アブストラクト（22巻1号：神奈川歯学）

神奈川歯学

Japanese

Title　： 臼歯用コンポジットレジンの吸水が機械的特性に及ぼす影響
Subtitle　： 原著
Authors　： 花岡孝治, 中嶋正, 久保田顕正, 熊田さえみ, 岩本次男
Authors（kana）　：
Organization　： 神奈川歯科大学保存学教室第一講座
Journal　： 神奈川歯学
Volume　： 22
Number　： 1
Page　： 158-174
Year/Month　： 1987 / 6
Article　： 原著
Publisher　： 神奈川歯科大学学会
Abstract　： 「緒言」口腔内に装用された修復物は, 種々なストレスが加わる過酷な環境条件においても形態的ならびに材質的に変化することなく, 永くその機能が維持されなければならない. 近年, 成形修復の主流としての前歯部のみならず臼歯部の実質欠損に対しても頻用されているコンポジットレジンは, 口腔内における化学的安定性をその特色の一つとするが, 高分子複合材料であるが故に水分に対して構造的欠陥を有していると考えられ, とくに, 本材が機械的特性に対する要求度の高い臼歯用として適用される場合には, 吸水による材質の劣化が修復物の破折や耐摩耗性の低下を招くことが懸念される. 臼歯用コンポジットレジンの吸水性, あるいは吸水の機械的性質に及ぼす影響に関しては, すでに多くの報告により各種物性値の低下が指摘されている. しかしながら, これらの研究において, 同一試片に対して複数のパラメーターにより吸水の影響を多角的に検討したものは少ない.
Practice　： 歯科学
Keywords　： コンポジットレジン, 破壊靱性, 吸水

English

Title　： The Influence of Water Sorption on the Mechanical Characteristics of Posterior Composite Resins
Subtitle　：
Authors　： Koji HANAOKA, Nori NAKAJIMA, Akimasa KUBOTA, Saemi KUMATA, Tsugio IWAMOTO
Authors（kana）　：
Organization　： Department of Restorative Dentistry, Kanagawa Dental College
Journal　： Kanagawa Shigaku
Volume　： 22
Number　： 1
Page　： 158-174
Year/Month　： 1987 / 6
Article　： Original article
Publisher　： Kanagawa Odontological Society
Abstract　： [Abstract]: This study was undertaken to investigate the influence of water sorption on the fracture behavior of posterior composite resin restorative material. Five posterior composite resins, P-10, Clearfil Posterior, Bell Feel, Palfique and Microrest AP were selected for the experiment while Concise, conventional composite resin, was used as a control. A rectangular specimen of 25 mm in length with a 3 mm square-section was prepared and weighed after 15 minutes storage in the artficial mouth followed by immersion in water for 1 and 7 days and 1, 2 and 3 months. After immersion in water each period, the specimen was again weighed for calculating the value of water sorption. To determine the fracture toughness of the materials by means of Indentation Microfracture (IM) method, the middle point of the bottom surface of each specimen was indented by the Vickers Hardness Tester under a 50 Kg load. The indented specimen was then subjected to the three-point-bending stress to measure the transverse strength and to examine the fatigue characteristics under repeated loads. Furthermore, the specimen fractured during the three-point-bending test was observed by SEM. Findings obtained were summarized as follows : 1) Less water sorption was detected in three hybrid type posterior composite resins and the conventional material compared with those in submicron (Palfique) and microfilled (Microrest AP) resins and the increase of water sorption was not significant in the former for more than one month immersion in water. 2) Values of the fracture toughness (Kc) in hybrid and conventional composite resins were much influenced by a relatively short period of water immersion, and the decrease of Kc value showed the close correlation with the increase of water sorption. 3) All materials demonstrated the decrease of transverse strength by water sorption. 4) By SEM observation, the wider semicircle roughened surface due to crack propagation was found beneath the indentation on the fractured surface of water absorbed hybrid composite resin. On the contrary, submicron or microfilled resins showed the scalelike exfoliation pattern on the corresponding area. 5) Crack growth in the longitudinal direction was observed adjacent to the "pre-crack zone" on the fatigue fractured surface of hybrid posterior composite resin.
Practice　： Dentistry
Keywords　：