Objective: This preliminary study was planned to provide information about preoperative mandibular canal (MC) position and the postoperative positional changes of MC and length in three dimensions, with the purpose of providing some assistance in reducing inferior alveolar neurosensory disturbance (IAND).Methods: MC was examined on CBCT data using SimPlant Pro Standalone 13.0. MC locations were measured in all dimensions, with respect to mandibular bony borders. Results:The results showed that MC is frequently located in the midthird of the ramus anteroposteriorly and superoinferiorly and in the midthird of the corpus superoinferiorly. Postoperatively, ramus width was increased, ramus length was decreased significantly, and MC was repositioned laterally and inferiorly. MC length was decreased on both sides, non-correlated with the set-back amounts. Conclusion:Preoperative results may be beneficial for the prediction of MC position for surgeons, and postoperative results will be used for the following studies to correlate postoperative positional changes with IAND.

Purpose: Inferior alveolar neurosensory disturbance (IAND) is the most common complication of bilateral sagittal split osteotomy (BSSO). The aim of the present study was to evaluate IAND with subjective tests postoperatively and assess the relationship between three-dimensional measurements of the mandibular canal (MC) and IAND. Methods: Eighteen patients (Mean age: 24.05 AE 5.85 years) treated withBSSOwereretrievedfromthearchive.Subjectivetests(lighttouch, tactile sensitivity, 2-point discrimination, brush-stroke directional discrimination, sharp/blunt discrimination, dental vitality, questionnaire) and three-dimensional measurements related to MC and fixation screws were done postoperatively (on average 20.43 AE 8.76 monthsaftersurgery).StatisticalsignificancewassetatP < 0.05. Results: Subjective test results were found compatible with each other except brush-stroke directional discrimination test. According to the questionnaire, IAND was apparent in all patients immediately after surgery, and recovery after 1 to 2 years was statistically significant (P < 0.05). Preoperative ramus width, medial and lateral cancellous bone lengths, the decrease in MC length, and the presence of screw in MC were not related to IAND (P < 0.05). Conclusions: There is a high incidence of IAND following BSSO, and the subjective tests are efficient to evaluate the disturbance. Spontaneous recovery of the nerve occurs during the follow-up periods. Instead of preoperative measurements of bone thickness, MC length, and the position of fixation screws, the surgical procedure seems to be more important in IAND occurrence.

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