Usage and status of cobalt-chromium removable partial dentures 5-6 years after placement.

The aim of this study was to describe the usage of cobalt-chromium (Co-Cr) removable partial dentures (RPDs) by patients 5-6 years after denture insertion and to find out the factors that affected their denture usage. A random sample of patients provided with Co-Cr RPDs from a dental teaching hospital in Hong Kong was selected. Patients were interviewed using a structured questionnaire concerning their assessment and use of the dentures. Those who had been constantly wearing their original RPDs were examined by one calibrated examiner under optimal clinical conditions. The response rate of the patients who could be contacted was 98%. The results from 189 patient interviews showed that usage of the RPDs declined with time and that half of the dentures had been discarded or replaced 5-6 years after insertion. These discarded RPDs had been in use for an average of 19.5 months. The main reason given by the patients for not using the RPDs was general dissatisfaction with the dentures in various combinations of comfort, fit and chewing ability and, less importantly, with food trapping and appearance. No statistically significant association between denture usage and their respective Kennedy classification was found. The status of the Co-Cr RPDs that had been constantly used for 5-6 years was generally good. The majority of these RPDs demonstrated fair to good cleanliness, stability and retention and had no defect of any sort.