Applying microwave technology to sintering dental zirconia
Affiliations
Affiliations
Al-Amiri Dental Center, Kuwait City, Kuwait.
Abstract
Statement of problem: When sintering zirconia, conventional processing may not provide uniform heating and consumes more energy than an alternative method using microwave energy.
Purpose: The purpose of this study was to compare the surface quality, mechanical and physical properties, and dimensional stability obtained by sintering yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in a conventional furnace versus a microwave furnace.
Material and methods: Twenty bars of Y-TZP were prepared from Zircad blocks. Ten specimens were used for sintering in a conventional furnace. The remaining 10 specimens were sintered in a microwave furnace. The sintering temperature used for both techniques was 1500°C. The flexural strength of all specimens was measured with the 3-point bend test with a universal testing machine with a cross head speed of 1.0 mm/min. Density was measured by applying the Archimedes method, and specimen length, width, and thickness were measured with a digital micrometer. The phase composition and average grain size of these ceramics were examined by using X-ray diffraction, and microstructure characteristics were studied with scanning electron microscopy. Data obtained were analyzed by using independent t tests (α=.05).
Results: No significant difference between conventional and microwave sintering for either flexural strength, t18=0.49 (P=.63) or density, t18=0.07 (P=.95) was found. Specimens in both groups exhibited a uniform firing shrinkage of approximately 24.6% in all dimensions. The surface of selected specimens examined with a scanning electron microscope showed no visible difference in grain shape or porosity size between the 2 sintering methods.
Conclusions: Under the conditions of this study, it appears that either microwave or conventional zirconia sintering may be used for processing zirconia for dental use. However, microwave energy provides uniformity of heating, allowing the use of higher heating rates, which can increase productivity and save energy.
Similar articles
[Translucency of dental zirconia ceramics sintered in conventional and microwave ovens].
Yuemei J, Ying Y, Wenhui Z, Guoxin H, Qiuxia Y.Hua Xi Kou Qiang Yi Xue Za Zhi. 2015 Dec;33(6):642-5. doi: 10.7518/hxkq.2015.06.019.PMID: 27051961 Free PMC article. Chinese.
Catramby MF, do Vale AL, Dos Santos HES, Elias CN.J Prosthet Dent. 2021 May;125(5):824.e1-824.e8. doi: 10.1016/j.prosdent.2021.01.022. Epub 2021 Mar 26.PMID: 33775390
Effect of hydrothermal degradation on three types of zirconias for dental application.
Flinn BD, Raigrodski AJ, Singh A, Mancl LA.J Prosthet Dent. 2014 Dec;112(6):1377-84. doi: 10.1016/j.prosdent.2014.07.015. Epub 2014 Sep 30.PMID: 25277037
Jerman E, Wiedenmann F, Eichberger M, Reichert A, Stawarczyk B.Dent Mater. 2020 Sep;36(9):1144-1150. doi: 10.1016/j.dental.2020.05.013. Epub 2020 Jun 30.PMID: 32620333 Review.
Ahmed WM, Troczynski T, McCullagh AP, Wyatt CCL, Carvalho RM.J Esthet Restor Dent. 2019 Sep;31(5):423-430. doi: 10.1111/jerd.12492. Epub 2019 May 29.PMID: 31140674 Review.
Cited by
Bennett C, Sojithamporn P, Thanakulwattana W, Wattanutchariya W, Leksakul K, Nakkiew W, Jantanasakulwong K, Rachtanapun P, Suhr J, Sawangrat C.Materials (Basel). 2022 Dec 2;15(23):8618. doi: 10.3390/ma15238618.PMID: 36500111 Free PMC article.
Fit of tooth-supported zirconia single crowns-A systematic review of the literature.
Ahmed WM, Shariati B, Gazzaz AZ, Sayed ME, Carvalho RM.Clin Exp Dent Res. 2020 Dec;6(6):700-716. doi: 10.1002/cre2.323. Epub 2020 Sep 3.PMID: 32885613 Free PMC article.
Weng MH, Lin CX, Huang CS, Tsai CY, Yang RY.Materials (Basel). 2020 Mar 27;13(7):1546. doi: 10.3390/ma13071546.PMID: 32230850 Free PMC article.
Influence of Aging on Biaxial Flexural Strength and Hardness of Translucent 3Y-TZP.
Moqbel NM, Al-Akhali M, Wille S, Kern M.Materials (Basel). 2019 Dec 19;13(1):27. doi: 10.3390/ma13010027.PMID: 31861613 Free PMC article.
Strength and aging resistance of monolithic zirconia: an update to current knowledge.
Kontonasaki E, Giasimakopoulos P, Rigos AE.Jpn Dent Sci Rev. 2020 Dec;56(1):1-23. doi: 10.1016/j.jdsr.2019.09.002. Epub 2019 Nov 14.PMID: 31768195 Free PMC article. Review.