By Kathleen O'Neill-Smith, RDH, MS
Sealants (such as DENTSPLY Professional's Delton, seen at right) are a well-documented preventive service and a proven component of oral health care. The ability of sealants to successfully prevent dental caries is to utilize risk-based therapy (risk assessment) of the individual and the tooth when determining the appropriateness for clinical treatment. The best predicators to indicate treatment are caries history of the patient, fluoride history of the patient, fissure anatomy, development abnormalities, and plaque load. Primary teeth (as well as permanent teeth) may be determined to be at risk due to fissure anatomy and caries risk factors. Any teeth judged at risk can benefit from sealant application.
Risk assessment of a patient may change over the patient's lifetime. Caries is a process and should not be viewed solely as a lesion. Contrary to previous beliefs, the rate of caries progress is slower and over a much longer period of time. Current research documents that it takes 12 to 24 months to clinically detect caries lesions, and three years for a caries lesion to progress from enamel to dentin. Caries risk may continue into adulthood and, depending on the patient risk assessment, permanent molars may be sealed immediately upon eruption or later in adulthood.
Sealants are a resin filling material capable of forming a bond to tooth structure effectively sealing pits and fissures. Sealants are relatively easy to apply and can be delegated to an appropriately educated individual. Sealant effectiveness is increased with proper clinical technique, appropriate follow-up, and resealing as necessary. Application is technique-sensitive and it's important to follow sealant placement procedures. As the steps are reviewed, factors influencing these steps will be included for consideration.
First, remove plaque and debris from teeth using an appropriate method such as rubber cup and pumice or an air-polisher. Various cleaning methods have been tested. One of the best is the ProphyJet® (seen at right), an air-polishing system utilizing sodium bicarbonate particles. Air polishing with the ProphyJet followed by acid etching produced the highest bond strength of all group tests. Isolate teeth with cotton rolls or other appropriate means, then air-dry the surface to be sealed for approximately 30 seconds. Adequately etch tooth surface for 15 to 20 seconds. Apply etch beyond the intended sealant outline. Thoroughly rinse for 20 to 30 seconds per tooth, then thoroughly air-dry for 15-30 seconds per tooth.
Second, consider applying a bonding primer and adhesive layer between etched enamel and the sealant. This is a variation from traditional sealant protocol since initial research suggested that a dentin-bonding agent did not enhance the retention of the sealants. Salivary contamination leads to significantly reduced bond strength. Furthermore, research points to the reduction in microleakage of sealants applied under conditions of salivary contamination and sealant survival; half the usual risk of failure for occlusal sealants and one-third the risk of failure for buccal/lingual sealants. Taking into consideration the patient's behavioral posture and the clinician's ability to keep the surface dry, adding the bonding step may be worth the extra time and cost.
Third, the sealant material is brushed or flowed onto the etched surface to adequately fill the pits and fissures. Avoid placing excess amounts of the sealant material that could create occlusal interference. Also take into consideration that "penetration, an important yet poorly recognized factor in sealant application and retention, is inversely proportional to the viscosity." Accordingly, the decision to use an unfilled versus a filled sealant material may affect its retention. Studies indicate that unfilled light-cured resin was significantly better retained than a filled light-cured resin. Besides a lack of equivalent penetration, a filled sealant has the disadvantage of requiring occlusal adjustment. Unfilled sealants will abrade quickly, while a filled sealant will require an occlusal adjustment as a part of the placement procedure. If filled sealant is used, check for occlusal interference with articulating paper. The dentist can adjust as necessary with rotary instruments.
A colored versus a clear sealant should also be considered. The colored (opaque) sealants are easy to see during application and allow easier assessment of retention. The latest marketing trends are color changes in the curing or the polymerized stage of the sealant, but the clinical value of this technology has yet to be determined.
Next, examine the surface for complete coverage with an explorer or sealant syringe tip. If necessary, reapply sealant using the appropriate technique. Check occlusal aspects.
The final segment of sealant placement is a watchful recall and repair process. Sealant success is very high with a follow-up maintenance protocol in place. In addition, clinicians should also consider the sequence of providing adjunctive preventive treatment such as fluoride therapy. Often, questions arise about sealant placement immediately after a fluoride treatment and whether the fluoride would interfere with etching and retention of the sealant. In fact, the research is conclusive that sealants can be placed or repaired after a fluoride treatment.
It is important to remember that, "caries risk, and therefore potential sealant benefit, may exist in any tooth with pit and fissure, at any age, including primary teeth of children and permanent teeth of children and adults." Unfortunately, despite its benefits, sealant treatment remains underutilized. Therefore, it is imperative that clinicians regularly review their patient's risk factors and routinely treatment-plan sealants as an essential part of preventive regimen.
Editor's Note: References available upon request.
Kathleen O'Neill-Smith is the Texas and Southeast Clinical Program Educator for DENTSPLY Professional. In her current position, she presents seminars and workshops on ultrasonic therapy, air polishing, and teeth whitening. She has presented numerous programs on a variety of topics including communication, leadership, and dental implant maintenance to state and national conferences. She has been recognized by the Texas State Board of Dental Examiners, Baylor College of Dentistry, The Dallas, Texas, and American Dental Hygienists'
