3次元顎運動学および咬合荷重の測定とモデリングにおける薄型電磁場センサー

Low-Profile Electromagnetic Field Sensors in the Measurement and Modelling of Three-Dimensional Jaw Kinematics and Occlusal Loading.

抄録

咀嚼時の動的咬合荷重は、歯科修復物や可撤式義歯の設計や機能評価、顎関節機能障害の評価において臨床的に重要である。本研究の目的は、歯列弓全体にわたる咀嚼および咬合時の被験者固有の動的咬合負荷を評価するためのモデリングフレームワークを開発することである。健康な成人男性1名を対象に、歯に取り付けた薄型の電磁場センサーを用いて顎運動を測定し、口腔内スキャナーを用いて咬合解剖学的構造を定量化した。試験中、被験者は両第2大臼歯、第1大臼歯、小臼歯および中切歯の間でゴム片を咀嚼し、最大圧縮した。咬合解剖学的構造、ゴムの形状、および実験的に測定されたゴムの材料特性を有限要素モデルに組み合わせました。測定された下顎運動を用いて、ゴム試料の咀嚼および咬合の運動学的シミュレーションを行った。そして、3次元的な動的咬合力と咬合面の接触圧を算出した。第一大臼歯での咀嚼と咬合では、歯列弓全体で最も大きな咬合力が生じ、切歯と第二大臼歯では大きな前方せん断力が生じた。咀嚼中、最初の歯とゴムの接触は、臼歯の頬側から完全な閉口時には舌側へと進展した。薄型の電磁場センサーは、咀嚼および咬合時の咬合荷重の有限要素モデルを駆動するのに十分な精度で、臨床的に適切な顎運動学的測定値を提供することが示された。提示されたモデリングの枠組みは、歯列弓全体にわたる生理的で動的な咬合負荷を計算するための基礎となる。

Dynamic occlusal loading during mastication is clinically relevant in the design and functional assessment of dental restorations and removable dentures, and in evaluating temporomandibular joint dysfunction. The aim of this study was to develop a modelling framework to evaluate subject-specific dynamic occlusal loading during chewing and biting over the entire dental arch. Measurements of jaw motion were performed on one healthy male adult using low-profile electromagnetic field sensors attached to the teeth, and occlusal anatomy quantified using an intra-oral scanner. During testing, the subject chewed and maximally compressed a piece of rubber between both second molars, first molars, premolars and their central incisors. The occlusal anatomy, rubber geometry and experimentally measured rubber material properties were combined in a finite element model. The measured mandibular motion was used to kinematically drive model simulations of chewing and biting of the rubber sample. Three-dimensional dynamic bite forces and contact pressures across the occlusal surfaces were then calculated. Both chewing and biting on the first molars produced the highest bite forces across the dental arch, and a large amount of anterior shear force was produced at the incisors and the second molars. During chewing, the initial tooth-rubber contact evolved from the buccal sides of the molars to the lingual sides at full mouth closure. Low-profile electromagnetic field sensors were shown to provide a clinically relevant measure of jaw kinematics with sufficient accuracy to drive finite element models of occlusal loading during chewing and biting. The modelling framework presented provides a basis for calculation of physiological, dynamic occlusal loading across the dental arch.