Abstract: PURPOSE: To investigate the incidence of bleeding events after surgical tooth extraction in patients without withdrawal of oral anticoagulant therapy. METHODS: This prospective cohort study included 51 patients who were treated with oral anticoagulants undergoing surgical dental extractions from July 2020 through September 2020. Surgical extraction referred to a procedure requiring the elevation of a mucoperiosteal flap and/or an osteotomy. The primary predictor variables were the kinds of anticoagulant drugs, including warfarin and aspirin. The primary outcome measurement was the incidence of bleeding events after surgical dental extraction. Chi-square test was used for statistical analysis with SPSS 17.0 software package. RESULTS: Twenty-six patients taking warfarin showed 9(34.6%) bleeding episodes and 25 patients receiving aspirin presented 10 (40%) bleeding episodes 30 minutes after tooth extractions, with a total of 19(37.3%) bleeding cases(P=0.691). Bleeding complications occurred in 4 patients(15.4%) in the warfarin group and 4 patients(16%) in the aspirin group respectively, at 1 hour after tooth extractions, with a total of 8 (15.7%) bleeding complications(P=0.952). Two patients（3.9%） developed delayed bleeding more than 24 hours after operation, both underwent molar extraction while taking warfarin(P=0.157). CONCLUSIONS: No significant difference was observed between patients with bleeding after surgical extractions. It is more likely to have delayed bleeding more than 24 hours after operation in patients taking warfarin undergoing molar extraction.

Key words: Oral anticoagulant therapy, Tooth extraction, Bleeding, Warfarin, Aspirin