Development of Estimation Models of Bone Height Considering the Potential Presence of Anterior Extension of the Mandibular Canal

Purpose: To evaluate the presence of the anterior extension (AE) of the mandibular canal and to measure the bone height (BH) at different points along the extension. Materials and Methods: Cone-beam computed tomography examinations of 108 patients were bilaterally evaluated regarding the presence of the AE, and linear measurements of the AE and BH were obtained. For comparisons between sides and genders, Student t test was applied. Variations in BH measurements were assessed by a 2-way analysis of variance. Through a simple linear regression analysis, formulas were determined for calculations of the BH in the AE. Results: A right AE was detected in 76.9% and left AE in 77.8% of the samples. In the majority of the cases, the extension was of the rectilinear type. The mean length of the AE was 8.5 mm, and there was no statistically significant difference observed in relation to gender or side. It was observed that the BH increases as it approaches the midline. Conclusion: The AE of the mandibular canal must be evaluated during presurgical planning. The formulae presented in this study provide a method to calculate BH values in the interforaminal region and can be used to assist in presurgical planning, especially in the cases in which the identification of the hipodense site, which corresponds to the AE, is not evident.