X線写真による歯冠歯根比と歯槽骨破壊との関連についての研究

Abstract

This study was performed to know the relationship between crown-root ratio and periodontal bone destruction.One hundred and thirty eight sets of 14-film intra-oral roentgenographs taken from patients with light and moderate periodontal disease by dental students in senior class were used.The routine paralleling long cone technique was used. Those patients were aged from 20 to 66, 73 males and 65 females.Single rooted teeth (5-5/5-5) except molars were evaluated in respect of crown-root ratio and bone destruction.These teeth were divided into groups (54, 3, 21 12, 3, 45, 54, 3, 21 12, 3, 45) and assessed independently with regard to the relationship between crown-root ratio and periodontal bone destruction.These teeth did not have metal crowns and other large restorations such as class 2, 4 or MOD inlays.The periodontal bone height was assessed by the method of Schei et al.The anatomical crown-root ratio was determined by measuring the level of cemento-enamel junction. The bone loss from the cemento-enamel junction was measured in percentage. The measuring was carried out by three trained examiners.The lowest crown-root ratio was observed in lower canine (0.44±0.06). The highest periodontal bone destruction was recognized in lower central incisor (28.4±14.0%). There was not statistically a significant correlation between crown-root ratio and periodontal bone destruction in each group.The periodontal bone destruction in different age groups was evaluated also. The periodontal bone had a tendency to be destroyed with increasing age.