Effect of Zirconia Core Thickness, Firing Cycle and Veneering Technique on Biaxial Flexural Strength of Veneering Porcelain in Porcelain Veneered Zirconia Restorations
Citation Information :
Alwthinani FK, Arora P. Effect of Zirconia Core Thickness, Firing Cycle and Veneering Technique on Biaxial Flexural Strength of Veneering Porcelain in Porcelain Veneered Zirconia Restorations. World J Dent 2022; 13 (3):191-200.
Aim: Evaluate the effect of different core thicknesses, firing cycles and veneering techniques on the biaxial flexural strength of veneering porcelain.
Materials and methods: One core material, Vita In-Ceram YZ, and one porcelain veneer material, VITA VM9, were used in this study. Vita YZ zirconia blocks were sectioned and sintered to provide slides of 1.65, 3.25, and 6.50 mm thickness. Two techniques were used to fabricate VITA VM9 porcelain veneer; Hand Layered (HL) and Pressed (PR). The assemblies were sintered as per three different firing cycles. Biaxial flexural strength was determined using a universal mechanical tester. Statistical analysis was conducted for all tests using ANOVA and Tukey post hoc test at p ≤ 0.05.
Results: In pooling all flexural strength values, for VITA VM9 porcelain, the highest value resulted by using 1.65 mm YZ core thickness (146.10 ± 23.08 MPa) while the lowest value was obtained using 6.50 mm thickness (140.91 ± 27.501 MPa). However, the difference was not statistically significant. The highest value resulted by using Cycle 2 (Heat Rate 20 C/ Min, Hold Time 2 Minutes) (154.34 ± 22.11 MPa), while the lowest value was measured using Cycle 1 (Heat Rate 55 °C/ Min, Hold Time 1 Minute) (127.42 ± 26.62 MPa), and the difference was statistically significant. In pooling all values of (HL) VITA VM9, the result was (142.66 ± 25.87) MPa which was lower than (PR) VITA VM9 (145.87 ± 25.56), but not by a statistically significant amount.
Conclusion: The effect of different YZ core thicknesses and veneering techniques on the biaxial flexural strength of VITA VM9 veneering porcelain was not statistically significant. Different firing cycles resulted in a significant effect on the biaxial flexural strength of porcelain veneer.
Clinical significance: The use of an appropriate firing cycle can help to enhance the biaxial flexural strength of porcelain veneer in zirconia-based restorations.
Piconi C, Maccauro G. Zirconia as a ceramic biomaterial. Biomaterials 1999;20(1):1–25. DOI: 10.1016/s0142-9612(98)00010-6
Blatz MB, Sadan A, Kern M. Resin ceramic bonding: a review of the literature. J Prosthet Dent 2003;89(3):268–274. DOI: 10.1067/mpr.2003.50
Kohal RJ, Klaus G. A zirconia implant-crown system: a case report. Int J Periodontics Restorative Dent 2004;24(2):147–153. PMID: 15119885.
Zinelis S, Thomas A, Syres K et al. Surface characterization of zirconia dental implant. Dent Mater 2010;26(4):295–305. DOI: 10.1016/j.dental.2009.11.079
Yildirim M, Edelhoff D, Hanisch O, et al. Ceramic abutments: a new era in achieving optimal esthetics in implant dentistry. Int J Periodontics Restorative Dent 2000;20(1):81–91. PMID: 11203552.
Keith O, Kusy RP, Whitley JQ. Zirconia brackets: an evaluation of morphology and coefficients of friction. Am J Orthod Dentofacial Orthop 1994;106(6):605–614. DOI: 10.1016/S0889-5406(94)70085-0
Koutayas SO, Kern M. All-ceramic posts and cores: the state of the art. Quintessence Int 1999;30(6):383–392. PMID: 10635273.
Tinschert J, Natt G, Mautsch W, et al. Fracture resistance of lithium disilicate-, alumina-, and zirconia-based three-unit fixed partial dentures: a laboratory study. Int J Prosthodont 2001;14(3): 231–238. PMID: 11484570.
Aboushelib MN, de Jager N, Kleverlaan CJ, et al. Microtensile bond strength of different components of core veneered all-ceramic restorations. Dent Mater 2005;21(9):984–991. DOI: 10.1016/j.dental.2005.03.013
Albakry M, Guazzato M, Swain MV. Fracture toughness and hardness evaluation of three pressable all-ceramic dental materials.J Dent 2003;31(3):181–188. DOI: 10.1016/s0300-5712(03)00025-3
Beuer F, Schweiger J, Eichberger M, et al. High-strength CAD/CAM-fabricated veneering material sintered to zirconia copings–a new fabrication mode for all-ceramic restorations. Dent Mater 2009;25(1):121–128. DOI: 10.1016/j.dental.2008.04.019
Sailer I, Pjetursson BE, Zwahlen M, et al. A systematic review of the survival and complication rates of all-ceramic and metal-ceramic reconstructions after an observation period of at least 3 years. Part II: fixed dental prostheses. Clin Oral Implants Res 2007;18(Suppl 3): 86–96. DOI: 10.1111/j.1600-0501.2007.01468.x
Zarone F, Russo S, Sorrentino R. From porcelain-fused to metal to zirconia: clinical and experimental considerations. Dent Mater 2011;27(1):83–96. DOI: 10.1016/j.dental.2010.10.024
Maria FSR, Rube'n AP, Antonio FF, et al. A prospective evaluation of zirconia anterior partial fixed dental prostheses: clinical results after seven years. J Prosthet Dent 2015;113(6):578–584. DOI: 10.1016/j.prosdent.2014.12.015
Tinschert J, Schulze KA, Natt G, et al. Clinical behavior of zirconia-based fixed partial dentures made of DC-Zirkon: 3-year results. Int J Prosthodont 2008;21(3):217–222. PMID: 18548959.
Marchack BW, Futatsuki Y, Marchack CB, et al. Customization of milled zirconia copings for all-ceramic crowns: A clinical report. J Prosthet Dent 2008;99(3):169–173. DOI: 10.1016/S0022-3913(08)00028-0
Guazzato M, Walton TR, Franlin W, et al. Influence of thickness and cooling rate on development of spontaneous cracks in porcelain/zirconia structures. Aust Dent J 2010;55(3):306–310. DOI: 10.1111/j.1834-7819.2010.01239.x
Rekow ED, Silva NRFA, Coelho PG, et al. Performance of dental ceramics challenges for improvements. J Dent Res 2011;90(8):937–952. DOI: 10.1177/0022034510391795
Alayad AS. Effect of zirconia core thickness and veneer firing cycle on the biaxial flexural strength of veneering ceramic.J Prosthodont 2018;29(1):26–33. DOI: 10.1111/jopr.12929
Lawn BR, Pajares A, Zhang Yu, et al. Materials design in the performance of all-ceramic crowns. Biomaterials 2004;25(14):2885–2892. DOI: 10.1016/j.biomaterials.2003.09.050
Swain MV. Unstable cracking (chipping) of veneering porcelain on all-ceramic dental crowns and fixed partial dentures. Acta Biomater 2009;5(5):668–1677. DOI: 10.1016/j.actbio.2008.12.016
Proos KA, Swain MV, Ironside J, et al. Influence of core thickness on a restored crown of a first premolar using finite element analysis. Int J Prosthodont 2003;16(5):474–480. PMID: 14651230.
Tan JP, Sederstrom D, Polansky JR, et al. The use of slow heating and slow cooling regimens to strengthen porcelain fused to zirconia. J Prosthet Dent 2012;107(3):163–169. DOI: 10.1016/S0022-3913(12)60050-X
Paulaa VG, Lorenzonid FC, Bonfante EA, et al. Slow cooling protocol improves fatigue life of zirconia crowns. Dent Mater 2015;31(2):77–87. DOI: 10.1016/j.dental.2014.10.005
Guess PC, Zhang Y, Thompson VP. Effect of veneering techniques on damage and reliability of Y-TZP trilayers. Eur J Esthet Dent 2009;4(3):262–276. PMID: 19704927.
Ezzat YE, Al-Rafee MA. Effect of veneering material and technique on the fracture resistance of porcelain-veneered zirconia crowns. Saudi J Oral Sci 2020;7(1):11–17. DOI: 10.4103/sjos.sjoralsci_69_18
Oh JW, Song KY, Ahn SG, et al. Effects of core characters and veneering technique on biaxial flexural strength in porcelain fused to metal and porcelain veneered zirconia. J Adv Prosthodont 2015;7(5):349–357. DOI: 10.4047/jap.2015.7.5.349
Turk AG, Ulusoy M, Yuce M, et al. Effect of different veneering techniques on the fracture strength of metal and zirconia . J Adv Prosthodont 2015;7(6):454–459. DOI: 10.4047/jap.2015.7.6.454
