Objectives: The objective of this study was to assess prospectively the effectiveness of ultrasonic denture hygiene interventions in improving denture cleanliness among community-dwelling elders. Methods: A randomized clinical trial was conducted among community-dwelling elders, in which a total of 66 subjects who received upper metal framework removable partial dentures in the past five years were recruited randomly from a computerized database. They were randomly allocated into three denture hygiene intervention groups: group 1 (mechanical cleaning with a toothbrush and ultrasonic cleaning with cetylpyridinium chloride mouthrinse), group 2 (mechanical cleaning with a toothbrush and ultrasonic cleaning with distilled water) and control (mechanical cleaning with a toothbrush only). Denture cleanliness was assessed at baseline and one month review using: i) Denture Cleanliness Index (DCI) scores; ii) plaque coverage percentage; and (iii) microbiological tests. Results: There were significantly greater reductions in mean DCI scores and mean percentage of plaque coverage area in group 1 and group 2 compared to the control group for both CoCr and acrylic fitting surfaces (p<0.001). Group 1 had significant reductions in the viable counts of bacteria (CoCr and acrylic) and yeast (CoCr only) (p<0.05), while only significant reductions in bacterial viable counts (CoCr and acrylic) (p<0.05) were documented in Group 2. No significant differences were detected between groups 1 and 2 with regards to all clinical and microbiological outcomes. When comparing these parameters for CoCr and acrylic surfaces, no significant differences were observed following the intervention period. Conclusions: The ultrasonic cleaner was significantly more effective than the control in the reduction of biofilm coverage on metal framework removable partial dentures during the one month intervention period. The adjunctive use of cetylpyridinium chloride with ultrasonic cleaning did not yield improved outcomes compared to water.

Inclusion Criteria:

• previously provided with cobalt chromium metal framework removable partial dentures (RPDs) within the past five years at Prince Philip Dental Hospital

Exclusion Criteria:

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