MINISTRY of PUBLIC HEALTH of UKRAINE
VINNITSYA NATIONAL MEDICAL UNIVERSITY
by N.I.Pirogov
It is "confirmed"
on a methodical meeting of
department of pediatric dentistry
head-chair
doc. Filimonov Yu.V.______________
" _____ " ______________ in 20
Methodical recommendation for 2d year students
of dental faculty
Educational discipline
Module ¹
Rich in content module ¹
Topic
Course
Faculty
Propedeutics of pediatric dentistry
1
3
Flowable and packable composites. Composition and
properties. Tooth filling.
2
dental
Vinnitsya 2010
1.
Actuality of theme: A specific of terms is cavities of mouth, stopping
functions in which, the anatomic features of temporal and permanent teeth explain
absence to this time of material which
would answer all of requirements. For
achievement of optimum clinical effect at stopping of teeth for children and for adults
it is very important to have material which next to all owned other properties and
aesthetically beautiful peculiarities a doctor. In addition had sufficient durability and
beautiful operating properties.
2. Concrete aims: to learn classification, composition basic properties of
composition stoppings materials. To learn to differentiate the systems
of different generations, know their composition, properties and method
of the use. To know instruments and materials for eventual treatment of
stoppings.
Names of previous disciplines
Skills are got
Normal anatomy
Able defirintiation temporal and permanent teeth. To
know the anatomic features of temporal teeth
depending on the stage of development of tooth.
Therapeutic dentistry
To know basic methods and principles of preparing of
teeth in grown man age. Oriented in the choice of
instruments for realization of that or other
manipulation. Able to pick up stopping material
depending on a situation.
Orthopaedic stomatology
Oriented in materials which are utillized in the clinic
of orthopaedic stomatology.
3. Base knowledges, abilities, habits which are necessary for study the topic.
1. To know instruments for preparation of stopping material and auxiliary
facilities for stopping of carious cavities.
2. To know instruments and materials for eventual treatment of stoppings.
3. To write classification
4. To transfer
basic
of composition
positive
and
materials.
negative
properties of composition
materials of the chemical and light hardening.
5.
To write the stages of stopping of carious cavity composition material of the
chemical.
4.1. List of basic terms, parameters, descriptions which a student must master at
preparation to employment:
Term
Composites materials
Determination
Contemporary filling materials, which have high
physic-chemical and esthetic properties
Chemical
polimerization
Material polimerization is provided as result of catalic
system, which is present in composite composition
Light curing
Polimerizetion is provided under the influence of light
polimerizetion).
with wave length 450 nm
4.2. Theoretical questions for lesson:
1.To know instruments for preparation of stopping material and anditional
remedies for filling of carious cavities.
2.To know instruments and materials for eventual treatment of filling.
3.To write classification of composition materials.
4.To transfer basic positive and negative properties of composition materials of
the light curing hardening.
6. To write the stages of stopping of carious cavity composition material of the
light curing hardening.
4.3. Practical tasks which are executed on the lesson:
.
1. To fill carious cavity of I-II classes by Blek with packeble composite
2. To fill carious cavity of V classes by Blek with light curing flowable composite
composites
3. To use flowable composite in sandwich technique
5. Plan and organizational structure of lesson from discipline.
¹
Stages
Distributing
Types of control
of time
1.
Preparatory stage
1.11.1 Oh the
Organization
al questions.
1.2 Forming of
motivation.
1.3 Control
initial level of
knoweledge .
2.
Basic
stage.
3.
Final stage
3.1.
Control of final level
of preparation.
General estimation of
educational activity of
student.
Informing of students
is about the topic of
next lesson.
3.2.
3.3
15 min
Facilities of
education
practical tasks,
textbooks,
situatioonal tasks,
manuals,
verbal questioning,
methodical
are after the
recommendations.
standardized lists of
questions.
55 min
20 min
tests tasks
Content of topic:
Resin composites are a combination of a resin matrix, which is polymerisable, and an
inorganic filler. Both components play a part in the final material's properties and both
have been varied in their composition to attain desirable properties for differing
situations. Although there are 'universal' composites that are intended for use in multiple
situations, composites are in fact a family of materials that can be utilised in many
situations in dentistry where aesthetics, bonding ability and strength are the prime
requirements.
Resin matrix
The setting reaction of a resin composite involves the polymerisation of the resin
matrix. This is the process whereby small components, termed monomers, combine to
form large-chain molecules. The longer the chain, the more viscous the material
becomes until it reaches a solid state. The polymerisation process is often described as
the setting reaction or curing process. During storage and the placing of restorations,
it is a requirement that the monomers are prevented from polymerising, otherwise the
material would be difficult to handle. In order for polymerisation of resins to occur
when desired, free radicals, highly reactive charged substances, need to be created
within the material. These initiate the chain reaction of polymerisation. Free radicals can
be created in one of two main ways with modern resin composites: by chemical reaction
or by light.
For light-curing materials, there is a single paste containing resin, filler and
camphorquinone. The cam-phorquinone has a breakable bond within it that is broken
when exposed to light of about 470 nm. The result of this is the production of free
radicals to initiate polymerisation.
Both methods of free radical production have their advantages and disadvantages.
Light curing allows the
operator to be in control of the working time, although materials will start to cure in the
presence of the dental surgery light, giving the operator just a few minutes to place the
resin composite before the paste becomes partially set and less manageable. Light
curing also has the advantage that if small additions or increments are required to build
up a tooth, then there is less wastage of material as only the amount required needs to be
dispensed, whereas if a chemically cured material was used each time a small amount
was needed, enough would need to be dispensed to allow proper mixing. The greatest
problem with light curing is that sufficient light of the correct wavelength needs to
satisfactorily penetrate the material in order to get a high enough degree of
polymerisation for the resin composite to have optimal properties. In deep cavities and
underneath crowns and veneers, chemically cured materials have the advantage in that
they will optimally polymerise whatever the depth or availability of light. The largest
disadvantage of chemical curing is that there is no control over working time and
materials may set sooner than expected or, conversely, have slumped from the position
they were placed in whilst waiting for the setting reaction to occur.
To try to overcome the problems with both types of curing, 'dual-cure' materials were
developed. These are partially set by light cure so that control of the working time is
maintained but they will undergo a slower chemical cure to permit full curing of the
whole restoration.
During polymerisation heat is produced and the resin shrinks as the monomer
molecules join together. The shrinkage of pure acrylic resin alone can be up to 21%.
This amount of shrinkage would have devastating consequences for a tooth, as it would
lead to stresses within the enamel and dentine as both sides of a cavity
were pulled together. If the bond to tooth tissue was not maintained there would be
considerable marginal micro-leakage, leading to sensitivity and secondary caries.
Shrinkage can be reduced by utilising higher molecular weight monomers. The
predominant substance used as a monomer in dental resin composites is Bis-GMA (Fig.
9.4). Bis-GMA produces a viscous, sticky resin; to help the material flow, smaller
molecular weight monomers are added, such as TEGDMA (tri-ethyleneglycol dimethacrylate). These are referred to as diluent monomers.
Larger methacrylate monomers, such as Bis-GMA, help reduce the shrinkage to a
certain extent, but that alone does not reduce it sufficiently for the material to be clinically acceptable. It is the filler particles that reduce the overall amount of shrinkage to a
degree that is acceptable, currently about 2%. In addition it is the amount and size of the
filler particles that define the categorisation and intended applications for resin
composites.
Filler particles
As a general rule, the more filler present, the stronger and harder wearing the resin
composite will be, whilst also being less affected by shrinkage. This, however, depends
on the filler being chemically united with the matrix. There is also a downside to having
too much filler, however: the resin composite becomes less manageable.
Early resin composites were filled with quartz particles of relatively large size. These
are known as macrofilled resin composites. They are strong, but give poor long-term
aesthetic results due to the size of the filler particles providing a surface that is not
readily polished and which easily takes up staining (Fig. 9.5). Filler particles in present
use are composed of glasses often containing
barium or strontium; these give the material radio-opacity which helps in the detection
of secondary caries.
Macrofilled resin composites have a high proportion of filler particles, about 86%
loading by volume, which reduces wear and increases strength, although, due to the
relatively poor aesthetic properties, they are really only suitable for posterior
restorations. In order to produce a material that could be polished and retain better
aesthetics, a later development was to introduce smaller particles composed of colloidal
silica. These are known as microfilled resin composites (Fig. 9.6).
During manufacture of microfilled resin composites, difficulty is encountered in
obtaining a high enough filler content, to the effect that the resin is only about 50%
loaded with filler. This low filler loading has an adverse impact upon the material's
long-term strength and wear resistance. Lower percentages of filler also mean more
polymerisation shrinkage with the problems which are associated with it. To try to
overcome the problems with both macro- and microfilled resin composites, a hybrid of
the two has been developed, containing both larger quartz particles and the smaller
silica particles (Fig. 9.7a).
Hybrid resin composites are in common usage as 'all purpose' materials, meaning they
are suitable for both posterior and anterior teeth. The problem of having larger crystals
that can protrude from the surface or be lost still remains, and has recently been
addressed by nanotechnology, replacing the larger particles with clusters of nano-
particles (Fig. 9.7b). These act together to give the material the strength of a hybrid, but,
as
wear occurs, they do not leave large voids, allowing the restoration surface to remain
polished and stain free.
In all composite materials, to ensure that the resin and filler work together to
strengthen the material and avoid loss of surface particles, the two components are
joined together by a silane coupling agent.
Flowable resin composites
■ Flowable composites are a relatively recent addition to the composite family.
They have a lower filler content of about 50-70% by volume and are thus less
viscous and are able to flow easily into cavities, though their wear resistance is
low. The utilisation of monomers with elastic properties has led to the practice of
using them to line cavities in posterior teeth prior to restoration with a more
conventional composite. The inherent elasticity may to some degree absorb the
stresses created during polymerisation shrinkage of the regular composite.
Packeble composite
These composite are recommended for use in I, II, VI class by Black. They are
composed of lighted activated , presence of fillers from 66% till 70% in volume.
Properties: high depth of cure, low polimerization shrinkage, low wear rate,
similar to amalgam.
Materials are for self-control:
Tasks for self-control (example)
1. Which of these statements apply to the packable composites?
a) their depth of cure allows bulk polymerization, which has been shown to be clinically
effective
*b) their wear rate is low which is similar to that of amalgam
c) they are radiolucent
*d) to have similar or slightly less polymerization shrinkage than all-purpose composites have
2. What are packable composite recommended for use in?
*a) I, II class by Black
b) III, IV, V class by Black
c) II, I class by Black
d) I, II, III, V class by Black
3. What does negative properties of flowable composites?
*a) lower filler and exhibit higher polymerization shrinkage
b) lower polymerization shrinkage, high depth of cure
c) realize fluoride
d) high regidity
4. What are size of inorganic fillers of flowable composite?
a) 3,5 µm
*b) from 0,7 to 3 µm
c) 0,01-0,5 µm
d) 5-8 µm
5. What are size of inorganic fillers of packable composite?
*a) 3,5 µm
b) 0,7-3 µm
c) 0,01-0,5 µm
d) 5-8 µm

Literature.
Basic:
1.Lectures which are read on the department of pediatric dentistry.
2. Л. О. Хоменко, О. І. Остапко, О. Ф. Конанович, та ін. Терапевтична
стоматологія дитячого віку.- Видавництво "Книга плюс", 2007 р.
3. Pediatric dentistry /Ed. R.R.Welbury.- Oxford, 1997 – 584p.
Additional:
1. Боровський Г.В., Барішева Ю.Д., Максимов К. М. и др. Терапевтическая
стоматология. — М.: Медицина, 1997.
2. Pinkham J.R. Pediatric dentistry. – 2nded.- W.B. Sounders Company. – 1994.- 647 p.