The Effect of Thermal Tempering on Fracture Resistance and Surface characterization‏ of Lithium Disilicate and Zirconia Reinforced Lithium Silicate Crowns
Nasser, K., El-Etreby, A., Nabih, S. (2023). The Effect of Thermal Tempering on Fracture Resistance and Surface characterization‏ of Lithium Disilicate and Zirconia Reinforced Lithium Silicate Crowns. EKB Journal Management System, 69(2), 1325-1332. doi: 10.21608/edj.2023.185843.2399
Khaled Nasser; Amr El-Etreby; Soha Nabih. "The Effect of Thermal Tempering on Fracture Resistance and Surface characterization‏ of Lithium Disilicate and Zirconia Reinforced Lithium Silicate Crowns". EKB Journal Management System, 69, 2, 2023, 1325-1332. doi: 10.21608/edj.2023.185843.2399
Nasser, K., El-Etreby, A., Nabih, S. (2023). 'The Effect of Thermal Tempering on Fracture Resistance and Surface characterization‏ of Lithium Disilicate and Zirconia Reinforced Lithium Silicate Crowns', EKB Journal Management System, 69(2), pp. 1325-1332. doi: 10.21608/edj.2023.185843.2399
Nasser, K., El-Etreby, A., Nabih, S. The Effect of Thermal Tempering on Fracture Resistance and Surface characterization‏ of Lithium Disilicate and Zirconia Reinforced Lithium Silicate Crowns. EKB Journal Management System, 2023; 69(2): 1325-1332. doi: 10.21608/edj.2023.185843.2399

The Effect of Thermal Tempering on Fracture Resistance and Surface characterization‏ of Lithium Disilicate and Zirconia Reinforced Lithium Silicate Crowns

Egyptian Dental Journal
Article 15, Volume 69, Issue 2 - Serial Number 4, April 2023, Page 1325-1332  XML PDF (1.13 MB)
Document Type: Original Article
DOI: 10.21608/edj.2023.185843.2399
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Authors
Khaled Nasser email orcid 1; Amr El-Etrebyorcid 2; Soha Nabihorcid 3
1Fixed Prosthodontics, Faculty of Dentistry, Delta University. Egypt
2Professor of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University. Egypt
3Lecturer of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University. Egypt
Abstract
Statement of problem: The manufacturer of newly introduced pressable ceramic claimed that the strength can be increased by subjecting the material to a thermal tempering cycle at 9% below pressing temperature after its pressing. However, the effect of this thermal tempering protocol on the fracture resistance of different heat-pressed glass ceramics is still not known.

Purpose: This in-vitro study aimed to investigate the effect of thermal tempering on the fracture resistance and microstructural features of two heat-pressed glass ceramics.

Materials and methods: A total of 28 glass-ceramic crowns were assigned into two groups according to the ceramic type (n =14): Group (A): Lithium Disilicate glass-ceramic crowns and Group (B): Zirconia Reinforced Lithium Silicate glass ceramic crowns. Crowns of each group were divided into two equal subgroups (n=7) according to the subsequent thermal tempering temperature: Subgroup (T0): crowns were not subjected to thermal tempering and subgroup (T1): crowns were subjected to a temperature of 9% below pressing temperature. Fracture resistance of all samples were tested. A two-way ANOVA test was used to study the effect of ceramic type, thermal tempering and their interactions on fracture resistance.
Results: When no thermal tempering was applied, IPS E.max press showed statistically significantly higher mean fracture resistance value than Celtra press (1819.04 N and 1286.4 N respectively). Thermal tempered Celta press crowns showed the highest fracture resistance value (1951.7 N).
Conclusions: Lithium disilicate crowns demonstrated higher fracture resistance than Zirconia-Reinforced Lithium Silicate (ZLS) crowns without tempering. Thermal tempered ZLS crowns demonstrated increase in fracture resistance.
Keywords
Keywords: Pressable ceramics; Lithium disilicate; Lithium silicate; Fracture resistance; Thermal tempering
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