Radiographic proximity of the third molar to the inferior alveolar canal as a predictor of clinical and health related quality of life outcomes after surgical removal

Abstract

Statement of the Problem: Specific radiographic findings indicate the proximity of mandibular third molars to the inferior alveolar canal (IAC) and an increased risk of nerve injury with their removal. No data exist to document other surgical outcomes for third molars in proximity to the IAC. This study was designed to assess whether removal of third molars in proximity to the IAC delays clinical or health related quality of life (HRQOL) outcomes as compared to those distant from the IAC. Materials and Methods: Recovery data were available for 547 patients enrolled in an IRB-approved clinical trial. After third molar surgery a HRQOL instrument, designed to assess recovery for pain, lifestyle, oral function, and other symptoms, was given to the patient to be completed each day for 14 days. At each postsurgery visit clinical data were collected detailing healing treatment rendered. Based on radiographic findings, patients with at least one mandibular third molar below the occlusal plane were identified. Signs indicating proximity to the IAC assessed from a presurgery panoramic radiograph, included those affecting the root in the area of the IAC (darkening, deflection, narrowing) and those affecting the IAC itself (diversion, narrowing). Outcomes for patients with at least one of these signs were compared to those with none. Method of Data Analysis: Recovery for each HRQOL measure was defined as the median number of days for patients to reach the point where they experienced “little/no trouble or pain.” Delayed clinical recovery was defined as a postsurgery visit with treatment. Patients with a nerve deficit postsurgery were excluded from the analysis because of the possible added impact on HRQOL outcomes. Clinical and HRQOL outomes for both cohorts were compared with Cochran-Mantel-Haensel statistics (P ≤ .05). Results: Three hundred two patients had at least one third molar below the occlusal plane. One hundred fifty-five patients were not assessed further because radiographic quality precluded identification of the targeted predictor variables. Of 147 patients, 104 (69%) had at least one predictor indicating proximity to the IAC. Of 104 patients, 64 (62%) in the proximal cohort had a surgery time of at least 30 min compared to 20/46 (43%) in the distant cohort (P = .03). No other demographic/surgical differences existed between the groups. No statistical differences were found between the groups for delayed clinical healing. If a third molar was proximal to the IAC, recovery was delayed two days for worst pain (P = .01), and one day for pain medications (P = .04). Recovery for the proximal cohort was delayed two days for oral function; interference with: mouth opening (P = .01), eating a usual diet (P = .02), and chewing (P = .03). The impact on lifestyle was minimal. For other symptoms only recovery for swelling was delayed (P = .05). On postsurgery days 1–5, sensory intensity of pain was worse for the proximal cohort (P = .001), but no differences existed for pain unpleasantness. Conclusion: Radiographic proximity of third molars to the IAC is predictive of reduced HRQOL outcomes. References Rood JP, Nooraldeen Shehab BAA: The radiologic prediction of inferior alveolar nerve injury during third molar surgery. Br J Oral Surg 28:20, 1990 Phillips C, White RP Jr, Shugars DA, et al: Risk factors associated with prolonged recovery and delayed healing after third molar surgery. J Oral Maxillofac Surg 61:1436, 2003 Funding Source: Dental Foundation of North Carolina, Oral and Maxillofacial Surgery Foundation, and AAOMS.