咬合力が歯周支持力の変化した歯に与える影響。三次元有限要素応力解析

Influence of Occlusal Bite Forces on Teeth with Altered Periodontal Support: A Three-Dimensional Finite Element Stress Analysis.

抄録

背景:

咀嚼力は、歯の臨床機能と耐荷重性を決定する歯根膜に様々な程度の応力とひずみを発生させる。歯に作用する複合的な力によって発生する応力を解析した研究はほとんどありません。そこで、本研究の目的は、骨の高さが正常な上顎中切歯と骨の高さが減少した上顎中切歯の歯根膜と歯槽骨にかかる様々な応力の影響を、有限要素法による応力解析を用いて比較検討することである。

Background: Masticatory forces generate various degrees of stress and strain in the periodontium of teeth which determine the clinical functions and load-bearing capacity of the teeth. There are few studies that have analyzed stress generated due to combined forces acting on the teeth. Thus, the objective of the present study was to do a comparative analysis of the influence of various stresses on the periodontal ligament and alveolar bone of maxillary central incisor with normal bone height and reduced bone height under simulated standard masticatory using finite element stress analysis.

方法論:

ANSYS社のソフトウェアを用いて歯の3Dモデルを作成しました。これらのモデルに，上顎中切歯の舌側表面に45°の角度で100Nおよび235.9Nというさまざまな斜めの力を加え，3次元の応力値を記録しました．FE解析の結果は、3D Von Mises Criteriaを用いて解析しました。

Methodology: A 3D model of the tooth was obtained with the help of ANSYS software. These models were subjected to various oblique forces, i.e., 100N and 235.9N, applied at 45° angle on the lingual surface of the maxillary central incisor and stress values were recorded in three dimensions. The results from FE analysis were analyzed using 3D Von Mises Criteria.

結果:

健全な歯周組織では、力の大きさに関わらず、歯根に最大の応力がかかり、次に皮質骨、海綿骨、PDLが続くことが観察された。骨の高さが減少した疾患歯周組織では、最大の応力がかかり、次に皮質骨、PDL、海綿骨が続くことが観察された。

Results: It was observed that in healthy periodontium; it was observed that among the periodontal structure studied, the maximum stress levels were exerted on root followed by cortical bone, cancellous bone, and PDL, irrespective of the force, as compared to the diseased periodontium, in which the bone height was reduced, the maximum stresses were on root followed by cortical bone, PDL, and cancellous bone.

結論:

歯周病治療の成功を左右する主な要因は，残存骨の高さ，歯にかかる力，歯内に発生する応力である。有限要素法は、様々な咬合力が歯根膜、歯根、皮質骨、海綿骨に与えるストレスを評価することができるため、この点において非常に重要であると考えられる。

Conclusion: The main factor governing the success of any periodontal procedure depends on the height of the remaining bone and the amount of force exerted on to the tooth and the stress generated within the tooth. The finite element method could be of substantial importance in this respect as it can assess the stresses of various occlusal forces on the periodontal ligament, root, cortical bone, and cancellous bone of teeth in a periodontally healthy and diseased state.