Journal Article

Minocycline hydrochloride ointment-assisted periodontal treatment of stage III/IV periodontitis associated with type 2 diabetes mellitus targeting Chinese people: study protocol for a randomised controlled trial

Zhao, Hongqiao, Cao, Jie, Xu, Li, Wang, Xiane, Liu, Kaining, Meng, Huanxin, Zhen, Min, Lin, Sichi, He, Lu, Yang, Gang, Hou, Jianxia, Li, Yi

2026

Overview

IntroductionScaling and root planing (SRP) combined with adjunctive antibiotic therapy is widely adopted in the management of periodontitis in patients with type 2 diabetes mellitus (T2DM), with the aims of ameliorating glycaemic control, alleviating local inflammation and facilitating periodontal tissue regeneration. As a topically administered adjunctive antibiotic for periodontal treatment, minocycline hydrochloride (MH) ointment has shown favourable clinical efficacy in systemically healthy patients with periodontitis. However, robust evidence supporting its clinical efficacy and potential glycaemic-improving effects in patients with periodontitis complicated by T2DM remains limited. The present study is designed to test the null hypothesis that no significant differences in clinical outcomes exist between SRP combined with MH and SRP alone in the management of periodontitis among patients with T2DM, with its primary objective to investigate whether MH as an SRP adjunct confers superior clinical benefits to SRP alone.Methods and analysisWe will conduct a randomised, single-blind, placebo-controlled clinical trial. 56 patients with T2DM-associated stage III/IV periodontitis will be recruited from the Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China. Eligible participants will be randomised into two groups: the experimental group will undergo SRP combined with topically administered MH ointment and the control group will undergo SRP with a matched placebo. The primary outcomes will include probing depth (PD) changes at periodontal pocket sites with a baseline PD ≥6 mm at 6 months post-baseline, with a specific focus on the percentage of such sites with PD reduced to ≤5 mm. The secondary outcomes will comprise PD changes at pocket sites with a baseline PD ≥5 mm at 6 months post-baseline, as well as clinical attachment loss, the plaque index, bleeding index, the levels of IL-1β, IL-17, calprotectin and insulin levels in gingival crevicular fluid and serum, complete blood count, blood biochemistry, including glycated haemoglobin levels, and the composition of subgingival plaques at baseline, and 2 and 6 months post-baseline.Ethics and disseminationThis study was approved by the Ethics Committee of Peking University School and Hospital of Stomatology (PKUSSIRB-2024102139b). Results will be published in a peer-reviewed scientific journal.Trial registration numberChiCTR2400092305.Protocol versionV.3.1 (date: 6 January 2026).

• Publisher: British Medical Journal Publishing Group,BMJ Publishing Group LTD,BMJ Publishing Group
• Subject: Adjuvants / Adult / Anti-Bacterial Agents - administration & dosage / Anti-Bacterial Agents - therapeutic use / Antibiotics / China / Clinical outcomes / Clinical Trial / Clinical trials / Combined Modality Therapy / Cytokines / Dental Scaling - methods / Dentistry / Dentistry and Oral Medicine / Diabetes / Diabetes Mellitus, Type 2 / Diabetes Mellitus, Type 2 - complications / East Asian People / Female / Glucose / Gum disease / Hemoglobin / Hospitals / Humans / Inflammation / Insulin resistance / Male / Metabolism / Middle Aged / Minocycline - administration & dosage / Minocycline - therapeutic use / Ointments / Periodontics / Periodontitis - complications / Periodontitis - drug therapy / Periodontitis - therapy / Protocol / Randomized Controlled Trials as Topic / Root Planing - methods / Single-Blind Method / Teeth / Treatment Outcome