AIM: To determine the distance from the anatomical root apex to the major apical foramen and the position of the major foramen on the root apex. METHODOLOGY: Crowns of 926 human teeth were sectioned at the cementum-enamel junction. Specimens were mounted on microscope slides for measurement parallel to the long axis of the teeth. The major foramen was identified as the largest-diameter opening at the root apex. A total of 1331 root specimens were evaluated using an optical stereomicroscope to an accuracy of 0.01 mm at 40 x (+/-10) magnification. The distance from the anatomical apex to the most apical point of the major foramen was measured, and its location (central, buccal, lingual, mesial and distal) was recorded. RESULTS: The mean distance between the major foramen and the anatomical root apex was 0.69 mm; the mean distance was larger in posterior teeth (0.82 mm) and smaller in anterior teeth (0.39 mm). A wide range of anatomical apex to major foramen distances were observed in all tooth groups: the greatest distance was in maxillary molars (0.95 mm) followed by mandibular pre-molars (0.87 mm) and mandibular molars (0.80 mm). The major foramen was at the tip of the root in 40% of teeth. The most frequent deviations of the foramen were to the buccal (20%) and distal (14%). CONCLUSION: In this sample of teeth without apical resorption the distance between the major foramen and the anatomical root apex was always <1 mm. Deviation of the major foramen from the anatomic apex varied widely amongst tooth groups.
AIM: To determine the distance from the anatomical root apex to the major apical foramen and the position of the major foramen on the root apex. METHODOLOGY: Crowns of 926 human teeth were sectioned at the cementum-enamel junction. Specimens were mounted on microscope slides for measurement parallel to the long axis of the teeth. The major foramen was identified as the largest-diameter opening at the root apex. A total of 1331 root specimens were evaluated using an optical stereomicroscope to an accuracy of 0.01 mm at 40 x (+/-10) magnification. The distance from the anatomical apex to the most apical point of the major foramen was measured, and its location (central, buccal, lingual, mesial and distal) was recorded. RESULTS: The mean distance between the major foramen and the anatomical root apex was 0.69 mm; the mean distance was larger in posterior teeth (0.82 mm) and smaller in anterior teeth (0.39 mm). A wide range of anatomical apex to major foramen distances were observed in all tooth groups: the greatest distance was in maxillary molars (0.95 mm) followed by mandibular pre-molars (0.87 mm) and mandibular molars (0.80 mm). The major foramen was at the tip of the root in 40% of teeth. The most frequent deviations of the foramen were to the buccal (20%) and distal (14%). CONCLUSION: In this sample of teeth without apical resorption the distance between the major foramen and the anatomical root apex was always <1 mm. Deviation of the major foramen from the anatomic apex varied widely amongst tooth groups.