アブストラクト（42巻2号：神奈川歯学）

神奈川歯学

Japanese

Title　： 縦断的成長資料を用いた顎顔面の成長発育に伴う下顎の回転と咬合系の変化に関する研究
Subtitle　： 原著
Authors　： 金根満, 笹栗健一, 秋本進
Authors（kana）　：
Organization　： 神奈川歯科大学, 成長発達歯科学講座, 歯科矯正学分野
Journal　： 神奈川歯学
Volume　： 42
Number　： 2
Page　： 117-126
Year/Month　： 2007 / 12
Article　： 原著
Publisher　： 神奈川歯科大学学会
Abstract　： 「緒言」成長発育に伴う咬合系の変化は, 成長期の小児を取り扱う歯科領域において中心的な課題であり, 特に不正咬合の予防や早期治療を実践する上で重要な課題となっている. 乳歯列咬合から混合歯列咬合, さらに永久歯列咬合へと変化していく過程は, ヒトの生涯において最も咬合変化の激しい時期であり, この過程を経て機能的な咬合を完成していく重要な時期である. しかし, 同時にこれらの変化に伴って咬合系あるいは骨格系の不正が発現し易い時期でもあり, 歯科医学的に極めて関心の高い時期でもある. 顎顔面の成長発育に伴う下顎の回転, スピー弯曲の形成, 歯軸の傾斜は, 咬合の発達あるいは不正咬合の発現において重要な意味をもっている. しかし, これらの現象に関しては, なお十分な研究がなされておらず, 臨床的な応用も進んでいない. 100年以上前, Spee FG(1890)1)は, 咬合平面に弯曲があることを見出し, 咬合機能上重要であることを示唆した.
Practice　： 歯科学
Keywords　： Occlusal Plane, Tangent Law, Mandibular Rotation, Curve of Spee

English

Title　： Longitudinal study regarding mandibular rotation and occlusion development during facial growth
Subtitle　：
Authors　： Keun-Man KIM, Kenichi SASAGURI, Susumu AKIMOTO
Authors（kana）　：
Organization　： Department of Craniofacial Growth and Development Dentistry, Division of Orthodontics, Kanagawa Dental College
Journal　： Kanagawa Shigaku
Volume　： 42
Number　： 2
Page　： 117-126
Year/Month　： 2007 / 12
Article　： Original article
Publisher　： Kanagawa Odontological Society
Abstract　： It has been pointed out that mandibular growth rotation is an important phenomenon in human facial growth. During facial growth, the occlusal plane is not arbitrarily designed. It has been postulated for almost a century that the occlusal plane is curved depending on the sagittal inclination of teeth. However, some factors involved such as alteration of the vertical height of the dentition, inclination of the occlusal plane and subsequent mandibular rotation during growth are only poorly established. This study was designed to examine the inter-relation among the occlusal plane rotation, mandibular growth rotation and the establishment of tooth axis during growth and development. The materials used in this study consisted of 546 lateral cephalograms from 39 children who belong to the Kanagawa Dental College longitudinal growth study and whose records were available at 6 through 14 years of age, taken every year with radiographs. We observed their growth changes in the growing stages from the first molar eruption (Initial stage) until the completion of permanent dentition (Final stage). We measured values regarding the posture of lower faces including the mandibular rotation, the occlusal plane rotation and the tooth axis to the closing axis according to the methods previously described by Bjork et al. and Orthlieb et al. The tangent law was evaluated for the sagittal organization of the mandibular teeth by geometrical analyses. Results showed that mandibular growth rotation is associated with occlusal plane rotation which is caused by a larger vertical height increase in molars than in anterior incisors. It was also shown that the mandibular incisors followed the tangent law, but the long axis of the posterior mandibular teeth exhibited almost the same angle of approximately 15 degrees as the direction of the tangent. This tooth axis arrangement was highly dependent upon the occlusal plane rotation and the mandibular rotation during growth and development. These tooth axis angles generate a horizontal strength component with a tendency of forward tooth movement and tightening of the proximal contacts. The results of this cephalometric reference could help dentists to determine a more suitable organization of the occlusion in the sagittal plane such as in orthodontics, prosthodontics and implant dentistry.
Practice　： Dentistry
Keywords　： Occlusal Plane, Tangent Law, Mandibular Rotation, Curve of Spee