Purpose: To evaluate the efficacy of manual and machine-aided cleaning to remove matured plaque from removable partial dentures (RPD).

Materials and methods: A total of 32 patients with bilateral free-end saddle RPDs were included. The plaque was stained, and the RPD was photographed on all sides. One saddle was randomly allocated to manual cleaning, while the other was allocated to no cleaning. The patient manually cleaned the saddle by applying a denture brush and gel. The whole RPD was then cleaned with the aide of a machine using a rotating needle device. After each step, plaque dyeing and photographing were repeated. The plaque proportions (% pixel) were measured using special software. For statistical analysis, mixed models were used to adjust for baseline covariates, including plaque and surfaces, and to cover all time points.

Results: The mean plaque area without cleaning at the fitting surface was higher than at the buccal/lingual surfaces (32.8% [95% CI: 28.1% to 36.4%] vs 15.3% [13.1% to 17.4%], respectively). Manual cleaning was not substantially better than no cleaning (4.6% [-0.1% to 9.2%] for the difference at fitting surfaces; disclaiming a substantial difference of > 10%; the difference found was even smaller at buccal/lingual surfaces). Machine-aided cleaning was substantially better than manual cleaning (16.1% [12.0% to 20.2%] for the difference at fitting surfaces and 7.3% [4.6% to 10.0%] at buccal/lingual surfaces). The combination of manual and machine-aided cleaning was not better than machine-aided cleaning alone (-0.2% [-2.6% to 2.1%] difference at fitting surface).

Conclusion: Manual cleaning is insufficient in removing matured denture plaque. Machine-aided cleaning is clearly superior to manual cleaning, especially at fitting surfaces.