Fifty patients were enrolled in this study with an average age (+/-standard deviation) of 44.28 (+/-13.05). On the coronal views cone-beam CT of the first molars, the distance between the top of the canal and alveolar crest vertical distance (VD), the distance between the upper-most point of the canal and the point perpendicular to the lingual cortical margin of the mandible lingual distance (LD), the location of the starting point of VD for reducing from the vertical reference line (VD point), and the inclination of the mandibular medial surface (lingual inclination) were measured, and a statistical evaluation was performed using SPSS for Windows version 15.0.
RESULTS:
The mean VD0 was 16.91+/-2.47 mm and VDx decreased with increasing x value. The mean LD was 5.27+/-1.36 mm. The VD began to decrease at the mean location of 6.12+/-0.96 mm from the vertical reference line. The mean lingual inclination was 1.52+/-0.72degrees.