楔状欠損充填材の力学的挙動に関する数値的検討．

Numerical Study of the Mechanical Behaviour of Wedge-Shaped Defect Filling Materials.

抄録

本稿では、非う蝕性歯頸部病変（NCCL）を有する歯の直接修復を扱う。NCCL欠損は徐々に成長することが可能であり、周辺組織の劣化を伴う。窩洞にセメント剤を充填する直接修復治療は、身近で一般的な治療法であると考えられている。本研究では，病変のない歯，V病変とU病変を有する歯，および歯牙修復システムのシミュレーションを行った．パラメータ化された数値歯牙モデルを構築した．欠損深さ0.8 mmと1.7 mmの2つのケースと，欠損端のフィレット半径0.1 mm，0.2 mm，0.3 mmの3つのバリアントが検討された．修復物には，Herculite XRV（Kerr Corp, Orange, CA, USA）とCharisma（Heraeus Kulzer GmbH, Hanau, Germany）という2種類のバイオマテリアルを用い，その効果を検討した．模型は，拮抗歯から100〜1000Nの垂直荷重を加えて変形させた．歯牙組織との界面領域における接触相互作用を考慮し，歯牙修復システムを検討した．研究の範囲内で，変形特性の分布の特徴や荷重レベル，欠損の深さ，「くさび」の曲率半径に対する依存性が確立された．

This paper deals with direct restorations of teeth with non-carious cervical lesions (NCCL). NCCL defects are capable of gradual growth and are accompanied by the degradation of the surrounding tissue. Direct restorative treatment, in which the cavity is filled with a cementing agent, is considered to be an accessible and common treatment option. The study included simulations of the teeth without lesions, the teeth with V and U lesions and the tooth-restorative system. Parameterised numerical tooth models were constructed. Two cases with defect depths of 0.8 mm and ~1.7 mm and three variants with fillet radii of the defect end of 0.1, 0.2 and 0.3 mm were considered. The effect of two biomaterials for restorations was studied, namely Herculite XRV (Kerr Corp, Orange, CA, USA) and Charisma (Heraeus Kulzer GmbH, Hanau, Germany). The models were deformed with a vertical load of 100 to 1000 N from the antagonist tooth. The tooth-restorative system was considered, taking into consideration the contact interaction in the interface areas with the tooth tissues. Within the limits of the research, the character of the distribution of the deformation characteristics and their dependence on the level of loading, the depth of the defect and the radius of the curvature of the "wedge" were established.