Scaling and root planning, and locally delivered minocycline reduces the load of Prevotella intermedia in an interdependent pattern, correlating with symptomatic improvements of chronic periodontitis: a short-term randomized clinical trial

Background: To evaluate the respective or combinatory efficacy of locally delivered 2% minocycline (MO) and scaling and root planning (SRP) by assessing both clinical parameters and the loads of four main periodontal pathogens in treating chronic periodontitis (CP). Methods: Seventy adults with CP were randomly assigned to the three treatment groups: 1) SRP alone; 2) MO alone; and 3) combinatory use of SRP and MO (SRP + MO). Before and 7 days after the treatments, we evaluated both clinical parameters (pocket depth [PD] and sulcus bleeding index [SBI]) and the gene load of four main periodontal pathogens (Aggregatibacter actinomycetemcomitans [Aa], Fusobacterium nucleatum [Fn], Porphyromonas gingivalis [Pg], and Prevotella intermedia [Pi]). Results: The bacterial prevalence per patient was Aa, 31.25%; Fn, 100%; Pg, 95.31%; and Pi, 98.44%. Seven days after treatments, the three treatments could significantly reduce both PD and SBI, but not detection frequencies of the four pathogens. For PD, the reduction efficacy of SRP + MO was significantly higher than that of both MO and SRP. Only Pg responded significantly to SRP. Pg and Fn could be significantly reduced in the presence of MO. Only SRP + MO but not the respective showed a significant reduction effect on the gene load of Pi. The reduction of PD significantly correlated with the gene load of Pi (r=0.26; P=0.042) but not of the other bacteria. Conclusion: SRP and MO could reduce the load of Pi in an interdependent pattern, which correlated with symptomatic improvements of CP