Dental sealants are a preventive measure designed to protect the chewing surfaces of back teeth (molars and premolars) from decay. They consist of a thin, protective plastic coating applied directly to the tooth. This material flows into the deep grooves and depressions, known as pits and fissures, which easily trap food particles and bacteria. By creating a smooth barrier, the sealant shields the enamel from acids, preventing cavities.
Preparing the Tooth Surface
The success of a dental sealant relies on a clean and completely dry tooth surface. The initial phase involves meticulously cleaning the tooth to remove all traces of plaque and debris. This is typically done using a specialized brush and a mild abrasive material like pumice.
Following cleaning, the tooth is isolated from the rest of the mouth using absorbent materials such as cotton rolls or a rubber dam. Maintaining a completely dry field is important, as any moisture or saliva contamination can compromise bonding and lead to premature sealant failure.
Conditioning for Adhesion
Once the tooth is clean and isolated, the enamel must be chemically prepared for secure adhesion. This involves applying an etchant, typically a gel containing phosphoric acid, directly onto the pits and fissures for 15 to 60 seconds.
This acid microscopically roughens the enamel surface, creating tiny, porous channels. These channels allow the liquid sealant material to flow in and physically interlock with the tooth structure, forming a strong mechanical bond. The etchant is then thoroughly rinsed off with water, and the tooth is completely dried with air. A properly prepared tooth will exhibit a distinct, dull, frosty white appearance, confirming the surface is ready for the sealant.
Applying and Curing the Sealant Material
With the conditioned tooth surface ready, the dental professional carefully applies the liquid sealant material directly into the prepared pits and fissures. This liquid resin, which is typically tooth-colored or clear, is painted onto the chewing surface using a fine brush or syringe tip. Precision ensures the material penetrates all grooves and covers the entire surface without incorporating air bubbles.
The thin resin is then transformed into a hard, durable plastic shield through photopolymerization. A handheld curing light emitting an intense beam of blue light is held over the tooth. This light activates molecules within the sealant, causing the resin to rapidly link together and harden the material within a few seconds per tooth.
Final Assessment and Longevity
Once the resin is cured, the sealant is instantly solid and ready. The final stage involves a thorough assessment to ensure patient comfort and sealant integrity. The professional checks the surface for any rough edges or excess material.
A bite-check is performed using articulating paper to confirm the sealant does not interfere with the patient’s natural bite (occlusion). Minor adjustments are made by polishing or trimming the sealant for a smooth, comfortable fit. With proper application, sealants can last several years, though regular check-ups are necessary to monitor their condition.