下顎前突症患者の咀嚼挙動の特徴

Characteristics of masticatory behavior of patients with mandibular prognathism.

抄録

背景:

下顎前突症患者は、その特徴的な顎顔面形態だけでなく、咀嚼機能にも不一致を示す。この形態と機能を理解することは、外科的矯正治療計画の確立や顎矯正手術後の回復のためのガイダンスとして不可欠である。しかし、外科矯正治療前後の咀嚼機能を客観的に評価した研究はまだほとんどない。特に、咀嚼回数、咀嚼速度、咀嚼時の姿勢など、毎日の食事でどのように咀嚼しているかを示す咀嚼行動については、下顎前突症患者においてまだ十分に検討されていません。本研究の目的は、下顎前突症患者の咀嚼行動を、個人差のある正常咬合患者の咀嚼行動と比較し、下顎前突症における咀嚼行動の特徴を明らかにするとともに、顎顔面形態との関連を検索することである。

BACKGROUND: Patients with mandibular prognathism exhibit not only its characteristic maxillofacial morphology but also discrepancies in stomatognathic function, and understanding this morphology and function is vital for establishing a plan for surgical orthodontic treatment or providing guidance for recovery after orthognathic surgery. However, few studies have yet addressed the objective evaluation of masticatory function before and after surgical orthodontic treatment. In particular, the masticatory behaviors that show how you chew in your daily meals, including the number of chews, chewing rate, and posture during chewing, has not yet been fully studied in patients with mandibular prognathism. The aim of this study was to compare the masticatory behaviors of patients with mandibular prognathism with that of patients with individualized normal occlusion, to clarify the characteristics of masticatory behaviors in mandibular prognathism and to search for a relationship with maxillofacial morphology.

方法:

下顎前突症患者23名（男性12名、女性11名、平均年齢17.9歳）（患者群）と、矯正治療により正常咬合となった患者23名（男性12名、女性11名、平均年齢24.4歳）（対照群）を対象とした。咀嚼行動は、参加者の右耳に装着したウェアラブル装置によって測定された。参加者が100gのおにぎりを食べている間、咀嚼回数、咀嚼速度、一口あたりの咀嚼回数、食事時間、頭頸部の姿勢などのパラメータが記録された。肥満度、咬合接触面積、側方セファログラムも測定し、咀嚼行動との関連を調べた。

METHODS: Participants were 23 patients (12 men, 11 women; mean age 17.9 years) with mandibular prognathism (patient group) and 23 patients (12 men, 11 women; mean age 24.4 years) with normal occlusion that had been achieved by orthodontic treatment (control group). Masticatory behaviors were measured by a wearable device fitted to each participant's right ear. Parameters such as number of chews, chewing rate, number of chews per bite, mealtime, and head and neck posture were recorded, while participants consumed a 100-g rice ball. Body mass index, occlusal contact area, and lateral cephalograms were also measured, and their associations with masticatory behaviors were investigated.

結果:

患者群では、咀嚼回数が少なく、食事時間が短く、頭頸部がより前傾していた。オーバージェットと頭頸部前後位との間には有意な正の相関があり、過蓋咬合と頭頸部前後位との間には有意な負の相関があった。

RESULTS: In patient group, the number of chews was lower, mealtime was shorter, and the head and neck were tilted further forward. There was a significant positive correlation between overjet and anteroposterior head and neck posture and a significant negative correlation between overbite and anteroposterior head and neck posture.

結論:

顎口腔系の形態的・機能的不一致により、患者群の咀嚼回数と咀嚼時間は短く、咀嚼時にさらに前傾していた。本研究で明らかになった下顎前突症患者の咀嚼行動の特徴は、矯正治療や顎矯正手術の前後に行動を変化させるための計画を立てる際に役立つと考えられる。

CONCLUSION: Due to morpho/functional discrepancies in the stomatognathic system, patient group chewed fewer times and for a shorter time and leaned further forward while chewing. The characteristics of the masticatory behaviors of patients with mandibular prognathism identified in the present study may be helpful when devising plans for changing behavior before and after orthodontic treatment or orthognathic surgery.