Pit and Fissure Sealants

Pit and Fissure Sealants
Pit and fissure sealants are preventive dental materials used to protect
occlusal surfaces of teeth from caries by sealing the grooves and pits that are
difficult to clean. According to Mitchell and Gordon (1990), sealants can be
classified based on several criteria, including polymerization methods, resin
systems, filler content, and color.

Classification of Pit and Fissure Sealants
1. Polymerization Methods
Sealants can be differentiated based on how they harden or polymerize:


a) Self-Activation (Mixing Two Components)

These sealants harden through a chemical reaction that occurs when
two components are mixed together. This method does not require any
external light source.



b) Light Activation

Sealants that require a light source to initiate the polymerization
process can be further categorized into generations:
First Generation: Ultraviolet Light
Utilizes UV light for curing, which can be less common due
to safety concerns.


Second Generation: Self-Cure
These sealants harden through a chemical reaction without
the need for light, similar to self-activating sealants.


Third Generation: Visible Light
Cured using visible light, which is more user-friendly and
safer than UV light.


Fourth Generation: Fluoride-Releasing
These sealants not only provide a physical barrier but also
release fluoride, which can help in remineralizing enamel and
providing additional protection against caries.







2. Resin System
The type of resin used in sealants can also classify them:

BIS-GMA (Bisphenol A Glycidyl Methacrylate)
A commonly used resin that provides good mechanical properties and
adhesion.


Urethane Acrylate
Offers enhanced flexibility and durability, making it suitable for
areas subject to stress.



3. Filled and Unfilled
Sealants can be categorized based on the presence of fillers:


Filled Sealants

Contain added particles that enhance strength and wear resistance.
They may provide better wear characteristics but can be more viscous and
difficult to apply.



Unfilled Sealants

Typically have a smoother flow and are easier to apply, but may not
be as durable as filled sealants.



4. Clear or Tinted
The color of the sealant can also influence its application:


Clear Sealants

Have better flow characteristics, allowing for easier penetration
into pits and fissures. They are less visible, which can be a
disadvantage in monitoring during follow-up visits.



Tinted Sealants

Easier for both patients and dentists to see, facilitating
monitoring and assessment during recalls. However, they may have
slightly different flow characteristics compared to clear sealants.



Application Process

Sealants are applied in a viscous liquid state that enters the
micropores of the tooth surface, which have been enlarged through acid
conditioning.
Once applied, the resin hardens due to either a self-hardening catalyst
or the application of a light source.
The extensions of the hardened resin that penetrate and fill the
micropores are referred to as "tags," which help in retaining the sealant on
the tooth surface.