Prof.d-r R.Kabaktchieva- 2014
 Fluorides
are highly effective in
reducing the number of carious lesions
occurring on the smooth surfaces of
enamel and cementum.

Fluorides are not equally effective in
protecting the occlusal pits and fissures,
where the majority of carious lesions
occur.
This
results in an increased
proportion in the ratio of occlusal
to interproximal lesions,
even though the total number
may be less.
 In
the late 1960s and early 1970s,
another option became available the use of pit-and-fissure sealants.
A
liquid resin, more commonly
called a dental sealant.
 The
placement of sealants is a highly
effective means of preventing carious
lesions
in the pits and fissures in both primary and
permanent teeth.
 Dental
sealant is placed over the occlusal
surface of the tooth, where it penetrates
the deep fissures to fill areas that cannot be
cleaned with the toothbrush.

1. One reason that 50% of the carious
lesions occur on the occlusal surface
is that the toothbrush bristle has a greater
diameter than the width of the fissure.
- the fissure cannot be cleaned with the
toothbrush.
 The

resin then solidifies;
The hardened sealant presents a barrier
between the tooth and the hostile oral
environment.

Concurrently, there is a significant reduction
of Streptococcus mutans on the treated tooth
surface.
Pits and fissures serve as reservoirs for
mutans streptococci;
 Therefore, sealing the niche reduces their
oral count.

 Sealants
present great preventive
value when placed correctly and
monitored regularly.
Sealant Use in Dental Care
 The
first successful use of resin sealants was
reported by Buonocore in the 1960s.

Buonocore first described placing sealants,
using a method to bond polymethylmethacrylate (PMMA) to human enamel
conditioned with phosphoric acid.
 This
concept, was realized later, after the
development of :
- bisphenol A-glycidyl methylacrylate
(Bis-GMA),
- urethane dimethacrylate (UDMA),
- triethylene glycol dimethacrylate
(TEGDMA)

resins.
They possessed better physical properties than PMMA.

Bisphenol A-glycidyl methylacrylate is a
mixture of Bis-GMA and methyl methacrylate;

Nuva-Seal, the first successful commercial
sealant, was placed on the market in 1972;

Since then, more effective sealants have
become available;

The primary difference between sealants is
the method of polymerization
Some
The
sealants contain fillers.
products was classified
like filled and unfilled sealants.

The filled sealants contain microscopic glass
beads, quartz particles, and other fillers used in
composite resins.

The fillers are coated with products such as silane
to facilitate their combination with the Bis-GMA
resin.

The fillers make the sealant more resistant to
abrasion and wear.

Because filled sealants are more resistant to
abrasion, the occlusion should be checked, and the
sealant height may need to be adjusted after
placement.
 The
unfilled sealants wear quicker but
usually do not need occlusal adjustment.
Criteria for Selecting Teeth for Sealant
Placement

A deep occlusal fissure, fossa, or incisal
lingual pit is present.

No harm can occur from sealing, when
in doubt, seal and monitor.
A sealant is indicated if:

The fossa (shallow depression) selected for
sealant placement is well isolated from
another fossa with a restoration.

The area selected is confined to a fully
erupted fossa, even though the distal fossa
is impossible to seal because of inadequate
eruption.

The selected tooth has an intact occlusal
surface when the contralateral tooth surface
(surface of tooth in opposite arch) is carious or
restored; teeth on opposite sides of the arches
usually are equally prone to caries.

An incipient lesion exists in the pit-and-fissure
area.

Sealant material can be flowed over a
conservative class I composite or amalgam to
improve the marginal integrity,
and into the remaining pits and fissures to
further prevent recurrent decay.
a
b
c
A. Five years after placement of a white pit-and-fissure sealant - tooth
M1
B. 5-year control: The first permanent molar in other side has been
restored with two amalgam restorations
C. 15-year sealant: 15 years after the single application of a white pit-andfissure sealant - the same tooth as in A., but 10 years later.
As can be seen, the sealant has served its purpose , but there has
been some loss in the peripheral fissures.
 All
teeth meeting the previous
criteria should be sealed and resealed as needed.
 Sealants
should be placed on the
teeth of children and adults if
there is evidence of existing or
impending caries susceptibility
Other Considerations in Tooth Selection

Аges 3 and 4 years (preschool) are the most
important times for sealing the eligible
deciduous teeth;

Ages 6 to 7 years - for the first permanent
molars;

Ages 11 to 13 years - for the second
permanent molars and premolars.
 The
disease susceptibility of the
tooth should be considered
when selecting teeth for sealants,
not the age of the individual.
Evaluating of occlusal risk

Rely on professional judgment, based on
the severity of the caries activity indicators:
- number of "sticky" fissures,
- level of plaque index,
- number of incipient and overt lesions,
- microbiologic test indications.

Combining sealant placement and
regular fluoride exposure would save many
school days, dental treatment and
would achieve better dental health.
A sealant is contraindicated if:

Patient behavior does not permit use of adequate
dry-field techniques throughout the procedure.

An open, frank, carious lesion exists on the same
tooth.

Caries exist on other surfaces of the same tooth
in which restoration will disrupt an intact sealant.

A large occlusal restoration is already present.
Polymerization of Sealants

The common sealant is a liquid resin called a
monomer (a molecule that can be bound to
similar molecules to form a polymer, which
contains two or more monomers).

When the catalyst acts on the monomer,
repeating chemical bonds begin to form, as the
hardening process - polymerization proceeds .

Finally, the resultant hard product is known as a
polymer.
Two methods have been used to
catalyze polymerization
The first method is light curing with the use of a
visible blue light,
 Тhe light-cured sealants contain a catalyst, such
as camphoroquinone, which is placed in the
monomer .
 The catalyst is sensitive and when the monomer
is exposed to the visible blue light, polymerization
is initiated.
 The
second method is self-curing,
in which a monomer and a catalyst are
mixed together to induce
polymerization without the use of a light
source;

synonyms for this process are cold
cure, autopolymerization, and
chemical activation.

In first-generation sealants, polymerization was initiated by
ultraviolet light;

Second-generation sealants were autopolymerized,

Third-generation sealants used visible blue light.

Fourth- and fifth-generation sealants added a step in which
dental-bonding agents were used as a primer before the sealants
were placed.

Sixth-generation sealants use a self-etching process.

Less frequently,
sealant.
glass ionomer cement is used as a dental
Light-emitting diode (LED) curing unit for direct,
intraoral exposure.
Types of Sealants
Glass Ionomer Cement Sealants
 Glass
ionomer cements have been
used as dental sealants.
 Тhey
do not have the same effective
retention rates as those of
conventional sealants.
Fluoride-Releasing Sealants
 Because
fluoride uptake increases
the enamel's resistance to caries,
the use of a fluoridated resin-based
sealant may provide an additional
anticariogenic effect if the fluoride
released is incorporated into the
adjacent enamel.
Fluoride is added to sealants by two
methods:

The first is by adding a soluble fluoride
to the unpolymerized resin.

The fluoride can be expected to leach
out over a period of time into the
adjacent enamel.

Eventually the fluoride content of the
sealant should be exhausted,
but the content of the enamel greatly
increased.

The second method of incorporating fluoride
is by the addition of an organic fluoride
compound that is chemically bound to the
resin to form an ion exchange resin.

When fluoride is low in the saliva, fluoride
would be released,

When the fluoride in the environment is high,
it should bind to the resin to form a reservoir
for fluoride release and recharge.

Fluoride-releasing sealants have shown
antibacterial properties as well as a greater
artificial caries resistance compared with a nonfluoridated sealant.

Fluoridated sealants have also demonstrated a
caries-inhibiting effect, with a significant reduction
in lesion depth in adjacent surface enamel and a
reduction in the frequency of wall lesions.

However, recent reviews revealed that, compared
with resin-based sealants, fluoride-containing
sealants have a poor retention rate after 48
months; they also have not proven to act as a
fluoride reservoir with long-term release of fluoride
into the oral environment.
Colored Versus Clear Sealants

Both clear and colored sealants are available.

They vary from translucent to white, yellow,
and pink.

The colored products permit a more precise
placement of the sealant.

Retention can be more accurately monitored
by both the patient and the operator placing
the sealant.

Some clinicians prefer the clear sealants,
because it is possible to see under the
sealant to detect if a carious lesion is active
or advancing.
Requisites for Sealant Retention
For sealant retention the surface of the tooth
must
 (1) have a maximum surface area,
 (2) have deep, irregular pits and fissures,
 (3) be clean,
 (4) be absolutely dry at the time of sealant
placement and uncontaminated with saliva
residue.
Increasing the Surface Area
 Sealants
 They
do not bond directly to the teeth.
are retained mainly by adhesive
forces.

To increase the surface area,
which in turn increases the adhesive potential,
tooth conditioners (also called etchants), which
are composed of a 30 to 50% concentration of
phosphoric acid, are placed on the occlusal
surface prior to the placement of the sealant.
The etchant may be either in liquid or gel form.
 The gel is easier to apply and easier to
remove.

Tooth after etchant is placed.
When a tooth is etched,
it appears chalky white .
Pit-and-Fissure Depth

Deep, irregular pits and fissures offer a much
more favorable surface contour for sealant
retention compared with broad, shallow
fossae.
An electron-scanning microscope
view of the deep pits and fissures
of the occlusal surface of a molar.
 Тhe
possibility of caries development
is increased when the fissure depth
and slope of the inclined planes is
increased

Thus, as the potential for caries
increases, so does the potential for
sealant retention.
Surface cleaning
 Тhe
cleaning preferences either
by acid etching or other methods
- all stains, deposits, debris, and
plaque should be removed from the
occlusal surface before applying the
sealant.
 Usually
the acid etching alone is
sufficient for surface cleaning.
 Other
methods used to clean the tooth
surface prior to placing the sealant
included,
- air-polishing,
- use of hydrogen peroxide,
- polishing with pumice,
- brushing with a non-fluoridated
toothpaste,
- use of laser.

The use of an air-polisher has proven to
thoroughly clean and removes residual
debris from pits and fissures.

Hydrogen peroxide has the disadvantage
that it produces a precipitate on the enamel
surface.

Comparison of acid etching with laser alone
did not demonstrate any significant
difference of sealant retention or
microleakage.

Cleaning teeth with the newer prophylaxis pastes
with or without fluoride (NuPro, Topex) was not
shown to affect the bond strength of sealants.

Simonsen accomplished the most effective
sealant longevity without use of a prior
prophylaxis.

Cleaning the tooth surface with oil-free pumice is
recommended for sixth-generation sealant material.
Sealant Retention
Resin sealants are retained better on recently
erupted teeth than on teeth with a more mature
surface. !!!!!
 They are retained better on first molars than on
second molars, and are better retained on
mandibular than on maxillary teeth.


The mandibular teeth being more accessible and
easier to see; also, gravity aids the flow of the
sealant into the fissures.

Sealants appear to be equally retained on
occlusal surfaces in primary and permanent
teeth.

When the resin sealant flows over the prepared surface,
it penetrates the finger-like depressions created by the
etching solution.

These projections of resin into the etched areas are
called tags
The tags are essential for retention.


Tags, 30 micron.
 If
sealants are lost, the teeth should be
resealed.

Over the first 3 months, the rapid loss of
sealants is probably caused by faulty
technique in placement.
 Pit-and-fissure
sealants applied during
childhood have a long-lasting, cariespreventive effect.
 Teeth
successfully sealed for 6 to 7
years are likely to remain sealed.
Preparing the Tooth for Sealant
Application

After the selected teeth are isolated, they are
thoroughly dried for approximately 10 seconds.

The liquid etchant is then placed on the tooth with
a small sponge or cotton. Аcid gels are applied
with a syringe

Тhe etching solution is gently daubed, not rubbed,
on the surface for 1 minute for permanent teeth
and for 11/2 minutes for deciduous teeth.

Аcid etching the enamel of both primary and
permanent teeth for only 20 seconds produced
similar sealant retention.

For 10 seconds the water is flowed over the
occlusal surface .

Following the water flush, the tooth surface is
dried for 10 seconds.

The dried tooth surface should have a white,
dull, frosty appearance.

Тhe surface area is greatly increased by the acid
etch.
Dryness

The teeth must be dry at the time of sealant
placement because sealants are
hydrophobic.

The presence of saliva on the tooth is even
more detrimental than water because its
organic components interpose a barrier
between the tooth and the sealant.
Sealant placement.
A. Gel etchant is applied to teeth,
B. Etched surface has a "frosty" appearance.
C. Application of resin-based sealant.
Application of the Sealant

Тhe material should first be placed in the fissures where
there is the maximum depth.

The sealant should not only fill the fissures but should have
some bulk over the fissure.
After the fissures are adequately covered, approximately
halfway up the inclined plane is covered too.


Following polymerization, If any voids are evident, additional
sealant can be added without the need for any additional
etching.

All the commercial sealants - both the light-cured and selfcured are of the same Bis-GMA chemical family, they easily
bond to one another.
Occlusal and Interproximal
Discrepancies

An excess of sealant may be flowed into a fossa or
into the interproximal spaces.

Тhe occlusion should be checked with articulating
paper.

If the premature contact of the occlusal contact is
unacceptable, a large, round cutting bur may be used
to rapidly create a broad resin fossa.

Тhe interproximal spaces can be checked with the
use of dental floss.
Evaluating Retention of Sealants
The finished sealant should be checked for
retention .
 In the event that the sealant does not adhere,
the placement procedures should be repeated,
with only about 15 seconds of etching needed
to remove the residual saliva before again
flushing, drying, and applying the sealant.


If two attempts are unsuccessful, the sealant
application should be postponed until
remineralization occurs.
 Teeth
that have been sealed and then
have lost the sealant have had fewer
lesions than control teeth.

This is possibly due to the presence
of tags that are retained in the enamel
after the bulk of the sealant has been
lost from the tooth surface.

Over the first 3 months, the rapid loss of sealants is
probably caused by faulty technique in placement.

After a year or so, the sealants become very difficult
to see or to discern tactilely, especially if they are
abraded to the point that they fill only the fissures.

Because the most rapid falloff of sealants occurs in
the early stages, an initial 3-month recall following
placement should be routine for determining if
sealants have been lost. If so, the teeth should be
resealed.
Teeth successfully sealed for 6 to 7 years are likely
to remain sealed.

 Тhe
pit-and-fissure sealants applied
during childhood have a long-lasting,
caries preventive effect.
 Where
resealing is accomplished as
needed at recall appointments,
a higher and more continuous level
of protection is achieved.
Sealants Versus Amalgams

When properly placed, sealants are no
temporary expedient for prevention;

They are the only effective predictable
clinical procedure available for preventing
occlusal caries.

The most frequent cause for sealant
replacement is loss of material, which mainly
occurs during the first 6 months;

To replace the sealant, only resealing is
necessary. No damage occurs to the tooth.

The sealant has the advantage of being
painless to apply and aesthetic,

The sealants have the highest objectives of
the dental profession - prevention of sound
teeth.
Options for Protecting the
Occlusal Surfaces

Several options are now available to
protect the occlusal surfaces,
with the selection depending on risk and
professional's judgment.

The first level of protection is simply
to place a conventional sealant over the
occlusal fissure system.

This sealing protect future pit-andfissure caries, as well as arrests
incipient or reverses small overt lesions.

The second option reported by Simonsen in 1978)
advocated the use of the smallest bur to remove the
carious material from the bottom of a pit or fissure
and then using an appropriate instrument to apply
either sealant or composite into the cavity
preparation.

This he termed a preventive dentistry restoration.

Following insertion of the restoration, sealant was
placed over the polymerized material as well as
flowed over the remaining fissure system.

Aside from protecting the fissures from future caries,
it also protects the composite from abrasion.

The third option is use of glass-ionomers
material for sealants, which is controversial.

Due to their fluoride release and cariostatic
effect, glass-ionomers have been used in
place of traditional materials, as a pit-andfissure sealant,

However, resin sealants have shown much
higher bond strength to enamel than glassionomers.





A fourth option reported by Garcia-Godoy in
1986 involves the use of a glass-ionomer
cement as the preventive glass-ionomer
restoration (PGIR).
The glass-ionomer cement (conventional or
resin-modified) is placed only in the cavity
preparation.
The occlusal surface is then etched with a gel
etchant avoiding, if possible, etching the glassionomer.
The conventional resin sealant is placed over
the glass-ionomer and the entire occlusal fissure
system.
In the event sealant is lost, the fluoride content
of the glass-ionomer helps prevent future
primary and secondary caries formation

"This combination of preventive
techniques (combined use of fluoride
and sealants) is expected to essentially
eliminate caries in teeth erupting”

In Bulgaria the dental profession have
accepted sealants as a routine method
for prevention.
De and remineralisation
 Demineralization
is caused by plaque
acids, which dissolve the tooth minerals
making up the basic calcium, phosphate,
and hydroxyl crystals of the enamel,
dentin, and cementum.
 Remineralization,
requires the
availability of the same ions,
preferably with fluoride as a catalyst
to reconstruct the missing or
damaged rods,
 This process Ten Cate calls nonrestorative repair.

Have shown that products containing amorphous
calcium phosphate (ACP) can stimulate
remineralization of tooth enamel.

Products containing ACP, or ingredients that form
ACP, can be found in:
- toothpastes,
- mouthrinses,
- artificial saliva,
- chewing gums,
- topically applied coatings,
- other vehicles for topical use.






 The
crystals and fluoride compound
of most dental products, interest in
the demineralization and
remineralization process are:
- hydroxyapatite (HAP),
- fluorhydroxyapatite (FHA),
- calcium fluoride (CaF2).
 The
long-term exposure of teeth
to low concentrations of fluoride
(as found in fluoridated water)
results in the gradual incorporation of
fluoride into the existing
hydroxyapatite (HAP) crystals
to form fluorhydroxyapatite (FHA),
which is more resistant to acid
damage.
 Conversely,
a higher concentration of fluoride
(as occurs with the use of topical fluoride
applications - fluoride dentifrices, foams, and
varnishes)
results in the formation of surface globules of
CaF2 .

If phosphates and proteins of the saliva coat
these globules, the globules become more
insoluble.
 When
the fluoride is incorporated into
HAP (hydroxyapatite crystals) to
form FHA (fluorhydroxyapatite ), it is
said to be firmly bound,
 while, loosely bound fluoride is in the
form of CaF2, which is adsorbed onto
the surface of HAP and FHA crystals.
The Relationship between HAP, FHA,
and CaF2
After an attack by plaque acid(s),
CaF2 dissolves first,
followed in sequence by HAP,
and finally, FHA (with its fluoride
substitutions).
 As the attack continues, the dissociated
ions increase the saturation level of the
immediate fluid sufficiently
to slow crystal dissolution and eventually
arrest further solution of the crystals.

 As the pH begins to return to normal,
crystals begin to re-form from the complex
pool of dissolved ions,
- some as HAP,
- some as FHA (with many of the fluoride ions
coming from the previous CaF2).

Finally, newly adsorbed CaF2 is precipitated.
 Any
defects are subsequently
replaced, in time, by calcium,
phosphate, and fluoride
from sources such as the saliva,
water, and toothpastes.

CaF2 provides a reservoir for fluoride
that is immediately available when and
where it is needed.

The only time the system breaks down
is when the attacks are too frequent and
too prolonged.
Depth of Remineralization
There is little controversy about the
success of topical procedures in
stimulating surface remineralization,
 and of the use of commercial fluoride
products such a dentifrices, gels, and
varnish to compensate for the daily wear
and tear of demineralization.


An in vitro study performed by Тen Cate
showed that оnly the outer part of the
enamel appeared to be responsive to
fluoride diffusion and remineralization.

The test for remineralization in these cases
is the lack of demonstrable caries progress
for 2 to 3 years.
Modern re/mineralising agents

In recent years, had the effect of
several new agents with unique qualities.

These are:
- amorphous calcium phosphate (ACP),
- casein phosphopeptides (CPP).
Means of remineralization based on
amorphous calcium phosphate
Remineralizing action has proven two-phase
system of Ca and P in toothpaste under the
brand name of "Enamel Care Toothpaste" with
producer Arm & Hammer Enamel Care.
 With this paste provides mixing of the two
phases adjacent to the enamel surface,
wherein the ions respond to the amorphous
calcium phosphate precipitating the enamel.
 Because the amorphous calcium phosphate is
highly soluble in all acidic attack, it is rapidly
released Ca and P.

Kazeinfosfopeptids (CPP) and
amorphous calcium phosphate (ACP)
 Australian
Eric Rejnolds opened
a new phenomenon of the
interaction between amorphous
calcium phosphate and milk
proteins.
 Products are:
Tooth mousse, MI paste
end