Comparison of cortical bone thickness and root proximity at maxillary and mandibular interradicular sites for orthodontic mini-implant placement.

OBJECTIVES: To compare maxillary and mandibular cortical bone thickness and rootic proximity for optimal mini-implant placement.

SETTING AND SAMPLE POPULATION: CT images from 14 men and 14 women were used to evaluate buccal interradicular cortical bone thickness and root proximity from mesial of the central incisor to the 2nd molar. Cortical bone thickness was measured at 0 degrees , 15 degrees , 30 degrees , and 45 degrees angles relative to the root surface using three-dimensional images.

RESULTS: For the cortical bone thickness, there was no statistically significant difference between the maxilla and the mandible in the anterior area; however, there was a significant difference in the posterior area. Cortical bone in the maxilla, mesial and distal to canine interradicular sites, was thickest while thickness in the mandible exhibited a gradual anterior to posterior increase. Cortical bone thickness in the maxilla increased as both level and angle increased, while the cortical bone thickness in the mandible was greatest at 4 mm from the alveolar crest. Root proximity mesial and distal to 2nd premolar interradicular sites was greatest.

CONCLUSION: Based on our results, cortical bone thickness depends on the interradicular site rather than sex or individual differences.