Comparative Study of Fracture Resistance of Different Ceramic Restorations | ||||
| Egyptian Dental Journal | ||||
| Article 23, Volume 67, Issue 2 - Serial Number 4, April 2021, Page 1563-1569 PDF (724.55 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/edj.2021.60504.1478 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
Marwa Mogahed  1; Mahmoud Shakal2; Fatma Hasaneen3
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| 1Instructor of Fixed Prosthodontics, Faculty of Dentistry, Tanta University. | ||||
| 2Professor of Fixed Prosthodontics, Faculty of Dentistry, Tanta University | ||||
| 3Lecturer of Fixed Prosthodontics, Faculty of Dentistry, Tanta University | ||||
| Abstract | ||||
| Objective: Comparison of fracture resistance of different ceramic restorations. Methodology: 64 ceramic crowns were fabricated. They were divided into 4 equal groups according to the type of ceramic used (16 each). Group I: lithium disilicate, Group II: Zirconia reinforced lithium silicate, Group III: monolithic zirconia and Group IV: bilayered zirconia. Models of prepared teeth #14 were used as abutments. Eight sample specimens from each group were thermocycled between 55° C and 5° C. Fracture resistance was tested for the specimens. The load to fracture was recorded. Mean value for each group was calculated and differences between groups were tested for statistical significance. One fractured specimen from each group was scanned by scanning electron microscopy to determine the failure mode. Results: it was found that the highest fracture resistance mean value was recorded with monolithic zirconia group followed by lithium disilicate group then bilayered zirconia group while the lowest fracture resistance mean value was recorded for zirconia reinforced lithium silicate group and this was statistically significant. The four tested groups showed lower fracture resistance mean values after thermocycling. The fractography showed that surface defects were the origin of fracture in glass ceramic groups. While monolithic zirconia showed internal surface cracks. Conclusions: Within the limitations of this study, the following conclusions can be drawn: monolithic zirconia has the highest fracture resistance among the tested groups, while zirconia reinforced lithium silicate group has the lowest fracture resistance. Thermal aging significantly reduces the fracture resistance in the four tested groups. | ||||
| Keywords | ||||
| ceramics; fracture resistance; failure mode | ||||
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