally.
Although, with initial proximal surface caries lesions, it is not
98
often necessary to extend the Class 2 preparation into occlusal
grooves, the operator will frequently need to replace an
existing restoration that was prepared with an occlusal
extension. If the restoration is extended into occlusal grooves,
this extension will provide resistance to displacement of the
restoration proximally. To provide enough resistance, however,
the extension into the occlusal surface must have a faciolingual
dimension of at least one fourth the distance between the facial
and lingual cusp tips, and the facial and lingual margins of the
occlusal extension must be approximately parallel to each other
in a mesiodistal direction.
Control questions to practical lesson
1. What for is etching needed?
2. What for is bonding needed?
3. What for is finishing and polishing needed?
4. What is the shrinkage stress?
5. What is the polymerization shrinkage?
6. What is for finishing and polishing can be used?
7. What for is matrix band needed and used?
8. What for is wedge needed and used?
9. What for is cord needed and used?
10. What for is formative ring needed and used?
11. What kind of matrix system you have to use in Class II
treatment?
12. What kind of resin composites you have to use in Class II
restoration?
13. What kind of cement you may use in Class II restoration?
14. What material can be used as base?
15. What material type can be used as subbase?
16. What material can be used as treatment liner?
17. What material type can be used as liner?
99
Situation tasks and test control
1. What type of composite is recommended for Class II usage?
A. Macrofilled
B. Microfilled
C. Minifilled
D. Any correct answer
2. What type of filling material is recommended for Class II
usage?
A. Amalgam
B. Zink-phosphate cement
C. ZOE cement
D. Polycarboxylate cement
E. Any correct answer
3. What accessories are recommended to prevent the formation
of butt?
A. Wedge
B. Matrix bend
C. Rings for contouring
D. Special tool for contact point formation
E. Wedge and matrix band
4. What accessories are recommended for Class II contact point
reconstruction?
A. Wedge
B. Matrix bend
C. All of the answers are correct
D. Rings for contouring
E. Special tool for contact point formation
100
5. The micro furrow between matrix band and tooth structure
in Class II restoration is recommended to fill with:
A. Dual-cured composite
B. Light-cured flow composite
C. Self-cured composite
D. No correct answer
6. The micro furrow between matrix band and tooth structure
in Class II restoration is recommended to fill with:
A. Light-cured flow composite
B. Macrofilled composite
C. Microfilled composite
D. Minifilled composite
E. No correct answer
7. What thickness of tooth walls in Class II amalgam
restoration is recommended?
A. 1.0 mm
B. 1.5 mm
C. 0.5 mm
D. Don’t less than 2.0 mm
E. No correct answer
8. What thickness of tooth walls in Class II light-cured
composite restoration is recommended?
A. Don’t less than 1.0 mm
B. Don’t less than 3.0 mm
C. Don’t less than 2.0 mm
D. Don’t less than 0.5 mm
E. No correct answer
9. What type of polishing accessories is recommended for the
foemation of proximal walls in Class II restorations?
A. abrasive disk
101
B.
C.
D.
E.
abrasive band
rubber cups
polishing rubber disks
All of the answers are correct
10. What thickness of flow light-cured composite layer is
recommended for usage?
A. Not more than 3 mm
B. 5 mm
C. Not more than 1 mm
D. Not more than 2 mm
E. No correct answer
11. What isolation accessories are recommended for Class II
restorations?
A. Rubber dam, cords
B. Cotton balls
C. Cords
D. Cotton balls and rubber dam
E. No correct answer
12. What isolation accessories are recommended for Class II
restorations?
A. Rubber dam
B. Cotton balls
C. Cords
D. All of the answers are correct
13. The modern nanohybrid composite enamel shades are
recommended to polymerize for:
A. 10 sec
B. 5 sec
C. 20 sec
D. 40 sec
102
E. Any correct answer
14. What thickness of „Dycal” (Dentsply) treatment liner is
recommended?
A. 1.5 mm
B. Not more than 1.0 mm
C. 0.5 mm
D. Not less than 2.0 mm
E. Any correct answer
15. The wedges can be produced of:
A. Wood
B. Metal
C. Resin
D. Wood and resin
E. All of the answers are correct
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
103
Practical lesson No 32
Theme: Filling of the caries cavity of the III and IV classes
according to Black classification
Short description of a theme
Class III caries is smooth-surface caries found on the
proximal surfaces of anterior teeth, usually slightly gingival to
the proximal contact, but does not involve the incisal angle of
the tooth. A caries-indicated class IV restoration is usually the
result of a large class III carious lesion that has undermined the
incisal edge. The need for class IV restoration due to traumatic
fracture occurs most often among children or young adults.
Patients demand superior esthetics from anterior
restorations. An esthetic restorative material must simulate the
natural tooth in color, translucence, and texture, yet must have
adequate strength and wear characteristics, good marginal
adaptation and sealing, insolubility and biocompability.
Regardless of the result desired, certain basic artistic
elements must be considered to ensure an optimally esthetic
result. In conservative esthetic dentistry these include:
- Shape or form.
- Symmetry and proportionality.
- Position and alignment.
- Surface texture.
- Color.
- Translucency.
104
By far the most commonly used restorative materials in
the anterior part of the mouth are resin-based composites.
Outline form for resin composite restorations is determined
solely by access and by the extent of the caries lesion. There is
no need for extension for prevention, and the removal of sound
tooth structure to gain mechanical undercut retention is
contraindicated. The lingual approach is preferred for class III
restorations, but it is not always possible, depending on the
location of the carious lesion. The number of burs for cavity
preparation should be kept to a minimum. A #2 round bur or
#329 pear-shaped carbide bur in a high-speed handpiece can be
used for initial access to the lesion. Initial penetration should
be made through the marginal ridge, away from the adjacent
tooth surface. The outline form of the preparation is then
extended to provide access to the dentinal caries lesion. A
larger round bur may be used in the low-speed handpiece to
excavate demineralized dentin. Narrow bevels (0.5 to 1.0mm)
may be placed on accessible enamel margins to remove fragile
enamel, to make margins smooth, and to enhance esthetics if
the margin is in a visible location. For placing bevels, a flameshaped finishing bur, a gingival margin trimmer, or another
hand instrument may be used. For class IV carious lesions, the
cavity design follows the conventional form of the class III
preparation and includes a portion of the incisal edge. Carious
tooth structure and weak incisal enamel are removed, and all
enamel margins are beveled, with wide bevels placed in the
incisal portion of the tooth where the enamel is thicker and the
stresses on the restoration are likely to be greater. For fractures,
if there is no caries or pulpal involvement, a bevel is often the
only preparation necessary. An enamel bevel of at last 1.0 mm
should be placed around. Increasing the width of the bevel
beyond 1.0 mm can be used to provide no additional strength,
but a wider bevel can achive a more harmonious esthetic blend
between the resin composite and enamel.
105
Clinical steps for a class III or class IV resin composite
restoration:
a) Select a shade before initiation of dehydration.
b) Place a rubber dam.
c) Prewedge if difficulty in achieving proximal contact is
anticipated.
d) Initiate the cavity preparation by accessing the caries lesion
through the marginal ridge. Remove the proximal plate of
enamel. Be careful to avoid damaging the adjacent tooth.
e) Remove the caries dentin with a round bur in a low-speed
handpiece.
f) Remove unsupported enamel if appropriate, and place
bevels with a finishing bur and\or gingival margin trimmer.
g) Etch the enamel. Be careful not to etch the adjacent tooth;
protect it with a matrix strip.
h) Place the primer and adhesive, following the
manufacturer’s instructions.
i) light cure as indicated.
j) If the preparation is large, place resin composite into the
deep areas.
k) Light cure for at least 40 seconds
l) Place a clear plastic strip or other matrix and wedge.
m) Add composite and contour the clear plastic matrix strip to
contain the material in the proper shape.
n) Light cure for at least 40 seconds
o) Remove the wedge and matrix strip, and inspect the
restoration for voids. Add composite if necessary.
p) Remove gingival flash with a №12 or №12b scalpel blade.
q) Remove flash from the other margins, and contour the
restoration with a finishing bur, finishing diamond, or
abrasive disc.
r) Remove the rubber dam.
s) Check the occlusion and adjust as necessary.
t) Finish and polish with disks, rubber points, etc.
106
u) Apply etchant to surface and margins. Rinse, then apply
and cure rebonding resin.
Glass-ionomer cement restoration.
Because of their anticaries potential, glass-ionomer
restorative material may be used in class III for patients with
high risk of caries. Preparations for these materials should
resemble those for resin composite; no bevels are necessary.
Only the tooth structure required to allow access for excavation
of the carious dentin should be removed. Because these
materials bond to enamel and dentin, the placement of retention
grooves or points is not necessary.
Control questions to practical lesson
1.
2.
3.
4.
5.
6.
7.
8.
9.
What for is matrix band needed and used?
What for is wedge needed and used?
What for is cord needed and used?
What for is etching needed?
What for is bonding needed?
What for is finishing and polishing needed?
What is the shrinkage stress?
What is the polymerization shrinkage?
What kind of matrix system you have to use in Class III
treatment?
10. What kind of matrix system you have to use in Class IV
treatment?
11. What kind of resin composites you have to use in Class III
restoration?
12. What kind of resin composites you have to use in Class IV
restoration?
13. What kind of cement you may use in Class III restoration?
14. What kind of cement you may use in Class IV restoration?
15. What material can be used as treatment liner?
16. What material type can be used as liner?
107
Situation tasks and test control
1. What type of composite is recommended for Class III usage?
A. Macrofilled
B. Microfilled
C. Minifilled
D. Nanohybrid
E. Any correct answer
2. What type of composite is recommended for Class III usage?
A. Microhybrid
B. Macrofilled
C. Microfilled
D. Minifilled
E. Any correct answer
3. What type of composite is recommended for Class IV
usage?
A. Macrofilled
B. Microfilled
C. Microhybrid
D. Minifilled
E. Any correct answer
4. What type of composite is recommended for Class IV
usage?
A. Macrofilled
B. Microfilled
C. Minifilled
D. Nanohybrid
E. Any correct answer
108
5. What type of filling material is recommended for Class IV
usage?
A. Amalgam
B. Zink-phosphate cement
C. ZOE cement
D. Polycarboxylate cement
E. Any correct answer
6. What type of filling material is recommended for Class III
usage?
A. Any correct answer
B. Amalgam
C. Zink-phosphate cement
D. ZOE cement
E. Polycarboxylate cement
7. What accessories are recommended for Class III contact
point reconstruction?
A. Wedge
B. Wedge and matrix band
C. Matrix bend
D. Rings for contouring
E. Special tool for contact point formation
8. What accessories are recommended for Class IV contact
point reconstruction?
A. Wedge
B. Matrix bend
C. Rings for contouring
D. Special tool for contact point formation
E. Wedge and matrix band
9. What type of polishing accessories is recommended for
Class III and IV usage?
109
A.
B.
C.
D.
E.
abrasive disk
abrasive band
rubber cups
All of the answers are correct
rubber disks
10. What isolation accessories are recommended for Class III
and IV restorations?
A. Rubber dam
B. Cotton balls
C. Cords
D. All of the answers are correct
11. The composite opaque shades are recommended to
polymerize for:
A. 10 sec
B. 5 sec
C. 20 sec
D. 40 sec
E. Any correct answer
12. The composite enamel shades are recommended to
polymerize for:
A. 10 sec
B. 5 sec
C. 20 sec
D. 40 sec
E. Any correct answer
13. What kind of matrix band is recommended for Class III and
IV light-cured composite restorations?
A. Plastic translucent band
B. Metal sectional matrix system
C. Metal band
D. All of the answers are correct
110
Reference literature
1. S. Hussain. Textbook of Dental Materials // Printed of
Gopsan Papers Ltd.– NewDelli, 2004.– 475 p.
2. T.M. Robertson, H.O. Heymann, E.J. Swift. Sturdevant’s
Art & Science of Operative Dentistry 4th Edition.– Mosby,
2002.– 947 p.
3. W.J. O’Brien. Dental Materials and their selection //
Quintessence Publishing.– Chicago, Berlin, Tokyo,
Copenhagen, London, 2002.– 418 p.
4. James B. Summitt, J. William Robbins, Richard S.
Schwartz. Fundamentals of Operative Dentistry (second
edition) // Quintessence Publishing, 2001.
111