Patient perceptions regarding benefits of single visit scale and polish: a randomised controlled trial

BACKGROUND Single visit scale and polish is frequently carried out in dental practices however there is little evidence to support (or refute) its clinical effectiveness. The purpose of this research was to compare patient-reported outcomes between groups receiving a scale and polish at 6-, 12-, and 24-month intervals. Outcomes recorded included participants' subjective assessment of their oral cleanliness; the perceived importance of scale and polish for oral health and aesthetics; and frequency at which this treatment is required. METHODS A practice-based randomised control trial was undertaken, with a 24-month follow-up period. Participants were healthy adults with no significant periodontal disease (BPE codes <3) randomly allocated to three groups to receive scale and polish at 6-, 12-, or 24-month intervals. Patient-reported outcomes were recorded at baseline and follow-up. Oral cleanliness was reported using a 5-point scale and recorded by examiners blinded to trial group allocation. A self-completed questionnaire enabled participants to report perceived importance of scale and polish (5-point scale), and required frequency of treatment (6-point scale). The main hypothesis was that participants receiving 6-monthly scale and polish would report higher levels of oral cleanliness compared to participants receiving scale and polish at 12- and 24-month intervals. RESULTS 369 participants were randomised: 125 to the 6-month group; 122 to the 12-month group; and 122 to the 24-month group. Complete data set analysis was carried out to include 107 (6-month group), 100 (12-month group) and 100 (24-month group) participants. Multiple imputation analyses were conducted where follow-up data was missing. The difference in the proportions of participants reporting a 'high' level of oral cleanliness at follow-up was significant (Chi-squared P = 0.003): 52.3% (6-month group), 47.0% (12-month group) and 30.0% (24-month group). Scale and polish was thought to be important by the majority in each group for keeping mouths clean and gums healthy, whitening teeth, and preventing bad breath and tooth decay; there were no statistically significant differences between groups at follow-up. Most participants at follow-up thought that the frequency of scale and polish should be "every 6 months" or more frequently: 77.9% (6-month group), 64.6% (12-month group), 71.7% (24-month group); differences between groups were not statistically significant (Chi squared P = 0.126). The results suggest that participants in the 24-month trial group were more likely to choose a scale and polish interval of "once a year" or less frequently (OR 2.89; 95% CI 1.36, 6.13). CONCLUSIONS The majority of healthy adults regarded 6-monthly single-visit scale and polish as being beneficial for their oral health. Receiving the treatment at different frequencies did not alter this belief; and those with the longest interval between scale and polish provision perceived that their mouth was less clean. In the absence of a strong evidence base to support (or refute) the effectiveness of single-visit scale and polish, the beliefs and preferences of patients regarding scale and polish may be influential drivers for maintaining provision of this treatment.