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- Title
Effects of Cyclic Loading on the Strength of All-Ceramic Materials.
- Authors
Ohyama, Takashi; Yoshinari, Masao; Oda, Yutaka
- Abstract
Purpose: To investigate the effects of fatigue on the strength of materials used in all-ceramic crowns, the biaxial flexural strength of air-ceramic restorative materials was measured with precracked and laminated specimens after cyclic loading. Materials and Methods: Two types of all-ceramic systems were used to prepare specimens: a glass-infiltrated alumina core system (In-Ceram) and a leucite-reinforced feldspathic porcelain system IPS-Empress). Monolayer and laminated disks with a diameter of about 11.75 mm and a thickness of 1.20 ± 0.05 mm were prepared. The biaxial flexural strength of the specimens that were polished and/or created with a precrack was measured. Their strength was also measured following cyclic loading. A cyclic load that was 60% of the mean breaking load of the specimens (before cyclic loading) was applied to specimens for 105 cycles in 37°C water. Results: Although 20% to 30% of the polished specimen samples fractured during cyclic loading, the biaxial flexural strength of specimens that survived the cyclic loading was nearly the same as that of specimens not subjected to the cyclic loading. The strength of the alumina system decreased with the introduction of precracks, and nearly all specimens fractured during cyclic loading. The strength of the leucite system, however, did not decrease with the presence of precracks, and no fractures were observed on these specimens during cyclic loading. Conclusion: These results suggest that although the alumina system has high flexural strength, it is more sensitive to flaws and susceptible to fatigue fracture. The effect of fatigue on the leucite system appears to be low.
- Subjects
DENTAL ceramics; DENTAL crowns; STRENGTH of materials; DENTAL materials; FLEXURE; MOUTH; DENTAL crown post &; core technique; MATERIAL fatigue
- Publication
International Journal of Prosthodontics, 1999, Vol 12, Issue 1, p28
- ISSN
0893-2174
- Publication type
Article