歯の咬耗と下顎頭位に関するX線学的研究 [in Japanese] Radiographic study of the relationship between dental attrition and condylar position [in Japanese]
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本研究は歯の咬耗, 下顎頭位および顎関節症状の相互の関連について検索することを目的として, 顎関節症状がなく顕著で生理的な歯の咬耗が広範にみられる中国吉林省農村部居住民71名 (軽度咬耗群: 30名, 高度咬耗群41名) および顎関節症状のある中国吉林省都市部住民36名を対象として, 側斜位経頭蓋投影法を行い, 得られた顎関節X線規格写真から下顎頭位を定量的に計測し, 以下の結果を得た。<BR>1. 軽度咬耗群 (30名) の下顎頭はすべて左右対称性にやや前方に位置していた。<BR>2. 高度咬耗群 (41名) 中26名 (63%) の下顎頭位は軽度咬耗群と同じであったが, 15名 (37%) は片側あるいは両側が後方に偏位していた。<BR>3. 顎関節症状のある群 (36名) の下顎頭は軽度咬耗群, 高度咬耗群よりも有意に片側あるいは両側が後方に偏位していた。<BR>以上より, 歯の咬耗によって下顎頭に偏位がみられても咀嚼系構成要素は生理的に調和し良好な機能を営んでいることが確認された。したがって, 環境に順応した生理的な歯の咬耗は, 咀嚼系の咬合と顎関節の機能的調和を保つ重要な役割を果たしていると考えられた。
This study was carried out to reveal the relation among dental attrition, condylar positions, and TMJ symptoms. The condylar positions of 71 people, who had remarkable dental attrition without TMJ symptoms (the non-symptom group), were radiographically assessed from lateral oblique transcranial radiographs using a modified Blaschke's method. The dental attrition was classified into two groups: a low-grade group (30 persons), and a severe-grade group (41 persons). Thirty-six people with TMJ symptoms (the symptom group) were also radiographically assessed, in the same manner as the non-symptom group. The condylar positions of the above groups were compared, and the results were summarized, as follows:<BR>1) In the low-grade attrition group without TMJ symptoms, the condyles were located to anterior direction near the center.<BR>2) In the severe attrition group without TMJ symptoms, the condylar positions of 26 persons (63%) were similar to that in the low-grade attrition group. However, the condylar positions of 15 persons (37%) showed more variation than in the low-grade attrition group.<BR>3) In the symptom group, the condyles were apparently located to more posterior direction than that in the low and severe attrition groups.<BR>In an environment where attrition appears conspicuously, the condyles are symmetrically located in a slightly anterior position near the center. Even if condylar dislocation is found by the attrition, masticatory elements are physiologically harmonized with a good function in some people. Consequently, physiological attrition, which adapted to the environment, plays an important role in keeping harmony between occlusion and TMJ function.
- Journal of the Japanese Society for the Temporomandibular Joint
Journal of the Japanese Society for the Temporomandibular Joint 13(1), 58-66, 2001-04-20
The Japanese Society for Temporomandibular Joint