Combined posterior superior alveolar and anterior middle superior alveolar nerve blocks with labial infiltration versus nerve blocks alone for pain management in minimally invasive non-surgical periodontal therapy: a split-mouth randomized controlled trial

Background To compare the efficacy of combining posterior superior alveolar (PSA) block, anterior middle superior alveolar (AMSA) block, and labial infiltration of the maxillary central incisor versus PSA+AMSA alone for pain control during minimally invasive nonsurgical periodontal therapy (MINST). Methods Twenty-four patients with stage Ⅱ-Ⅲ periodontitis were enrolled in the single-center, single-blind, split-mouth randomized controlled trial. The maxillary right and left quadrants were randomized to receive either PSA+AMSA blocks and labial infiltration (test group) or PSA+AMSA alone (control group) during subgingival instrumentation. Pain levels during injection and treatment were assessed using a 100 mm visual analog scale (VAS). Primary outcomes included intraoperative and injection-related pain scores, while secondary outcomes comprised treatment duration, injection time, patient satisfaction, and adverse events. Data were analyzed using GraphPad Prism 9. Results Twenty-one subjects completed the study. No significant difference in injection pain was observed between groups (test: 22.74±14.10 mm vs. control: 20.21±12.27 mm; P =0.248). However, the test group exhibited a statistically significant reduction in intraoperative pain (test: 11.07±10.36 mm vs. control: 16.43±11.55 mm; P =0.021). Patient satisfaction was significantly higher in the test group [test: 90 (IQR 90–100) vs. control: 90 (80–90); P =0.004]. No clinically meaningful differences were detected in treatment duration or adverse event rates (P>0.05). Conclusions The combined PSA+AMSA blocks and labial infiltration protocol reduced intraoperative pain and improved satisfaction versus PSA+AMSA blocks, without prolonging treatment. Despite clinical promise, the small sample size limits generalizability, necessitating multicenter trials to validate efficacy and broader applicability. Trial registration The trial protocol was retrospectively registered in the Chinese Clinical Trial Registry (ChiCTR2400086566) on 05-07-2024.