Estrogen deficiency increases variability of tissue mineral density of alveolar bone surrounding teeth

Abstract

Objective Estrogen deficiency increases bone remodeling leading to increased variability of tissue mineral density (TMD). Due to the functional demands of mastication, alveolar bone around teeth is inherently a highly remodeled region of bone tissue with a highly variable distribution of TMD. This study investigated the effect of estrogen deficiency on the TMD distribution of alveolar bone. Design Using three-dimensional micro-computed tomography images of sham surgery (Sham) and ovariectomized (OVX) rat mandible sections, alveolar bone region (AB) and control bone region (CB) of interest were isolated. Based on histograms of gray levels equivalent to TMD values, mean (Mean), standard deviation (SD) and coefficient of variation (COV = SD/Mean) were computed. Fifth and 95th percentile gray level values were also obtained (Low 5 and High 5, respectively). Absolute value of percentage (%) differences of the gray level parameters between AB and CB regions were computed. Results Both SD and COV were significantly higher in AB region than those in CB region for all specimens of both Sham and OVX groups ( p < 0.001). The mean values of % differences for SD were moderately higher ( p < 0.073) and those for COV and Low 5 were significantly higher for the OVX group than for the Sham group ( p < 0.04). Conclusions Higher variability of mineralization observed in AB of OVX group indicates that estrogen deficiency amplifies the active bone remodeling of AB already present due to the mastication. These findings provide an insight that the increased variability of TMD induced by estrogen deficiency may compromise the mechanical stability of the tooth-bearing alveolar bone.