咬合接触が咀嚼運動に及ぼす機能的意義に関する臨床的研究

[A clinical study of the functional significance of the occlusal contacts on chewing movements].

抄録

本研究は、32名の若年成人を対象に、下顎第一大臼歯歯冠面の変化に応じて、咬合接触が咀嚼運動に及ぼす影響を検討することを目的とした。本研究では、コントロール、様々なタイプの咬合接触欠損、歯牙への咬合面接触の過度の状態という3つの実験要素を含んでいる。対照試験では、咀嚼運動の一貫性を試験した。次に，咬合接触欠損が咀嚼運動に及ぼす影響について検討した．すなわち，歯周機械受容欠損（感覚ブロック），歯冠接触完全欠損，歯冠面部分欠損（頬側または舌側の犬歯および傾斜）である．第3に，過大条件下での実験として，咀嚼運動に対する被験歯に与える咬合偏位干渉の影響を検討した．その結果，以下の結果が得られた．1.1.咀嚼運動の一貫性については，コントロール試験において，各被験者の日内変動パラメータの信頼性は高かったが，日間変動パラメータの信頼性は不十分であった．2.2.咬合接触欠損の影響は，歯根膜機械受容欠損，完全歯冠欠損，犬歯欠損および傾斜欠損において，咀嚼運動の経路およびリズムに有意に影響した．3.3.偏向性咬合干渉の影響は、閉口路の後方偏位、咬合点の下方偏位、閉口期の持続時間の延長、咬合期の持続時間の短縮などのパラメータにおいて有意であった。下顎第一大臼歯の片側の咬合欠損あるいは干渉状態が咀嚼運動に何らかの影響を与える可能性が示唆され，その歯に対する適切な咬合接触が咀嚼運動の経路やリズムを安定に保つのに役立つ可能性が示唆された．

The study was aimed to investigate the effects of the occlusal contacts on chewing movements according to the changes of the mandibular first molar crown surfaces in 32 young adults. The study includes three components of the experiments as the control, various types of occlusal contact defects and the excessive conditions of occlusal surface contacts on the tooth. The chewing movement consistency was tested in the control study. The effects of the occlusal contact defects to the chewing movements, i.e., a periodontal mechanoreceptive defect (sensory block), a complete defect of coronal contact, partial defects (buccal or lingual cusp and inclination) of coronal surface, were then examined. Third, the effects of the occlusal deflective interference provided for the subjected tooth to the chewing movement was examined as the experiment in the excessive condition. The results obtained were as follows: 1. The consistency of segmental single tooth chewing movements was tested in the control study and revealed highly reliable among parameters of intra-day variance, but not enough for the inter-day variance in each subject. 2. The effects of occlusal contact defects were significant to the path and the rhythm of chewing movements in a poriodontal mechanoreceptive defect, complete coronal defect, cusp and inclination defects. 3. The effects of deflective occlusal interference were significant in the parameters, such as posterior deviation during closing path and inferior deviation of occluding point, prolonged duration in the closing phase, and shortening of duration in the occluding phase. It is suggested that either the occlusal defects or the interference conditions on one side of the first mandibular molar tooth may provide some effects to the chewing movements, and that appropriate occlusal contacts for the tooth may serve to maintain stabilized the path and the rhythm during chewing movements.