BACKGROUND Information is lacking about antiadhesion effect of titanium dioxide (TiO2) coating on denture base resins in the mouth. OBJECTIVE The purpose of this clinical study was to investigate the antiadhesion effect of TiO2 coating on denture base resins. METHODS Ten healthy dentate participants (mean 27 ±2 years of age) participated in this study. Disks and palatal appliances were made with denture base resin. They were divided into 2 groups: a TiO2-coated group and an uncoated group. A primer and a top coat containing TiO2 were applied to the surfaces of the resin by means of an air spray. In the denture plaque staining test, resin disks were fixed to the retainer, placed in each participant's mouth for 3 days, and stained with a dental plaque-disclosing solution. The staining rate was calculated. The resin disks and palatal appliances were used to measure the total number of microbes. The resin specimens were placed in each participant's mouth for either 3 or 7 days and swabbed to count the total number of microbes. The chewing gum adherence test was performed both subjectively and objectively. Subjectively, each participant wearing a palatal appliance rated adherence using a visual analog scale. The objective test was performed with a chewing gum adhesion test. The staining rate, the total number of microbes, and the visual analog scale values were statistically analyzed using the Wilcoxon signed rank test, and the adhesive force was statistically analyzed using a Student t test. RESULTS In the denture plaque staining test, the measurement of microbes, and the resin chewing gum adherence test results, significant differences were observed between the TiO2-coated groups and the uncoated groups. CONCLUSIONS TiO2 coating of the denture base acrylic resin inhibited the adhesion of microbes, denture plaque, and highly adhesive food.