West China Journal of Stomatology ›› 2021, Vol. 39 ›› Issue (5): 598-604.doi: 10.7518/hxkq.2021.05.016

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Distal-triangular flap design for impacted mandibular third molars: a randomized controlled trial

Liu Jiyuan(), Liu Chang, Pan Jian, Qu Tao, Hua Chengge.()   

  1. State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
  • Received:2020-12-21 Revised:2021-06-19 Online:2021-10-01 Published:2021-10-11
  • Contact: Hua Chengge. E-mail:20532465@qq.com;huacg@163.com
  • Supported by:
    Key Research and Development Foundation of Sichuan Province(2018SZ0181);Correspondence: Hua Chengge, E-mail: huacg@163.com

Abstract: Objective

This prospective study was performed to evaluate whether the distal-triangular flap was a practical alternative surgical approach for extracting mandibular third molars.


Sixty participants with impacted mandibular third molars were randomly divided into three groups: group A, distal-triangular flap; group B, Szmyd flap; and group C, envelope flap. The impacted third molars were extracted by the corresponding flapping method. During a three-month follow-up observation after the extraction, the postoperative pain, swelling, mouth opening, and periodontal status were recorded and analyzed by ANOVA and chi-square tests.


The 60 participants had successful extraction and 3-month follow-up observation. No participant suffered from postoperative infections, lower lip disorder, or tongue sensory disorders. No statistical differences were found in the postoperative symptoms and signs of the three flap designs, such as postoperative pain, swelling, mouth opening, and periodontal status (P>0.05).


The distal-triangular flap was as safe and reliable as the Szmyd and envelope flaps but more advantageous because of its convenient operative field exposure and low requirement for the patient's mouth opening. Thus, the distal-triangular flap is one of the alternative flap options for extracting impacted mandibular third molars.

Key words: mandibular third molar extraction, distal-triangular flap, Szymd flap, envelope flap, postoperative complication

CLC Number: