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.

A comparative clinical study investigating the efficacy of a dentifrice containing 8% strontium acetate and 1040 ppm fluoride in a silica base and a control dentifrice containing 1450 ppm fluoride in a silica base to provide immediate relief of dentin hypersensitivity.

OBJECTIVE: The objective of this clinical study was to evaluate and compare the efficacy of a dentifrice containing 8% strontium acetate and 1040 ppm fluoride (from sodium fluoride) in a silica base (test dentifrice) to a control dentifrice containing 1450 ppm fluoride (from sodium fluoride) in a silica base, to reduce dentin hypersensitivity immediately after a single dab-on self-application, and after subsequent twice-daily brushing for three days. METHODS: This was a randomized, examiner-blind, two-arm parallel group, three-day clinical study with seventy-nine subjects, stratified based on baseline tooth sensitivity. Tooth sensitivity was determined through subject responses to both evaporative (Schiff and Visual Analogue Scale [VAS]) and tactile stimuli (Yeaple probe), prior to and immediately after subjects self-applied a single pea-sized amount of either the test or control dentifrice to qualifying sensitive teeth, massaging the toothpaste onto the sensitive area for one minute. Tooth sensitivity was further assessed in response to the same stimuli after subjects brushed twice daily for an additional three days. Subject assessments were performed by the same examiner throughout the study. RESULTS: Seventy-nine subjects completed this clinical study. Both subject groups exhibited reductions in dentin hypersensitivity directly after a single dab-on application. These reductions were significant across all measures for the test dentifrice. Between-treatment analyses showed the test dentifrice to be significantly better at relieving subjects' sensitivity across all measures (Schiff p = 0.0003, tactile p = 0.0003, and VAS p = 0.0077) compared to the control. After the additional three days of twice-daily brushing, between-treatment analyses showed the test dentifrice to be significantly better at relieving subjects' sensitivity across all measures (Schiff p = 0.0102, tactile p = 0.0493, and VAS p = 0.0067) than the control dentifrice. CONCLUSION: The 8% strontium acetate, 1040 ppm fluoride dentifrice provided significant within-treatment reductions in dentin hypersensitivity for all measures at both time points (immediate and three-day brushing). Compared to the control dentifrice, significant between-treatment reductions in sensitivity were observed after a single dab-on application for all measures, and following the additional twice-daily brushing for three days in favor of the 8% strontium acetate, 1040 ppm fluoride dentifrice.

Topographic distribution of bacteria associated with oral malodour on the tongue.

OBJECTIVE: To investigate the topographic distribution of bacterial types and loads associated with mid-morning oral malodour on the tongue surface. DESIGN: Fifty subjects with good oral health and at least 20 natural uncrowned teeth were included. Samples were taken with sterile brushes from the dorsal anterior (DA), dorsal middle (DM), dorsal posterior (DP), dorsal posterior to the circumvallate papillae (DPCP), lateral posterior (LP) and ventral posterior (VP) tongue surfaces. Samples were cultured on appropriate media for anaerobic bacteria, aerobic bacteria, Gram-negative anaerobic bacteria, volatile sulphur compound (VSC)-producing bacteria and Streptococcus saliuarius. Malodour was assessed by trained judges on an intensity basis. RESULTS: The counts of all bacterial groups were consistently highest at the DPCP surface. Mean VSC-producing bacterial counts (colony forming units/brush x10(5)) were 1.45, 5.67, 32.52, 88.94, 6.46 and 0.33 at DA, DM, DP, DPCP, LP and VP surfaces, respectively. Anaerobic, Gram-negative and VSC counts at DPCP surfaces increased with malodour intensity, whereas aerobic and S. saliuarius counts decreased; however these differences were not statistically significant. CONCLUSION: It is concluded that the DPCP area consistently carries the highest load of bacteria capable of contributing to oral malodour. The study demonstrates that tongue surfaces not accessible to routine oral hygiene procedures can significantly contribute to oral malodour.