Abstract
BACKGROUND: Implementing local adjunctive therapy during scaling and root planing has become increasingly crucial for optimizing the therapeutic efficacy of periodontitis and reshaping the periodontal microecological environment. OBJECTIVE: This study aimed to reveal the additional clearance effect of local adjunctive therapy on the microbiota of periodontitis. DESIGN: An autologous randomized controlled trial included 25 periodontitis patients. After scaling and root planing, one oral side randomly received laser or minocycline, the other as control. Three hundred and seventy-six subgingival samples were collected at nine time points within 1 month for integrated analysis of microbiota and clinical indicators. RESULTS: Compared with laser adjunctive therapy, minocycline hydrochloride adjunctive therapy showed no difference in pathogen clearance rate within 6 h, but significant differences emerged in days 1, 3 and 7 (χ² test, P < 0.05). Meanwhile, within the 7-day period, the number of core bacteria of periodontitis with significant intergroup differences increased progressively over time (LDA > 2.0, P < 0.05). After 4 weeks, minocycline hydrochloride adjunctive therapy eliminated 12 more core bacteria of periodontitis than scaling and root planing alone, while significantly reduced the bleeding on probing (Wilcoxon test, p = 0.0085) and clinical attachment loss indicators (Wilcoxon test, p = 0.0456). In the long term, minocycline hydrochloride adjunctive therapy weakened microbial network connectivity, strongly influencing bacterial interactions involving Leptotrichia, Dialister and Atopobium. CONCLUSIONS: Minocycline hydrochloride local adjunctive therapy outperforms semiconductor laser local adjunctive therapy in terms of eliminating periodontitis core bacteria, improving the microbial community structure, and enhancing clinical indicators.