To study the clinical effect of medical collagen sponge in the prevention of postoperative complications after extracting mandibular impacted teeth.

100 cases bilateral extraction of mandibular third molar were required as the objects of the study. Patients were randomly divided into two groups. In test group medical collagen sponge was implanted after tooth extraction, while the control group extraction did not put in any drug. The tooth socket was examined in 30 min and 7 d respectively.

Low incidence of bleeding, swelling, limitation of mouth opening and dry socket occurred in the test group, which is statistically significant with the control group (P＜0.05).

Medical collagen sponge can reduce the incidence of postoperative complications of impacted mandibular third molar extraction.