Preventitive Procedures: Enamel Sealants

An enamel sealant or a pit and fissure resin sealant is an organic polyer, which bonds to the enamel surface mainly by mechanical retention. Because sealants usually contain no therapeutic ingredient (fluoride, etc), their success lies in their ability to adhere firmly to the enamel surface. The sealant acts as a physical barrier to prevent oral bacteria and their nutrients from collecting within a pit or fissure and creating the acid environment essential to the initiation of dental decay.

Current Philosophies On Why Sealants Are Used

• Sealants prevent tooth decay (cavities), and since tooth decay is a chronic disease affecting all age groups, and oral health is vital to general health


• Fluoride both systemic and topical application, help fight decay on tooth surfaces, but it is least effective in the pits and fissures. Sealant placement adds to the preventative purpose that fluoride provide, and when combined the benefits of each are enhanced
• Teeth are not equally susceptible to decay
• newly erupted permanent molars develop decay faster than newly erupted permanent incisors, cuspids and premolars. Thus causing a higher percentage in the molars
• If a sealant is properly applied, it prevents the accumulation of bacterial plaque and acids, and therefore decay. Sealants have been shown to reduce decay by 10%

The Purpose of Applying Sealants

Using sealants also has a number of long-term ramifications such as:

• they prevent bacteria, bacterial bi-products and food debris from entering pits and fissures
• sealants plug pit and fissure depressions, thus making cleaning by tooth brushing easier
• aid in preventing the destruction of vital tooth tissue due to decay
• beneficial in preventing the expense and potential tooth loos associated with decay (from a filling)

Advantages of Applying Sealants

• significantly reduce a child's risk for having untreated dental decay
• it is possible to achieve 100% retention if periodic reapplication is done

Disadvantages of Applying Sealants

• the life of the sealant is determined by the operators skill and the clinical conditions at the time of placement
• very technique sensitive. Insufficient rinsing, drying, incomplete acid-etch, airline contamination, and placement of insufficient coating, can all contribute to an inadequate seal.
• new areas of plaque retention can be created by sealants improperly placed.

Chemical Composition of an Enamel Sealant

Bis-Gma           +        MMA    +       Accelerator       =     SEALANTS

Bisphenol A -           Methyl               benzoylperoxide

Ethylene glycol        methacrylate      or diketone

dimethacrylate          monomer

The Bis-GMA resin is sometimes strengthened by adding a filler particle, such as glass, porcelain or quartz, then it is known as "partially filled". However most sealants are "unfilled" and contain no filler materials.

When an unfilled sealants is used, "high spots", which are inevitable, are worn away by the patients own occlusion in a few days and therefore, does not require an adjustment. Partically filled sealants will need to be ajusted.

Some brands contain fluoride that is released after polymerization (hardening)

Differences between specific brands of sealant material may include:

• method of polymerization
• presence of fillers
• presence of colouring agents
• presence of fluoride

Polymerization

Defined as the process of changing a simple chemical substance into another compound having the same elements, usually the same proportion, but with a higher molecular weight.

It is simply the acts creating a polymer from two or more monomers. As it specifically relates to this procedure, chemical or light-induced polymeriaztion methods have been used to transform a liquid or malleable semi-liquid into a durably hard, solid sealant.

Advantages Of Coloured Sealants

The hardened sealants may be: clear, white, tinted (yellow) or pink

•  may allow for more accurate placement
• provides a better visualisation and more accurate assessment of their presence for patients upon self inspection and as well as for operator visits
• decreases exam time during the recall appointments
• it becomes an easier concept to explain to patients or parents as being as decay preventative restoration

Teeth That Would Benefit From Sealants

• the biting surfaces of the primary molars
• the biting surfaces of the permanent molars
• surfaces where other pits and fissures are present.

Generally sealants are indicated for children and teens, but adults are also sealants candidates if they are judged to be at risk for pit and fissure decay.

The most two most important considerations when selecting teeth for sealants are: 1 the morphology of the pits and fissures should be deep, 2 the teeth must be sufficiently erupted so that a dry field can be maintained during isolation.