フライドポテトを食べるときの下顎運動が顎関節の形態に及ぼす影響について

The effect of mandibular movement on temporomandibular joint morphology while eating French fries.

抄録

背景:

咀嚼の好発側は、ほとんど顎関節症の患側と同じであることが報告されています。顎関節形態のアンバランスな変化は、片側咀嚼癖と関連していることが明らかにされた。本研究の目的は、3Dモーションキャプチャシステムを用いて、フライドポテトを食べる際の下顎運動が顎関節のリモデリングに与える影響について検討することであった。

BACKGROUND: The preferred masticatory side was reported to be almost always the same as the affected side of the temporomandibular disorder. Unbalanced alterations of temporomandibular joint morphology were found to be associated with unilaterally masticatory habits. The aim of this study was to investigate the effect of the mandibular movement on the remodeling of temporomandibular joint during eating French fries using a 3D motion capture system.

方法:

顎顔面変形症でなく、健康な顎関節を持つボランティア12名を募集した。下顎と上顎の3次元モデルをコンピュータ断層撮影により作成した．被験者には，片側咀嚼でフライドポテトを食べるように指示し，その様子を3次元モーションキャプチャシステムで記録した．片側咀嚼時の切歯と顆頭の軌跡と顆頭加速度を分析した．

METHODS: Twelve volunteers with non-maxillofacial deformity and a healthy temporomandibular joint were recruited. The 3D models of the mandible and the maxilla were reconstructed according to computed tomography. The subjects were asked to eat French fries by unilaterally mastication, which was recorded by a 3D motion capture system. The trajectories of the incisors and the condyles and the condylar acceleration during unilateral mastication were analyzed.

結果:

切歯咬合時の咬筋の軌跡に左右差は認められなかった（P>0.05）．片側咀嚼時，咀嚼顆路の平均変位と加速度は，非咀嚼顆路の平均変位と加速度より有意に小さかった（P<0.05）．咀嚼顆路の軌跡角度は，非咀嚼顆路の軌跡角度よりも有意に急であった（P＜0.05）．嚥下時，下顎の明らかな運動は認められなかった．

RESULTS: During incisal biting, there was no significant difference in the condylar trajectories between the left and right sides (P>0.05). During unilateral mastication, the average displacement and acceleration of the masticatory condyles were significantly lower than those of the non-masticatory condyles (P<0.05). The trajectory angles of the masticatory condyles were significantly steeper than those of the non-masticatory condyle (P<0.05). During swallowing, there was no obvious movement of the mandible.

結論:

片側咀嚼では，顎関節窩の中で顆頭が動く部位に有意差があり，さらに顎関節の圧迫部位が異なることが分かりました．このように、片側咀嚼は、両側の顎関節のリモデリングのパターンを著しく異ならせている可能性があります。

CONCLUSIONS: Between both temporomandibular joints, unilateral mastication resulted in significant differences in the regions of the condylar movement within the articular fossa, and then caused different compressive regions of the temporomandibular joints. Thus, unilateral mastication might result in a significantly different pattern of temporomandibular joint remodeling between the two sides.