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The objective of this study was to assess the level of root caries in a population of diabetic adults. Diabetics are of special interest because they are alleged to be periodontally compromised and have atypical patterns of refined carbohydrate ingestion. Diabetic subjects were patients of the Joslin Diabetic Center in Boston and had significantly elevated blood glucose and glycosylated hemoglobin levels over at least a ten-year period. Eligible subjects had to be between the ages of 45 and 65 and have a minimum of ten teeth and three sites with recession. Data were collected on coronal caries, oral hygiene, gingivitis, pocket depth, recession, and root caries and were compared with data from control subjects from a larger nondiabetic study group. There were 88 diabetics and 185 controls with mean ages of 55.7 and 56.3 years, respectively. The groups were found to be similar with respect to the numbers of buccal surface sites with gingival recession and the numbers of carious root lesions. There was a distinct difference, however, with respect to restored root surfaces: 1.76 mean filled surfaces were observed in the controls, as compared with 0.49 in the diabetics. A Katz Root Caries Index (for which lesions are calculated as a percentage of the numbers of exposed root surfaces) was determined to be 15.2 for the controls and 7.1 for the diabetics. A reasonable inference is that these differences are the result of a restricted ingestion of refined carbohydrates by the diabetic group. This was confirmed by a dietary survey of subsamples from the diabetic and nondiabetic groups.

Dental plaque was obtained from one or two sound root surfaces of subjects with different degrees of root-surface caries experience. From subjects with root-surface caries, plaque samples were also obtained from either one incipient or one more advanced lesion. Proportions of the total flora were determined for total streptococci and different streptococcal species, total and different Actinomyces species, and lactobacilli. A sample of saliva was obtained from about one-third of the subjects for determination of the concentrations of mutans streptococci and lactobacilli. The main observations were: (1) Subjects without root-surface caries or restorations (group I), as compared with subjects with root-surface caries with or without restorations (group II), were characterized by having a lower prevalence and proportion of mutans streptococci and a higher prevalence and proportion of A. naeslundii in plaque on sound root surfaces; (2) subjects in group I also tended to have a lower salivary concentration of mutans streptococci and lactobacilli than subjects in group II; (3) dental plaque on sound surfaces in group II subjects contained a lower proportion of mutans streptococci than plaque associated with incipient or advanced lesions; and (4) the prevalence and proportion of lactobacilli in plaque associated with sound as well as carious root surfaces were very low. The data reinforce findings from other studies and indicate that, as for coronal caries, the plaque and saliva populations of mutans streptococci specifically are correlated positively with the presence of root-surface caries.

While there is broad consensus in the research community that fluoride dentifrices provide important anticaries benefits, debate still remains as to the most efficient form of fluoride used in toothpastes. Recently, the authors of this paper collaborated as part of a scientific advisory group whose objective was to comprehensively review all clinical information available comparing the anticaries efficacy of the two agents most widely used in fluoridated toothpastes, sodium fluoride (NaF) and sodium monofluorophosphate (SMFP). This review included a detailed analysis of each published study pertinent to the question, a comprehensive meta-analysis of all available clinical findings, and an epidemiological assessment of how anticaries benefits of dentifrices may be anticipated to propagate with time. Overall, the use of meta-analysis of head-to-head clinical comparisons between the two fluoride-active systems was found to be the most valid means for comparing the relative efficacy of NaF and SMFP dentifrices. Results of this analysis demonstrated that NaF was significantly more effective than SMFP in preventing caries (p0.01). While the numerical difference in efficacy between NaF and SMFP measured between 5 and 10% (total DMFS) over a 2- to 3-year clinical period, this could be expected, on theoretical grounds, to propagate to substantially larger differences (e.g. 10-20%) over 10-20 years. Hence, the difference in efficacy between these two actives was judged to be clinically important as well as statistically significant. Based upon these findings the authors recommend that NaF be used as the active system in fluoridated dentifrices whenever practically feasible. However, the authors caution that this recommendation pertains to the formulation of NaF in highly compatible abrasive systems, which must be demonstrated by critical evaluation of ionic fluoride within formulations for stability, availability and bioavailability. One additional recommendation emanating from this review is that important improvements must be made in the design, execution and reporting of future caries clinical trials in order to bring these important methods up to scientifically acceptable standards.

The purpose of this study was to investigate in vivo enamel fluoride uptake of a slow-release boron trifluoride BIS-GMA resin material. Study subjects were orthodontic patients with at least one pair of permanent bicuspid teeth indicated for extraction. The material was applied to the buccal surface of the test tooth 1 month prior to extraction; the contralateral tooth served as the control tooth. Following extraction, the resin was removed by soaking in acetone for 36 h and polishing with a sodium bicarbonate slurry. Prior scanning electron microscopic studies have shown that this cleaning procedure effectively removes all residual resin. Enamel fluoride analyses were completed for 12 pairs of teeth from 9 subjects. The mean differences in enamel fluoride concentrations between the treated and control teeth were significantly different from zero at the 0.01 level. At each successive depth, the absolute mean amount of fluoride uptake by the test teeth was fairly constant; however, the proportional mean amount or percent increase in fluoride concentration resulting from treatment became greater in the deeper enamel layers. The data suggest that this material has the potential to provide an effective means of introducing substantial amounts of permanently bound fluoride into surface enamel, even into the deeper layers.

Fourteen hundred and forty-seven 12–16-yr-old subjects in selected fluoridated and non-fluoridated areas were assessed for caries experience (DMFS index) and enamel fluoride (biopsy technique). Fluoride was measured as log e mass F corrected to a standardized depth. A square root transformation of decayed, missing and filled surfaces (DMFS) was carried out in order to achieve homogeneity of variance for this variable across all levels of fluoride. A simple, linear relationship was found between log e mass F and √(DMFS). Taking age into account, the Pearsonian correlation was R = 0.40, corresponding to 16 per cent of the variance explained. Within communities the fluoride-caries relationship was consistent with the overall model but could not be demonstrated as securely because of the smaller sample sizes and the limited range of fluoride values at this level of disaggregation.

Changes in oral Streptococcus mutans populations were recorded in conjunction with a one-year clinical trial of the anticaries activity of topically applied vancomycin. At the outset, 268 children aged 9–11 years were randomly assigned to the experimental or control group. Subjects in the experimental group were treated with a 3 per cent vancomycin gel applied in pretrimmed plastic trays for 5 min on school days. Plaque samples were taken every 4–6 weeks over a 12-month period from one sound occlusal surface, two sound approximal surfaces and one sound smooth surface. The surfaces assayed were the same at each sampling. Strep. mutans populations were determined in these samples using a selective medium. Significant reductions in numbers were observed consistently in occlusal surfaces. Sporadic and less pronounced effects were detectable on approximal and smooth surfaces. The treatment effects disappeared when treatment was suspended during the summer and re-appeared when treatment was resumed after the vacation.

As part of a collaborative multidisciplinary investigation of root surface caries (RSC), 273 subjects (median age = 57) were clinically evaluated for coronal caries, debris, calculus, gingivitis, periodontal pocketing, recession, abrasion, as well as RSC. The entire study group was divided into three subgroups: (1) subjects whose exposed root surface were without lesions or restorations (non-diseased individuals, n = 43); (2) subjects whose exposed root surfaces had one or more lesions and may or may not have had restorations (diseased individuals, n = 110); (3) subjects with one or more restorations but no lesions, since it was not known whether these restorations were preceded by RSC or abrasion the disease status of these individuals was unclear (n = 120). A comparison of Subgroup 1 (unequivocally non-diseased) and Subgroup 2 (unequivocally diseased) revealed that subjects without RSC had more teeth, less coronal caries, less recession, less debris, less calculus, less gingivitis, and more abrasion. We infer that the common factor underlying most if not all of the subgroup differences is oral hygiene which must therefore be a major disease determinant.

The purpose of this study was to assess the reliability of the iodide permeability test when applied to the human dentition. Twenty-two subjects were seen once a week for three weeks. At each visit, consecutive iodide permeability measurements were obtained: four from the right central incisor and four from the left. Results of these trials were examined for the degree of variability from one replication to another within the same day, as well as for the variability from one week to the next. Within-day and between-week reliability of the test results was assessed by two indices: the Hoyt Index, which estimates the reliability of the average of the four replicate measurements per tooth, and the Intraclass correlation, which estimates the reliability of a single measurement. The results indicate that the iodide permeability test produces sufficiently replicable measurements for use in future clinical studies.

A double-blind clinical trial was conducted in a non-fluoridated community to determine the effect on enamel fluoride and caries experience of daily rinsing in school with 1,000 parts/10(6) solutions of ammonium fluoride or sodium fluoride at pH 4.4. Subjects were 10- to 12-year-old children (n approximately equal to 200/group at baseline), about one-half of whom reported the usage of fluoride supplements. Dental caries (DFS index) and enamel fluoride (in vivo biopsy) were evaluated at baseline, 12 months, and 24 months. Supplement users had higher enamel fluoride levels and less caries experience initially, as well as generally lower caries increments over the study. In year 1, the overall caries reductions (supplement users and non-users combined) were 23 % (ammonium fluoride) and 33 % (sodium fluoride), P less than 0.01. For year 2, treatment effects were significantly greater: 54 % (ammonium fluoride) and 47 % (sodium fluoride). In newly erupted teeth, the effects of the ammonium fluoride (70 % DFS reduction) was significantly greater (P = 0.013) than that of the sodium fluoride (48 % DFS reduction). Enamel fluoride levels at the end of 2 years were 3,124 parts/10(6) (ammonium fluoride), 2,771 parts/10(6) (sodium fluoride), and 2,603 parts/10(6) (placebo), P = 0.025.

A clinical trial was conducted in a non-fluoridated water, high-caries community in which school children (average age = 13.04yr) were randomly assigned to one of four groups subjected to two different fluoride procedures. Clinical and radiographic examinations were conducted at baseline, 12, 24 and 36 months. After 12 months, there was a small but significant rinse effect and a small gel effect which fell short of significance. The effects were additive, and subjects who received both forms of fluoride treatment experienced a 19 per cent reduction in decayed + filled (DF) surface increment. The pattern of incremental findings at the end of 24 months was similar to that at 12 months. Both gel and rinse effects were significant and of similar size; subjects receiving both treatments experienced a 31 per cent reduction in DF surface increment. The incremental findings after 24–36 months 2 yr and 1 yr were similar. The effects were reduced relative to those seen at 24 months; the gel effect was still statistically significant, but the rinse effect was not. Possible mechanisms underlying the treatment effects include deposition of CaF 2 and fluorapatite, and suppression of microbial flora.

The purpose of this study was to assess the effect upon the quantification of root surface caries (RSC) of (1) the separation of the disease into its discrete clinical phases, (2) the confounding caused by the presence of restored abraded surfaces, and (3) the decision rule formulated for dealing with lesions and restorations which involve both crown and root. It was found that the apparent prevalence of RSC varied widely depending upon arbitrary decisions as to what stages of the disease were included in the measurement scheme. The addition of restorations (confined to the root) greatly enlarged the various disease measures, but probably also introduced some degree of error since there are several indications from the data and the clinical patterns of affected surfaces which suggest that some of the restored surfaces were formerly abraded rather than carious. The inclusion of lesions and restorations involving both root and crown produced another conspicuous increment in all disease measures, which is a cause for concern given that these components are included in some studies and ignored in others. These findings serve as the basis for several recommendations for future prevalence and incidence studies of RSC.

A one-year pilot study was conducted to determine whether a single annual application of 0.05 M H3PO4, followed by 1.2 per cent acidulated phosphate-fluoride, pH 3.2, would result in decreased caries experience when compared to the use of the same fluoride agent without prior etching. A significant difference in caries experience was observed in favour of subjects exposed to the mild etching procedure. The clinical findings were paralleled by biopsy results showing significantly higher enamel fluoride in children receiving the phosphoric acid pre-treatment.

A model relating caries to surface enamel fluoride and plaque has been derived by exploratory data analyses. Since the model was obtained a posteriori, it is best viewed in qualitative terms as a hypothesis for future testing. The model prompts a re-evaluation of expectations relative to the effects of surface enamel apatitic fluoride, and a consideration that the effectiveness of a given measure of fluoride may vary as a function of inherent challenge. Thus, further studies are needed, aimed at quantifying the parameters of resistance and challenge, and characterizing the relationship between them.

A one-year clinical trial was conducted in which, at the outset, 268 children aged 9–11 years were randomly assigned to the treatment or control group. At baseline a clinical and radiographic assessment of dental caries was performed. Thereafter, every morning in school, treated subjects self-applied, for 5 minutes, pre-trimmed plastic trays containing a sponge rubber insert and filled with a 3 per cent vancomycin gel. Participants were monitored every 4–6 weeks for their level of Streptococcus mutans on specific surfaces. After 12 months, the overall caries increment in treated subjects averaged one less DF surface than in the controls (4.42 DFS vs. 3.43 DFS, p = 0.032). The reductions in caries were significant in fissures but not on the smooth or approximal surfaces; also in newly erupting teeth but not in teeth present at baseline.

A technique is described for the estimation of fluoride (F) in enamel samples of varying weight. The data are used to derive a generalized relationship of F to sample weight that permits the adjustment of any observed F value to the "expected" value at a standaidized weight.

Three groups of children (age 8–11 yr), rinsed daily in school for 3 yr with 5 ml of either (1) acidulated phosphate fluoride (APF, 0.02 per cent F, 0.1 M phosphate, pH 4.0); (2) neutral NaF (0.02 per cent F) or (3) a neutral placebo. The solutions were kept in the mouth for 1 min and then swallowed. At the end of the study, reductions in DFS of 30 and 27 per cent were observed in the APF and the neutral NaF groups, respectively. The caries reduction in the teeth initially erupted was 25 per cent in both groups. Analyses of enamel biopsies from teeth initially erupted indicated small posteruptive F uptakes in both treatment groups. The APF solution was superior to the neutral NaF in depositing fluoride in intact enamel. The fluoride acquisition of teeth erupting during the study was substantially greater than that of teeth initially erupted.