Mechanical Therapy With Adjunctive Minocycline Microspheres Reduces Red-Complex Bacteria in Smokers

Background: Smoking increases the risk for periodontal disease and reduces the healing response. We examined the antimicrobial and clinical effects of scaling and root planing (SRP) with and without minocycline HCl 1 mg microspheres (MM) relative to smoking status in subjects with periodontitis. Methods: A total of 127 subjects (46 never smokers, 44 former smokers, and 37 current smokers) with moderate to advanced periodontitis were randomized to receive MM + SRP (N = 62) or SRP alone (N = 65). Subgingival plaque samples collected at baseline and day 30 were examined for the presence of 40 periodontal bacteria by DNA probe analysis. Results: MM + SRP reduced red-complex bacteria (RCB) numbers and proportions to a greater extent than SRP alone, irrespective of smoking status. RCB numbers were not reduced by SRP in current smokers. The difference in the reduction in numbers of RCB by SRP relative to MM + SRP in current smokers was statistically significant (P < 0.05). Numbers and proportions of orange complex bacteria (OCB) were reduced in all groups treated with MM + SRP. Proportions of OCB increased in current smokers treated with SRP alone. In current smokers, MM + SRP significantly reduced probing depth (PD), increased clinical attachment level (CAL), and reduced bleeding on probing (BOP) to a greater extent than SRP alone (P < 0.05). Conclusions: SRP alone was ineffective at reducing numbers or proportions of RCB or OCB in current smokers, whereas MM + SRP significantly reduced both. MM + SRP also improved PD, BOP, and CAL to a greater extent than SRP alone independent of smoking status.