TRENDS IN PREVENTIVE CARE: CARIES RISK ASSESSMENT AND INDICATIONS FOR SEALANTS JILL RETHMAN, R.D.H., B.A. A B S T R A C T Background. In the 21st century, risk assessment models will continue to be developed. By understanding patients susceptibility to disease, better treatment and preventive regimens can be offered. As the causative agent of dental caries is bacterial, the interaction between the susceptible host, the causative agent and the environment determine whether caries occurs regardless of the patient s age. Clinical Implications. This article reviews risk assessment for dental caries and the implication for developing preventive strategies. It also describes the indications and uses of sealants in the prevention of dental caries. A key component of any preventive program is to assess a person s risk of developing a disease. In the case of dental caries, it is suggested that a risk profile be performed on a number of levels: community, individual, tooth and tooth surface. 1 This expanded approach considers risk implications from various factors that could influence carious activity and may help dental professionals better manage patients from a preventive perspective. It is also important to consider factors unique to the patient, such as behavioral patterns, systemic influences and past dental history (Box, General Risk Factors for Caries ). For example, one who receives regular care but exhibits poor oral hygiene may benefit from preventive measures, such as sealant application, in selected sites. Specific considerations for community, individual, tooth and tooth surface caries risk assessments are outlined below. Community. A community is defined as any group with common traits, shared features or communal experiences. Therefore, a city, state, school district or neighborhood could be considered a community. Under this definition, a military institution, nursing home facility or managed care organization is also a community. Caries risk assessment for a community is determined by identifying the frequency of decay occurrence, including untreated as well as restored surfaces. This type of historical perspective can help identify groups within the community who, due to the presence of various risk factors, are the most susceptible to the ravages of decay. Therefore, preventive measures can be initiated with these target populations since they would potentially derive the most benefit. Individual assessment. Assessment of a person s risk for dental caries relies on a number of factors. These factors could include caries histo- 8S JADA, Vol. 131, June 2000
ry, preventive practices, nutritional habits and medical conditions (Box, General Risk Factors for Caries ). 2,3 Caries risk is not stagnant in a patient and can vary from one point of time in his or her life to another. Such variation in susceptibility requires ongoing monitoring by the oral health care professional, since changes in health status, use of medications and other lifetime events can increase risk. 4 Based on the clinical evaluation and information derived from a patient s medical and dental history, he or she can be classified as being at low, moderate or high risk (Box, Factors in Low, Moderate and High Caries Risk Assessment ). 5,6 In addition, inadequately restored surfaces, poor oral hygiene, exposed root surfaces, orthodontic treatment and elevated Streptococcus mutans levels could be factors. 5 Tooth assessment. Research indicates that the teeth most susceptible to pit and fissure decay are the first and second permanent molars. 7,8 Although the life expectancy of primary teeth is limited, their importance in securing adequate spacing for the permanent dentition cannot be underestimated. Therefore, it may be appropriate to initiate preventive measures for primary molars and premolars when at risk. An evaluation of individual tooth morphology, the level of carious activity and the pattern of caries can help determine if individual teeth are at risk. Evidence is suggesting that caries in the primary dentition increases a child s risk of caries in his or her permanent dentition. Tooth surface assessment. It is well-documented that pit and fissure configuration can be a significant risk factor for occlusal caries. 9 Pits and fissures compose only 12.5 percent of tooth surfaces, yet they account for 88 percent of caries in children. 10 Deep pits and fissures that are not easily cleaned can harbor bacteria that break down the enamel surface. Permanent molars have the most susceptible pits and fissures. Premolar teeth are less susceptible, but in some patients, maxillary incisors with fissured or pitted surfaces may also be at risk. The professional dental community seems reticent to include sealants in a preventive oral health program. INDICATIONS FOR SEALANT USE The above discussion of risk assessment indicates that caries is bacteria- and host-related, not age-dependent. Therefore, preventive measures, such as sealants, to target those at risk should not be based on age. Although sealant use is strongly advocated by the ADA and several oral healthcare agencies, sealant application remains low. 11 Between 1988 and 1991, only 18.5 percent of U.S. school-aged children received sealants; 23 percent of nonminority children had at least one sealed permanent tooth, while only 7 percent of minority children did. 10 A goal set by the U.S. Public Health Service for the year 2000, outlined in their program Healthy GENERAL RISK FACTORS FOR CARIES. dbehavioral (for example, deficient oral hygiene, cariogenic diet) denvironmental (for example, low fluoride intake) dmedical (for example, xerostomia) doral (for example, exposed cementum, history of dental caries) People 2000, was for 50 percent of children aged 8 and 14 to have one or more sealed permanent molars. 12 Recent data show that 23 percent of children in grades 2 and 3 and 20 percent of children in grades 8 and 9 have their first molars sealed. 13 Clearly, the goal of Healthy People 2000 will not be met. Healthy People 2010 has reaffirmed this goal: 50 percent of children aged 8 and 14 should have sealants on one or more permanent teeth. 14 This discrepancy in recommended usage of sealants and the lack of application indicates a low level of awareness in the general public. Among the populace, the benefits of sealants for disease prevention appear to be unknown. Further, the professional dental community seems reticent to include sealants in a preventive oral health program, even though evidence in the literature supports their efficacy. Numerous reasons for lack of sealant use by the dental community have been cited. They include the misconceptions that sealants seal in existing decay, sealants are easily lost, patients prefer other restoratives, patients do not want the initial expense and sealant JADA, Vol. 131, June 2000 9S
FACTORS IN LOW, MODERATE AND HIGH CARIES RISK ASSESSMENT. CHILDREN ADULTS Low risk dno new or incipient carious lesions in the past year Low risk dno new or incipient carious lesions Moderate risk (any of the following) done new, incipient or recurrent carious lesion in the past year dhigh caries experience in siblings or parents dhistory of pit and fissure caries dearly childhood caries dproximal radiolucency Moderate risk (any one of the following) done to two new, incipient or recurrent carious lesions during the past three years dhistory of numerous or severe caries High risk Two or more new, incipient or recurrent carious lesions in the past year, or two or more of the following: dsiblings or parents with high caries rate dhistory of pit and fissure caries dearly childhood caries dproximal radiolucency High risk Three or more carious lesions in the past three years, or two or more of the following: dhistory of numerous or severe caries Modified from American Dental Association Council on Access, Prevention and International Relations 5 and Niessen and DeSpain. 6 effectiveness is not proven. 15 Following is a brief review to support sealant use. Sealants and incipient lesions. Numerous studies have shown that bacteria become nonviable and caries does not progress when sealants are applied to incipient lesions. 16-18 It appears that sealant material effectively eliminates the nutrient source for S. mutans, thus changing a lesion from caries-active to caries-inactive. 19 To ensure an effective seal, careful technique when applying sealants is needed, leaving no open margins. In addition, ongoing assessment of margins to test intactness is important. Sealant retention. To be effective, sealants must remain in place and completely cover pits and fissures. Two factors most likely to affect retention are proper application and the tooth s eruption status. 20,21 While sealant placement is fairly uncomplicated, the manufacturers procedures must be followed. Regarding eruption status, it has been shown that 10S JADA, Vol. 131, June 2000
sealants placed early in eruption are far more likely to need replacement. A study by Dennison and colleagues 22 reported that when an operculum existed over the distal marginal ridge of molars, the sealant replacement rate was 54 percent. In contrast, the replacement rate was 0 percent for a selected sample of sealants placed at later eruption stages over a five-year period. 24 This creates a dilemma for the practitioner, however, as some permanent molars erupt with fissures that seem at risk of decay. Since they appear at-risk early in the eruption stage, the clinician may opt to seal such surfaces, knowing that replacement may be inevitable. Sealant efficacy. Simonsen conducted the longest clinical study to date on sealant retention and effectiveness. 23 In children who received a single sealant application, 74 percent of the pit and fissure surfaces of permanent first molars were cariesfree after 15 years. 23 Over the past 20 years, numerous studies have shown the effectiveness of sealants. Moreover, the literature suggests that occlusal caries susceptibility remains throughout life. 24 Therefore, lifelong, ongoing risk assessment of the patient is needed to determine when sealant use is appropriate. Sealant cost-effectiveness. Limited studies have been conducted to determine the costeffectiveness of sealants. However, in a 1992 study by Kuthy, 25 dental insurance claims for over 1.3 million children were reviewed over a three-year period. This investigation determined that the average one-surface restoration charge was more than double the average sealant charge. 25 An additional consideration, though, is that sealants are rarely retained completely over the tooth s lifetime and must be reapplied. Therefore, it is important to place sealants using the community, individual, tooth and tooth-surface risk assessment approach. Furthermore, the potential reduction of future expensive restorative procedures by using sealants as preventive measures is an important (although difficult to estimate) consideration. THE ROLE OF SEALANTS IN PREVENTIVE DENTAL PRACTICE Conservative oral health promotion efforts continue to replace Sealants are an essential component of a modern, sciencebased, preventionoriented practice. more drastic disease-intervening concepts in dentistry. In this context, the role of sealants is clear. 26 Sealants are highly effective in preventing pit and fissure caries. Sealants may be placed with confidence on sound teeth, as well as on teeth with incipient caries activity. They can be provided without anesthesia and without cutting healthy tooth structure. Sealants are esthetically appropriate and relatively inexpensive compared to alternative clinical procedures, and they can be reapplied at any time without removing tooth structure. Sealants prevent disease rather than treat its sequelae. For this and many other reasons, sealants are an essential component of a modern, science-based, prevention-oriented practice. CONCLUSION Assessing risk for disease development is an important component of any disease prevention program. Risk susceptibility can be determined on a variety of levels, including community, individual, tooth and tooth surface. Since dental caries is a bacteria-dependent, multifactorial disease, preventive measures such as sealants, can be implemented once those at risk are identified. Diagnostic tests and preventive therapies will be critical in the dental practice of the future, where health and wellness will be the primary goals. Ms. Rethman is a dental hygienist and educator, as well as the editor of The Journal of Practical Hygiene. Address reprint requests to Ms. Rethman at 47-140 Heno Place, Kaneohe, Hawaii 96744. Special thanks to Drs. Lynn Douglas Mouden, Linda Niessen and Michael Rethman for their assistance in preparing and reviewing this manuscript. 1. Workshop on guidelines for sealant use. J Public Health Dent 1995;55(5)(special issue): 263-73. 2. Leverett D, Featherstone J, Proskin H, et al. Caries risk assessment by a cross-sectional discrimination model. J Dent Res 1993;72:529-37. 3. Leverett D, Proskin H, Featherstone J, et al. Caries risk assessment in a longitudinal discrimination study. J Dent Res 1993;72:538-43. 4. Gift H. Issues of aging and oral health promotion. Gerodontics 1988;4:194-206. 5. American Dental Association Council on Access, Prevention and International Relations. Caries diagnosis and risk assessment: a review of preventive strategies and management. JADA 1995;126(supple):1-24S. 6. Niessen LC, DeSpain B. Clinical strategies for prevention of oral diseases. J Esthet Dent 1996;8(1):3-11. 7. Brown LJ, Selwitz RH. The impact of recent changes in the epidemiology of dental caries on guidelines for the use of dental sealants. J Public Health Dent 1995;55:274-91. 8. Li S, Kingman A, Forthofer R, Swango P. Comparison of tooth surface-specific dental caries attack patterns in U.S. schoolchildren from two national surveys. J Dent Res 1993;72:1398-405. 9. Graves R, Abernathy J, Disney J, et al. University of North Carolina caries risk assessment study III. Multiple factors in JADA, Vol. 131, June 2000 11S
caries prevalence. J Public Health Dent 1991; 51:134-43. 10. Brown L, Kaste L, Selwitz R, Furman L. Dental caries and sealant usage in U.S. children, 1988-1991: selected findings from the Third National Health and Nutrition Examination Survey. JADA 1996;127:335-43. 11. Siegal M. Promotion and use of pit and fissure sealants: an introduction to the special issue. J Public Health Dent 1995;5:259-60. 12. U.S. Department of Health and Human Services, Public Health Service. Healthy People 2000: National health promotion and disease prevention objectives. Washington, D.C.: U.S. Government Printing Office; 1990. 13. Clark D, Berkowitz J. The relationship between the number of sound, decayed, and filled permanent tooth surfaces and the number of sealed surfaces in children and adolescents. J Public Health Dent 1997;57:171-5. 14. U.S. Public Health Service. Healthy People 2010 (conference edition). Vol. 2. Washington, D.C.: Department of Health and Human Services; 2000. 15. Gift H, Frew R, Hefferren J. Attitudes toward and use of pit and fissure sealants. J Dent Child 1975;42:460-6. 16. Handelman S. Microbiologic aspects of sealing carious lesions. J Prev Dent 1976; 3(2):29-32. 17. Going R, Loesche W, Grainger D, Syed S. The viability of microorganisms in carious lesions five years after covering with a fissure sealant. JADA 1978;97:455-62. 18. Kramer P, Zelante F, Simionato M. The immediate and long-term effects of invasive and non-invasive pit and fissure sealing techniques on the microflora in occlusal fissures of human teeth. Pediatr Dent 1993;15:108-12. 19. Mertz-Fairhurst E, Schuster G, Fairhurst C. Arresting caries by sealants: results of a clinical study. JADA 1986;112: 194-7. 20. National Institutes of Health consensus development conference statement on dental sealants and the prevention of tooth decay. JADA 1984;108:233-6. 21. Simonsen R. Pit and fissure sealant. J Pract Hyg 1996;1:37-8. 22. Dennison JB, Straffon LH, More FG. Evaluating tooth eruption on sealant efficacy. JADA 1990;121(5):610-4. 23. Simonsen RJ. Retention and effectiveness of dental sealant after 15 years. JADA 1991;122(11):34-42. 24. Ripa L, Leske G, Varma A. Longitudinal studies of the caries susceptibility of occlusal and proximal surfaces of first permanent molars. J Public Health Dent 1988;48:8-13. 25. Kuthy R. Charges for sealants and onesurface, posterior permanent restorations: three years of insurance claims data. Pediatr Dent 1992;14:405-6. 26. Slavkin H. Placing health promotion into the context of our lives. JADA 1998;129:91-5. 27. Wilkins E. Clinical practice of the dental hygienist. 8th ed. Philadelphia: Lippincott, Williams & Wilkins; 1999:482. 12S JADA, Vol. 131, June 2000