Fracture strength of two oxide ceramic crown systems after cyclic pre-loading and thermocycling

• Published in: Journal of oral rehabilitation 2006-09, Vol.33 (9), p.682-689
• Main Authors: VON STEYERN, P. VULT, EBBESSON, S., HOLMGREN, J., HAAG, P., NILNER, K.
• Format: Article
• Language: English
• Subjects: all-ceramic crowns; aluminium oxide; Aluminum Oxide; Compressive Strength; Crowns; dental ceramics; Dental Materials; Dental Porcelain; Dental Restoration Failure; Dental Stress Analysis; Dentistry; Denture Design - standards; Hot Temperature - adverse effects; Humans; Materials Testing - methods; Stress, Mechanical; thermocycling; Zirconium; zirconium-di-oxide
• ISSN: 0305-182X; 1365-2842; 1365-2842
• DOI: 10.1111/j.1365-2842.2005.01604.x

summary  The aim of the present study was to investigate the fracture resistance of zirconia crowns and to compare the results with crowns made of a material with known clinical performance (alumina) in away that reflects clinical aspects. Sixty crowns were made, 30 identical crowns of alumina and 30 of zirconia. Each group of 30 was randomly divided into three groups of 10 crowns that were to undergo different treatments: (i) water storage only, (ii) pre‐loading (10 000 cycles, 30–300 N, 1 Hz), (iii) thermocycling (5–55°, 5000 cycles) + pre‐loading (10 000 cycles, 30–300 N, 1 Hz). Subsequently, all 60 crowns were subjected to load until fracture occurred. There were two types of fracture: total fracture and partial fracture. Fracture strengths (N) were: group 1, alumina 905/zirconia 975 (P = 0·38); group 2, alumina 904/zirconia 1108 (P  0·05). Total fractures were more frequent in the alumina group (P