Repeated placement of minocycline microspheres gives small additional probing depth reductions in periodontal therapy

Abstract

Design In this 9-month multicentre, controlled trial, 748 patients with moderate to advanced periodontitis were randomised into one of three parallel groups: (1) control group (scaling alone), (2) scaling plus vehicle and (3) scaling plus minocycline microspheres. Only sites initially 5 mm or deeper were included in the statistical analysis.Intervention At baseline all patients received scaling. At baseline, 3 and 6 months placebo or minocycline microsphere groups received placebo (vehicle) or minocycline microspheres to sites with probing depth ≥5 mm.Outcome measures Probing depth (PD) measurements were taken at baseline, 1, 3, 6 and 9 months and treatment outcome was assessed as changes in PD.Results At 9 months a significant reduction in mean PD was noted in all three groups of ∼1 mm. When compared to scaling, the minocycline microspheres group displayed a significantly greater reduction in probing depth of ∼0.3 mm. This difference remained when looking into predetermined subgroups such as age, gender and smoking status.Conclusion Extrapolation from Table 2 in the Williams et al article indicates an NNT of 9. Thus, one would need to treat nine sites for one site to obtain an additional ∼0.3 mm pocket depth reduction.