Vibeke Baelum

Reliability of a new caries diagnostic system differentiating between active and inactive caries lesions.

Current scoring systems for dental caries do not consider the dynamic nature of the disease. The aims of the present study were to describe a new set of clinical caries diagnostic criteria which differentiate between active and inactive caries lesions at both the cavitated and non–cavitated levels and to evaluate the reliability of this criteria system in a population with high caries experience. Ten diagnostic codes were defined: 0 = sound; 1 = active (intact); 2 = active (surface discontinuity); 3 = active (cavity); 4 = inactive (intact); 5 = inactive (surface discontinuity); 6 = inactive (cavity); 7 = filling; 8 = filling with active caries; 9 = filling with inactive caries. Distinction between active and inactive caries lesions was made on the basis of a combination of visual and tactile criteria. The inter– and intra–examiner reliability was assessed through repeated examinations of 50 children by 2 recorders over a period of 3 years. The percentage agreement of caries diagnoses varied between 94.2 and 96.2%. The kappa values ranged between 0.74 and 0.85 for intra–examiner examinations and between 0.78 and 0.80 for inter–examiner examinations; 81.6% of all misclassifications involved non–cavitated caries lesions. Disagreement between sound surfaces and non–cavitated active or non–cavitated inactive lesions (31.3 and 31.2%, respectively) was more common than disagreement between non–cavitated active and non–cavitated inactive lesions (10.6%). The probability of reconfirming a sound, non–cavitated active or non–cavitated inactive caries lesion – given that the surface was diagnosed as either sound, non–cavitated active or non–cavitated inactive at the first examination – was 98.0, 68.7 and 72.5%, respectively. The results show that the use of a new set of clinical caries diagnostic criteria based on activity assessment can be performed with a high reliability, even when non–cavitated diagnoses are included in the criteria system.

Dental Tissue Effects of Fluoride

It is now well-established that a linear relationship exists between fluoride dose and enamel fluorosis in human populations. With increasing severity, the subsurface enamel all along the tooth becomes increasingly porous (hypomineralized), and the lesion extends toward the inner enamel. In dentin, hypomineralization results in an enhancement of the incremental lines. After eruption, the more severe forms are subject to extensive mechanical breakdown of the surface. The continuum of fluoride-induced changes can best be classified by the TF index, which reflects, on an ordinal scale, the histopathological features and increases in enamel fluoride concentrations. Human and animal studies have shown that it is possible to develop dental fluorosis by exposure during enamel maturation alone. It is less apparent whether an effect of fluoride on the stage of enamel matrix secretion, alone, is able to produce changes in enamel similar to those described as dental fluorosis in man. The clinical concept of post-eruptive maturation of erupting sound human enamel, resulting in fluoride uptake, most likely reflects subclinical caries. Incorporation of fluoride into enamel is principally possible only as a result of concomitant enamel dissolution (caries lesion development). At higher fluoride concentrations, calcium-fluoride-like material may form, although the formation, identification, and dissolution of this compound are far from resolved. It is concluded that dental fluorosis is a sensitive way of recording past fluoride exposure because, so far, no other agent or condition in man is known to create changes within the dentition similar to those induced by fluoride. Since the predominant cariostatic effect of fluoride is not due to its uptake by the enamel during tooth development, it is possible to obtain extensive caries reductions without a concomitant risk of dental fluorosis.

The Nature and Mechanisms of Dental Fluorosis in Man

Any use of fluorides, whether systemic or topical, in caries prevention and treatment in children results in ingestion and absorption of fluoride into the blood circulation. The mineralization of teeth under formation may be affected so that dental fluorosis may occur. Dental fluorosis reflects an increasing porosity of the surface and subsurface enamel, causing the enamel to appear opaque. The clinical features represent a continuum of changes ranging from fine white opaque lines running across the tooth on all parts of the enamel to entirely chalky white teeth. In the latter cases, the enamel may be so porous (or hypomineralized) that the outer enamel breaks apart posteruptively and the exposed porous subsurface enamel becomes discolored. These changes can be classified clinically by the TF index to reflect, in an ordinal scale, the histopathological changes associated with dental fluorosis. Compared with Deans and the TS1F index, we consider the TF index to be more precise. Recent studies on human enamel representing the entire spectrum of dental fluorosis have demonstrated a clear association between increasing TF score and increasing fluoride content of the enamel. So far, no useful data on dose (expressed in mg fluoride/kg b.w.) -response (dental fluorosis) relationships are available. In this paper, we have, therefore, re-evaluated the original data by Dean et al. (1941, 1942), Richards et al. (1967), and Butler et al. (1985) from the USA, by applying the equation of Galagan and Vermillion (1957) which permits the calculation of water intake as a function of temperature. By so doing, it can be demonstrated that there is a linear association between fluoride dose and dental fluorosis (r2 = 0.87). Even with very low fluoride intake from water, a certain level of dental fluorosis will be found in a population. When the linear dose-response curve is applied to previous data from the use of fluoride supplements, these data are in full accordance. This indicates that we already have useful data available which to some extent allows us to predict prevalence and severity of fluorosis in a child population which is exposed to a known amount of fluoride. Because dental fluorosis may occur in some individuals and populations to a higher prevalence and degree than expected, and there exist rare cases who exhibit clinical changes similar to those of fluorosis—but with no known excessive fluoride background—it is concluded that it is important to intensify studies on factors which alone or in combination can make individuals more or less susceptible to the effect of fluoride.

Construct and Predictive Validity of Clinical Caries Diagnostic Criteria Assessing Lesion Activity

Even though there is no “gold standard” for determining caries lesion activity, it is nonetheless possible to evaluate the validity of such diagnostic measures. The aim of this study was to estimate the construct and predictive validity of caries lesion activity assessments by means of their ability to reflect known effects of fluoride on caries. A three-year trial of the effect of daily supervised brushing with fluoride toothpaste was carried out among 273 12-year-old children. All children were examined clinically according to diagnostic criteria for activity assessment. The relative risk (fluoride vs. control) for caries lesion transitions among diagnostic categories was calculated. Fluoride inhibited progression of caries at all stages of lesion formation while at the same time enhancing lesion regression. The effects were most pronounced for active non-cavitated lesions. It is concluded that the clinical diagnostic criteria have construct and predictive validity for the assessment of caries lesion activity.

Tooth Mortality in an Adult Rural Population in Kenya

This paper reports on the pattern of tooth loss in a random sample of 1131 adults aged from 15 to 65 years in a rural area of Kenya in which access to formal dental care is minimal. We found that the majority of the population retained most of their dentition in a functional state even up to the age of 65 years: In all age groups, more than 50% had at least 26 teeth present, and more than 90% had at least 16 teeth present. The prevalence of edentulousness was less than 0.3%. The principal cause of tooth loss in all age groups was caries, and this was true for all tooth-types except incisors, for which periodontal disease was the main cause of tooth loss. The cultural practice of removing lower central incisors was observed only in those over 40 years of age. More teeth were lost due to caries among women than among men, while the reverse was true for teeth lost due to periodontal diseases. In view of the fact that most people retain most of their teeth throughout life, it is suggested that the most appropriate strategies for dental health care in this population should be those promoting self care, rather than the introduction of a formal treatment-oriented approach provided by dentists.

A Comparison of Clinical and Radiographic Caries Diagnoses in Posterior Teeth of 12–Year–Old Lithuanian Children

Bite–wing radiography has been recommended for use in adolescents as clinical examinations alone may lead to underestimation of carious lesions in approximal and occlusal surfaces. The aim of this study was to describe the relationship between clinical and radiographic caries diagnoses among 12–year–old Lithuanians using a new clinical scoring system which differentiates between cavitated and non–cavitated caries lesions. Eight hundred and seventy–two children were examined clinically and two standardized posterior bite–wing radiographs were taken of each participant. Bite–wing radiography contributed significantly to the total number of lesions diagnosed only at the dentin level in approximal surfaces. Clinical examination performed better than radiographic examination at the non–cavitated/enamel level, particularly on occlusal surfaces. Less than 2% of the clinically sound surfaces were diagnosed with dentin lesions/fillings radiographically. When using the cavitated level of clinical diagnosis, the frequency of ‘hidden’ caries lesions increased from 1.9 to 2.9% in approximal surfaces, and from 1.7 to 5.2% in occlusal surfaces. The intra–examiner reliability data for the clinical and radiographic recordings supported the conclusion of an additional diagnostic value of bite–wings only for approximal surfaces. The findings demonstrate that the diagnostic yield of bite–wing radiography is higher for approximal than for occlusal surfaces. The efficacy of bite–wings depends on the refinement of the clinical caries diagnostic criteria. ‘Hidden’ caries does not seem to be a major problem when the clinical caries diagnostic criteria include non–cavitated diagnoses.

Pattern of dental caries in an adult rural population.

A study was conducted amongst 1,131 randomly selected persons aged 15-65 years in a rural area of Kenya, having minimal access to dental care. A relatively low prevalence of frank cavitation was found in the 15- to 24-year-old cohort, but in the older age groups over 80% were so affected. Caries in the youngest cohort was characterized by a predominance of enamel lesions. At the age of 25-34 years, however, involvement of pulpal tissues and loss of teeth due to caries was more common, and this age group exhibited the largest number of dentinal lesions. The 35- to 44-year-old cohort exhibited fewer enamel and dentinal lesions, but more pulpally involved lesions and more extracted teeth. In the group aged 45-54 years, enamel and dentinal lesions were less common, and at the age of 55-65 years, such lesions were less common in comparison to their occurrence in younger cohorts. The 55- to 65-year cohort could generally be characterized as having larger numbers of root surface lesions, lesions involving the pulp, and extracted teeth. Root surface lesions were principally associated with age over 35 years. In all age groups caries exhibited a skewed distribution, most of the lesions occurring in a minority of individuals. This study demonstrates that caries activity continues throughout life and is not a phenomenon confined to any one period of life.

Ten–Year Incidence of Dental Caries in Adult and Elderly Chinese

Only very few longitudinal studies on dental caries are available in adults and elderly. Therefore, the aim of the present study was to describe the patterns of lesion progression in a group of adult and elderly Chinese followed over a 10–year period of time. In 1984, 587 persons aged 20–80 years were examined and by 1994, 440 of these were still available and re–examined by the same two examiners. All restorations, periodontal conditions and dental caries were recorded for all teeth and surfaces. Only caries data are reported here. Dental caries on coronal surfaces was classified as sound, non–cavitated, cavitated without or with pulp involvement or filled. On root surfaces, lesions were classified as sound, active caries or restored. Prior to analysis of the data, a series of drop–out analyses was carried out showing that most of the drop–outs were above 60 years of age at baseline, and death of participants was the major drop–out reason. A total of 2,114 teeth were lost, 36% of which had a deep dentin lesion at baseline. The distribution of persons according to number of new lesions/restorations over 10 years was highly skewed in all age groups, the prevalence increasing with age. Molars had the highest risk of becoming carious/restored over the 10–year period, and a remarkably low proportion of teeth had the same caries diagnosis after 10 years, indicative of lesion progression. When comparing the 1984 DFT/DMFT with the figures for 1994, there were no statistically significant differences indicating that the period and cohort effects cancel out each other. There was a significant increase with age of the number of new DFT. It can be concluded that dental caries is a major health problem in contemporary adult and elderly Chinese populations, and that caries incidence increases with old age.

Associations between Salivary Levels of Streptococcus mutans, Streptococcus sobrinus, Lactobacilli, and Caries Experience in Kenyan Adolescents

Salivary levels of mutans streptococci (S. mutans and S. sobrinus) and lactobacilli were determined in a random sample of rural Kenyans between 15 and 19 years of age (n = 149). It is possible for the natural history of dental caries in this population to be studied since it is characterized by a limited access to conventional dental treatment. Using a short set of biochemical tests, we identified from seven to ten presumptive mutans streptococcus colonies-cultured from the saliva of each individual-to differentiate between S. mutans and S. sobrinus. No colonies resembling S. rattus (S. mutans serotype b) were isolated. Lactobacilli were identified as Gram-positive, catalase-negative rods. The mean D1-4MFS and D3-4MFS were 7.03 ± 6.43 and 1.46 ± 3.44, respectively. The mean mutans streptococcus and lactobacillus levels were 8. 7 x 104 and 6. 7 x 104, respectively. The salivary mutans streptococcus and lactobacillus levels were significantly correlated (p<0.01). Of the subjects, 64% harbored only S. mutans, 4% only S. sobrinus, 30% both species, and 2% neither. Lactobacilli were ubiquitous. The caries experience of the group was significantly (p<0.001) correlated with both the total salivary level of mutans streptococci and the salivary S. mutans levels, but not with the salivary S. sobrinus level.

The Highly Leukotoxic JP2 Clone of Actinobacillus actinomycetemcomitans and Progression of Periodontal Attachment Loss

The JP2 clone of Actinobacillus actinomycetemcomitans has been implicated in the etiology of periodontitis in adolescents. The aim of this two-year longitudinal study was to describe clinical attachment loss (CAL) progression and to assess its association with baseline occurrence of the JP2 and non-JP2 types of A. actinomycetemcomitans. Clinical re-examination of 121 adolescents in Morocco was performed. Progression of CAL ≥ 1 mm, ≥ 2 mm, ≥ 3 mm, and ≥ 4 mm on at least one site was found in 58%, 48%, 22%, and 6% of the subjects, respectively. Subjects who, at baseline, harbored the JP2 clone had a significantly higher progression of CAL than did subjects harboring non-JP2 types of A. actinomycetemcomitans. Subjects harboring non-JP2 types displayed a marginally higher CAL progression than did subjects who were culture-negative for A. actinomycetemcomitans.