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Objectives: To develop a new model to establish teenagers’ perceptions of the aesthetic impact of fluorosis, in the context of overall facial appearance. This web-based model was used to compare different degrees of fluorosis at any one distance, while also comparing the same level of fluorosis at different ‘distances’. Methods: A 14-year-old subject was used as the model face. Different degrees of fluorosis were ‘built-up’ on this subject's teeth using digital simulation. A web-based questionnaire showed 30 photographs, displaying four levels of fluorosis, in addition to fluorosis-free, at five different ‘distances’. The closest images were shown with and without retractors, while the more distant pictures showed more of the subject's face. Teenage pupils (n = 217) were then asked to grade the acceptability of the appearances and indicate if they would wish treatment for each such appearance. Results: At any one distance, acceptability fell as fluorosis level increased. When the same degree of fluorosis was compared at different distances, acceptability improved as the teeth were viewed from further away. Pictures taken without retractors had higher acceptability than those taken with retractors in place. Conclusions: Teenagers can discriminate between various degrees of fluorosis. However, more distant viewing of fluorosed teeth, within the overall context of the face, improves acceptability of the appearance.

Aim To investigate current knowledge, examination habits and preventive practices of primary healthcare professionals in Scotland, with respect to oral cancer, and to determine any relevant training needs. Setting Primary care. Method Questionnaires were sent to a random sample of 357 general medical practitioners (GMPs) and 331 dental practitioners throughout Scotland. Additionally, focus group research and interviews were conducted amongst primary healthcare team members. Results Whilst 58% of dental respondents reported examining regularly for signs of oral cancer, GMPs examined patients' mouths usually in response to a complaint of soreness. The majority of GMPs (85%) and dentists (63%) indicated that they felt less than confident in detecting oral cancer, with over 70% of GMPs identifying lack of training as an important barrier. Many practitioners were unclear concerning the relative importance of the presence of potentially malignant lesions in the oral cavity. A high proportion of the GMPs indicated that they should have a major role to play in oral cancer detection (66%) but many felt strongly that this should be primarily the remit of the dental team. Conclusion The study revealed a need for continuing education programmes for primary care practitioners in oral cancer-related activities. This should aim to improve diagnostic skills and seek to increase practitioners' participation in preventive activities.

Background and Objective: Tooth loss has been associated with cardiovascular disease (CVD), but the mechanisms are unclear. We evaluated the association of total tooth loss with prevalent CVD in men and women; as well as with citrus fruit consumption, plasma vitamin C, and inflammatory and thrombotic variables. Methods: We used an age-and sex-stratified population survey, of men and women aged 25–74 years, in North Glasgow. Results: Thirty-eight percent of women and 29% of men were edentulous. Total tooth loss was associated with prevalent CVD in both sexes. After adjustment for major potential confounders (age, sex, smoking, and social class), the odds ratio (95% CI) for prevalent CVD was 1.55 (1.13, 2.13) in the edentulous. Total tooth loss was also associated with low citrus fruit consumption and low plasma vitamin C levels, increased plasma C-reactive protein in men, and with increased plasma interleukin-6, fibrinogen, and factor VIII levels in women. Conclusion: Prevalent CVD is associated with total tooth loss. Possible mechanisms include low intake of citrus fruit, and hence, low plasma vitamin C levels, and a predisposition to low-grade inflammation and thrombosis. It may be prudent to ensure adequate vitamin C intake in people with no teeth.

OBJECTIVES: To undertake a blind caries and fluorosis prevalence study of Grade 1 (aged 5/6 yr) and Grade 4-7 (aged 8-12 yr) children from naturally water-fluoridated (1 ppm, since 1985) Burghead, Findhorn and Kinloss (F), and nearby nonfluoridated Buckie and Portessie (N-F), in rural Morayshire, Scotland. METHODS: A blind clinical (+ 10% repeats) caries study of the above townships' 5/6-yr-old lifetime (15 F; 43 N-F), and 8-12-yr-old lifetime (55 F; 136 N-F)/school-lifetime (31 F; 37 N-F) residents was undertaken following bussing of these children to a common examination site in close-by Elgin Town Hall. Initially, each child was asked about their own perception of the aesthetics of their maxillary front teeth. Fluorosis was assessed clinically using the TF Index, as well as photographically - for later blind scoring (+ 10% repeats for lifetime 8-12-yr-olds) of slides by four dental and two lay 'jurors', alongside a now-established UK 'bench-mark' mildly mottled (TFI = 2), fluorosis comparator slide, judged in previous studies to be aesthetically lay-acceptable. In addition, by parental questionnaire, information was sought concerning their child's fluoride supplement and dentifrice usage histories. RESULTS: For 5/6-yr-olds, mean primary caries scores were 96.0% less in fluoridated than nonfluoridated subjects (P lt 0.01). In 8-12-yr-olds, DMFT values favoured water-fluoridated subjects; their caries-free trend was significant (P lt 0.001 overall). Clinically, 33% of all lifetime F subjects and 18% of all N-F pupils had fluorosed maxillary anterior teeth (P = 0.045), but no statistically significant difference was found between the 7% F and 3% N-F subjects with TFI scores gt 2 (P = 0.25). Photographically, 'jury' mottling assessment (+ 10% repeats) of projected slides resulted in at least 1 : 6 positive scores in 43.6% of F and 30.9% of N-F pupils, albeit they unanimously scored only nine F and five N-F children as having fluorosed teeth (P lt 0.01). In no case did all members score TFI gt 2. Dental and lay scorers rated TFI = (1/2) in only a further 9.1% and 5.5% of F subjects, respectively, compared to 0.7% and 1.5% respectively of N-F pupils. Again, TFI gt 2 was scored unanimously in no child. No differences were found regarding the children's own degree of anterior tooth aesthetic nonacceptability between F (11%) and N-F (12%) prevalence (P = 0.75). Finally, only one F child had taken F supplements and, while 26 N-F had used F drops, no significant relationship was found between their usage and TFI values in the latter group (P = 0.49). Additionally, no relationship was noted between clinical TFI scores and the age at which parents stated fluoridated dentifrice toothbrushing commenced, between 0 and 24 + months of age. CONCLUSIONS: Considerable caries benefit has accrued to those Morayshire rural children who have received naturally fluoridated water (at 1 ppm) throughout their lives, as compared to their socioeconomically similar, nonfluoridated rural counterparts. Furthermore, in spite of all but two subjects claiming to have brushed regularly with fluoridated dentifrice (and no evidence of the availability of nonfluoridated toothpaste being purchasable in the five townships), only borderline mild fluorosis disadvantages have been noted clinically, and none by the subjects' own aesthetic perceptions. Finally, no evidence was found to suggest any delay in permanent tooth eruption patterns of the F subjects. It would seem appropriate therefore, that adjustment of Scots' drinking waters' natural fluoride levels to 1 ppm should be pursued to extend similar dental advantages to the vast majority of that population (both young and old) which, it is well documented, has the worst dental health of mainland UK.

Objectives: To evaluate a modified tooth stain index and determine the effect of dietary factors on stain formation. Methods: At baseline, 182 adult volunteers were given a full oral prophylaxis followed by stain assessment using a modification of the Lobene index. This involved assigning separate scores to the mesial (M) and distal (D) sites of each tooth, in addition to the standard gingival area (G) and tooth body (B). For each site, stain intensity and areas were scored. The sum of (intensity×area) scores was calculated for all sites (GBMD-value) and for the gingival and body sites only (GB-value). The subjects used a standard abrasive dentifrice and a soft toothbrush for 6 weeks. Results: Stain was reassessed and the average increase in GBMD-value was 20.9 (sd=9.9) (buccal aspect) and 29.9 (sd=18.0) (lingual aspect). The corresponding GB-values were 4.4 (sd=4.8) and 12.5 (sd=10.2). The coefficients of variation of the GBMD index values were consistently lower than those of the GB values. Smoking and tea-drinking were found to be the only significant (p

To examine the effect of reported toothbrushing frequency and method of rinsing after brushing on caries experience and increment.Data are presented from 2621 adolescents (mean age 12.5 years at outset) participating in a 3-year double-blind caries clinical trial. At baseline, examiners questioned each participant about their toothbrushing habits, and at subsequent examinations, this information was obtained using a self-administered computer-based questionnaire. Participants used a fluoride-containing dentifrice throughout and clinical examinations were conducted using a mirror, CPITN probe and fibre-optic transillumination.The reported brushing frequency increased throughout the trial. Caries experience at baseline was inversely related to toothbrushing frequency with mean DMFS=9.66, 8.12 and 7.63 respectively for1/day, 1/day and1/day brushers (P0.001). Mean 3-year DMFS increments of 8.90, 6.63 and 5.48 (P0.01) were observed in those reporting to brush1/day, 1/day or1/day, on not less than two of the three clinical examinations during the trial. Caries increment was also significantly related to the claimed method used to rinse post-brushing. Overall frequency of brushing and rinsing method accounted for over 50% of the explained variance in the ANOVA model used to analyse the DMFS increments.Stated toothbrushing frequency and rinsing method after brushing were found to be strongly correlated with caries experience and caries increment. These factors should be reflected in the design of oral health education material and taken into account in the design and analysis of caries clinical trials.

This study reports on the caries susceptibility of tooth surfaces in 4294 adolescents (mean age 12.5 yr) during a 3-yr, double-blind clinical caries trial, conducted in Lanarkshire, Scotland, between 1988 and 1992. Children were selected on the grounds of dental maturity and past caries experience. Clinical examinations with mirror, CPITN probe and fibre optic trans-illumination were carried out on the permanent dentition, with the buccal pits of mandibular molars and palatal pits of maxillary molars being recorded as separate sites. At baseline 6061 surfaces were decayed (1.0% of 601 160 surfaces examined), 20 160 (3.4%) filled, and 10 909 (1.8%) missing due to caries. The number of surfaces recorded as sound at baseline in subjects completing the study was 454 663. Of these 8176 (1.8%) new surfaces were decayed, 14 832 (3.3%) filled and 4000 (0.9%) missing at the final examination. Molar occlusal surfaces showed greatest susceptibility to attack, 35.8% of those at risk becoming carious in the course of the study. All buccal and lingual smooth surfaces showed a low susceptibility, but 8.8% of buccal and palatal pits developed caries. At the final clinical - only examination, pit and fissure caries accounted for 48%, inter proximal surfaces for 39%, and smooth surfaces for 13% of caries prevalence. However, overall the contribution of these surfaces to 3-yr increments was, 40%, 47%, and 13%, respectively.

The presence of fissure sealants was recorded in 4294 adolescents during a 3-year, double-blind clinical caries trial, conducted in Lanarkshire, Scotland, between 1988 and 1992. Of 68,704 occlusal surfaces examined at baseline, sealants were detected on 7011 (10.2%) surfaces, in 1596 subjects. Of these, 17.4% were judged as incompletely sealed. At the final examination 24.3% of sealants originally recorded as complete were missing, with partial loss observed on a further 18.2% of surfaces. At that time, 21.4% of surfaces 'unsealed but sound' at baseline were recorded as decayed, filled or extracted due to caries, compared with 14.4% of surfaces on which an intact sealant had been recorded (P < 0.001). In contrast, of those surfaces on which the sealant was noted as deficient at the outset, 22.9% were judged to have been affected by caries. This study shows that sealants should be repaired when deficient if they are to be effective.

Whilst the limited usefulness of caries activity tests based solely on counts of mutans streptococci is becoming increasingly apparent, to date, little attention has been paid to potential differences in the virulence of strains isolated from patients with varying disease experience. Recently an in vitro test was described involving the dissolution of bovine enamel, as a means of determining the cariogenic potential of S. mutans strains. The current study aimed to investigate this test further and to compare the dissolution of bovine enamel and different hydroxyapatite preparations as a possible means of differentiating strains of S. mutans with regard to cariogenicity. In the presence of a 5 per cent sucrose solution, six strains were incubated with either bovine enamel, solid hydroxyapatite, or powdered hydroxyapatite for 5, 24 or 48 h, following which acid anion production, calcium release and change in pH were measured. The results showed that incubation with the powdered hydroxyapatite for 5 h resulted in significant differences between strains which correlated with clinical disease experience. It is suggested that this improved assay could be used to investigate further the clinical significance of the relationship between in vitro cariogenic potential and caries experience. Keywords - S. mutans , Hydroxyapatite, Dental caries, Caries risk.

Strains of Streptococcus mutans isolated from the plaque of 6 subjects were studied using an in vitro model to determine whether differences in their cariogenic potential could be detected, and if so, whether the results correlated with the caries experience of the individuals. Each strain was incubated with a bovine enamel slab and 5% (w/v) sucrose for 24-h periods. The acidogenic potential was assessed by pH measurement and analysis of acid anion production. Microradio-graphic and microdensitometric assessment of the enamel, together with measurement of the change in calcium concentration of the reaction mixture were used to determine the demineralizing potential of each strain. Significant differences in cariogenic potential were found between some of the strains tested, and correlations were found between 3 of the test parameters and the decayed-missing-filled-surface score of the individuals. The results suggest that the caries experience of individuals may be related, to some extent, to the cariogenic potential of their S. mutans strains.

A 6-yr double-blind study was undertaken to compare the caries inhibiting-effectiveness of (a) 1 mgF− tablets (daily at school) plus fortnightly rinsing at school with 1000 ppmF−; (b) 1 mgF− tablets plus placebo rinsing; and (c) placebo tablets plus 1000 ppmF− rinsing. Participants were aged 4.5–5 yr at outset of the trial. At baseline, and annually thereafter, clinical caries and bitewing X-ray examinations were undertaken, hence ethical approval for a negative control was not feasible. Fissure sealant presence was also recorded. Initially, 192 children from predominantly low socio-economic backgrounds were enrolled, and baseline analyses showed no significant differences between groups with respect to primary caries prevalence. After 6 yr, 112 children remained, by which time no significant differences were noted between DMFT and DMFS values for those in the active tablet/active rinse group, as compared to those in the placebo tablet/active rinse group. However, in relation to both indices, in permanent first molars, the effectiveness of the active tablet/placebo rinse regime appeared to be significantly poorer than the placebo tablet/active rinse programme. For the active tablet/active rinse group, the DMFT difference was significantly less than the active tablet/placebo rinse group (37.9%), although for the DMFS difference, significance was not achieved. Similar trends were noted when DMFT and DMFS values for all permanent teeth were considered. The occlusal caries prevalence in permanent first molars followed the DMFT pattern, but differences between combined tablet/rinsing children and tablet-only children could be ascribed solely to the effectiveness of sealant presence. As F− rinsing was supervised, the most likely explanation of these results is that children involved with active F− tablet ingestion were cither not receiving them, or these formulations were being used in such a manner that no extra benefit was obtained. Further cost-effectiveness studies would therefore seem necessary to determine whether ancillary employment would be justified in terms of increased caries benefit.

Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species were investigated on three occasions at annual intervals in a group of 372 Scottish adolescents. Counts of the micro-organisms studied were logarithmically distributed, with Candida spp. being isolated from approximately half the subjects. Counts of lactobacilli, mutans streptococci, and candida were significantly intercorrelated, while veillonella were associated consistently with mutans streptococci alone. Levels of each of the four micro-organisms were significantly correlated over the three examinations, with levels of the Candida spp. being the most stable over the period studied.

An in vitro pH-cycling experiment was carried out to investigate the effect of fluoride concentration on enamel demineralization and remineralization. Artificial caries lesions were formed in an acid-buffered solution and subjected daily to a 3-hour acid attack, a 5-min immersion in the test NaF solution (0, 1, 250, 500, 1,000, 1,750 and 2,500 ppm F), and to 21 h in an artificial saliva. Changes in mineral content were assessed weekly for 5 weeks using microradiography/microdensitometry. The lesions in the control group (0 ppm F) and the 1-ppm F group demineralized. Remineralization was significantly higher in the 500-ppm F group compared to the 250-ppm F group. However, higher fluoride concentrations did not produce any further significant increase in remineralization. Laminations were apparent in lesions subjected to the 250- and 500-ppm F solutions.

To assess levels of fluorosis and fluorosis of esthetic concern in children from a naturally fluoridated and a non-fluoridated area of Sweden, and to determine the relative contributions of fluoridated water, parental educational level, and infant oral health-related behaviors.A parental questionnaire collected information concerning child F-supplement and F-dentifrice usage histories, and socio-economic status. Photographic examination of 1336 subjects (F=791; N-F=545) was undertaken. Fluorosis was assessed (blind to F-exposure) in a random sample (n=250) of 35 mm slides by four dental and two lay "jurors" (with 10% random repeat-viewing for inter-observer and intra-observer agreement). Four outcomes were assessed on each slide: fluorosis at any level, fluorosis of esthetic concern, acceptability of appearance, and treatment needs. Ordinal logistic regression models were used to determine significant determinants.For presence of fluorosis of esthetic concern, majority jury agreements (3 of 6) were seen in only 2.3% (N-F) and 13.4% (F) pupils (p0.001), albeit jurors unanimously scored only 13 F and 2 N-F exposed children as having esthetically unacceptable fluorosed teeth (p0.001). The over-riding significant factor in terms of fluorosis of esthetic concern was exposure to water fluoridation in infancy in both unadjusted and adjusted models.The important factor in relation to fluorosis of esthetic concern was explained by exposure to fluoridated water in infancy, and was not explained by age, sex, level of parental education or early childhood oral health behaviors. However, prevalence of this condition was relatively low. These findings should inform policies on appropriate total fluoride exposure levels during infancy.

Dental fluorosis occurs when excess fluoride is incorporated into the enamel of developing teeth, resulting in a mottled appearance on eruption. The effects can range from mild white striations to more severe pitting and staining. In recent years there has been an increase in the prevalence of dental fluorosis, which is probably linked to an increase in fluoride intake during tooth development. One of the key questions in dental public health concerns the appropriate level of exposure to fluoride at a young age. There is clear evidence that water fluoridation is associated with a decrease in the prevalence of tooth decay, but this health benefit has to be weighed against the potential side effects, one of which is dental fluorosis. Outside areas of naturally high water fluoride levels fluorosis is almost invariably mild, but relatively little is known about the true aesthetic impact of this condition, especially amongst the general public. Previous research on public perception of mild fluorosis is unconvincing due to the use of unrealistic images in the assessments (see Edwards et al. [2005]). We used realistic views of a single model with healthy teeth and then digitally modifying the teeth to simulate the appearance of dental fluorosis. These images were then presented to teenage members of the general public via a web-site interface and their appearance was rated using a questionnaire.

To determine the prevalence and severity of dental fluorosis in children aged 7-9 years from non-water-fluoridated Halmstad, Sweden, and to relate the results to their reported fluoride exposure history during infancy.In Spring 2002, a questionnaire distributed to a cluster random sample of 1039 parents enquired into their child's early oral health behaviors and included a "photographic toothpaste menu". The permanent upper anterior teeth (13-23) were examined clinically (+10% repeats) using a modified Thylstrup-Fejerskov Index.Complete data were available for 53% (n=548) of the sampled children. The prevalence offluorosis at any level was 49% (95% CI: 45-54%), and of fluorosis with esthetic concern (TF scoreor =3) 4% (95% CI: 3-6%). Based on repeat observations, reliability was good (kappa = 0.82). There was no statistically significant increased risk of dental fluorosis prevalence associated with any of the fluoride exposure risk factors examined, including reported usage of (1000 ppm) fluoride toothpaste from time of first deciduous tooth eruption.While there were low levels of dental fluorosis of esthetic concern, half the children had some degree of dental fluorosis. The prevalence of dental fluorosis was not explained by the risk factors, including fluoride toothpaste usage as explored in this study.

To undertake a blind caries and fluorosis prevalence study of Grade 1 (aged 5/6 yr) and Grade 4-7 (aged 8-12 yr) children from naturally water-fluoridated (1 ppm, since 1985) Burghead, FindhornKinloss (F), and nearby nonfluoridated BuckiePortessie (N-F), in rural Morayshire, Scotland.A blind clinical (+ 10% repeats) caries study of the above townships' 5/6-yr-old lifetime (15 F; 43 N-F), and 8-12-yr-old lifetime (55 F; 136 N-F)/school-lifetime (31 F; 37 N-F) residents was undertaken following bussing of these children to a common examination site in close-by Elgin Town Hall. Initially, each child was asked about their own perception of the aesthetics of their maxillary front teeth. Fluorosis was assessed clinically using the TF Index, as well as photographically - for later blind scoring (+ 10% repeats for lifetime 8-12-yr-olds) of slides by four dental and two lay 'jurors', alongside a now-established UK 'bench-mark' mildly mottled (TFI = 2), fluorosis comparator slide, judged in previous studies to be aesthetically lay-acceptable. In addition, by parental questionnaire, information was sought concerning their child's fluoride supplement and dentifrice usage histories.For 5/6-yr-olds, mean primary caries scores were 96.0% less in fluoridated than nonfluoridated subjects (P0.01). In 8-12-yr-olds, DMFT values favoured water-fluoridated subjects; their caries-free trend was significant (P0.001 overall). Clinically, 33% of all lifetime F subjects and 18% of all N-F pupils had fluorosed maxillary anterior teeth (P = 0.045), but no statistically significant difference was found between the 7% F and 3% N-F subjects with TFI scores2 (P = 0.25). Photographically, 'jury' mottling assessment (+ 10% repeats) of projected slides resulted in at least 1 : 6 positive scores in 43.6% of F and 30.9% of N-F pupils, albeit they unanimously scored only nine F and five N-F children as having fluorosed teeth (P0.01). In no case did all members score TFI2. Dental and lay scorers rated TFI = (1/2) in only a further 9.1% and 5.5% of F subjects, respectively, compared to 0.7% and 1.5% respectively of N-F pupils. Again, TFI2 was scored unanimously in no child. No differences were found regarding the children's own degree of anterior tooth aesthetic nonacceptability between F (11%) and N-F (12%) prevalence (P = 0.75). Finally, only one F child had taken F supplements and, while 26 N-F had used F drops, no significant relationship was found between their usage and TFI values in the latter group (P = 0.49). Additionally, no relationship was noted between clinical TFI scores and the age at which parents stated fluoridated dentifrice toothbrushing commenced, between 0 and 24 + months of age.Considerable caries benefit has accrued to those Morayshire rural children who have received naturally fluoridated water (at 1 ppm) throughout their lives, as compared to their socioeconomically similar, nonfluoridated rural counterparts. Furthermore, in spite of all but two subjects claiming to have brushed regularly with fluoridated dentifrice (and no evidence of the availability of nonfluoridated toothpaste being purchasable in the five townships), only borderline mild fluorosis disadvantages have been noted clinically, and none by the subjects' own aesthetic perceptions. Finally, no evidence was found to suggest any delay in permanent tooth eruption patterns of the F subjects. It would seem appropriate therefore, that adjustment of Scots' drinking waters' natural fluoride levels to 1 ppm should be pursued to extend similar dental advantages to the vast majority of that population (both young and old) which, it is well documented, has the worst dental health of mainland UK.

Salt fluoridation is recognised world-wide as a proven and viable alternative means of consumer choice-related, community-based fluoridation where water fluoridation is either technically or politically impossible. However, as most salt consumed is contained within cooked food products, rather than sprinkled over prepared food at the table, the purpose of this study was to investigate the effects on salivary fluoride concentration of consuming baked food products prepared with 250 and 350 ppm fluoridated salt (as KF). Six food items were baked with (a) normal non-fluoridated salt, (b) 250 mg F/kg salt and (c) 350 mg F/kg salt. Eleven adult volunteers consumed these foodstuffs on separate occasions and salivary samples were collected for fluoride analyses before and at various time points (1-30 min) after eating. For most foodstuffs, small but significant increases in salivary fluoride concentration occurred for at least 5 min after ingestion of the fluoridated salt-containing items. Salivary fluoride concentrations peaked 1 or 2 min after eating, with highest values for the six test foods ranging from 0.16 to 0.25 ppm F, and from 0.18 to 0.44 ppm F for the 250 and 350 mg F/kg salt products, respectively. In all cases, salivary fluoride concentrations had returned to baseline by 20 min. The clinical significance of such small, short-term increases in salivary fluoride is uncertain, but the findings suggest that a more frequent intake of foods with fluoridated salt substituted for normal salt could help sustain slightly elevated salivary fluoride concentrations for more prolonged periods of the day, and might thus potentiate the cariostatic effects of saliva on tooth mineral.

In situ cariogenicity-testing models must show evidence of compliance with valid clinical parameters, and this has been achieved with respect to pyrophosphate-, monofluorophosphate-, and zinc citrate trihydrate-containing dentifrices, where earlier in vitro studies failed to predict clinical efficacy. Parameters for validity testing should include the use of enamel fluoride uptake, plaque and/or saliva fluoride assessments, re-/demineralization assays of appliance-borne enamel slabs or slices, and plaque microbial, biochemical, and pH studies. Model reliability must be capable of withstanding repeat calibration experiments where the dosage, frequency of application, and/or duration of exposure to a new product may be varied. Furthermore, the number of enamel slabs/slices carried per appliance (and the number of artificial caries lesions per enamel insert) requires to be defined. Such studies should be repeated, but whether in the same or different subjects, or with or without cross-over, has to be determined. However, the capability of reproducing a clinically proven dose-response is essential. Models must be sensitive enough to detect changes in any test product F concentration, but only equivalence claims should be permitted. Thus, superiority cannot be established, since accuracy may not be assumed beyond the upward limits of a clinically validated range. Finally, models should not be so exclusive in design as to preclude independent verification of their findings.

Over the past 2 decades, it has been suggested that with the generalized availability of fluoridated dentifrices, and coupled with a possible increased likelihood of fluorosis, the benefits of community-based fluoridation have receded. However, while this may be so for dentally motivated populations, there are convincing data to suggest that the least fortunate amongst us could still benefit from communally delivered fluoride. Furthermore, the deleterious effects of such program withdrawals have been demonstrated and, with respect to fluorosis fears, client assessment of their own fluorosis status has indicated few concerns. Alternative, centrally delivered means of fluoride dispensing, e.g. via schools, etc., although effective in the short-term, are impractical over longer time-spans. Nonetheless, at the individual level, fluoride supplements and dentifrices, in particular, are successful caries inhibitors. This is especially so if these vehicles are employed in their most effective, proven manners. Finally, fears relating to disfiguring fluorosis should be allayed, but where fluoride abuses result in mild mottling, a simple remineralizing technique obviates the need for traumatic restorative procedures.

As caries prevalence in some countries declines, and panel sizes for discriminating anti-caries clinical trials inevitably increase, the need for participant pre-selection grows to avoid escalating cost and manpower problems. Hence, retrospective analyses of data were undertaken, from a 3-yr double-blind caries clinical trial where a linear fluoride dose-response had been obtained. As a result, it was demonstrated that the eruption status of permanent second molars, in 3005 participants aged 11-12 yr at outset, when coupled with their baseline clinical DMFT values, provided a sound basis for panellist size prediction without loss of sensitivity. Thus, had only those subjects with DMFT greater than 4, with at least three of their permanent second molars erupted been selected following clinical baseline examination, the same sensitivity would have been achieved with 52% fewer subjects. Furthermore, using these criteria, selection can be made on site, in real time, and a child informed whether its immediate participation in a trial is possible.

– Salt fluoridation is effective at inhibiting caries, but fluorosis prevalence data are deficient. Objectives: The purpose was to undertake a blind study of caries and tooth mottling in 8th grade school pupils from south-east Hungary who had resided (test) or not resided (control), until November 1985, in a 350 ppm F−/kg domestic salt-fluoridated area during their early years of life. Methods: In Szeged, blind clinical caries and anterior tooth mottling scoring (+10% repeats) of 49 previously salt-fluoridated (mean age 14.14 years) and 59 non-salt-fluoridated subjects (mean age 14.08 years) were undertaken by one examiner, in June 1997. In addition, radiographic and photographic recordings were taken. In Glasgow, four dental and two lay staff scored the projected 35 mm colour transparencies (+10% repeats) of each pupil's six upper anterior teeth, for tooth mottling. All clinical, radiographic and photographic data were then analysed. Results: Mean DMFS scores were 9.18 (SD = 10.72) for test users and 4.51 (SD = 6.24) for control users (P < 0.01) and, based on repeat observations, clinical reliability = 0.99; X-ray reliability = 0.95. Clinically, three test children had fluorosis of 10 teeth, with eight teeth in two controls. Photographic scoring by the clinical examiner gave a 97.2% clinical match, while photographic agreements for all four dentist pairs were 92.5%–97.2%, with lay observers' agreements at 89.8%. For both groups, 10% repeats produced 98.5% agreements. In a sole test case “fluorosis” photographic unanimity was obtained, and non-unanimous “possible fluorosis” was recorded by two to four panel members for only three other test and two control subjects. Conclusions: No evidence was found that significant anterior tooth fluorosis resulted in subjects exposed previously to 350 ppm F−/kg domestic salt from birth to 2.3–4.8 years of age. However, no caries benefit was demonstrated after the 11.5-year salt fluoridation gap. Caries differences seemed social class-related, city-based controls having less disease than rural test subjects, in spite of an identical F− tablet regimen in all schools from 1987, until subjects were 10 years old. These data emphasise (a) the superiority of sustained community-delivered fluoridation and (b) the need to maintain constant fluoride delivery to tooth surfaces, certainly well beyond 10 years of age.

This study reports the first ever national oral health survey of Omani 12-year-olds. Conducted in October 1993, of the 3,435 children examined, 1,438 (41.9%) were caries-free, although regional variations ranged from 24.8% to 61.9%. Overall, the national DMFT averaged 1.53, the majority of caries experienced being in the form of untreated decay, with occlusal surfaces of first permanent molars being the most commonly involved site. Oral hygiene was poor, only 11% of those examined being scored as plaque-free.

The hypotheses to be tested were: (i) that chewing sugar-free gum frequently and for long periods would be associated with higher amounts of supragingival calculus, and (ii) that there would be no site-specificity of calculus deposition on the lingual surfaces of the 6 lower anterior teeth. Subjects, 436 in Glasgow and 191 in Winnipeg, were scored for calculus at mesial, lingual, and distal sites on the lingual surface of each of the 6 lower anterior teeth, by the Volpe-Manhold method. They also answered questions on the time since the last prophylaxis, the frequency of gum chewing, the type of gum chewed, and the length of a typical gum-chewing episode. A subset (233) of the Glasgow subjects were scaled and re-scored for calculus 3 months later. When the data for the logarithmic transformations of the initial calculus scores were subjected to stepwise multiple-regression analysis, the only factor which correlated significantly with initial calculus scores in both cities was the time since the last prophylaxis. In the Glasgow subjects scored 3 months after a prophylaxis, there was a negative correlation between chewing sugar-free gum and calculus scores, whereas in the Winnipeg subjects, age and the chewing of sucrose-containing and sugar-free gum were positively correlated with calculus scores. Thus, the results were contradictory with respect to the first-tested hypothesis. The calculus distribution patterns were very similar in the subset of Glasgow subjects and the Winnipeg subjects, with the amounts on the lateral incisors and canines averaging 70.2% and 44.5%, respectively, of those on the central incisors. Thus, the second hypothesis was disproved.

The prevalence of recurrent caries was recorded at the annual examinations of a 3-year double-blind caries clinical trial involving 4,294 children age 12-13 years at baseline. Recurrent caries was defined as clinically apparent disease affecting the restoration margins. Examination of all surfaces of undried teeth was carried out using a CPITN-C probe. The proportion of children with recurrent caries was 7.5, 9.5, 6.3 and 8.0% at baseline, year 1, year 2, and year 3. The proportions of restorations with recurrent caries was 1.9, 1.8, 1.0 and 1.1%, respectively, at each examination. A number of oral hygiene parameters were collected via a computer questionnaire. Water rinsing after brushing proved to be associated with recurrent caries (p0.01), those using a beaker having more recurrent caries than those using less diluting methods. Subjects who brushed twice a day (at the final examination) had less recurrent caries than those reporting to brush less often (p0.01). Both these results are consistent with previous findings on the association between DMFS increments and oral hygiene practices.

The limited usefulness of caries activity tests based solely on counts of mutans streptococci has been recognised increasingly. Such tests do not account for potential differences in cariogenicity of Streptococcus mutans strains harboured by individual patients. Hence, this study describes the evaluation of a simple and inexpensive method involving the dissolution of powdered hydroxyapatite as a means of determining the cariogenic potential of 64 freshly isolated strains of S. mutans from 24 children. Whilst it is apparent that differences between strains isolated from individuals could be demonstrated using this test, the variability observed was such that it was not possible to relate in vitro cariogenicity to actual clinical caries experience.

Data on toothbrushing habits were collected during a 3-year caries clinical trial of sodium monofluorophosphate toothpastes in Lanarkshire, Scotland, involving 3,005 schoolchildren of mean age 12.5 years at baseline. Stated normal brushing frequency and oral rinsing method after brushing were recorded. Half the panel indicated they rinsed their mouths after toothbrushing using a beaker. The proportion of the panel brushing once per day or more increased during the trial. Differences in oral habits were observed between the sexes, with 42% of girls and 52% of boys being non-beaker rinsers and 73% of girls, but only 44% of boys, brushing their teeth at least twice per day. Twice-a-day brushers had a consistently lower caries increment than less frequent brushers. This was also seen in the baseline prevalence data, but did not account for all incremental differences noted. Subjects using beakers had consistently higher increments than non-beaker rinsers. Again, this difference could not be explained by variations in baseline prevalence. Differences in the caries increment were also observed between boys and girls, these appearing to be linked both to the cumulative effect of male/female habit variations plus a difference in the baseline caries prevalence. A dose response to the three fluoride levels, i.e 1,000, 1,500, and 2,500 ppm F, was seen for the different habit combinations which again could not be explained by differences in the baseline caries prevalence.

Salivary, clinical, and microbiological factors were compared with subsequent 2-yr caries increment in a group of 372 Scottish adolescents. The caries increment was significantly correlated with previous caries experience, salivary buffering capacity and counts of lactobacilli, mutans streptococci and Candida. Veillonella levels and salivary flow rate were not correlated with caries increment. Significant improvements in the predictions were obtained when the results of more than one test were included using stepwise regression analysis. On an individual basis, using stepwise discriminant analysis, the caries increment group (low, medium, or high) was identified correctly in 49% of all subjects, but this was reduced to 45% if previous caries experience was excluded from the analysis.

Human enamel sections and slabs, mounted on a mandibular removable appliance, were worn by 5 adult subjects for a 1-week period. Plaque was allowed to accumulate on the in situ test sites and on the adjacent natural dentition. At the end of the experimental period, the plaque microflora associated with (1) the enamel sections, (2) the enamel slabs, and (3) the acrylic base of the appliance test site was compared with that obtained from lingual and interproximal areas of the lower molar teeth. In addition, the acid anion and pH profiles of plaque obtained from both the exogenous and natural tooth surfaces were also determined. Although some quantitative differences were found between the proportions of isolates obtained from the different enamel surfaces, qualitatively the microflora was very similar, and no significant differences were found in the plaque lactate/acetate ratios or pH measurements following a sucrose mouthrinse. Thus, human tooth specimens mounted on the intra-oral device produced a plaque ecosystem similar to that present on the adjacent natural dentition, suggesting that the model is suitable for studies on early plaque development and the microbiology of enamel demineralization.

During the third examination of a 3-year anti-caries dentifrice study, bitewing radiographs were read to detect occlusal, as well as approximal caries lesions in 2623 subjects aged 14-15 years. These analyses showed that 1.4% of 2107 upper molars and 7.2% of 2288 lower molars (P less than 0.001), previously scored as clinically 'sound', were carious at a radiographic Grade '3' score (dentinal involvement), and 0.2% had radiographic pulpal lesions. However, for teeth which had been deemed as having a 'suspicion' of caries clinically, but which a 0.6 mm blunted probe would not enter, 29.1% of lower molars had definite radiographic evidence of dentinal caries as compared to only 7.6% of upper molars (P less than 0.001), and a further 0.5% exhibited pulpal extension. In addition, 23.9% of lower premolars also showed dentinal involvement in this group. Overall, 12.1% of lower molars and 3.1% of upper molars showed definite radiographic evidence of occlusal caries in the absence of a firm clinical indication. Thus, the use of bitewing radiographs would appear to be a most helpful adjunct to clinical caries diagnosis, not only of approximal lesions, but also for the detection of early occlusal caries, in these days of generally available topical fluoride.

Salivary and microbiological caries activity tests were investigated on three occasions in a group of 372 Scottish adolescents. Counts of lactobacilli, mutans streptococci, and candida were consistently and significantly associated with caries prevalence, as either DS or DMFS score, and buffering capacity was consistently inversely related to DMFS score. However, veillonella counts and salivary flow rate were not correlated with caries prevalence. Significant improvements in the associations were obtained when the results of more than one test were included using stepwise regression analysis. On an individual basis, at most, stepwise discriminant analysis identified the DMFS group correctly in 49% of all subjects, and the DS group in 47%.

The possibility of gingival fluid being a source of plaque fluoride has been investigated in dogs anaesthetised for veterinary examination and dental treatment. The radionuclide18F was injected intravenously and the tracer was detected in gingival fluid within 5 min of injection. The concentration of tracer in plaque was similar to that in plasma by 25 min, even in the absence of saliva, but gingival fluid and plasma had substantially the same concentration at all times. After 25 min the concentration in gingival fluid and plaque were also observed to be the same. The results suggest that gingival fluid is one source of plaque fluoride but calculation shows that it is unlikely to account for the whole.

Fissure sealant presence was recorded at baseline and annually during a 3-year, double-blind clinical caries trial which involved 3005 children aged 12-13 years at outset. At baseline, initially, 2002 sealants were noted in 431 subjects (14.3%), a figure not dissimilar to that found for Scottish 12-year-olds in the UK National Survey completed in the same year. By the fourth examination, 400 (17.3%) children had 2209 surfaces sealed. After one year, 14%, and at 3 years, 26% of baseline sealants were missing. Overall, at the last examination, 25% of baseline unsealed surfaces were carious compared to 15% of those originally sealed (P less than 0.001), although for molars, the equivalent figures were 49% and 24% (P less than 0.001). Finally, analysis showed that at baseline, as few as 15% of sealants had been placed by general dental practitioners, and this low proportion was maintained throughout the study period. While sealant placement in the Scots' age group was low, nevertheless the prevalence recorded was greater, at least by a factor of three, than has been reported elsewhere in the UK.

A novel lower removable acrylic appliance to investigate the pathogenesis of the incipient carious lesion in enamel is described. Pilot enamel demineralisation and remineralisation studies have been u

A double-blind study with Nuva-seal and Alphaseal in contralateral quaurants of the same mouths obtained complete retention rates for Nuva-seal of 94·5 per cent of 293 sealed sites at 1 year and 83·1 per cent of 225 sites by 2 years. The corresponding Alphaseal data was poorer at 89·9 per cent and 78·7 per cent respectively. Only 1 sealed surface (0·2 per cent) was carious at 2 years. Nuva-seal first permanent molar retention was also superior to that of Alphaseal, 93·5 per cent compared to 85·6 per cent at 1 year, and 81·1 per cent compared to 70·1 per cent at 2 years. However, retention in these teeth for 6- to 7-year-old children was inferior to that of 8- to 11-year-old children for both sealants although only the Alphaseal data was significant. This material also had a significantly greater loss rate than Nuva-seal at 6 months and 18 months in 6- to 7-year-old children. The use of Nuva-seal with adequate attention to clinical detail and monitoring of UV sources can thus provide substantial clinical benefit in first permanent molars.

Mixed salivary fluoride levels have been measured after 9 subjects sucked or slowly dissolved three different brands of 1 mg F–– fluoride tablets. Results indicate that for all preparations

Examination of 11-year-old Scots children who had participated in a 5-year, fortnightly dental health education and preventive dentistry programme showed that, compared with a similar age-matched group, the regimen produced mean DMF and DMFS reductions of 48.6% and 42.1%, respectively. In addition, the plaque and gingival indices differed significantly and 22.5% of test children were caries-free compared with only 7.6% of controls.

Characteristics of calcium glycerophosphates (frequently designated α- and β-) relative to their caries-inhibiting use were compared in free and tabletted forms. Dissolution in water and the mouth and in the presence of citric acid were comparable for each glycerophosphate. Relevant discrimination between the two glycerophosphates and tablets made from them could not be made, and the differing clinical effects which have been reported for different calcium glycerophosphates cannot at present be explained by differences between the two preparations. Proof of anti-caries differences between different calcium glycerophosphate isomers is likely to await the availability of pure isomers.

This paper describes a method for measuring calcium and phosphorus levels in very small samples of dissolved enamel. The technique is an extension of a method first used by von der Fehr and S

Fissure sealing of first permanent molars. An improved technique applied by a dental auxiliary