Purpose: The purpose of this single-blind randomised controlled clinical trial was to verify the impact of progressive toothbrush age on clinical variables of dental plaque and gingival conditions. Materials and Methods: A total of 110 undergraduates were randomly assigned to one of four groups according to toothbrush age, as measured at 4, 8, 12, and 16 weeks. Clinical parameters (plaque and gingival indices) were assessed at 1 week (initial) and final periods. The wear of toothbrushes was evaluated by the wear index. Results: Despite progressive toothbrush age, plaque and gingival indices were similar after the toothbrushing periods (p > 0.05, ANOVA). Significantly more plaque and gingivitis were present on lingual/palatal surfaces as compared with facial surfaces for all weeks, including the baseline (P 0.001, paired t test.). The wear index increased from 4 weeks to 16 weeks. Plaque and gingival indices did not show statistical differences among 'lowest wear', 'moderate wear' and 'highest wear' (P > 0.05, ANOVA). Conclusion: Under the experimental conditions of this study, progressive toothbrush age did not lead to a decrease in plaque control. It was concluded that toothbrush age may not be critical in ensuring optimal plaque control. Keywords: dental plaque, gingivitis, oral hygiene, plaque control, toothbrush