Influence of tooth removal on mandibular bone response to mastication

The quantification of biomechanical response of mandibular bone to mastication is an integral component for a key in understanding the biological consequence of masticatory functions. Understanding the response of mandibular bone to external loading may also well explain the mechanisms of bone turnover. In this study, three finite element (FE) models simulating the lower second premolar, first and second molars along with their supporting structures were developed to determine stress/strain levels and distribution under different occlusal loading. The changes in stress/strain values and profiles have been investigated in three scenarios: pre-extraction of the lower first molar, post-extraction and after full healing of the extracted socket. The mastication induced equivalent strains within the supporting mandibular bone at each of these three scenarios were quantified and compared against the Frost's mechanostat theory. The results of stress/strain profiles show considerably lower magnitudes in the post-extracted and healed scenarios compared with the pre-extraction case. Following the Frost's MES hypothesis, the initial equivalent strains are related to local bone remodelling. It is found that in the extracted case the bone near the tooth socket undergoes resorption from lingual respect whilst filling the cavity, whereas in the healed case bone turnover reaches equilibrium. The results provide important data for clinical assessment of constructing dentures or other restorative devices.