ABSTRACT
Introduction: Following the teeth loss, the changes in the shape and angulations of alveolar ridge happens Tomographic images can be helpful for providing the sufficient details about vertical and horizontal dimension of alveolar bone, situation of vital and anatomic structures, and deduction of surgical injuries
Objective: Considering the importance of spiral tomography in determination of mandibular canal and vertical height of alveolar ridge, we decided to use this advanced method in evaluation of the alveolar bone height from crest to mandibular canal
Materials and Methods: Three dry human mandibles were selected in this analytical study for comparison of tomography and real measurements. Cross-sectional tomographic slices with 2 mm thickness ware taken at three or four different locations distal to the mental foramen by means of Cronex Tome unit [Sordex, Helsinki Finland] in each side. These sites marked by gutta-percha filled pits. On tomographic image, a line was drawn from crest to the inferior border of mandible [MC] and the distance from crest to mandibular canal was measured on MC line. Meanwhile the distance from the crest to mandibular canal was measured. Subsequently, vertical sections were provided at the sites marked by gutta- percha, perpendicular to the lower border of the mandible by special disk .The real anatomical bone height, after estimation of magnification factor 1.5 were compared. SPSS software [version No 11.5] and sign test analysis were used in order to evaluate the statistical details
Results: In measurement of the distance between crest to mandibular canal, showed no significant difference between tomographic measurements and real dimensions. Measuring height in tomography indicated an underestimation ranging 3.7 to 0.07
Conclusion: This point that there is an underestimation in measurement of height justifies the safety of spiral tomography in estimation of distance from crest to mandibular canal. Which itself prevents serious injuries to neurovascular bundle