Clinical evidence of the role of pre-eruptive fluoride in caries prevention.

Recent clinical and laboratory evidence has suggested that systemic fluoride plays a more minor role in caries inhibition than was previously believed. This paper reviews clinical data on water fluoridation, the topical administration of fluorides, and fluoride supplements in the light of more recent understanding of the disease dental caries. Due to reduced functional usage, erupting teeth tend to accumulate plaque which has cariogenic potential. For this reason, the period from tooth emergence to the establishment of interproximal contact and full occlusion is the most critical for caries initiation. Analyses of clinical data indicate that maximum protection against caries is obtained when teeth erupt into an environment with low concentrations of ionic fluoride. The similarity in caries reductions obtained in water fluoridation studies and long-term studies with topically administered fluoride regimens, including fluoride-containing dentifrices, indicates that the pre-eruptive effect of fluoride is of borderline significance relative to the more significant post-eruptive effect. Water fluoridation and topical fluoride programs are thus important measures for the control of caries at the community level. For the individual, topical application of fluoride is seen as an integral part of caries treatment aimed at arresting progressive caries. Fluoride application is thus considered a supportive therapy, in conjunction with cariogenic plaque control. Daily use of fluoridated dentifrices from tooth eruption is more efficacious than daily use of fluoride supplements from birth.

Dentifrice usage among Danish children.

The usage of dentifrice was studied in 179 Danish children of approximate ages 3, 7, 9, and 16 years. The usage was assessed by measurement of the aggregated quantities used at home during a two-week period. Information was also obtained on toothbrushing habits. The mean daily usage with the same brand of dentifrice increased from 1.1 g among 3-year-olds to 1.5, 2.3, and 3.4 g among 7-, 9-, and 16-year-olds, respectively. The amount used showed a significant, positive relationship to the orifice diameter of the tube. However, the lengths of ribbon of paste squeezed out per brushing were quite similar, regardless of tube orifice diameter. When the usage data were considered in light of the fact that young children swallow an average of 15 to 30% of the dentifrice used for brushing, it became obvious that a notable number of the 3- and 7-year-olds can be expected to ingest fluoride from 1000- and 1500-ppm-F dentifrices in quantities exceeding recommended daily doses.

Dental plaque and caries on occlusal surfaces of first permanent molars in relation to stage of eruption.

The occlusal surfaces of partly and fully erupted first right permanent molars were examined with respect to the occurrence and distribution of plaque and dental caries in a group of 57 six- to eight-year-old children. The children were classified into four groups ranging from one tooth partially erupted to full occlusion. Occlusal plaque was recorded at two levels of examination: (1) visible plaque and (2) detailed mapping by means of a plaque detector system. Dental caries was recorded after professional cleaning. The recording of plaque was repeated after 48 hr without oral hygiene. The findings showed a significant reduction in the easily detectable plaque in fully erupted teeth, compared with the three groups representing partly erupted teeth. The detailed mapping of plaque showed a clear pattern of preferential locations related to the macromorphology of the occlusal surfaces, and revealed reduction in the frequency of thick plaque accumulation in the fully erupted teeth. The proportion of active lesions was reduced in fully erupted teeth, and arrested lesions were mainly observed in the same group. This indicated that erupting teeth are more likely to develop dental caries, due to favorable conditions for plaque accumulation. Functional usage of teeth in addition to improved access for toothbrushing promoted arrestment of lesions initiated during eruption.

The microflora associated with the development of initial enamel decalcification below orthodontic bands in vivo in children living in a fluoridated-water area.

Thirty-four caries-free teeth destined for orthodontic extraction were banded to provide a protected area for the accumulation of plaque. The teeth were extracted at one, two, four, eight, and 14 days after being banded, and samples of the flora below the band were analyzed for the presence of Streptococcus sanguis, Streptococcus 'mitior', 'mutans streptococci', Actinomyces viscosus, Actinomyces naeslundii, Actinomyces odontolyticus, Lactobacillus species, and Veillonella. After plaque sampling, the teeth were sent to the Royal Dental College (Copenhagen) for histological analysis. The results showed that S. mutans could colonize the area below the band after one day, but that colonization was only 100% at 14 days. Lactobacillus was only isolated from 2/8 samples at four days and from 4/8 samples at 14 days. S. sanguis and 'S. mitior' were regularly isolated at all banding times, and Veillonella was isolated from all samples. A. viscosus was the most commonly isolated Actinomyces. The numbers of Streptococcus and Veillonella were significantly higher at day 1 than at day 14 (p less than 0.05). S. mutans and A. viscosus were isolated more frequently at day 14 than at day 1 (p less than 0.01). Histological examination revealed that dissolution of the enamel below a band could occur after two days, but that even after 14 days dissolution could be questionable. Dissolution was detected in areas where S. mutans was not isolated (8/34), but S. mutans was also present in samples showing dissolution (12/34). There was no relationship between dissolution and the numbers of S. mutans; however, the isolation frequency of S. mutans was associated with dissolution (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A light and scanning electron microscopic study of enamel decalcification in children living in a water-fluoridated area.

Eleven children, each having one or two pairs of premolars to be extracted for orthodontic purposes, participated in the study. The model involved placement of a special orthodontic band that allowed the accumulation of plaque in a defined area between the band and the buccal enamel. Examination of enamel changes was carried out in experimental teeth that had been exposed to local plaque accumulation for one, two, four, eight or 14 days. The specimens were examined under the light (LM) and the scanning electron microscope (SEM). All teeth had signs of very mild dental fluorosis. No indications of demineralization were noted after one day. SEM examination showed signs of crystal dissolution in some of the two-day specimens. Six of eight four-day specimens exhibited surface dissolution. All eight- and 14-day specimens showed signs of surface demineralization in the LM as well as in the SEM. These observations documented that undisturbed bacterial deposits are capable of initiating enamel demineralization within short time periods, even in children living in a water-fluoridated area.

The relationship between water-borne fluoride, dental fluorosis and skeletal development in 11-15 year old Tanzanian girls.

Dental fluorosis was evaluated by a classification system, previously shown to be sensitive, and skeletal changes evaluated by bone maturity and structure. Dental fluorosis was more severe in posterior than in anterior teeth in both jaws irrespective of fluoride concentration of the drinking water. There appeared to be no dependence between fluoride content of the water and skeletal maturity or structure, but there was a definite relationship between the degree of dental fluorosis and skeletal maturity within the high fluoride area. Fluoride concentrations in the drinking water above 3 parts/10(6) seemed to affect all mineralizing tissues under formation. The unique pattern of enamel formation and mineralization renders it the only hard tissue which permits an early diagnosis of the biological effect of even low fluoride doses on the human body.

Automated image analysis applied to the odontoblast-predentine region in undemineralized sections of human permanent third molars.

A computerized histomorphometric analysis was made by Karnovsky-fixed, hydroxethylmethacrylate embedded and toluidine blue/pyronin-stained sections to determine: (1) the two-dimensional size of the coronal odontoblasts given by their cytoplasm:nucleus ratio; (2) the ratio between the number of coronal odontoblasts and dentinal tubules; and (3) the relation between odontoblast size and adjacent predentine. All conditions were measured in relation to three well-defined sectioning profiles of the dentinal tubules. The sections were randomly taken from 10 unerupted and erupted third-molar crowns. Sixty-three photomicrographs (x100), equally distributed among the three sectioning profiles, were scanned in a high-resolution scanner to produce images for the analysis. After initial user interaction for the description of training classes on one image, an automatic segmentation of the images with respect to odontoblast cell nuclei, cytoplasm and background was computed by statistical discriminant analysis. In longitudinal profiles of the dentinal tubules the cytoplasm:nucleus ratio in erupted teeth was 3.1 +/- 0.54, and the mean of the odontoblast cell:dentinal tubule ration was 1.19 +/- 0.20. Analysis of cytoplasm:nucleus ratio and the adjacent predentine in relation to the chosen sectioning profiles disclosed that there was less variation in the predentine measurements in the longitudinal sections. Thus, in future two-dimensional studies of the odontoblast-predentine region only longitudinal sectioning profiles should be analysed. The use of advanced image processing on undemineralized tooth sections provides a rational foundation for further work on the reactions of the odontoblasts to external injuries including dental caries.

Distribution of dental fluorosis in the primary dentition.

By the use of a new classification system of dental fluorosis, primary and permanent teeth were examined in samples of children born in areas with 3.5, 6.0 and 21.0 parts/10(6) F- in the water supplies. The severity of dental fluorosis was lower than in the corresponding permanent teeth, but a significant increase in severity was noted with increasing concentration of fluoride in the drinking water. The distribution of dental fluorosis within the dentition followed the same pattern irrespective of fluoride content of the water. Thus, a progressive increase in severity was noted from the anterior to the posterior teeth. This pattern is presumably determined by variations in enamel thickness. The much thinner enamel layer of primary teeth may also explain the lower degree of dental fluorosis in these teeth rather than a maternal barrier to fluoride. The degree of dental fluorosis observed in medium and high fluoride areas did not support the hypothesis that the rapidly growing skeleton of infants prevents fluoride-derived enamel changes.

Clinical appearance of dental fluorosis in permanent teeth in relation to histologic changes.

Based on studies in Northern Tanzania a new classification system of dental fluorosis is proposed. The classification system includes 10 scores designed to characterize the degree of dental fluorosis affecting buccal/lingual and occlusal surfaces. With aid of polarized and ordinary light microscopy the histologic features behind the individual scores are described. The macroscopic appearance of increasing degrees of dental fluorosis were well correlated to the degree of subsurface porosity. Above a certain level of subsurface hypomineralization various degrees of loss of surface enamel occurred, presumably as a result of posteruptively acquired injuries. Application of the new classification system to samples of children born in areas with 3.5, 6.0 and 21.0 parts/10(6) F- in the water supplies revealed that the distribution of dental fluorosis within the individual followed the same pattern irrespective of fluoride concentration in the water. While the classical Dean index was unable to distinguish between dental fluorosis in the 6.0 and the 21.0 parts/10(6) area it was possible with the new system to disclose that particularly the posterior teeth were significantly more affected in the latter area. Comparisons of degree of dental fluorosis with available measurements of enamel thickness proved that the within-tooth as well as within-dentition variations are determined by enamel thickness rather than length of exposure to body fluids. The limitations of the Dean index are discussed with special attention to its validity as a biological index in relation to current efforts to determine the minimal toxic effect of fluoride on the dental hard tissues.

A practice-based study on stepwise excavation of deep carious lesions in permanent teeth: a 1-year follow-up study.

This study reports results from a practice-based study in which deep carious lesions were treated by general dental practitioners using stepwise excavation. The material comprised 94 teeth with deep carious lesions which the clinicians considered would result in pulp perforation if treated by a single and terminal excavation. At the first visit excavation of the peripheral dentine was completed. The outermost part of the central and necrotic dentine was gently removed with a sharp excavator. Standardized assessments of the dentine colour and consistency were made before application of a calcium hydroxide-containing base material and temporary filling. The final excavation was completed after a treatment interval ranging from 2 to 19 months, with a median of 6 months. Reassessments of the dentine colour and consistency were made before complete removal of demineralized dentine. The central dentine was significantly browner and less softened after the sealing period. After removal of the dark-brownish dentine during the final excavation, the colour and consistency of the exposed central dentine was found to resemble that of the completely excavated peripheral dentine. Only five cases resulted in pulp perforation during the final excavation. The high success rate of teeth surviving the final treatment without pulp exposure after 1 year of observation shows that it was possible for dentists in general practice to administer and manage the treatment of deep carious lesions, a process which may prolong tooth survival compared with conventional endodontic techniques.

Development in dental caries among children in 1961-79 in a Danish community with school dental service.

Data on prevalence of dental caries and increment of treated teeth are reported from children receiving dental care from a Public Child Dental Health Service established in 1959. Data are obtained from records in three periods: 1961-63, 1968-70, and 1976-78. The prevalence of dental caries in 8-year-olds (n approximately 300) after initial dental care remained at the same level in 1961 and 1968. In 1976 the prevalence was reduced by 30%. Increments of treated teeth in 8-11-year-old children (n approximately 1600) were reduced by more than 50% from 1961-63 to 1968-70, but remained then at the same level in 1976-78. Increments of restored surfaces of permanent incisor teeth were reduced by 90% in 1968-70 and further by 50% to almost nil in 1976-78. These data suggest a remarkable reduction in caries activity in the population, presumably resulting from the school-based preventive programs introduced in 1960, and widespread use of fluoridated dentifrice in Denmark from 1968. The apparently maintained level of restorative work in the last period is discussed and interpreted in the light of the more favorable dentist to population ratio and the markedly reduced intervals of recall visits in the same period.

Retention and effectiveness of a chemically polymerized pit and fissure sealant after 12 months.

The aim of the present study was to evaluate the retention and effectiveness of a bis-GMA type of fissure sealant which polymerizes after conventional mixing of the two catalyst/activator components (Concise Enamel Bond System). Unilateral sealing of homologous pairs of permanent first molars was carried out by a dental hygienist. Of the 451 sealed sites sealant was present in 73%, partly missing in 8%, and completely missing in 18% after 1 year. The effectiveness of the treatment in preventing occlusal caries was highly significant and the caries reduction was found to be about 70%. A strong relationship between status of sealant and occlusal decay was demonstrated. The shortcomings of the half-mouth design when evaluating sealants as a caries-preventive measure in public dental health programs are discussed.

Promoting changes in clinical practice. Treatment time and outcome studies in a Danish public child dental health clinic.

This paper examines the characteristics of the process of innovation as applied to provision of dental health to children. The data are from a demonstration project conducted in a Danish public child dental health clinic to evaluate the appropriateness and effectiveness of an individualized and alternative, mainly non-operative caries treatment strategy that was implemented in 1987. The aim of the strategy was to avoid operative intervention and sealants, and was based on three principles: caries is a localized disease; intensive training in home-based treatment, and individualized risk assessments and controls in conjunction with professional plaque removal. The major influence on the innovation process appeared to be personal education of the personnel, active participation in research, and feedback from clinical observations. In 1992 an additional feedback measure was introduced addressing the question: how much time does the individual child spend on treatment during one year? Mean total treatment time varied from 12 min 1- to 4-yr-olds to 44-58 min for 7- to 17-yr-olds. About 60% of the total treatment time was used on non-operative caries treatment (diagnosis, risk assessment, plaque removal, toothbrushing training) and about 25% on operative caries treatment for 3- to 17-yr-olds. The 1-2-yr-olds required only non-operative treatment. The new treatment strategy reduced operative procedures by 60%. The paper introduces an easily applicable measure of treatment outcome in terms of teeth that have not been restored or sealed as a result of regular professional treatment or care. The main conclusion drawn is that the dominant moving forces in the innovation process were professional responsibility and self-adjustment by a constant learning process involving clinical feedback measures in conjunction with modern understanding of caries as a localized disease caused by local evolution of microbial cariogenic biofilms.

Results after 3 years of non-operative occlusal caries treatment of erupting permanent first molars.

The aim of the study was to describe the 3-yr results of a treatment program designed to control occlusal caries on the basis of intensive patient education and professional toothcleaning. The sample consisted of 56 children 6-8 yr old with their permanent right first molars in different stages of eruption. The results were compared with record data from 58 children of the same age who had received a traditional caries treatment program including fissure sealing (control group). After 1 yr a significant reduction of occlusal surfaces with visible plaque was noted in the study group as well as an increased proportion of arrested lesions. These results were maintained after 2 and 3 yr. Ten (9%) teeth were sealed and one filled during the study period. Examination of record data in the control group over a 3-yr period revealed that 76 (65%) first molars were sealed and 7 (6%) were filled. During the first year 1/3 of the children in the study group needed 5-6 recall visits, whereas in the following period all children were only seen 1-4 times. In contrast, 50% of the children in the control group needed 5-6 recalls in the 3rd yr. Our data indicate that professional care for erupting teeth on an individual basis has a long-term effect on occlusal surfaces as well. The alternative technique required less clinical time than the traditional application of sealants.

Evaluation of a pit- and fissure-sealing program in a public dental health service after 2 years.

The aim of the present study was to test the caries-preventive effect of a bis-GMA type fissure sealant (Concise Enamel Bond System) in a public dental health service for children. The study compared one group of children, in which all sound permanent teeth were sealed, and a control group in which no sealants were placed. During the study period all children received systematic restorative care, while sealing was performed on the basis of diagnoses made at subsequent examinations by one of the authors. After 2 years a total of 187 children were available for re-examination. Sealant retention was comparable to that obtained in previous studies, but no statistically significant reduction in overall caries increment could be demonstrated. Further analysis showed that only 223 sites had been sealed, while the majority of all erupting sites (394) were either carious or filled before they were screened for the purpose of sealing. It is therefore assumed that only teeth less susceptible to occlusal decay were sealed, thereby explaining the lack of benefit derived from the sealing program.

Restorative caries treatment patterns in Danish 20-year-old males in 1986 and 1991.

This study examines the restorative caries treatment pattern in Danish 20-year-old military conscripts in 1986 and 1991. The study groups comprised 85 and 164 males born in 1966 and 1971, respectively. The examination was performed as a part of the routine for each conscript according to directions from Dental Service, Danish Defense Forces and included surface recording of fillings on all teeth except third molars. Two bitewing radiographs were taken of all conscripts in the 1986-group and of those who gave permission (59) in the 1991-group. The mean number of filled surfaces was 10.2 and 8.8 in 1986 and in 1991, respectively. 80% of the occlusal surfaces on permanent first molars were filled in the 1986-group and filled or sealed in the 1991-group in contrast to 45% of permanent second molars. Data from maxillary molars indicated a tendency to placement of fillings related to tooth specific morphology whereas extended fillings involving the entire occlusal surface dominated on mandibular molars. The X-ray examination disclosed that the majority of approximal molar surfaces were classified as sound in both study groups. Less than 1% of the approximal molar surfaces were recorded as having lesions penetrating deep into the dentin. In 1981 and in 1986 the participants in the study groups were 15 yr old. In these years the mean number of filled surfaces in Danish children amounted to 11.0 and 6.9 respectively, which indicates that very few lesions in need of operative treatment developed from age 15 to age 20 in both study groups.

Results after 1 year of non-operative occlusal caries treatment of erupting permanent first molars.

The aim of this study was to evaluate a treatment program designed to control occlusal caries on the basis of intensive patient education and professional toothcleaning. The sample consisted of 56 6-8-yr-old children with their permanent right first molars in different stages of eruption. Data from the program were compared with previous data recorded in a similar sample of children. After 1 yr the majority of children in the study group had their permanent right first molars in full occlusion. A significant decrease of surfaces with easily detectable plaque and an increase of surfaces without plaque was observed. The proportion of arrested lesions increased and active enamel lesions decreased. Fissure sealing was only needed in two teeth in contrast to more than 2/3 of molars in a comparable sample of children. The program proved to be an efficient alternative to fissure sealing in preventing occlusal caries in erupting teeth.

Fluoride in mixed human saliva after different topical fluoride treatments and possible relation to caries inhibition.

Fluoride concentrations in mixed saliva were measured at different intervals following topical treatments with various fluoride preparations and procedures such as dentifrice, tablets, mouthrinse and topical solution. The results were related to available caries reduction data from corresponding clinical trials previously published. Salivary fluoride levels varied widely reflecting the different dosages applied, whereas the caries reduction data irrespective of type of treatment appear very similar, with a magnitude of about 30%. When combining salivary fluoride data with recent understanding of enamel-fluoride kinetics it was possible to explain the clinical caries reductions.

Dental health status and attitudes to dental care in families participating in a Danish fluoride tablet program.

The caries experience and dental fluorosis of 84 Danish children, who had used fluoride tablets for 1-4 yr in the period 1976-80, were compared with those of a group matching in sex, age, place of living, and socioeconomic status. The average age of the children at the time of examination was 5.8 yr. A recording of mothers' attitudes to dental care, knowledge about tooth brushing, attitudes to candy, and number of teeth in the maxilla showed no difference between the fluoride tablet group and the non-users' group. Moreover, there was no significant difference between the two groups with respect to dental caries. The findings are discussed in relation to recent reports on the decline of dental caries resulting from widespread use of local administration of fluorides.

Three-year caries increments after fluoride rinses or topical applications with a fluoride varnish.

251 9-12-yr-old children completed a 3-yr, double-blind, clinical trial of two caries preventive fluoride programs. Caries increments and progression patterns were compared in two groups of children who rinsed every fortnight with a 0.2% NaF solution or received biannual topical applications with a fluoride varnish (Fluor-Protector). Clinically recorded mean DFS increments were 3.3 +/- 0.2 (SE) in the rinse group and 3.5 +/- 0.2 in the varnish group. In both groups nearly half of these increments were recorded in the occlusal surfaces of second molars. The mean incremental DFS recorded radiographically on approximal surfaces of posterior teeth were 1.1 +/- 0.2 and 1.5 +/- 0.2 in the rinse and varnish group, respectively. None of the inter-group differences were statistically significant (P greater than 0.05). Detailed analyses of the radiographic scores revealed a similar and extremely slow caries progression in the two study groups and they strengthened the conclusion of equal clinical efficacy of the two treatments. None of the fluoride programs had been able to change preestablished patterns of caries development among the children.