Methods: In-vivo worn brush heads were obtained during a randomized, cross-over study among a general population using Oral-B® oscillating-rotating toothbrush handles with Oral-B® Precision Clean® (PC) and Store Brand EASYFLEX® (SB, Ranir) brush heads. Subjects were balanced for age and gender and randomized to one of 4 cohorts (4, 6, 8, 13 weeks product use) and to one of two treatment sequences. 267 subjects completed the study. A subset of 136 representative worn brush heads were assessed for cleaning efficacy using a six-axes industry robot brushing dental models covered with plaque substitute (PS) via controlled and standardized brushing time, motions and force. 3D laser scanning was used to detect PS remaining on the dental models. Differences of remaining PS were analyzed using an ANOVA model.
Results: Mean cleaning efficacy differences in favor of PC ranged from 2.5% (Week 4, lingual) to 14.5% (Week 8, occlusal) and were directionally in favor of PC at all sites and all usage durations (28/28). Group differences were statistically significant (p<0.05) for the majority of comparisons (19/28), including occlusal, gingival margin and interdental sites across all time periods. Comparing PC brush heads at 13 weeks with SB brush heads at 4 weeks showed that cleaning efficacy was statistically significantly (p<0.05) better for PC at buccal, occlusal, gingival margin and interdental sites.
Conclusions: Wear of brush heads is clinically relevant as worn brush heads are less effective in tooth brushing. PC brush heads maintain their superior cleaning efficacy vs. SB throughout the recommended brush head lifetime (3 months). PC brush heads after 13 weeks showed significantly greater cleaning vs. a 4 week SB brush head.