(PR82) Evaluating the Relationship Between the Proximity of Periapical Lesion to Mandibular Canal Using CBCT and Paresthesia Occurrence After Apicoectomy

Objective: To measure the proximity between the periapical lesion to the mandibular canal on the pre-operative CBCT scan to see if paresthesia is experienced during the post-operative follow-up visit for patients who underwent apicoectomy on posterior mandibular teeth.

Methods: The selection criteria for this study were: patients who received apicoectomy surgery on posterior mandibular teeth between January 1, 2015 and December 31, 2019, patients with pre-operative CBCT scans, patients who had histological diagnosis of either periapical granuloma or periapical cyst, and patients who attended their follow-up visit within 21 days after surgery. Nine scans were evaluated for this study. One observer evaluated the CBCT scans on the Sidexis CBCT viewing software. The observer toggled all three planes of the CBCT scan until the lesion looked closest to the mandibular canal. On the coronal plane, the observer used the ruler tool to measure the closest distance between the border of the lesion and the border of the canal. Three measurements were taken for each case. Once measurements were completed the observer accessed the patient’s chart to look for reports of paresthesia during the follow-up visit.

Results: From the nine scans evaluated, the measured distance between the lesion to the mandibular canal ranged from 0.96±0.27mm to 10.04±0.23mm. The mean follow-up time was 7.67 days after surgery. None of the patients experienced post-operative paresthesia.

Conclusion: From the limited data, it was observed that periapical lesions that were as close as 0.81mm to the mandibular canal did not result in paresthesia after apicoectomy surgery.