PREVENTION V

1. PREVENTION V PIT AND FISSURE (Dental) SEALANTS

2. HISTORY • The concept of sealing the fissures of teeth is over 100 years old. In 1895, Wilson, described in Dental Digest the use of oxyphosphate cement to seal fissures. • Contemporary pit and fissure sealants were introduced into clinical dentistry in 1967 by Michael Buonocore of the Eastman Dental Center, Rochester. • Dr. Buonocore is credited with developing the field of adhesive dentistry through his introduction of the concept of acid etching of tooth enamel, and his documentation of the ability of resin materials to ‘adhere’ to such etched enamel surfaces. • The effectiveness of pit and fissure sealants as a preventive tool was recognized with provisional approval by the American Dental Association Council on Dental Therapeutics in 1971; full approval came in 1976. • Since then the use of pit and fissure sealants, now generally referred to as dental sealants, has increased steadily.

3. SEALANT USAGE • Surveys show an increase in sealant use among dentists from 38% in 1974 to as high as 90-95% of dentists in recent surveys. • The most recent National Health and Nutrition Survey (NHANES), reported in 2005 that 42% of 6-19 year old children had caries in one or more of their permanent teeth, with the majority of lesions being on the occlusal surface. • 32.2% of 6-19 year olds had one or more sealed permanent teeth. • Prevalence of sealed teeth was higher for children 12-15 (37.4%) than children 6-11 (29.5%) • The prevalence of sealed teeth increased from 19.6 % in 1988-1994 to 32.2% in 199-2002. • Sealants demonstrated to reduce caries by 84% after one year and 58% after 4 years.

4. CARIES PREVALENCE • As we have discussed, there has been a significant decline in caries prevalence among school aged children in the past 20-30 years. • Among 2-11 year old children, the NHANES study found 41% had caries in their primary teeth. The prevalence of caries was higher in Mexican American children (54.9%) than in black children; and higher in black children (43.3%) than non-Hispanic white children (37.9%). • Children from economically disadvantage families (100% of the federal poverty level—FPL) had a caries prevalence of 55.3%. Caries is correlated with reduced family income. • There was no change in dental caries prevalence in children 2-11 between 1988-1994 and 1998-2002.

5. RELATIVE DISTRIBUTION OF CARIES • While over time there has been a general reduction in dental caries, there has also been a change in the relative distribution, or pattern, of caries on different tooth surfaces. • There has been a greater percentage reduction for smooth surface caries (mesial and distal surfaces) compared to pit and fissure caries. • Overall, 88% of the caries in school children occurs in pits and fissures, and only 12% on the proximal surfaces. • This differential is related to the more significant impact of fluorides on smooth surfaces in reducing enamel solubility; and serves to underscore the imperative of dental sealants in a comprehensive program of prevention.

6. TOOTH SURFACE ATTACK RATES IN PERMANENT TEETH BY SURFACE

7. PREVALENCE OF SEALANTS1988-1994 AND 1999-2002

8. PRINCIPLES UNDERLYING SEALANT USE • Prevention of dental caries is preferable to treatment; sound, nondiseased teeth are to be more highly valued than adequately restored teeth. • For equivalent outcomes, the least invasive approach, using the simplest intervention for managing dental caries is preferred. • Minimizing the cost of preventing or controlling pit and fissure caries is desirable. • Strategies for sealant use may vary between individual care and community-based programs.

9. SCIENTIFIC FACTS RELATED TO SEALANT USE • Sealants have been demonstrated to be a safe and effective long-term method to prevent pit and fissure caries. • Pit and fissure caries attack begins in childhood and continues through adolescence and into adulthood. • In addition to preventing carious lesions, sealants can arrest caries progression. • Effective sealant use requires meticulous attention to detail in application technique, particularly moisture control. Sealant retention should be checked within one year of application.

10. RISK ASSESSMENT IN TREATMENT PLANNING FOR SEALANTS • Determination of the need for sealants begins with an assessment of the individuals risk for dental caries, as well as an assessment of the risk of the individual tooth. • Factors to evaluate when considering individual teeth include: • individual’s risk for developing caries • pit and fissure morphology • caries pattern • status of the proximal surface of the tooth in question. • Not all permanent teeth have defined pits and fissures. Teeth with well-coalesced groups do not require fissure sealants. • Children who grow and develop in communities with water fluoridation have few pits and fissures with concomitantly more well-coalesced grooves.

11. TREATMENT DECISION MAKING • Studies suggest that the first and second permanent molars are at the greatest risk for pit and fissure caries; premolars are at significantly less risk. • Primary teeth have an aprismatic layer of enamel and do not etch in the same manner as permanent teeth, consequently sealant retention is not as great on primary teeth. Additionally, the grooves of primary teeth tend to be well-coalesced in comparison to permanent teeth. • In general, primary teeth are not sealed. • The cost-benefit effectiveness is greatest in sealing first and second permanent molars, and they should be given preferential treatment to premolars in application of sealants. • Generally, insurance programs will not pay for sealants on primary teeth or premolars. • Indiscriminate sealing of teeth with low risk of caries reduces the overall cost-effectiveness of sealants.

12. TREATMENT DECISION MAKING • Diagnosing dental caries on occlusal surface surfaces can be challenging: Is it the lesion cavitated or not. • As previously discussed in caries diagnosis, unless a tooth is clearly cavitated a sealant should be placed. Cavitation of the enamel indicates that the caries has penetrated past the DEJ. • Cavitation is defined by cariologists as a lesion in which the 0.5 mm rounded tip of a WHO probe engages the lesion. • If cavitated, a restoration should be placed, the pulpal extent of which in into the dentin.

13. EFFICACY OF SEALANTS • Sealants are effective as long as they remain intact. With complete retention, sealed surfaces are virtually impervious to decay. • Therefore, the effectiveness of sealants in preventing decay is measured by the retention of the sealant. • However, there is some evidence that caries resistance is imparted by the presence of the resin “tags” in the etched microporosities. If true, the bulk of the sealant could be lost and if the resin tags remain intact, caries prevention will be effected. • Glass ionomer sealants also may have imparted caries resistance while in place.

14. VARIABLES AFFECTING SEALANT RETENTION • Position of the teeth in the mouth • better sealant retention in mandibular versus maxillary arch--??? • Skill of operator • more skillful and experienced operators produce better sealant retention • Eruption status of the tooth • the younger the child, the more difficult to maintain a dry field due to the eruption status of the teeth; partially erupted molars are difficult to isolate. As a consequence typically delay sealant placement on first and second molars until completely erupted. • Patient Cooperation • children who present problems with cooperation make gaining and maintaining a dry field more difficult.

15. SEALANT RETENTION • A compilation and summary of over 75 studies of sealant retention indicates: • 94% of sealants were intact after one year • 83% of sealants were intact two years after placement. • 67% were intact five years after placement. • 57% were intact after ten years.

16. UPDATING TECHINQUE:MATERIALS • There is a wide variety of sealant materials from which to choose. • Sealants are often classified by their method of polymerization, either auto-polymerizing (chemically cured), or visible light-cured sealants; they are also classified by whether they are ‘filled’ resins, or ‘unfilled’ resins--though increasingly the market is dominated by filled resins. • Numerous studies have compared bond strengths and retention rates between the two and found they offer comparable results.

17. UPDATING TECHINQUE:MATERIALS • A further materials’ issue is the use of resin-based sealants versus glass ionomer sealants . Glass ionomer sealants release fluoride in addition to sealing the tooth. • A traditional criticism of glass ionomer sealants is there is some evidence that glass ionomer sealants are not retained as well as resin-based sealants. • However, a recent systematic review of the literature found that the difference in retention between the two sealants was small. • Advocates of glass ionomer sealants argue that when sealants are lost (whether in whole or part) the exposed fissure is more resistant to caries due to the fluoride release from the glass ionomer. • Additionally, glass ionomer sealants are not as moisture sensitive in placement as are resin-based sealants.

18. UPDATING TECHNIQUE:CLEANING THE FISSURE • Prior to acid etching the enamel, it is important to be sure that the tooth surface and fissure areas are free of gross plaque that might interfere with the etching process. • Historically, it was recommended that this be done with a prophylaxis cup or bristle brush and pumice. • Recent studies have shown that cleaning the tooth with a pumice prophylaxis does not significantly increase bond strength. • Current recommendation is to run an explorer through the fissures and rinse forcefully with water; or, brush the fissures thoroughly with a tooth brush to remove the gross plaque. • Complete debridement of plaque from the fissure is viewed to be essentially impossible and not an imperative for successful etching and sealant retention.

19. UPDATING TECHNIQUE:ISOLATION • Adequate isolation of the tooth is the most critical aspect of the sealant application process. • Salivary contamination of a tooth surface during or after acid etching will have a deleterious effect on the ultimate bond between the enamel and resin. • Studies have shown that even a one second exposure of etched enamel to saliva adversely affected bond strength and sealant retention. • Several studies have shown that rubber dam isolation and cotton roll isolation provide comparable retention rates. • However, it is obvious that rubber dam provides the best, most controllable, isolation. • When sealants are treatment planned for a tooth in a quadrant where restorative therapy will also be accomplished, the sealant should be placed under rubber dam isolation in the context of the restorative treatment.

20. UPDATING TECHNIQUE:ETCHING • The most commonly used etchant is 37% orthophosphoric acid; it is available as both a liquid and a gel. • Etchant should be applied to all of the fissures and extend 2mm up the the cuspal inclines. • Soft tissue exposure to the etchant is to be avoided. • Historically, etchant times were 30-60 seconds; however, recent studies have concluded that 15-20 seconds is comparable and adequate. • Rinse time is not important as previously thought (20 seconds). What is critical is that the etchant be completely rinsed away. • On thorough drying the enamel should present a chalky, frosted appearance; if it does not, it must be re-etched..

21. DEMINERALIZATION PATTERNS(SEM X 5,000) Enamel prism centers mainly involved

22. DEMINERALIZATION PATTERNS(SEM X 5,000) Enamel prism peripheries mainly involved.

23. UPDATING TECHNIQUE:APPLYING THE SEALANT • All susceptible pits and fissures should be sealed; this includes the buccal pit of mandibular molars, and the lingual groove of maxillary molars. • Recent studies have shown that using priming and bonding agents, as an intermediate step, prior to placing the sealant, increases sealant retention. Therefore it is recommended that a prime and bond technique be used. With some marketed materials this is a two step procedure. However, there are one-step prime and bond products on the market today, and these are recommended as they are more efficient. (3M/ESPE’s Prompt L-Pop and Caulk’s Prime and Bond) • An additional advantage of using prime and bond before placing the sealant, is that should the area become contaminated with saliva, it only needs to be re-washed, not re-etched. • Care should be taken not to place excess sealant, which may affect the child’s occlusion; and increase the potential for the sealant bond being fractured.

24. PENETRATION OF MICROSCOPIC SEALANT TAGS

25. OCCLUSAL SEALANT AFTER REMOVAL OF ENAMEL BY DEMINERALIZATION

26. INNER SURFACE OF SEALANT AFTER REMOVAL OF ENAMEL BY DEMINERALIZATION

27. POLYMERIZED SEALANT TAGS (SEM X 3,000)

28. UPDATING TECHNIQUE:POLYMERIZATION • In one study it was found that the longer sealants were allowed to remain on the tooth surface before being polymerized, the more sealant penetrated the microporosities, creating longer resin tags, which are the critical dimension for micromechanical retention. • Sealants in which polymerization was not effected for 20 seconds after application, had nearly three times longer resin tags than those of sealants polymerized after 5-10 seconds. This is true when bonding composites to etched enamel as well. • When isolation can be adequately maintained, it appears to be beneficial to wait for 20 seconds after sealant application before applying the light activation. • The above is applicable only if a prime and bond technique is not employed.

29. UPDATING TECHNIQUE:EVALUATING THE SEALANT • All sealants should be visibly and tactually inspected for complete coverage, and the absence of voids or air bubbles. • Attempts should be made to dislodge the sealant with an explorer. • An evaluation of the occlusion should be conducted. Filled resin sealants (which we utilize) in contrast to unfilled resin sealants, are not easily abraded and can create occlusal interferences. They should be adjusted with a rotary instrument, if determined to be in hyperocclusion. • The interproximals of the tooth should be evaluated as well to ensure no sealant has flowed into the area inadvertently.