Digital Radiographic Analysis of Mineral Density of Adjacent Alveolar Bone in Relation to the Molar Translation Rate After Use of Retromolar Implant Anchorage

Abstract

Molar translation using retromolar implants provides an unique opportunity to measure the rate of orthodontic tooth movement, because implants do not permit any reactive movement from the force. Contrast-corrected digital radiography was utilized to investigate the rate of molar translation related to the mineral density of adjacent alveolar bone. It was hypothesized that the rate of molar translation was inversely correlated with bone mineral density ahead of the moving tooth. Periapical radiographs were obtained every six months during 24 months of active treatment of eight patients (age: 24 to 48 years). Distance from three reference points (crown tip, mid-root, apex) and mineral density of four circular areas in front of the translating molar were analyzed for correlation. The primary method of analysis was the use of Pearson correlation coefficients between rate change and bone mineral density, and between rate change and age. The results showed that rate change of molar translation at the root apex was inversely correlated to the mineral density of adjacent alveolar bone. The correlations were not significant when examining the rate over the first six months; however, the correlations were significant after the second follow-up evaluation at 12 months. The correlation was also significant when using the overall means up to last follow-up visit. However, patient age was not significantly related to the rate of molar translation in this study.