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Published on: September 8, 2023
Relationship between visualization of retromolar foramen and canal and mandibular canal morphology and gonial angle
Shigeo Osato1, Tadakazu Miyao2, Irika Miyao2
1dento-Oral Science Institute, #2F Fukuoka 3rd Bldg, 1-4-7, Iidabashi, Chiyoda-ku, Tokyo 102-0072, Japan; Implant Research and Educational Academy, #2F Fukuoka 3rd Bldg, 1-4-7, Iidabashi, Chiyoda-ku, Tokyo 102-0072, Japan.
Background:
The characteristics of the mandibular canal morphology and the gonial angle (GA) in the mandible where the retromolar foramen and canal (RMF/RMC) are observed remain unclear.
Purpose:
This study examined the visualization of the RMF/RMC using various methods and assessed the associations of their variations with mandibular canal morphology and GA.
Methods:
RMFs/RMCs were visualized using digital macro photography, digital panoramic radiography, and cone-beam computed tomography (CBCT) in 54 sides of 27 dried dentate mandibles. The diameter and canal morphology (A-E types) of the RMF/RMC, GA, inclination angle of the mandibular canal (IAMC), curvature of the mandibular canal (CMC), and mental angle were analyzed.
Results:
RMFs were identified in seven (25.93 %) mandibles and nine (16.67 %) sides, while RMF cecums were observed in three (11.11 %) mandibles and three (5.56 %) sides using CBCT. RMFs appeared as a single foramen on one side, with a mean diameter of 0.94 ± 0.37 mm and greater in males (by 0.56 mm). RMCs of Types A-div.1 and B-div.1 were identified. Males had significantly greater D1 height and D2 horizontal distance than females. IAMC of the RMF/RMC presence group significantly exceeded that of the RMF/RMC absence group by 6.04°. In both groups, GA was significantly negatively correlated with IAMC (r = -0.83 and -0.55, respectively); the correlation between GA and CMC was significantly higher in the presence group than in the absence group.
Conclusions:
RMF/RMC visualization was significantly better with CBCT. This study enhances our anatomical knowledge and aids surgical and anesthetic procedures regarding the retromolar area.
