Robot and mechanical testing of a specialist manual toothbrush for cleaning efficacy and improved force control.

BACKGROUND: Toothbrushes require flexibility to access all dental surfaces and remove plaque effectively, but they should also aim to prevent or limit overbrushing and consequent damage to teeth and gums. In two studies, the physical properties and cleaning performance of specialist test toothbrushes with flexible necks were compared to a reference rigid-necked toothbrush. METHODS: In Study 1, a universal testing machine (Instron E 10,000) with a specially designed setup was used to test the deflection behaviour of toothbrush head and neck. Untufted toothbrushes were fixed in a custom holder and force was applied to the head while the deflection was measured. In Study 2, one control and five test toothbrushes were assessed using a robot system to simulate the cleaning of artificial plaque from defined surfaces of artificial replicated human teeth in a model oral cavity (typodonts). RESULTS: Study 1 showed that the flexible-neck toothbrush deflected 2 to 2.5 times more than the rigid-neck reference toothbrush when same force was applied to the toothbrush head. Study 2 revealed that all five test toothbrushes showed statistically superior simulated plaque removal to the reference toothbrush. This superiority was observed for all test toothbrushes employing horizontal and rotating brushing action (all p = 0.001) but only three of the five toothbrushes when vertical brushing was employed (all p = 0.001). Cleaning efficacy of the test toothbrushes was demonstrated both interdentally and at the gumline locations. The Complete Protection toothbrush showed the most effective cleaning performance followed by the Repair and Protect and Rapid Relief toothbrushes. CONCLUSION: The addition of a flexible-neck component to the toothbrush designs helped to reduce stiffness and may allow more effective cleaning compared to rigid designs with controlled force distribution on the teeth and gums. This may help to provide plaque control at all potential risk areas in an in vitro robot model and could support good oral hygiene in-use.

A randomised clinical study investigating efficacy of a stannous fluoride toothpaste in improving gingival health after 3 weeks' use.

BACKGROUND: This examiner-blind, stratified, parallel study aimed to evaluate the anti-gingivitis efficacy of a non-aqueous (anhydrous) 0.454% w/w stannous fluoride toothpaste ('Test') versus a sodium monofluorophosphate toothpaste ('Control') in people with clinically-confirmed mild-moderate gingivitis. Plaque-induced gingivitis can progress to irreversible periodontitis if left untreated. This can be controlled by an effective oral hygiene regimen such as one including toothbrushing with a toothpaste containing the chemotherapeutic agent stannous fluoride. Long-term studies over 4-12 weeks have shown the efficacy of stannous fluoride; however, shorter term studies are needed to examine if the effects on measures of gingivitis and plaque control occur sooner. METHODS: Eligible participants were randomised to 3 weeks' twice-daily brushing (for 1 min) with Test or Control toothpastes. The primary efficacy variable was between-treatment difference in Bleeding Index (BI) at 3 weeks; secondary variables were between-treatment differences in number of bleeding sites, modified Gingival Index (MGI), and Turesky modification of the Quigley-Hein Plaque Index (TPI) at Weeks 2 and 3. RESULTS: A statistically significant (p < 0.0001) lower BI score was reported for Test (n = 65) versus Control (n = 65) groups at Week 2 (mean difference: - 0.07 [95% CI - 0.9, - 0.05]; 32.7% difference) and Week 3 (mean difference: - 0.06 [95% CI - 0.8, - 0.04]; 29.2% difference). The Test group also demonstrated statistically significant lower (all p < 0.0001 versus Control) number of bleeding sites (Weeks 2/3 mean difference [95% CI]: - 10.04 [- 12.3, - 7.5]/ - 8.2 [- 11.1, - 5.3] sites; 33.0%/29.3% difference); MGI score (Weeks 2/3 mean difference [95% CI]: - 0.09 [- 0.13, - 0.06]/ - 0.10 [- 0.14, - 0.06]; 4.3%/4.7% difference); overall TPI score (Weeks 2/3 mean difference [95% CI]: - 0.45 [- 0.55, - 0.35/ - 0.42 [- 0.53, - 0.30] difference; 16.0%/15.1% difference) and interproximal TPI score (Weeks 2/3 mean difference [95% CI]: - 0.42 [- 0.52, - 0.30]/ - 0.41 [- 0.52, - 0.29]; 14.6%/14.1% difference). Both toothpastes were generally well tolerated. CONCLUSION: Three weeks' twice-daily brushing with the 0.454% w/w stannous fluoride Test toothpaste compared to the Control toothpaste led to statistically significant lower gingival bleeding, gingival inflammation and plaque levels in adults with mild-moderate gingivitis. These results indicate that plaque and gingivitis-reducing benefits of 0.454% w/w stannous fluoride may be seen from 2 weeks' use. Trial registration ClinicalTrials.gov Identifier: NCT04050722; 08/08/2019.