Data sources: The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, the metaRegister of Controlled Trials and the US National Institutes of Health Clinical Trials Register.

Study selection: Randomised controlled trials (excluding split mouth) of routine scale and polish treatments with and without OHI in healthy dentate adults without severe periodontitis.

Data extraction and synthesis: Study assessment, data extraction and risk of bias assessment were carried out independently by two reviewers. Mean and standardised mean differences were calculated when different scales were reported. Fixed effects models were used as there were only a small number of studies.

Results: Three studies involving a total of 837 patients, and all considered to be at unclear risk of bias were included. No studies reported any adverse effects. Only one trial (conducted in general practice) provided data comparing scale and polish versus no scale and polish. It found no evidence to claim or refute benefit for scale and polish treatments for the outcomes of gingivitis, calculus and plaque. Two studies, both at unclear risk of bias, compared routine scale and polish provided at different time intervals. When comparing six with 12 months there was insufficient evidence to determine a difference for gingivitis at 24 months. There were some statistically significant differences in favour of scaling and polishing provided at more frequent intervals, in particular between three and 12 months for the outcome of gingivitis at 24 months, with OHI, MD -0.14 (95% CI -0.23 to -0.05; P value = 0.003) and without OHI MD -0.21 (95% CI -0.30 to -0.12; P value < 0.001) (mean per patient measured on 0-3 scale), based on one study. There was some evidence of a reduction in calculus. This body of evidence was assessed as of low quality.One study provided data for the comparison of scale and polish treatment with and without OHI. There was a reduction in gingivitis for the 12-month scale and polish treatment when assessed at 24 months MD -0.14 (95% CI -0.22 to -0.06) in favour of including OHI. There were also significant reductions in plaque for both three and 12-month scale and polish treatments when OHI was included. The body of evidence was once again assessed as of low quality.

Conclusions: There is insufficient evidence to determine the effects of routine scale and polish treatments. High quality trials conducted in general dental practice settings with sufficiently long follow-up periods (five years or more) are required to address the objectives of this review.