A randomised clinical study to evaluate experimental children's toothpastes in an in-situ palatal caries model in children aged 11-14 years.

OBJECTIVES: To compare three children's sodium fluoride toothpastes to placebo with respect to enamel remineralisation potential, enamel fluoride uptake and net acid resistance using an in situ palatal caries model in children aged 11-14 years following a single brushing. DESIGN: This was a randomised, single blind (laboratory analyst), single-centre, four-treatment, crossover study with a 7-day washout period between treatments. The treatments were 1,426 ppm fluoride, 1,000 ppm fluoride, 500 ppm fluoride and 0 ppm fluoride (placebo) toothpaste (NaF/silica). A custom made in situ palatal appliance was used by each subject in all treatment periods. At each of the four treatment visits subjects wore the appliance containing four partially demineralised human enamel specimens for 5 minutes and then brushed their teeth using a standardised procedure for 60 seconds under supervision using 1.0 g (±0.1 g) of their assigned toothpaste. After 4 hours the appliance was removed and enamel specimen recovered. This process was repeated until all subjects completed all four study treatment visits. Recovered enamel specimens were analysed for per cent surface microhardness recovery (%SMHR; Knoop) and enamel fluoride uptake (EFU; microdrill biopsy). Subsequently, specimens were demineralised in vitro to determine their % net acid resistance (%NAR; Knoop). RESULTS: All three fluoride toothpastes demonstrated significantly greater %SMHR, EFU and %NAR compared with 0 ppm F toothpaste. The model demonstrated a dose response over the range 0 to 1,426 ppm fluoride for %SMHR, EFU and %NAR. There was no significant difference between 500 ppm F and 1,000 ppm F for %SMHR and between 1,000 ppm F and 1,426 ppm F for %SMHR, EFU and %NAR. CONCLUSIONS: The present in situ study demonstrated that the children's fluoride toothpastes tested are capable of delivering cariostatic amounts of fluoride to early caries lesions following a single brushing.

A randomised clinical study to evaluate the effect of brushing duration on fluoride levels in dental biofilm fluid and saliva in children aged 4-5 years.

OBJECTIVES: To compare the effect of 40 seconds versus 2 minutes brushing on saliva and dental biofilm fluid fluoride in children ages 4-5 years over 1 hour. DESIGN: This was a single-blind, cross-over, randomised, two-period clinical study in healthy children. Three days before the start of each treatment subjects received a thorough brushing and then refrained from all oral hygiene procedures. At treatment visits, after collecting baseline biofilm and saliva samples, staff brushed the occlusal surfaces of the subject's posterior teeth with a pea-sized amount (0.25 g) of NaF/silica toothpaste for the randomised time. Samples were taken at 5 minutes, 15 minutes, 30 minutes and 60 minutes after brushing and analysed for fluoride using a microanalytical methodology. There was a minimum 4-day washout period between treatments. RESULTS: Log changes from baseline biofilm fluid and saliva fluoride were statistically significant (P < 0.05) for both brushing times at all post-brushing time-points [except 60 minutes saliva where P = 0.06 (t-test)]. Statistically significantly greater ln-AUC (area under the curve) was found for biofilm fluid and salivary fluoride after brushing for 2 minutes compared with brushing for 40 seconds over the 1-hour test period. There was a statistically significantly higher concentration of fluoride in the log change from baseline saliva levels after 5, 15, 30 and 60 minutes for the 2-minute brushing time compared with 40 seconds brushing time. There was no statistically significant difference in concentration of log change from baseline fluoride levels in biofilm fluid at each individual time-point (5, 15, 30 and 60 minutes) for the 2-minute brushing time compared with the 40-second brushing time, but significant differences were observed for 15, 30 and 60 minutes in favour of 2-minute brushing time when log biofilm fluid value was analysed. CONCLUSION: The findings provide further evidence for the benefits of increased duration of brushing with respect to fluoride delivery.

Comparison of a dietary survey and the duplicate plate method for determining dietary fluoride ingested by young children: a pilot study.

BACKGROUND: Investigators have attempted to establish the diet's contribution to the total body burden of fluoride in response to a reported trend towards an increase in fluoride intake. AIM: The aim of this study was to compare the suitability of two methods to collect dietary data for fluoride intake assessment. DESIGN: Assessments were made in 12 children using the duplicate plate and dietary diary methods following a randomized cross-over design. Foods and beverages were analysed for fluoride, and total fluoride intake per day was calculated. Results from each method were compared. RESULTS: Mean beverage fluoride intake was estimated at 316 +/- 120 and 422 +/- 195 microg/day utilizing the diary and duplicate plate methods, respectively. Mean food fluoride intake was estimated at 188 +/- 48 microg/day using the diary, whereas it was 130 +/- 41 microg using the duplicate plate method. Total fluoride intake was 504 +/- 138 and 552 +/- 192 microg/day utilizing the diary and duplicate methods. Large variations in daily fluoride intake from both beverages and food were observed between and within children. CONCLUSIONS: Both methods had inherent shortcomings and sources of error. The duplicate method was more labour intensive and costly; however, the diary method required a large number of assumptions. A combination of both methods seems to be most suitable to obtain reliable data.

The fluoride content of foods and beverages from negligibly and optimally fluoridated communities.

In the spring of 1996, foods and beverages most commonly consumed by adolescents were analyzed for fluoride as part of a larger investigation. These foods were selected by interviewing 711 adolescents, 12-14 years of age, who were long-time residents of either an optimally or negligibly fluoridated community. The brand names of the identified foods and beverages most commonly purchased were determined by interviews with the parents. A total of 441 brand-name food and beverage items were purchased from both communities and were individually analyzed for fluoride. These analyses were done in order to estimate the fluoride content of various kinds of foods and beverages and to determine whether or not there was a significant difference between the two communities in the amount of fluoride ingested from these dietary sources. The food and beverage items were classified into dietary groups based on US Department of Agriculture (USDA) guidelines. Overall, the fluoride content of the sampled foods and beverages was low. In addition, there was no significant difference in the fluoride content of the same pre-packaged or ready-to-eat food or beverage items purchased in the two communities. However, a significant difference was found between the two communities in the fluoride content of fountain beverages and in cooked or reconstituted foods prepared using local water from the respective communities. Based on these results, we have estimated the mean daily, dietary fluoride intake for 3-5-year-old children who are more susceptible to developing dental fluorosis.