Comparison of conventional and resin-modified glass-ionomer luting cements in the retention of post-crowns by fatigue loading.
Fatigue testing may be used for in vitro evaluation of luting cements, allowing comparison of materials under controlled conditions. It is recognized that glass-ionomer cements are materials which are susceptible to microcracking, even during curing prior to load application, and their failure can be related to crack propagation. The aim of this study was to compare the retention of post-crowns cemented with conventional and resin-modified glass-ionomer cements, the latter having significantly greater fracture toughness, under cyclic loads which are representative of physiological service. A custom-designed fatigue machine was used for three tests each comprising 18 specimens in a modified randomized complete block programme. Correlation of load amplitude to endurance was low, as expected from static test experience, but cement comparison was made through Kaplan-Meier survival and cumulative hazard functions. Differences in the performance of the cements were indicated, but were not statistically significant in this study, although analysis by Cox's proportional hazards model indicated that significance may be gained by a larger study.
Department of Restorative Dentistry, The Queen's University of Belfast, Northern Ireland, UK.
C A
CA
Mitchell
J F
JF
Orr
D000180:Acrylic Resins; D000818:Animals; D002417:Cattle; D002484:Cementation / Q000379:methods*; D016009:Chi-Square Distribution; D003188:Composite Resins; D003442:Crowns; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D008422:Materials Testing / Q000379:methods; D011176:Post and Core Technique; D016016:Proportional Hazards Models; D016019:Survival Analysis; D016474:Weight-Bearing
D000180:Acrylic Resins; D003188:Composite Resins; D005899:Glass Ionomer Cements; C084550:Vitremer; C045751:Aqua-cem; C084541:Fuji glass-ionomer lining cement