NIH: Consensus Development Conference on Diagnosis and Management of Dental Caries Throughout Life: Background

Norman Tinanoff, D.D.S., M.S., and Joanna Douglass, B.D.S., D.D.S.:

Historically, dental management of both primary and permanent teeth has involved clinical or radiographic identification of carious lesions followed by surgical intervention to remove affected enamel and dentin and placement of restorative material to rebuild missing tooth structure. Even with preventive therapies and improved understanding of the dental caries disease process, only modest changes have occurred in this surgical model of treatment.

The dental caries process involves cyclical exposure of tooth enamel and dentin to periods of demineralization and remineralization. An acidic oral environment, primarily due to acid byproducts of bacteria that adhere to teeth, will demineralize teeth, especially if the acidic periods are frequent and prolonged. Remineralizing periods, due to salivary buffering and trace amounts of fluoride, can reverse mineral loss. If demineralization over time exceeds remineralization, however, an initial carious lesion can develop that may progress to a frank cavity.

Dental therapy needs to address this disease process by fostering remineralization as well as restoring teeth. Treatment of a child requires an understanding of the carious process that includes the patient�s age, caries risk, prior treatment outcomes, and location and extent of lesions. A child who has been identified as being at low risk for dental caries may need fewer diagnostic procedures and therapy. Conversely, a child who is caries-active may need more frequent examinations and therapy.

Primary Teeth

The vast majority of the literature regarding diagnosis and prevention of caries relates to permanent teeth. Although much of this information can be extrapolated to primary teeth, there are important differences. The pits and fissures of primary teeth are less pronounced than those of permanent teeth, making these surfaces less susceptible to caries. However, primary teeth have thinner enamel and dentin and broader proximal contacts than permanent teeth, making them more caries-susceptible (American Academy, 1999-2000).

Unlike therapy for permanent teeth, therapy for primary teeth only needs to last several years. Yet primary teeth are critical for eating and for aesthetics reasons as well as for maintaining space for succedaneous teeth.

Caries in the Primary Dentition

An understanding of the natural history of caries progression in the primary dentition is necessary to determine where lesions are likely to occur, to assess an individual�s caries risk, and to determine what therapy is best. Those teeth that have been exposed to a cariogenic environment the longest generally will be the first to show signs of disease. Consequently, children may develop lesions on their maxillary anterior teeth soon after eruption. If these children continue to be at high risk they may develop fissure caries of the molars and, later, proximal caries of the molars (Johnsen, Gerstenmaier, DiSantis, et al., 1986; Douglass, O�Sullivan, Tinanoff, 1996). Children with moderate caries risk may develop caries at a later age. These are normally fissure caries on the primary molars and possibly posterior proximal lesions (Johnsen, 1995; Douglass, Tinanoff, Tang, et al., 2000). In general, caries on maxillary anterior primary teeth, on the smooth surfaces of primary molars, or on the mandibular primary anterior teeth all suggest high caries activity.

At the individual lesion level, caries progression and appropriate therapy are dependent on the site of the lesion and risk factors. Buccal-lingual smooth surface lesions, even if cavitated, may be readily amenable to preventive regimens, while cavitated pit and fissure or cavitated proximal lesions may need restorative and preventive therapy. The potential for remineralization and appropriate restorative therapy in primary teeth depends on caries activity. One study found that proximal lesion progression through the enamel among a group of high-risk subjects not receiving fluoride took approximately 1_ years, compared to 3_ years in low-risk children receiving regular topical fluoride therapy (Shwartz, Grondahl, Pliskin, et al., 1984).

Caries Risk Assessment for Primary Teeth

The goal of dental caries therapy is to minimize caries experience while employing the fewest possible interventions consistent with the child�s risk. A weakness in current caries risk assessment is the lack of a single predictor with both high positive predictive values (proportion of children predicted to get the disease who actually do so) and high negative predictive values (proportion of children predicted to not get the disease who do not). Since caries has multiple causes, multiple risk factors may have to be assessed to determine risk. Combinations of biological variables (e.g., caries experience, plaque index, streptococcus, lactobacillus, and salivary fluoride levels) (Leverett, Featherstone, Proskin, et al., 1993) and social variables (e.g., race, parents� education) (Demers, Brodeur, Mouton, et al., 1992; Disney, Graves, Stamm, et al., 1992) have shown better assessment results than single factors.

In the child patient, key risk factors are the age at which a child becomes colonized with cariogenic flora (Thibodeau, O�Sullivan, Tinanoff, 1993) and the age at which visual caries is found (O�Sullivan, Tinanoff, 1983). Additional information for caries risk assessment includes exposure to fluoride (both systemically and topically), tooth cleaning ability, and diet. Even though these factors do not provide sufficient evidence for a risk assessment analysis, collection of this data may be valuable in developing a prevention program.

Parent and Practitioner Preferences

A child�s parent(s), with the advice of the dental professional, are the people who must make decisions for dental therapy (Rule, Veatch, 1993). In light of their own experience, many parents expect surgical treatment of their children�s dental caries. The dental professional should present parents with enough information to enable them to make an informed choice from among all available therapies. Such decisions should also take into account the effects of various therapies on the prevention of disease in teeth that have not erupted. Because of their training and experience, dental professionals may favor certain therapeutic approaches, and such preferences also need to be considered in treatment decisions.

Preventive Therapy

Daily response to fluoride exposure through water supplies or supplemental tablets should be recommended for all children as a primary preventive measure. Perhaps the next best method is daily use of a fluoridated dentifrice. Other kinds of fluoride use should be based on the child�s risk. Professional fluoride treatments have been shown to reduce dental caries in primary teeth and should be administered to children at risk. Fluoride varnishes have been shown to be efficacious and have gained popularity recently because they are easy to use and less fluoride is delivered to the mouth (this conference). Fluoride mouth rinses or brush-on fluoride gels have been advised for patients at high risk, but no studies were found that analyzed whether home fluoride protocols reduce caries in primary teeth.

Evidence has accumulated that certain antimicrobials can reduce cariogenic flora and therefore may affect caries activity (this conference). Further research is needed to determine the efficacy and optimal antimicrobial regimen necessary for preventing caries in high-caries risk children.

Sealants are a conservative way to prevent pit and fissure caries by obliterating the deep fissures in primary and permanent molars (this conference). Numerous studies have shown the efficacy of pit and fissure sealant for both permanent and primary teeth (Ripa, 1979), and such treatment should be considered for children who are likely to develop carious lesions in fissures.

Restraint in sugar consumption is also regarded as an important approach to reducing caries. Numerous epidemiological, laboratory, and clinical studies (this conference) make it clear that restricting consumption of sucrose may reduce dental caries. Unfortunately, there are no reports of studies demonstrating that dietary counseling can be effective in reducing caries activity.

But there is good evidence that chewing gum with xylitol reduces caries in primary teeth. Several trials have shown that children who changed to xylitol gum have fewer caries lesions than children who chewed sugared gum, and remarkably, than children who did not chew gum (this conference).

Poor oral hygiene is widely considered a factor in caries activity. Conversely, toothbrushing, flossing, and professional tooth cleaning have long been considered basic components of caries prevention. Yet clinical studies generally do not demonstrate a relationship between dental plaque scores and dental caries prevalence, or between unmedicated toothcleaning procedures and caries prevalence (Sutcliffe, 1966). Even though there may be no firm scientific connection between oral hygiene and caries, caries reductions have been noted in children who receive frequent professional prophylaxis along with some form of fluoride therapy (Lindhe, Axelsson, Tollskog, 1975) or who brushed frequently with a fluoridated dentifrice (Leske, Ripa, Barenie, 1976). If the specific contribution of toothcleaning remains unknown, however, there does exist a significant body of research suggesting that regular brushing should at least be encouraged as a delivery system for a fluoride dentifrice (this conference).

Restorative Therapy

Restorative therapy should always be used in conjunction with preventive therapy and should also be based on an understanding of a child�s risk factors and age. The principal role of restorative therapy is to eliminate cavitations that make plaque removal difficult and consequently increase the likelihood that a tooth will undergo further demineralization. Restorations are essential where a remineralization environment cannot be maintained, where initial therapy was unsuccessful, or where restoration of tooth integrity and function is necessary. If, for example, a posterior proximal cavitation is not restored, it will most likely progress and threaten the integrity of cusps, cause space loss, and eventually affect the pulp.

The size of the carious lesion, the therapeutic and esthetic requirements of the restorative material, and caries risk factors and age must be considered when restoring a tooth. There is an emerging class of restorative materials that are considered therapeutic because they release fluoride. Although some of these materials may not have the integrity of conventional materials, they can be used in certain situations or for certain age groups. Young children at high risk for future caries should be treated aggressively to minimize the need for additional restorations. There is good evidence that stainless steel crown restorations function better in such children than multisurface intercoronal restorations (Levering, Messer, 1988).

Summary

The information presented in this and other papers at this conference suggests that sufficient evidence exists to transcend traditional surgical management of dental caries. New information on diagnosis, lesion progression, risk assessment, and caries prevention provides insight on tooth management that relies less on surgical techniques and more on monitoring and prevention. Patients and practitioners alike will derive great benefit from treatment decisions based on our emerging understanding of dental caries as a multifaceted disease process that should be approached with broad-ranging, outcomes-based therapy.

Figure. A concept for primary teeth diagnosis and therapy based on caries risk assessment

Table. Possible diagnostic procedures, preventive therapy, and restorative therapy in primary teeth based on a child's caries risk assessment and age

References

American Academy of Pediatric Dentistry. Reference Manual, 1999-2000, p.106.

Demers M, Brodeur JM, Mouton C, Simard PL, Trakan L, Veilleux G. A multivariate model to predict caries increment in Montreal children aged 5 years. Comm Dent Health 1992;9:273�81.

Disney JA, Graves RC, Stamm JW, Bohannon HM, Abernathy JR, Zach DD. The University of North Carolina caries risk assessment study: further developments in caries risk prediction. Comm Dent Oral Epidemiol 1992;20:64�75.

Douglass JM, O�Sullivan DM, Tinanoff N. Temporal changes in dental caries levels and patterns in a Native American preschool population. J. Public Health Dent 1996;56:171�5.

Douglass JM, Tinanoff N, Tang JM, Altman DS. Dental caries patterns and oral health behaviors in Arizona infants and toddlers. Comm Dent Oral Epidemiol 2000;29:14�22.

Johnsen DC, Gerstenmaier JH, DiSantis TA, Berkowitz RJ. Susceptibility of nursing-caries children to future approximal molar decay. Pediatr Dentist 1986;8:168�70.

Johnsen DC. The preschool "passage": An overview of dental health. Dent Clin North Am 1995;39:695�707.

Leske GS, Ripa LW, Barenie JT. Comparisons of caries prevalence of children with different daily toothbrushing frequencies. Comm Dent Oral Epidemiol 1976;4:102�5.

Leverett DH, Featherstone JDB, Proskin HM, Adair SM, Eisenberg AD, Mundorff-Shrestha SA, et al. Caries risk assessment by a cross-sectional discrimination model. J Dent Res 1993;72:529�37.

Lindhe J, Axelsson P, Tollskog G. Effect of proper oral hygiene on gingivitis and dental caries in Swedish school-children. Comm Dent Oral Epidemiol 1975;3:150�5.

Messer LB, Levering NJ. The durability of primary molar restorations: II. Observations and prediction of success of stainless steel crowns. Pediatr Dentist 1988;10:81�5.

O'Sullivan DM, Tinanoff, N. Maxillary anterior caries associated with increased caries in other primary teeth. J Dent Res 1993;72:1577�80.

Ripa LW. Sealant retention on primary teeth: a critique of clinical and laboratory studies. J Pedod 1979;3:275�90.

Rule JT, Veatch RM. Ethical Questions in Dentistry. Chicago: Quintessence, 1993.

Shwartz M, Grondahl HG, Pliskin JS, Boffa J. A longitudinal analysis from bite-wing radiographs of the rate of progression of approximal carious lesions through human dental enamel. Arch Oral Biol 1984;29:529�36.

Sutcliffe P. Oral cleanliness and dental caries. In: The Prevention of Oral Disease, ed. Murray JJ, third ed. Oxford: Oxford University Press, 1966.

Thibodeau EA, O�Sullivan DM, Tinanoff N. Mutans streptococci and caries prevalence in preschool children. Comm Dent Oral Epidemiol 1993;21:288�91.

Abstracts Index