Assessment of Anatomical Location and Variation of Mandibular Foramen Using Cone-Beam Computed Tomography: A Cross-Sectional Study

Background: Determining the exact location of mandibular foramen is an important factor prior to Inferior Alveolar Nerve (IAN) block injection. The aim of this study is to assess the position of Mandibular Foramen (MF) and its variations using Cone-Beam Computed Tomography (CBCT). 
Methods: This study was conducted on CBCT images of 80 females and 80 males (18 to 68 years). The distance between the MF and the anterior border of ramus (A), inferior border of mandible (B), superior border of mandible (C), and occlusal plane was measured. Data were analyzed by the student t-test, bivariate correlation analysis, paired sample t-test, and Pearson’s correlation coefficient. 
Results: The mean amount of A, B and C distances, and the mean distance from the occlusal plane to the center of MF were 13.76, 24.24, 12.32, and 7.59 mm, respectively, with no significant difference between the right and left sides (p>0.05). The mean B and C distances were significantly smaller in females than males (p<0.05). The mean size of the measured angle was 43.2°. Significant correlations were noted between aging and decreased A distance, and reduction in the angle between the contralateral premolars and MF (p<0.05). 
Conclusion: Knowledge about the position of MF can enhance the surgical procedures in this region. Using a 21-25 mm needle would be associated with lower risk of needle fracture during IAN block injection. Also, needle insertion angle <45-degrees is optimal for the samples assessed in this study.