[Clinical effect of semilunar-tunnel technique in guided tissue regeneration]

Objective: To evaluate the clinical effectiveness, safety, short-term and long-term clinical and radiographic outcomes of a novel surgical approach, the semilunar-tunnel flap technique (SLTT), applied to guided tissue regeneration and to provide a theoretical basis for the exploration of a more minimally invasive, reliable and stable technique for periodontal tissue regeneration. Methods: Totally 20 patients, who received initial periodontal treatment in the Fourth Clinical Division of Peking University School and Hospital of Stomatology from January 2019 to June 2020, with at least 1 affected tooth in anterior region in the mouth and with intrabony defects were selected and randomly divided into two groups with 10 cases in each group. The test group used the SLTT technique and the control group used the modified papilla preserved technique (MPPT) for guided tissue regeneration. The changes in clinical indices such as clinical attachment level (CAL), probing depth (PD), bleeding index (BI), papilla height loss (PHL, distance from interproximal contact area to the zenith of the papilla), defect depth (distance from bone crest to bottom of the defect) before and 6 months after surgery were evaluated. The early wound healing index (EHI) at 2 weeks after surgery in each of the groups were observed. Results: There were significant reductions in PD [test group: (6.50±0.85) mm before and (2.10±0.74) mm after surgery, control group: (6.60±0.97) mm before and (2.40±0.70) mm after surgery], CAL [test group: (8.70±0.95) mm and (4.00±1.15) mm, control group: (8.40±1.17) mm and (4.50±1.18) mm], BI [test group: 3.00 (2.75, 3.00) and 1.00 (1.00, 2.00), control group: 3.00 (2.00, 3.00) and 1.00 (0.75, 1.25)] and defect depth [test group: (4.71±0.95) mm and (-0.20±0.85) mm, control group: (4.38±0.97) mm and (0.99±0.80) mm] between two groups after surgical treatments in 6 months (P<0.05). The changes in PHL [test group: (2.20±1.03) mm and (2.00±0.94) mm; control group: (1.80±1.23) mm and (2.10±0.99) mm] were not significant. The EHI at 2 weeks postoperation was significantly lower in the test group (1.30±0.48) than in the control group (2.10±0.99) (P=0.042) and the improvement in defect depth change was significantly higher in the test group [(4.91±1.18) mm] than in the control group [(3.39±0.95) mm] (P<0.05). The radiographic bone fill rate in test group (1.05±0.17) was significantly higher than that in the control group (0.78±0.14) (P=0.001). There were no significant differences in the PD, CAL, BI, and PHL change between the test and control groups. Conclusions: The SLTT technique applied to guided tissue regeneration was safe and effective. The technique allowed overgrafting in the bone defect area, obtained more effective hard tissue regeneration and achieved possibly better postoperative aesthetic results.