Effect of Variable Holding Time on Biaxial Strength of Conventional Sintering 4Y and 5Y PSZ
Main Article Content
Abstract
Background: The biaxial strength of dental zirconia restorations is strongly influenced by sintering environments. Variations in sintering protocols could affect zirconia materials' flexural strength.
Aim of the study: To examine the effects of varying sintering holding time settings on 4Y and 5Y PSZ translucent zirconia's biaxial flexural strength.
Materials & Methods: A digitally designed 3D STL file of disc sample was made, then using CAD CAM, the disc specimens were milled out of 4Y PSZ super translucent multilayered STML and 5Y PSZ ultratranslucent multilayered UTML zirconia ceramics (Kurary Noritake). Specimens of both two main ceramic groups were distributed into 3 subgroups and subjected to 1, 2 and 3 hours holding sintering time at 15500C. After sintering, samples were subjected to piston on 3-balls biaxial flexural strength tests, load was applied until failure occurred, strength results were statistically analyzed utilizing SPSS program and the findings were compared among groups through the use of 1-way ANOVA and T tests, level of significance was set at 0.05.
Results: According to our study findings, the 4YSTML 2 hours holding revealed highest flexural strength for tested zirconia disc samples, whereas the lowest strength values was for 5YUTML 1 hour holding.
Conclusions: At 15500C sintering temperature, translucent 4Y and 5Y PSZ zirconia showed highest biaxial flexural strength when sintered conventionally for 2 hours, the strength was affected negatively by increased and decreased holding time.
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References
Chevalier, J. (2006). What future for zirconia as a biomaterial? Biomaterials, 27(4), 535–543. https://doi.org/10.1016/j.biomaterials.2005.07.034.
Harada R, Takemoto S, Hattori M, Yoshinari M, Oda Y, Kawada E. The influence of colored zirconia on the optical properties of all-ceramic restorations. Dent Mater J 2015; 34(6):918–24. https://doi.org/10.4012/dmj.2015-171 https://doi.org/10.4012/dmj.2015-171.
Jassim ZM, Majeed MA. Comparative evaluation of the fracture strength of monolithic crowns fabricated from different all-ceramic CAD/CAM materials (in Vitro Study) Biomed Pharm J 2018; 11(3):1689–97. https://doi.org/10.13005/bpj/1538.
Zhang, Y. Lawn, B. Novel zirconia materials in dentistry, J. Dent. Res. 97 (2018) 140-147. https://doi.org/10.1177/0022034517737483.
Koçak, E.F. Y. Uçar, C. Kurtoğlu, W.M. Johnston, Color and translucency of zirconia infrastructures and porcelain-layered systems, J. Prosthet. Dent. 121 (2019) 510-516. https://doi.org/10.1016/j.prosdent.2018.08.001.
Zhang F., Inokoshi M., Batuk M., Hadermann J., Naert I., Van Meerbeek B., Vleugels J. Strength, toughness and aging stability of highly-translucent Y-TZP ceramics for dental restorations. Dent. Mater. 2016; 32: e327–e337. https://doi.org/10.1016/j.dental.2016.09.025.
Amaral M, Valandro LF, Bottino MA, Souza RO. Low-temperature degradation of a Y-TZP ceramic after surface treatments. J Biomed Mater Res B Appl Biomater 2013; 101:1387-92. https://doi.org/10.1002/jbm.b.32957.
Anusavice KJ, Shen C, Rawls HR, editors. Phillips’ science of dental materials. Dental ceramics. Twelfth Ed. St. Louis: Elsevier/Saunders; 2013. p. 418–73.
Luz JN, Kaizer MdR, Ramos NdC, Anami LC, Thompson VP, Saavedra GdSFA, et al. Novel speed sintered zirconia by microwave technology. Dent. Mater. 2021; 37(5): 875–81. https://doi.org/10.1016/j.dental.2021.02.026.
Moratal S, Gil-Flores L, Salvador MD, Suarez M, Penaranda-Foix FL, Borrell A. Study of colored on the microwave sintering behavior of dental zirconia ceramics. J. Asian Ceram Soc 2021; 9(1):188–96. https://doi.org/10.1080/21870764.2020.1860433.
Lawson NC, Maharishi A. Strength and translucency of zirconia after high-speed sintering. J Esthet Restor Dent 2020; 32(2):219–25. https://doi.org/10.1111/jerd.12524.
Lameira DP, Silva WAB, Silva FA, De Souza GM. Fracture strength of aged monolithic and bilayer zirconia-based crowns. Bio Med Res Int 2015; 19:1-7. https://doi.org/10.1155/2015/418641.
Lümkemann, Nina, and Bogna Stawarczyk. “Impact of Hydrothermal Aging on the Light Transmittance and Flexural Strength of Colored Yttria-Stabilized Zirconia Materials of Different Formulations.” The Journal of Prosthetic Dentistry 125, no. 3 (March 2021): 518–26. https://doi.org/10.1016/j.prosdent.2020.01.016.
Juntavee N, Attashu S. Effect of different sintering process on fexural strength of translucency monolithic zirconia. J Clin Exp Dent.2018; 10:e821–e30. https://doi.org/10.4317/jced.54749.
Ebeid K, Wille S, Hamdy A, Salah T, El-Etreby A, Kern M. Effect of changes in sintering parameters on monolithic translucent zirconia. Dent Mater.2014; 30:E419–E24. https://doi.org/10.1016/j.dental.2014.09.003.
Ersoy NM, Aydogdu HM, Degirmenci BU, Cokuk N, Sevimay M. The effects of sintering temperature and duration on the fexural strength and grain size of zirconia. Acta Biomater Odontol Scand. 2015; 1:43–50. https://doi.org/10.3109/23337931.2015.1068126.
https://www.kuraraynoritake.com/world/product/cad_materials/katana_zirconia.html.
International Organization for Standardization ISO 6872. International standard for dental ceramic. Geneva: International Organization for Standardization; 1995 https://www.iso.org/standard/13389.html.
Durkan R, Deste Gökay G, Şimşek H, Yilmaz B. Biaxial flexural strength and phase transformation characteristics of dental monolithic zirconia ceramics with different sintering durations: An in vitro study. J Prosthet Dent. 2022; 128:498–504. https://doi.org/10.1016/j.prosdent.2021.04.003.
Song JY, Park SW, Lee K, Yun KD, Lim HP. Fracture strength and microstructure of Y-TZP zirconia after different surface treatments. J Prosthet Dent 2013; 110:274-80. https://doi.org/10.1016/s0022-3913(13)60376-5.
Stawarczyk, B., Keul, C., Eichberger, M., Figge, D., Edelhoff, D., & Lümkemann, N. (2017). Three generations of zirconia: From veneered to monolithic. Part I. Quintessence international (Berlin, Germany: 1985), 48(5), 369–380. https://doi.org/10.3290/j.qi.a38057.
Wiedhahn K, Fritzsche G, Wiedhahn C, Schenk O. Zirconia crowns - the new standard for single-visit dentistry? Int J Comput Dent 2016; 19(1):9–26. PubMed ID (PMID): 27027100
Abd El-Ghany OS, Sherief AH. Zirconia based ceramics, some clinical and biological aspects: Review. Future Dent J 2016; 2(2):55–64. https://doi.org/10.1016/j.fdj.2016.10.002.
Jerman E, Wiedenmann F, Eichberger M, Reichert A, Stawarczyk B. Effect of high- speed sintering on the flexural strength of hydrothermal and thermo-mechanically aged zirconia materials. Dent Mater 2020; 36(9):1144–50. https://doi.org/10.1016/j.dental.2020.05.013.
Lin WS, Ercoli C, Feng C, Morton D. The effect of core material, veneering porcelain, and fabrication technique on the biaxial flexural strength and Weibull analysis of selected dental ceramics. J Prosthodontics 2012; 21:353-62. https://doi.org/10.1111/j.1532-849x.2012.00845.x.
Da J, Fraga S, Vogel GF, May LG. Influence of the geometry of ceramic specimens on biaxial flexural strength: experimental testing and finite element analysis. Ceramica 2018; 64:120–5, http://dx.doi.org/10.1590/0366-69132018643692287.
Wendler M, Belli R, Petschelt A, Mevec D, Harrer W, Lube T,. Chairside CAD/CAM materials. Part 2: flexural strength testing. Dent Mater 2017; 33:99–109, http://dx.doi.org/10.1016/j.dental.2016.10.008.
Kwon, S.J., et al., Comparison of the mechanical properties of translucent zirconia and lithium disilicate. Journal of Prosthetic Dentistry, 2018. 120(1): p. 132-137. https://doi.org/10.1016/j.prosdent.2017.08.004.
Pereira, G.K.R., et al., Mechanical reliability, fatigue strength and survival analysis of new polycrystalline translucent zirconia ceramics for monolithic restorations. Journal of the Mechanical Behavior of Biomedical Materials, 2018. 85: p. 57-65. https://doi.org/10.1016/j.jmbbm.2018.05.029.
Denry I, Kelly JR. Emerging ceramic-based materials for dentistry. J Dent Res 2014; 93:1235-42. https://doi.org/10.1177/0022034514553627.
Kulyk, V.; Duriagina, Z.; Kostryzhev, A.; Vasyliv, B.; Marenych, O. Effects of Sintering Temperature and Yttria Content on Microstructure, Phase Balance, Fracture Surface Morphology, and Strength of Yttria-Stabilized Zirconia. Appl. Sci. 2022, 12, 11617. https://doi.org/10.3390/app122211617.
Elshazly ES, El-Hout SM, Ali MES. Yttria tetragonal zirconia biomaterials: kinetic investigation. J Mater Sci Technol 2011; 27:332-7. https://doi.org/10.1016/s1005-0302(11)60070-4.
Ruiz L, Readey MJ. Effect of heat-treatment on grain size, phase assemblage and mechanical properties of 3 mol% Y-TZP. J Am Ceram Soc 1996; 79:2331-40. https://doi.org/10.1111/j.1151-2916.1996.tb08980.x.
Lubauer J., Schuenemann F.H., Belli R., Lohbauer U. Speed-sintering and the mechanical properties of 3–5 mol% Y2O3-stabilized zirconia. Odontology. 2023; 111:883–890 https://doi.org/10.1007/s10266-023-00796-y.
Dahl P, Kaus I, Zhao Z, Johnsson M, Nygren M, Wiik K, et al. Densification and properties of zirconia prepared by three different sintering techniques. Ceram Int 2007; 33:1603–10, http://dx.doi.org/10.1016/j.ceramint.2006.07.005.
Zhang F, Vanmeensel K, Inokoshi M, Batuk M, Hadermann J, Van Meerbeek B, et al. 3Y-TZP ceramics with improved hydrothermal degradation resistance and fracture toughness. J Eur Ceram Soc 2014; 34:2453–63, http://dx.doi.org/10.1016/j.jeurceramsoc.2014.02.026.
Darvell BW. Materials science for dentistry. 1st ed. Elsevier Inc.; 2009, http://dx.doi.org/10.1533/9781845696 672.163.
Trunec M. Effect of grain size on mechanical properties of 3Y-TZP ceramics. Ceram – Silikaty 2008; 52:165–71. https://www.researchgate.net/publication/282368627_.
Jenni Hjerppea , Pekka K. Vallittua, Kaj Fröbergc, Lippo V.J. Lassila. Effect of sintering time on biaxial strength of zirconium dioxide dental materials 25 (2009) 166–171 https://doi.org/10.1016/j.dental.2008.05.011.
Kulyk, V., Duriagina, Z., Vasyliv B., et al. (2021). Effects of yttria content and sintering temperature on the microstructure and tendency to brittle fracture of yttria-stabilized zirconia. Archives of Materials Science and Engineering, 109 (2), 65-79. https://doi.org/10.5604/01.3001.0015.2625.