ビデオ内視鏡を用いた咀嚼の食塊形成機能評価

Abstract

歯科補綴学の分野で従来行われてきた咀嚼機能評価の多くは,咀嚼後の試料を口腔外に取り出して評価するため,咀嚼・嚥下という一連の運動としての評価は困難であった.本研究では,摂食・嚥下障害の分野で咽頭期嚥下の評価に用いられる嚥下内視鏡検査を応用し,咀嚼・嚥下の一連の運動中に,ビデオ内視鏡を用いて食塊を直接観察し,咀嚼機能を食塊形成の点から評価することを試みた.対象は健常有歯顎者10名とした.被験食品は白色と緑色の2色米飯および2色ういろうとし,咀嚼回数を10,15,20,30回と規定して摂食させた.経鼻的に挿入したビデオ内視鏡にて,摂食中の中咽頭内の食塊を静止画にて観察し,その際,食塊の粉砕程度を粉砕度,まとまり程度を集合度,緑色と白色の混合程度を混和度とし,0,1,2の3段階の定性的評価を行った.また,1回の嚥下ごとに飲み込みやすさに関する主観的評価を視覚的アナログ尺度(Visual analogue scale:VAS)を用いて行った.米飯およびういろう摂食時において,集合度には咀嚼回数との相関は認めず,常に高い値を示した.粉砕度と混和度については,咀嚼回数の増加に伴って,高い値を示し,有意な高い正の相関が認められた(p<0.01).また,嚥下の容易さについてのVAS値と,咀嚼回数,粉砕度,混和度との間に有意な正の相関が認められた(p<0.05).以上より,これまで咽頭期の嚥下機能評価に限定されていたビデオ内視鏡が咀嚼機能評価にも十分に適用可能であることが明らかになった.また,咀嚼を十分行うことにより,形成される食塊の粉砕度や混和度が調節され,円滑な嚥下の遂行につながることが示された.In the field of prosthodontics, many methods for evaluating the masticatory function were carried out by ejection of the food bolus from the mouth. Yet, these methods could not evaluate mastication and swallowing function comprehensively. The purpose of present study is to evaluate masticatory functions during a series of masticatory and swallowing movements by using videoendoscopy (VE). Subjects are ten healthy dentulous adults without dysphagia. The test foods used were two-colored (green and white) molded rice and uirou. The test foods were consumed under the restriction on the number of mastication (10, 15, 20, and 30). The food bolus in the oropharynx was evaluated qualitatively by using VE in terms of the degree of grindability, cohesiveness, and mixing. In addition, the degree of easiness of swallowing was measured with visual analogue scale (VAS). In both rice and uirou, degree of cohesiveness showed a constant high value under all conditions. The significant correlation coefficients were observed between the number of mastication, the degree of grindability, and mixing. In addition, the significant correlation coefficients were observed between the value of VAS, degree of grindability, mixing, and the number of mastication. The present study demonstrates that VE can be applicable for evaluating the masticatory function, although the aim of VE has so far been limited to the evaluation of swallowing in the pharyngeal stage. And also, although these results suggest that adequate mastication induces smooth swallowing, it could be adjusted to the degree of grindability and mixing of food bolus by mastication