Bone resorption effected by denture use and osteporosis

点击翻译按钮获取中文摘要

This study developed bone mineral density (BMD) measuring system with computed radiography (CR) and examined BMD distribution in edentulous mandible with this system.The results are as followings :1. Measuring system for BMD using computed radiography(1) The accuracy was l.4% (relative error) and the reproducibility was l.l%(CV).(2) The new method that divides mandible into small portions allows the exact measurement at the precise position in the mandible.2. Distribution of BMD in edentulous mandibleBMI of cortical bone in lingual and inferior border side decreased from incisor to molar region, however, BMD in labial or buccal side increased.BMD of cancellous bone in lingual and inferior border side decreased from incisor to premolar to molar region.However BMD in labial and buccal side showed no changes.In anterior cancellous region, BMD in inferior border side significantly showed higher than in alveolar side (p<O.OO1).In molar cancellous region, BMD in buccal side was significantly higher than in lingual side(p<O.OO1). In cancellous and cortical bone, BMD at the mylohyoid ridge was significantly higher than the surrounding areas (p<O.OOl).The great individual varoination was found ; in cortical region-near mental foramen and at alveolar crest in molar region, in cancellous region-at the lingual and the inferior border in anterior region and at the labial side 6mm anterior to the mental foramen.The conclusions are as followings :(1) BMD seems to change in accordance with places of the muscle attachment and with the route of mandibular canal.(2) The stability of implants can be best obtained by deep placement of the fixture between the mental foramina in anterior region and placement into buccal cancellous bone in molar region.(3) BMD at alveolar crest in molar region may be useful for detecting changes from denture condition.(4) The 3-D distribution of BMD in edentulous mandible may be useful for osteoporosis screening.