Dental caries 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.

Sealant application

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.

Tooth indications

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.