アブストラクト（19巻1号：神奈川歯学）

神奈川歯学

Japanese

Title　： 臼歯部用コンポジットレジンの破壊靱性について
Subtitle　： 原著
Authors　： 吉本壮平
Authors（kana）　：
Organization　： 東日本学園大学歯学部歯科保存学第二講座
Journal　： 神奈川歯学
Volume　： 19
Number　： 1
Page　： 19-30
Year/Month　： 1984 / 6
Article　： 原著
Publisher　： 神奈川歯科大学学会
Abstract　： 「緒言」 臼歯咬合面の実質欠損修復に適応される材料には, 強大な咬合圧に十分耐え得る強靱性が要求される. とくに修復物縁端部における材料の耐久性は, 修復物の辺縁封鎖の維持に直接的な関連を有し, 「縁端強さ」なる用語が用いられて修復材料の具備すべき性質中その重要性が最も強調されている. しかしながら, この「縁端強さ」を定量的に評価するための特殊な測定法はなく, 通常, 引張り, 曲げ, 剪断, あるいはその他の一般的な機械的性質を総合して評価するものとされて来た. 臨床の実際において, 口腔内に装用された修復物が種々の力学的要素を含む咬合圧にさらされた場合, その内部には圧縮, 引張り, 剪断などの複合した応力が生ずると考えられ, さらに修復物縁端部の形状の特殊性や咬合の繰返しによる材料の疲労現象などが加わり, その部の破壊のメカニズムをより一層複雑なものとしていると考えられる. このことは, in vitroで評価された材料の機械的性質と, in vivoにおける修復物辺縁の破折傾向との間に時として相関が認められない場合のあることによっても推測し得る.
Practice　： 歯科学
Keywords　：

English

Title　： Study on the Fracture Toughness of Posterior Composite Resin Restorative Material
Subtitle　：
Authors　： Sohei YOSHIMOTO
Authors（kana）　：
Organization　： Department of Operative Dentistry, School of Dentistry, Higashi-Nippon-Gakuen University
Journal　： Kanagawa Shigaku
Volume　： 19
Number　： 1
Page　： 19-30
Year/Month　： 1984 / 6
Article　： Original article
Publisher　： Kanagawa Odontological Society
Abstract　： There is no specific test for evaluating the edge strength of restorative materials, though it has been much emphasized in regard to the importance for this property. As it is considered that the marginal breakdown of restorations are mainly attributed to the propagation of cracks initiated in the bulk of materials during mastication, the fracture toughness is supposed to be the most requisite property to resist toward the fracture of materials themselves. In this study, therefore, the propriety in the application of the indentation method for determining the fracture toughness of posterior composite resin (3M. Co.) was examind. The indentation method is routinely being applied to the ceramics technology and is reported to be the proper and simple method to evaluate the fracture toughness of brittle materials such as ceramic and the other sintered materials. Two measurements of fracture toughness (KC1 and KC2) for posterior composite resin were calculated numerically from the values obtained by Vickers hardness test and the conventionally determined fracture toughness (KIC) by three points bending test was also calculated for comparing with the values of KC1 and KC2, respectively. On the other hand, elastic modulus of composite resin obtained from the indentation method was evaluated and compared with those from compression and transverse tests. Furthermore, the area fraction of porosity observed on the fractured surface of specimens were determined in relation to the fracture toughness of materials. Results obtaincd were as follows: 1) Linear correlation was found between crack length and diagonal of Vickers indentation. 2) Values of KC1 and KC2 obtained from indentation method were closely approximate with that of KIC. 3) From the result stated above, possibility in the application of indentation method for cvaluating the fractvre toughness of posterior composite resin was suggested. 4) It was also confirmed that the elastic modulus of the materials could be determined by the indentation method instead of use the conventional test. 5) Area fractions of porosity on the fractured surface of specimens were approximately 8 per cent and the fracture toughness of the materials were not affected by these amounts of porosity.
Practice　： Dentistry
Keywords　：