Abstract: Objective: To preliminarily investigate postoperative complications, movement of impacted mandibular third molars (IMTMs) and related factors after the surgery of partial odontectomy to extract IMTMs close to inferior alveolar nerve canal (LANC).Methods: 44 IMTMs, which met the inclusive criteria, were included. They were all extracted by partial odontectomy. Occurrence of postoperative pain, dentine hypersensitivity at the 24th hour and the 7th day after partial odontectomy were recorded. At the 6th month, migration of the roots was measured. When the roots departed from the LANC, they were removed. At the 7th day after the removal, the sensory function of IAN was checked.Results: The incidence of postoperative pain was 31.8% at the 24th hour, showing a significant correlation (P<0.05) with the status of eruption and the depth of the impacted tooth. No pain was observed for all patients on the 7th day after surgery. The incidence of dentine hypersensitivity was 79.5% at the 24th hour postoperative, showing a significant correlation (P<0.05) with the status of eruption, the depth of the impacted tooth and the exposure of dental pulp. However the incidence decreased to 27.3% on the 7th day postoperative. All the roots departed from IANC, and the average moving distance was 2.5±0.6mm in the 6th month, which had a negative correlation (P<0.05) with the age. No case of IAN injury was noted following root removal.Conclusion: Partial odontectomy is a worthwhile approach to extract the IMTMs close to the IAN, as it minimizes or even eliminates the IAN injury risk and postoperative complications.

Key words: Partial odontectomy, IAN, Postoperative pain, Dentine hypersensitivity