Purpose: To evaluate the anti-plaque efficacy (Study 1) and the anti-gingivitis efficacy (Study 2) of a manual toothbrush with tapered bristles compared to marketed control manual toothbrushes. Methods: Studies 1 and 2 were independent, randomized and controlled, single-center, examiner-blind clinical trials in generally healthy adults. Study 1 included a 2-day acclimation period, followed by a 5-day twice daily toothbrushing test phase with the assigned brush. Baseline and Day 5 pre-and post-brushing plaque levels were assessed via Turesky Modified Quigley-Hein Plaque Index (TMQHPI). In Study 2, subjects with existing gingivitis brushed with their assigned toothbrush twice daily for 4 weeks. Gingivitis was measured using the Mazza Modification of the Papillary Bleeding Index at Baseline and Weeks 2 and 4. In both trials, subjects were randomly assigned to either the manual toothbrush with tapered bristles (Oral-B Super Thin Indicator toothbrush, OM159) or the marketed control (Study 1: Oral-B Complete Clean & Sensitive toothbrush; Study 2 Crest Pro-Health Complete 7 Brush 35 toothbrush) for use with a regular fluoridated dentifrice. Results: 40 (Study 1) and 63 (Study 2) subjects were randomized in each trial. In Study 1, both the tapered bristle and marketed control brushes provided significant (P< 0.0001) mean whole mouth plaque reductions at Day 1 and Day 5 post-brushing relative to pre-brushing as measured via TMQPHI, with no between-brush significant differences. Both groups showed a significant reduction in Day 5 post-brushing mean plaque scores versus Day 1 pre-brushing mean plaque scores (P< 0.0001), but the reductions were not significantly different between groups (P= 0.4274). In Study 2, both the tapered bristle brush and the marketed control brush produced significant (P< 0.0001) reductions in both gingivitis and number of gingival bleeding sites at both Weeks 2 and 4 versus baseline. At Week 4, the tapered filament toothbrush group showed 8.6% less gingivitis (P= 0.0017) and 33.4% fewer bleeding sites (P= 0.0030) versus the control brush. All toothbrushes were well-tolerated. (Am J Dent 2017;30:272-278). Clinical significance: Twice daily customary use of a manual toothbrush with tapered bristles provided clinically meaningful plaque and gingivitis reduction benefits.