Brush head composition, wear profile, and cleaning efficacy: an assessment of three electric brush heads using in vitro methods.

OBJECTIVE: The objective of this research was to evaluate a current store brand (SB) brush head for composition/physical characteristics, Wear Index (WI), and cleaning efficacy versus the previous SB brush head refill design (SB control) and the Oral-B Precision Clean brush head (positive control, PC). METHODS: This research consisted of three parts: 1) Analytical analysis using Fourier Transform Infrared (FT-IR) spectrometry to evaluate the chemical composition of the current SB brush head bristles relative to the SB control. In addition, physical parameters such as bristle count and diameter were determined. 2) Wear Index (WI) investigation to determine the Wear Index scores of in vitro-aged brush heads at four weeks (one month) and 13 weeks (three months) by a trained investigator. To "age" the brush heads, a robot system was used as a new alternative in vitro method to simulate aging by consumer use. 3) Robot testing to determine the cleaning performance of in vitro-aged brush heads, comparing one month-aged current SB brush heads with the SB control (one and three months-aged) and the PC brush heads (three months-aged) in a standardized fashion. RESULTS: 1) FT-IR analysis revealed that the chemical composition of the current and control SB refill brush heads is identical. In terms of physical parameters, the current SB brush head has 12% more bristles and a slightly oval brush head compared to the round brush head of the SB control. 2) Wear Index analysis showed there was no difference in the one month-aged current SB brush head versus the one month-aged SB control (1.67 vs. 1.50, p = 0.65) or versus the three months-aged PC brush head (1.67 vs. 1.50, p = 0.65). The one month-aged current SB brush head demonstrated statistically significantly less wear than the three months-aged SB control (1.67 vs. 2.67, p = 0.01). 3) Analysis of cleaning efficacy shows that the one month-aged current SB brush head had improved cleaning performance over the one month-aged SB control brush head (p < 0.05), despite no statistically significant difference in wear. Both the one month-aged current and control SB brush heads showed statistically significantly lower cleaning performance compared to the three months-aged PC brush heads (p < 0.01). CONCLUSION: While the current SB brush head showed improved cleaning over the SB control, it demonstrated significantly lower durability and cleaning in comparison to the PC brush head. Dental professionals should be aware of these differences, both in durability and in cleaning performance, when recommending brush heads to their patients.

Brush head wear, subject-perceived and laboratory cleaning performance of two oscillating-rotating electric toothbrush heads over 3 months.

PURPOSE: To evaluate the progression of wear and the effect of wear on subject-perceived and laboratory cleaning efficacy of two oscillating-rotating electric brush heads, Oral-B Precision Clean (PC) and a store brand Easyflex (SB) brush head, after 4, 6, 8 and 13 weeks of use. METHODS: This research consisted of three phases: (1) Subject questionnaires--A crossover, single-blinded study was conducted among healthy adults who were regular users of Oral-B oscillating-rotating electric toothbrushes. Subjects were recruited from a general population and randomized based on age and gender into one of four cohorts reflecting the time period of use for each product: 4, 6, 8 or 13 weeks. After brushing with their first product (either PC or SB) for the designated period of time, subjects completed a questionnaire evaluating the brush head on 17 attributes related to perceived cleaning performance, brush head condition (i.e., durability) and brush head feel (i.e., gentleness). Subjects then used the second test product for the same period of time and completed the same questionnaire. (2) Wear index investigation--At the end of each time period, subjects' worn brush head pairs were evaluated by an independent, blinded investigator to determine the wear index score. (3) Robot testing--To analyze the laboratory cleaning efficacy of worn refills in the laboratory, a representative sample of 12 subject brush head pairs for each of the four cohorts were evaluated (96 brush heads in total). To analyze the laboratory cleaning efficacy for PC at Week 13 with SB at Week 4, a separate set of 20 subjects (40 brush heads in total) were evaluated. A robot was used to brush standard typodonts (Frasaco A3) covered with plaque substitute with the worn brush head for 2 minutes under standardized, controlled conditions simulating human brushing behavior. A 3D laser scan system was used to measure the area still covered with plaque substitute at different dental sites. RESULTS: Subject questionnaire--267 subjects completed study questionnaires. Statistically significant superior ratings (P < 0.05) were obtained with the PC brush head compared to the SB brush head for virtually all attributes at all four time periods (16/17 attributes for Weeks 4, 6 and 8 and 17/17 at Week 13). Highly significant advantages (P < 0.0001) were seen for 'overall rating', 'overall cleaning' and 'ready to replace brush head' attributes. Wear Index-- A total of 486 brush head samples (243 pairs) were analyzed for wear. At all four time periods, PC brush heads had a statistically significantly lower (P < 0.0005) mean wear index than SB brush heads. Robot Test--136 brush heads were analyzed using a laboratory (robot) test to investigate cleaning efficacy. Directionally higher laboratory cleaning for PC versus SB was observed for all dental sites (35/35) for all time periods. Comparing PC at Week 13 with SB at Week 4 showed statistically significant differences (P < 0.05) in favor of PC for the majority of dental sites and time periods (23/35).