Assessment of position of mandibular canal in relation to mandibular plane in different growth patterns

ObjectivesTo evaluate the position and curvature of mandibular canal in relation to mandibular plane in horizontal (HG), average (AG) and vertical (VG) growth patterns.Methods100 lateral cephalograms were screened & analysed from amongst patient's records available in the institution. The growth pattern was assessed by FMA angle, Y-Axis, SN-Go-Gn angle and Jaraback's ratio, on the basis of these values, a sample was selected of 20 lateral cephalographs each in horizontal, average and vertical growth pattern. Rickett's Xi point was identified and mandibular canal was traced on each lateral cephalogram using Xi point which denotes the origin of mandibular canal. Distance between, Gonial point to Xi point, Mental foramen to mandibular plane (MF–M), Mandibular foramen to pterygoid vertical (Xi–PTV) and from deepest point on mandibular canal to mandibular plane (Mc–M) were measured to evaluate the position and curvature of mandibular canal in different growth patterns.ResultsIt was observed that, the distance from gonial point to mandibular foramen, mental foramen to mandibular border, mandibular foramen to pterygoid vertical was increased in horizontal growth pattern i.e., 22.05 mm ± 1.82, 15.12 mm ± 1.06, 57.20 mm ± 1.23, whereas it was reduced in vertical growth pattern i.e., 14.90 mm ± 1.55, 8.84 mm ± 1.41, 47.95 mm ± 2.25 respectively. Depth of curvature of mandibular canal was increased in horizontal growth pattern, 22.25 mm ± 4.89; while it was reduced in vertical growth pattern i.e., 16.32 mm ± 1.18.ConclusionsThe findings of this study showed that the position and curvature of the mandibular canal reflect the outer morphology and growth pattern of the mandible.