is one of the most common chronic diseases across all ages around
the world. It usually starts in childhood and is a common cause
of tooth loss in young adults. In the past decades, advances
have been made to prevent dental caries and improvement in oral
hygiene. Application of fluoride and dental sealants have widely
gained popularity since these are easy, safe and affordable ways
to prevent tooth decay or their progression.
Dental sealant types
There are various kinds of dental sealants, depending on the
materials they contain, how they were manufactured or polymerized,
and whether they contain fluoride or not. They can be resins
that are filled, unfilled, fluoride-containing, polyurethane,
or bisphenol-A-glycidyl. Filler materials are quartz and silica.
Sealants may be autopolymerized or photopolymerized. The only
difference between the two is the amount of labor and time. Performance-wise,
there has been no proven significant advantage of one type of
sealant from another.
Glass ionomers as sealants have been introduced but studies
show that these were inferior to the traditional sealants, owing
to decrease in tensile strength. However, improvements have been
made to strengthen the material but still no conclusive data
have been published.
Effectiveness of sealants
A meta-analysis of randomized or quasi-randomized trials published
in 2004 showed that application of a resin-based sealant resulted
in a more than 50% decrease in cavities in permanent teeth after
4.5 years, when compared to those that were left unsealed. This
concurs with a previous study in 2001 that found evidence of
the effectiveness of visible-light cured resin sealants.
Aside from caries prevention, effectiveness of sealants can
also be measured by its retention rate and its cost-effectiveness.
Autopolymerizing polymers and visible-light curing sealants have
the same retention rates, and fluoride-containing visible-light
curing sealants show similar retention rates. Studies have concluded
that fluoride does not significantly affect the binding of the
sealant to the tooth, hence retention rates are also not changed.
The application of sealants in general is more cost-effective
than non-application. A study done in 2001 concluded that sealants
placed on moderate to high-risk children resulted in less expenditure
for further treatment and/or reconstruction. However, it is not
advisable that sealants be placed on low-risk patients as this
causes an expenditure that is not necessary.
A tooth must be properly identified as needing sealing before
the procedure is done. Once identified, the tooth must be thoroughly
cleaned and it must be ensured that any debris must be completely
removed from the pits and fissures. The tooth must then be isolated
to provide a dry working area. Cotton rolls, angles and/ or rubber
dams may be used. When a dry working space has been guaranteed,
the next step is to dry the tooth itself. Any moisture contamination
will increase the risk of sealant failure. In fact, moisture
contamination secondary to poor technique is the most common
reason for sealant failure.
Etching the tooth surface with and orthophisphoric acid is done
to create an uneven surface on the tooth. This aids in sealant
adherence. Etching is usually done between 30-60 seconds, although
some claim that 15 seconds is enough and prolonging the etching
time does not show any benefits. Before applying the sealant,
the etching process should leave the tooth surface “chalky
white”. Otherwise, etching should be repeated.
Sealants should be prepared, mixed and applied according to
the manufacturer’s instructions for optimum performance
and to avoid injuries. The sealant should completely cover all
the pits and fissures, making sure that the tooth is sealed.
To reduce contamination, it is suggested that polymerization
should be done soon after placing the sealant, though no studies
have been done to confirm this. Occlusion may be checked with
an occlusion paper.
The last step to sealant application is patient education. It
must be conveyed that good oral hygiene should be practiced and
regular follow ups done.
While fluoride is helpful on smooth surfaces, dental sealants
effectively prevent dental caries on pitted and fissured surfaces
of the teeth. It is a well-known fact that dental caries begin
in areas that are not easily accessible to daily brushing. As
such, the molars and pre-molars are considered the high-risk
teeth for dental caries. A consensus has been reached that only
those teeth with high-risk and those individuals with high-risk
behavior (poor oral hygiene, increased carbohydrate intake, history
of caries) should receive sealant treatment. Teeth that have
shown early signs of tooth decay (the “white spot”),
even if these are not molars, should also be treated.
Indications for dental sealant use in children
Children are considered a high-risk age group because most of
them exhibit poor dental hygiene and the love for candies and
the need for increased carbohydrate intake perpetuates this dilemma.
Typically, children should get dental sealants once their premolars
and molars are out. However, occasionally, children may need
sealants on baby teeth so that these will not fall off prematurely.
Baby teeth are important in saving the space of the permanent
teeth that is to erupt in their place.
Absolute indications for sealant application lie in the question
whether or not the child will benefit from the procedure. It
must be borne in mind that dental sealant is not cheap and not
every tooth needs it.