A CONTROLLED CYCLIC LOADING ON THE SURFACE TREATED AND BONDED CERAMIC: STAIRCASE METHOD
이양진,
소속 상세정보
이양진 ( Yi Yang-Jin ) - 강릉대학교 치과대학 치과보철학교실
KMID : 0362420080460030298
Abstract
Statement of Problem: Effect of surface treatment of ceramic under loading does not appear to have been investigated.
Purpose: The aim of this study was to investigate the effect of surface treatment of esthetic ceramic, which is performed to increase the bonding strength, on the fracture stress under controlled cyclic loading condition.
Material and Methods: Sixty 1.0 mm-thick specimens were made from Mark II Vitablocs (Vita Zahnfabrik, Germany) and divided into 3 groups: polished (control), sandblasted, and etched. Specimens of each group were bonded to a dentin analog material base including micro-channels to facilitate the flow of water to the bonding interface. Bonded ceramics were cyclically loaded with a flat-end piston in the water (500,000 cycles, 15Hz). Following completion of cyclic loading, specimens were examined for subsurface crack formation and subsequent stress was determined and loaded to next specimen by the staircase method according to the crack existence.
Results: There were significant differences of mean fatigue limit in the sandblasted (222.86 ± 23.42 N) and etched group (222.86 ± 14.16 N) when compared to polished group (251.43 ± 10.6 N) (P<.05; Wald-type pair-wise comparison and post hoc Bonferroni test). Of cracked specimens, surface treated group showed longer crack propagation after 24 hours. All failures originated from the radial cracking without cone crack. Fracture resistance of this study was very low and comparable to failure load in the oral cavity.
Conclusion: Well controlled cyclic loading could induce clinically relevant cracks and fracture resistance of Mark II ceramic was relatively low applicable only to anterior restorations. Surface treatment of inner surface of feldspathic porcelain in the matsicatory area could influence lifetime of restorations.
키워드
Surface treatment;Ceramic;Sandblasting;Etching;Cyclic loading;Fracture
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