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Trabecular bone ratio of the mandibular condyle according to the presence of teeth in Koreans : a micro-CT study

Other Titles
 Micro-CT로 분석한 치아 존재에 따른 한국인 아래턱뼈 관절돌기 잔기둥뼈 양의 변화 양상 
Authors
 선경훈 
Issue Date
2011
Description
Dept. of Dental Science/박사
Abstract
The mandibular condyle comprises the temporomandibular joint within the glenoid fossa of the temporal bone. During mastication, mechanical pressure from the dentition is transmitted to the trabecular bone of the mandible, and the effects of mandibular movements reach not only the mandibular body but also the mandibular condyle. The occlusal forces, which could thus affect condylar growth, vary with tooth loss, age, and sex. It is known that the trabecular bone of the mandibular condyle is denser in dentate subjects than in edentate subjects. However, since the different tooth groups (incisor, premolar, and molar) have different functions, they could exert different effects on the mandibular condyle. The aim of this study was to elucidate the bone quality of the Korean mandibular condyle according to the presence of teeth using micro-computed tomography (micro-CT), thereby clarifying the influences of tooth presence on the condylar microstructure.Thirty-one sides (24 bilateral and 7 unilateral) were prepared from fully and partially dentate Korean mandibles. The specimens were scanned and reconstructed into a 3D structure using a micro-CT system. The specimen was sectioned vertically, passing through the medial and lateral poles of the mandibular condyle (P0) to enable measurement of the trabecular bone ratio (TBR). Likewise, three additional images from the specimen were acquired from the following sections: 2 mm posterior (Pp2), 1 mm posterior (Pp1), and 1 mm anterior (Pa1) to section P0. The TBR was then measured automatically with image-analysis software. We classified all of the specimens into three groups for each region: group I [dentate at the incisor–premolar region (IP) and the molar region (M)], group II (dentate at IP and edentulous at M), and group III (edentulous at IP and M). Likewise, another three groups based on the presence of teeth in the contralateral dental arch were classified: group IV (dentate at IP and M), group V (dentate at IP and edentulous at M), and group VI (edentulous at IP and M). Mean and standard deviation values were calculated, and the t-test, one-way ANOVA and post-hoc analysis (Scheffétest) were performed to examine differences among the three groups on the ipsilateral and contralateral sides, respectively, and between the sexes.Statistical analysis indicated the presence of significant differences between all of the sectional images among the three groups from the ipsilateral side of the specimens. The mean TBR was significantly higher in the fully dentate group than in the other two groups in all sections. The results of the other three groups, classified according to the presence of the contralateral teeth, were similar to those of the corresponding ipsilateral groups. The mean TBR was higher among the males than the females in each group. However, there were no significant differences in the fully edentulous groups.The density of the trabecular bone of the mandibular condyle was significantly associated with the presence of the molars, but not the incisors or premolars. There were significant differences between males and females. The present study has provided data regarding the bone quality and quantity of the microstructure of the mandibular condyle according to the presence or absence of teeth.
URI
https://ir.ymlib.yonsei.ac.kr/handle/22282913/133525
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Appears in Collections:
2. Thesis / Dissertation (학위논문) > 2. College of Dentistry (치과대학) > Ph.D. (박사)
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