Mandibular Bone Mineral Density Changes Dependet on the Denture Support. A Six Month Follow up Study

Abstract

Reduction in the height of the alveolar edentulous ridge in denture wearers is a well documented problem which depends on various local and systemic factors. Changes of bone mineral density (BMD) in denture wearers have not yet been documented in follow-up studies. The aim of this study was to determine the changes in BMD of the mandible in complete (CD) and removable free-end saddle denture wearers (RPD) during a six month period (both groups had complete dentures in the maxilla). Twenty RPD patients (5 male, 15 female) and 20 CD wearers (7 male, 13 female) participated. The BMD measurements were performed on digitised dental panoramic radiographs (DPR) with a 5 step copper stepwedge attached to each film cassette. Grey levels of each step of the stepwedge were transformed to optical density values and using the 3rd degree polynomial the regression formula was calculated for each digitised image to express BMD values of the measured region of interest (ROI) in the copper stepwedge thickness equivalents. The results revealed that the BMD values of the examined ROIs under the distal end of the CD decreased, and in contrast, the matching BMD values under the distal end of the RPD increased, during the six month period, although the changes did not reach a statistically significant level (p>0.05). The BMD values on gonion increased significantly in both examined groups (p<0.05), which was attributed to the increased load of the strain forces of the masseter muscle at gonion after the denture delivery. Supported by the Ministry of Science and Technology, Republic of Croatia, Project No. 065911