Objective:The repair of small and medium-sized defects in the oral has always been a challenge,free skin flap and distal pedicled tissue flaps are difficult to meet clinical needs,and the traditional under-chin flap has the risk of donor-area injury.This study aims to investigate the efficacy of V-shaped folded submental flap in the repair of small-sized and medium-sized oral defects. Methods:The clinical data of 28 patients with oral defect lesions,who were hospitalized in the Department of Stomatology,Third Xiangya Hospital of Central South University from March 2019 to December 2022,were retrospectively analyzed.Patients were divided into a V-shaped folded group(17 cases)and a conventional group(11 cases)according to different surgical methods.The V-shaped folded group was treated with a V-shaped folded submental flap for postoperative soft tissue repair,while the conventional group was treated with a conventional submental flap for repair.The postoperative follow-up time was 6-48 months.The survival status,repair time,and repair effect of the 2 groups were compared. Results:There was no significant difference in flap survival rate,flap size,flap preparation time,repair surgery time,and postoperative hospital stay between the 2 groups(all P>0.05).At 6 months after the surgery,the V-shaped folded group had no difficulty in raising the head or everting the lower lip,no"cat ear"deformity in the submental skin.Scars in the V-shaped folding group were hidden at the lower edge of the mandible.The wound aesthetics and functional scores in the V-shaped folded group were significantly higher than those in the conventional group(both P<0.05). Conclusion:The V-shaped foldable submental flap has the advantages of flexible design,simple preparation,reliable blood supply,and protection of the donor area,which can effectively protect the appearance of the chin and avoid functional disorders.