Authors: Burch, JG. Hulen, S.
Title: The relationship of the apical foramen to the anatomic apex of the tooth root.
Journal: Oral Surg Oral Med Oral Pathol
Date: Aug 1972
Citation: 34(2):262-8
Category: Anatomical Considerations
Evidence-based Ranking: 5
Purpose/Objectives: The purpose was to make determinations of the incidence, magnitude, and direction of deviation of the major apical foramen from the anatomic apex of each root of each class tooth.

Materials & Methods: 877 fully developed, permanent teeth were selected, stained with blue ink to help id one major foramen – selected by being the largest diameter opening within 4mm of the root apex – and categorized. Measurements made first to see if the foramina deviated from the anatomic apex, if so the displacement was recorded. If there was deviation, a measurement was made to determine how much deviation then another measurement from the anatomic apex to the most occlusal point of the apical foramen. All the date was recorded, then calculated.

Results: The results were reported in tables I through VI. The frequency of deviation of the major foramen from the anatomic apex ranged from 78.0% in maxillary incisors to a maximum of 98.9% in the distal root of mandibular molars. The largest average deviation was 0.78mm in mandibular molar distal roots, and the least was in the mandibular incisors averaging only 0.46mm. The average for all roots examined was 0.59mm deviation. Certain groups deviated in one direction – mandibular – incisors showed 56.7% deviation to the buccal, canines 40.8% buccal, and molars deviation was to the distal (45.4 – 62.8%). Excluding the molars, the average deviation of the major foramina in the maxillary and mandibular arches was similar. Mandibular molars showed mesial roots having one common foramen (56 of 92).

Author’s Conclusion: The percentage of major foramina opened short of the anatomic apices ranged from 78.0% to 98.9% with a mean of 92.4%. The average distance between the foramen and the anatomic root apex was 0.59mm. This should be kept in mind during measurement, instrumentation and filling of root canals.