Relationship between the apices of the lower molars and mandibular canal--a radiographic study.

The study was performed on forty-six randomly chosen dry mandibles. The molar areas of each mandible were radiographed by the paralleling technique, and an additional radiograph at -20 degrees angulation of the same area was taken. Measurements of the distance between the upper border of the mandibular canal and the root apices of the first and second molars were taken. The location of the mandibular canal in the buccolingual plane was determined. The obtained data were statistically evaluated. Statistically significant symmetry of the relationship of the mandibular canal to the root apices was established between the right and left sides of the same mandible. In the majority of cases the mandibular canal was buccal to the apices of the second molar, and in the first molar area the canal was lingual to the root apices in almost half of the cases. Most frequently, the upper border of the mandibular canal was located 3.5 to 5.4 mm below the root apices of both first and second molars. In no case was the mandibular canal found in close proximity, both in the vertical and in the buccolingual planes, to the first and second molar apices.