自由側咀嚼と片側咀嚼の機能の違いに関する研究

[A study on the differences in function of free-sided and unilateral chewing].

抄録

目的:

片側咀嚼では、最初に飲み込むまでの咀嚼ストローク数が多くなる。片側咀嚼では、粉砕された食物の粒子が口腔前庭に貯蔵される割合が高いと言われている。しかし、咀嚼効率に関与する咀嚼方法（自由側咀嚼か片側咀嚼か）の影響は解明されていない。そこで、自由側咀嚼と片側咀嚼が咀嚼効率に及ぼす影響を明確に表すために、自由側咀嚼と片側咀嚼の機能の違いを検討することを目的とした。

PURPOSE: Unilateral chewing requires a greater number of chewing strokes up to the point of the first swallowing. The rate of storage of ground food particles in the oral vestibule is said to be high during unilateral chewing. However, influence of the masticatory method, that is free-sided or unilateral chewing, involved in masticatory efficiency has not been elucidated. On that point, in order to clearly represent the effects that free-sided (bilateral) chewing and unilateral chewing have on the chewing efficiency, our purpose was to examine the difference of the functions of both free-sided chewing and unilateral chewing.

方法:

正常な咬合関係を有する歯列矯正者116名を被験者とし、ピーナッツを最初に飲み込むまでの咀嚼回数（咀嚼回数と略す）を自由側咀嚼と片側咀嚼で比較した。続いて、唾液分泌量、咬合力、後歯の接触点に関する計算を行った。唾液分泌量、咬合力、後歯部接触点の3項目の平均値から、全被験者を2群（高得点群、低得点群）に分類した。2群では、自由側咀嚼と片側咀嚼の回数の差をカウントした。また、2群に分けて、自由側咀嚼と片側咀嚼で、最初の嚥下直前の粗大粒子残存量を調査した。

METHODS: We used 116 dentate subjects with normal occlusal relations, and compared the number of chewing strokes for peanuts up to the point of the first swallowing (abbreviated as "chewing strokes") for both free-sided chewing and unilateral chewing. Following this, we made calculations regarding the amount of saliva secretion, occlusal force, and contact points of posterior teeth. Based on the averages of three parameters (saliva secretion, occlusal force and contact points of posterior teeth), all the subjects were classified into two groups (high score group and low score group). In the two groups, we counted the difference in the number of free-sided chewing and unilateral chewing. And also in two groups, the amount of remaining coarse particles immediately prior to the first swallowing was investigated between free-sided chewing and unilateral chewing.

結果:

自由側咀嚼の咀嚼ストローク数は、片側咀嚼の咀嚼ストローク数と比較して、すべての被験者で10％少なかった。さらに、自由側咀嚼の咀嚼ストローク数は、3つのパラメータにおいて、両群とも片側咀嚼の咀嚼ストローク数を下回った。また、唾液分泌量および咬合力低スコア群では、片側咀嚼よりも自由側咀嚼の方が粗大粒子残存量が有意に少なかった。

RESULTS: The number of chewing strokes by free-sided chewing for all subjects was 10% less than that of unilateral chewing. Furthermore, the numbers of chewing strokes by free-sided chewing were all less than those of unilateral chewing in both groups on three parameters. The amount of remaining coarse particles by free-sided chewing was significantly smaller than that of unilateral chewing in the low score group of saliva secretion and occlusal force.

結論:

唾液分泌量、咬合力、臼歯部接触点の3項目において、高得点群、低得点群ともに、片側咀嚼よりも自由側咀嚼の方が咀嚼回数が少なかった。

CONCLUSIONS: The number of chewing strokes by free-sided chewing was less than that of unilateral chewing in both of the high score group and low score group on the amount of saliva secretion, occlusal force, and contact points of posterior teeth.