Association of biomechanical responses of the alveolar and craniofacial bones to orthodntic forces with the biologic remodelings

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A series of biomechanical stucies were conducted by use of finite element analysis in order to elucidate the association between bone remodeling in the craniofacial region and mechanical stresses.For the association of alveolar bone remodeling with mechanical stimuli from orthodonitic forces, experimental movement of rat upper molars and finite element stress analysis for the periodontium were integrated. As a result the experimental tooth movement, aging changes in the periodontium were demonstrated to substantially decrease the efficiency of tooth movement. Further, it was revealed from this study that essential factor for the reduced tooth movement was a decreases in cellular activity in the PDL pertinent to alveolar bone remodeling. These findings were then integrated with finite element stress analysis, indicating that local ncrease in stress in the compression area, which is an initiator for alveolar bone resorption and the subsequent tooth movement, may delay bone remodeling in … More adults in association with the less cellular activity.For the association of craniofacial bone remodeling with mechanical stimuli from therapeutic orthopedic and functional loadings, finite element stress analysis was applied to the naso-maxillary complex and mandible. In the naso-maxillary complex, sutural responses to orthopedic maxillary retraction forces were examined. This study demonstrated an important role of biomechanical responses of the sutures, which are also determined by the varying directions of forces, in growth and remodeling of the complex. For the temporomandibular joint (TMJ) components, stress distributions were analyzed with various craniofaical morphologies in the vertical direction.From the analysis, vertical discrepancies in the craniofacial complex were shown to highly relate to abnormal condylar resorption, occasionally experienced in daily orthodontic practice.In summary of these studies, it is concluded that various bone remodelings in the craniofacial region, irrespective of therapeutic on idiopathic ones, are highly pertinent to mechanical stresses from artificial and functional loading, which are also affected by various biologic factors. Less