Introduction

Sealants are a useful dental tool to prevent cavities from developing on the chewing surfaces of the teeth. They can be painted onto permanent teeth in school-age children to protect teeth, especially those in the back of the mouth.

Definition of sealants

A dental sealant is a thin coating applied to the occlusal surface (chewing surface of the back teeth: molars and premolars) that prevents cavities from forming for many years.

Importance of cavity prevention in dentistry

Cavity prevention is critical to maintaining good oral health. In addition to routine dental care including daily brushing, flossing, and regular dental checkups; sealant application can protect the back teeth from cavities which may develop because they are more difficult to keep clean. 

Cavities are common in children and it is estimated that about 520,000,000 children worldwide have a reported cavity. Globally it is estimated that about 2.4 billion people have at least one cavity.¹ With such a shockingly high statistic, it is no surprise that cavities and poor dental health are the most common chronic conditions of childhood.² A prior history of cavities is a good indicator of future risk. According to the United States Centers for Disease Control, sealants can help prevent up to 50% of cavities in the four years after they are placed.²

The presence of a cavity in a tooth can lead you to develop other complications including severe mouth and tooth pain, decay of the pulp and tooth structure, and a decreased quality of life. Any change in physical appearance due to decaying teeth can also lead to low self-esteem and depression. For these reasons, it is important that cavities be taken care of and prevented as much as possible.¹

To prepare the teeth for sealants, there are several key steps.

Cavity preparation  

It is important to prepare the tooth before applying the sealant material. This helps to remove carious (tooth decay) parts of the tooth surface, protect the pulp, and extend the life of the sealant as much as possible. There are numerous steps which should be taken to prepare the tooth for the sealant.

Cavity preparation has 7 principles that are listed below

Outline form-  to identify the outline of the carious area and its depth on the surface of the tooth/teeth

Resistance form- to form and shape the tooth so that the sealant will attach properly when applied

Retention from- additional forming and shaping to ensure that the sealant won’t be lifted up with normal chewing motions

Convenience form- this ensures that the formed area is easy for the dentist to work on

Caries removal- to remove any remaining debris, infected tooth, old sealant or filling materials, and to clean out the depressed areas very well

Refinement- to protect any exposed pulp and ensure that all shaping is comfortable to the patient and appropriate for the sealant application

Cleansing- to provide the final cleansing of extra materials from the tooth and verify that the bite is comfortable

Filling- to fill the tooth with dental material like composite or amalgam

Understanding dental sealants

There are two different types of dental sealants and the choice of material is made based on age, severity of tooth decay, and standard practices of the particular dental office. Typically, resin-based sealants seem to be more durable than glass ionomer sealants. However, applying a resin sealant may be more difficult on a child since the area needs to be dry during the procedure.

Composition and types of dental sealants

2 types of sealants are glass ionomer and resin-based

Composition of resin-based sealants

Resin-based sealants are made up of a mixture of several components which can be shaded to appear like part of the tooth. These sealants have good bonding but do require etching, rinsing, and thoroughly drying the tooth before application can occur. They have been shown to have better retention. The components of the resin include:¹

• Dimethacrylate monomers (plastic)-water repellent
• Initiators/pigments
• Inorganic fillers
• Fluoride

Composition of glass ionomer-based sealants

Glass ionomer-based sealants are made up of:¹

• Conventional polyacrylic acid, water, and aluminium/calcium/fluoride powder
• Resin modified(RMG) conventional + hydroxyethyl methacrylate

These sealants are a little easier to apply because they do not require as much tooth preparation (etching) and can be used in wet conditions. This may make them ideal to use on children. Glass ionomer sealants do not require occlusal adjustment (levelling down to match the normal bite) because they will naturally wear down. This makes them quick to place.

Purpose of sealants in dentistry

Some people have difficulty with removing plaque and food particles from the fissures of the molars (depression and grooves in the posterior teeth) through brushing and flossing. Sealants can be applied to the surface of the tooth and it will help prevent the formation of cavities since the at-risk surfaces are covered.

Sealant application techniques

Surface preparation

Before applying the chosen sealant material, the dentist will clean and dry your teeth first. Then they will apply an acidic solution, rinse it with water, and dry it with the help of a rubber dam (a small latex sheet to isolate the tooth from the surrounding teeth and liquids). The dentist will then continue to prepare the tooth with etching and cleaning out debris from the grooves.

Application methods

Application is an important step and the correct method must be used. The sealant material must be carefully applied from one end of the tooth to the other to avoid air bubbles. If bubbles do form, they must be removed. 

If more than one tooth is being sealed then the process should start from the posterior (back) teeth.

Curing process

Some sealants (resin-based) require a special light to “cure” (set) them. Others are able to cure spontaneously. 

Advantages and limitations

Advantages of using sealants

• Easy and painless- sealants don't require any invasive surgical process to apply and the procedure is totally painless
• Short procedure- each tooth takes only a few minutes so in one appointment all teeth can be treated
• Reduce risk of cavities by up to 80%- in 6-year molars²
• Long lasting- it can be re-applied once it deteriorates 
• Cost-effective it's a fairly inexpensive procedure
• Prevent decay

Limitations of sealants

• Sealants do not protect the side surface of the tooth from decay
• Dental sealants have a definite life span of up to 10 years but can become loose or fall off
• Cannot be used if a cavity has already formed

Summary

Dental sealants are a thin coating which is applied on the occlusal surface of the molars to prevent cavities. Since it is difficult to remove plaque and food particles from the back teeth by brushing and flossing, sealants can help with dental care and reduce the risk of cavity development.

There are 2 types of sealants available: glass ionomer and resin-based. Ultimately, the choice of material depends on the person, the tooth, and the dentist’s preference. Sealants are a great tool to improve dental health, especially in children.