The study aimed to evaluate the microbial contamination and plaque scores of nanogold-coated and uncoated toothbrushes. This study was designed as a single-centre, parallel, examiner-blinded, randomized, two-group clinical trial. Eighty-four participants were enrolled and randomly assigned to receive either a nanogold or uncoated toothbrush. Basic periodontal therapy was performed for all the recruited subjects, and plaque scores of zero were considered baseline values. All participants were instructed to follow a twice-daily brushing regimen without dentifrice and to refrain from other oral hygiene care during the one-week study period. Plaque levels were assessed after oneweek using the Turesky modification of the Quigley-Hein Plaque Index (TMQHPI). The bristles were tested for microbial contamination by viable cell counting. The recorded data were statistically analysed, and a P-value of <.05 was accepted as statistically significant. After oneweek of brushing without using toothpaste, the mean plaque index scores were 0.37±0.07 in the nanogold group and 0.58±0.10 in the uncoated group. A significant difference in the mean plaque scores was observed between the groups (P<.001). The mean colony-forming unit (CFU) was 21±48.8 for the nanogold-coated group and 100±128.4 for the uncoated group. The difference in the mean CFUs observed between the groups was significant (P=.014). The use of a nanogold-coated toothbrush demonstrated significantly lower bristle contamination and lower plaque scores after oneweek compared with uncoated toothbrushes without using dentifrice.