Sealants: basic information, advanced technology.

Pit and fissure sealants are an integral part of a complete preventive program and a proven component of oral health care. Sealants, and other preventive measures such as limiting dietary sucrose, the use of fluorides, and the control of dental plaque are major factors in the prevention of dental caries.

A sealant is defined as an organic polymer (resin) that flows into the pit or fissure, and bonds to the enamel surface. Its purpose is to provide a physical barrier to "seal off" the pit or fissure, to prevent oral bacteria and their nutrients from collecting within the pit or fissure, to create the acidic environment necessary for the initiation of dental caries, and to fill the pit or fissure as deep as possible. Even when sealant material is worn or cracked away on the surface around the pit or fissure, the sealant in the deepest aspects of the pit or fissures can remain intact and provide continued protection. The sealant procedure is esthetic, noninvasive, and performed without anesthetic.

This is also an extremely cost-effective method of prevention for dental patients. Sealants are a procedure provided in dental offices by licensed dental professionals ... dentists, dental hygienists, and depending on the particular state expanded function regulations, dental assistants.

In determining who should receive a dental sealant, the first step is to assess the caries risk of the individual tooth. Caries risk factors include poor oral hygiene, a cariogenic diet, family history, low fluoride intake, pit and fissure anatomy, and any history of caries. Other considerations are the patient's history of preventive care, if they are currently in the process of orthodontia, and medical issues such as xerostomia. Keep in mind that teeth should be assessed individually to determine their risk.

If teeth are determined to be caries-free, they can be sealed. Teeth with deep grooves and pits will especially benefit from sealants placed as soon as possible after eruption, much more so than teeth with no deep grooves. Radiographs are helpful prior to sealant placement to determine if interproximal decay is present. If interproximal decay were present, then a sealant would be contraindicated. Although studies have shown that sealing incipient decay will arrest it, frank occlusal decay should not be sealed, nor should primary teeth that are close to exfoliation.

There are certain situations when a sealant would not be recommended: the presence of behavior management issues, the inability to isolate and maintain a dry field, the presence of decay, pit and fissures that are well coalesced and basically self-cleansing, and any allergies to the sealant material.

Sealants are generally either resin-based or glass ionomers. Resin-based sealants, with their characteristics of flow ability and retentiveness, work exceptionally well and serve their function for many years when placed properly. Their limitation clinically is that the tooth must be properly isolated, and contamination must be avoided throughout the procedure as it can result in failure of a resin sealant.

Glass ionomers are an alternative to resin sealants, and can be considered for use in certain situations. For example, when dealing with patient management issues, glass ionomers can be used with primary molars having deeply pitted or fissured surfaces that are difficult to isolate. Other situations would be permanent first or second molars that are not yet fully erupted, or situations where a "transitional" sealant can be considered prior to the placement of a resin sealant. In other situations beyond these special cases, resin sealants are preferred because of their demonstrated superior bond strength and retention.

The standard procedure of using an explorer, visual examination, and radiographs to determine caries is most commonly used to determine the need of a sealant placement on a tooth surface. A new technology that is becoming popular is the DIAGNOdentAE by Kavo, which uses laser fluorescence directed to the occlusal surface to determine demineralization and caries. If the tooth is determined to be appropriate for a sealant, the decision must be made if a resin-based or glass ionomer sealant will be placed.

If using a resin-based sealant, isolation of the tooth and avoiding contamination of the surface during the procedure is extremely important. Using the traditional technique of sealant placement, the procedure is as follows:

* Clean, isolate, and dry the selected teeth.

* Etch for 15 seconds with phosphoric acid.

* Rinse thoroughly.

* Dry tooth until "frosty."

* If frosty appearance is not obtained, apply etchant again, rinse and dry.

* Apply sealant.

* Light-cure. * Check for coverage.

* Wipe off air-inhibited layer.

An alternative to the traditional technique is using a self-etching adhesive instead of phosphoric acid. When considering this treatment, it is important to know the effectiveness of the adhesive bond to uncut enamel. Adper[TM] Prompt[TM] adhesive from 3M ESPE is unique in that its acidic nature provides a high bond to both cut and uncut enamel surfaces without having to first etch the enamel, making it ideal for sealant placement. This alternative sealant technique, which does not require a rinsing step, is as follows:

* Clean/isolate/dry selected teeth.

* Apply Adper Prompt Self-Etch adhesive for 15 seconds with a scrubbing motion.

* Gently, but thoroughly, dry the adhesive for 10 seconds; the tooth surface will appear glossy but not moist.

* Apply sealant.

* Light-cure.

* Check for coverage.

* Wipe off air-inhibited layer.

This technique has the benefit of timesavings, lowers the complexity of the procedure due to the elimination of the rinsing step, and decreases the challenge of patient management. In addition, studies have shown that when using the Adper Prompt Self-Etch adhesive there is significantly less microleakage compared to conditioning with phosphoric acid before sealant application.

If an unfilled sealant is used, occlusal adjustments are not required due to the "self-occluding" nature of the material. However, if a filled sealant is placed, the occlusion should be checked with articulating paper and adjusted if necessary.

The patient must be educated that sealants are part of a total preventive program, and are not substitutes for other preventive measures. It should also be mentioned that sealants might be retained for many years. However, if deficiencies arise and are noted during recare appointments, they need to be corrected.

Sealants are one of the best preventive measures we can offer our patients, and are cost-effective when placed by a dental auxiliary. If sealants are charged at approximately $45 per tooth, and four teeth can usually be sealed in 30 minutes, this yields a production rate of $360 per hour. There are 36 states that currently offer sealant placement as an expanded function for dental assistants. This service is also an excellent manner in which the dental assistant can add value to the dental practice not only via production, but also to the patient as a preventive care option.

With proper placement and maintenance, a sealant has proven longevity and will protect the caries susceptible pits and fissures of the tooth from decay. With professional dental care, fluoride therapies, patient compliance with plaque removal, and sealant placement, we have the tools to help our patients keep their teeth for a lifetime.

Ellen Neuenfeldt, RDH, BS, is a Professional Relations Manager at 3M ESPE who focuses on the members and professional associations of dental assistants, dental hygienists, and pediatric dentists. In addition to her position at 3M ESPE, she practices dental hygiene one evening per week in a general practice, and places sealants using both the traditional and new "no rinse" techique.