Bristle cofounder here. In short, we found that people using an electric toothbrush have increased commensal species in their oral microbiome compared to those using a manual brush. We looked at potential confounders, and found that this effect was negated if you only brush once per day.<p>We also found that bacterial species that cause bad breath (halitosis) were higher in people using a manual brush, but only people under 30 had reduced scores when using an electric brush. Surprisingly, people with existing gum disease did not benefit as much from an electric toothbrush.<p>Our data suggest that an electric toothbrush is better at removing biofilm than a manual one. Additionally, accumulation of biofilm seeds an environment for slow-growing anaerobic species. Frequent efficient removal of this biofilm is important for growth of commensal species, and reduction in pathogenic anaerobes that can cause disease.<p>TLDR: Brush 2x per day, and use an electric toothbrush, especially if you're under 30 and don't have existing gum disease.