World Journal of Dentistry

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VOLUME 10 , ISSUE 4 ( July-August, 2019 ) > List of Articles


Flexural Strength of Monolithic Zirconia after Different Surface Treatments

Hamid Neshandar Asli, Samiyeh Rahimabadi, Mehran Falahchai

Keywords : Ceramics, Crowns, Dental materials, Dental polishing, Dental porcelain, Surface properties

Citation Information : Asli HN, Rahimabadi S, Falahchai M. Flexural Strength of Monolithic Zirconia after Different Surface Treatments. World J Dent 2019; 10 (4):264-269.

DOI: 10.5005/jp-journals-10015-1653

License: CC BY-NC 4.0

Published Online: 01-08-2019

Copyright Statement:  Copyright © 2019; The Author(s).


Aim: The purpose of this study was to evaluate the effect of grinding, over-glazing, regrinding, and polishing on flexural strength of monolithic zirconia. Materials and methods: In this in vitro study, 50 bar-shaped zirconia specimens were fabricated and divided into 5 groups (n = 10) of no-treatment control group (C), grinding (G), grinding + glazing (GGl), grinding + glazing + grinding (GGlG), and grinding + glazing + grinding + polishing (GGlGP). A universal testing machine was used to measure the flexural strength. Data were analyzed using the Tukey\'s HSD test and ANOVA (p < 0.05). Results: There were significant differences between group C and other groups (p < 0.001). Group C showed the highest mean flexural strength among all groups. There was also a significant difference between groups GGlG and GGlGP (p = 0.031), and the latter group showed higher mean flexural strength. There was no significant difference between other groups (p > 0.001). Conclusion: Regrinding does not have a significant effect on flexural strength of monolithic zirconia compared with grinding. Glazing slightly decreased the flexural strength of ground zirconia surfaces, which was not statistically significant. Polishing improved the flexural strength of ground zirconia surfaces; however, their mean flexural strength was significantly lower than that of the control group. Clinical significance: Grinding may lead to significant strength reduction and decrease the durability of zirconia restorations. Therefore, polishing of ground surfaces is suggested while glazing has an adverse effect on the strength.

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  1. Sandhu R, Kheur M, Kheur S. Effect of simulated chairside grinding procedures using commercially available abrasive agents on the surface properties of zirconia. J Indian Prosthodont Soc 2017;17(1): 22–28. DOI: 10.4103/0972-4052.194938.
  2. Hjerppe J, Narhi TO, Vallittu PK, et al. Surface roughness and the flexural and bend strength of zirconia after different surface treatments. J Prosthet Dent 2016;116(4):577–583. DOI: 10.1016/j.prosdent.2016.02.018.
  3. Amaya-Pajares SP, Ritter AV, Vera Resendiz C, et al. Effect of Finishing and Polishing on the Surface Roughness of Four Ceramic Materials after Occlusal Adjustment. J Esthet Restor Dent 2016;28(6):382–396. DOI: 10.1111/jerd.12222.
  4. Mohammadibassir M, Rezvani MB, Golzari H, et al. Effect of Two Polishing Systems on Surface Roughness, Topography, and Flexural Strength of a Monolithic Lithium Disilicate Ceramic. J Prosthodont 2019;28(1):e172–e180. DOI: 10.1111/jopr.12586.
  5. Park C, Vang MS, Park SW, et al. Effect of various polishing systems on the surface roughness and phase transformation of zirconia and the durability of the polishing systems. J Prosthet Dent 2017;117(3): 430–437. DOI: 10.1016/j.prosdent.2016.10.005.
  6. Atsu SS, Kilicarslan MA, Kucukesmen HC, et al. Effect of zirconium-oxide ceramic surface treatments on the bond strength to adhesive resin. J Prosthet Dent 2006;95(6):430–436. DOI: 10.1016/j.prosdent.2006.03.016.
  7. Alao AR, Stoll R, Song XF, et al. Surface quality of yttria-stabilized tetragonal zirconia polycrystal in CAD/CAM milling, sintering, polishing and sandblasting processes. J Mech Behav Biomed Mater 2017;65:102–116. DOI: 10.1016/j.jmbbm.2016.08.021.
  8. Mohammadi-Bassir M, Babasafari M, Rezvani MB, et al. Effect of coarse grinding, overglazing, and 2 polishing systems on the flexural strength, surface roughness, and phase transformation of yttrium-stabilized tetragonal zirconia. J Prosthet Dent 2017;118(5):658–665. DOI: 10.1016/j.prosdent.2016.12.019.
  9. Huh YH, Yang EC, Park CJ, et al. In vitro evaluation of the polishing effect and optical properties of monolithic zirconia. J Prosthet Dent 2017;119(6):994–999. DOI: 10.1016/j.prosdent.2017.06.015.
  10. Chougule KJ, Wadkar AP. An In vitro Comparative Evaluation of Flexural Strength of Monolithic Zirconia after Surface Alteration Utilising Two Different Techniques. J Clin Diagn Res 2017;11(8): ZC20–ZC23. DOI: 10.7860/JCDR/2017/25177.10361.
  11. Zucuni CP, Guilardi Luís F, Rippe Marilia P, et al. Fatigue strength of yttria-stabilized zirconia polycrystals: Effects of grinding, polishing, glazing, and heat treatment. J Mech Behav Biomed Mater 2017;75:512–520. DOI: 10.1016/j.jmbbm.2017.06.016.
  12. İşeri U, Özkurt Z, Yalnız A, et al. Comparison of different grinding procedures on the flexural strength of zirconia. J Prosthet Dent 2012;107(5):309–315. DOI: 10.1016/S0022-3913(12)60081-X.
  13. Aboushelib MN, Wang H. Effect of surface treatment on flexural strength of zirconia bars. J Prosthet Dent 2010;104(2):98–104. DOI: 10.1016/S0022-3913(10)60100-X.
  14. Huh YH, Park CJ, Cho LR. Evaluation of various polishing systems and the phase transformation of monolithic zirconia. J Prosthet Dent 2016;116(3):440–449. DOI: 10.1016/j.prosdent.2016.01.021.
  15. Schatz C, Strickstrock M, Roos M, et al. Influence of Specimen Preparation and Test Methods on the Flexural Strength Results of Monolithic Zirconia Materials. Materials (Basel) 2016;9(3):E180. DOI: 10.3390/ma9030180.
  16. Bindl A, Luthy H, Mormann WH. Strength and fracture pattern of monolithic CAD/CAM-generated posterior crowns. Dent Mater 2006;22(1):29–36. DOI: 10.1016/
  17. Kosmač T, Oblak C, Jevnikar P, et al. The effect of surface grinding and sandblasting on flexural strength and reliability of Y-TZP zirconia ceramic. Dent Mater 1999;15(6):426–433. DOI: 10.1016/S0109-5641(99)00070-6.
  18. Khayat W, Chebib N, Finkelman M, et al. Effect of grinding and polishing on roughness and strength of zirconia. J Prosthet Dent 2018;119(4):626–631. DOI: 10.1016/j.prosdent.2017.04.003.
  19. Kim J-W, Covel N, Guess P, et al. Concerns of hydrothermal degradation in CAD/CAM zirconia. J Dent Res 2010;89(1):91–95. DOI: 10.1177/0022034509354193.
  20. Lai X, Si W, Jiang D, et al. Effects of small-grit grinding and glazing on mechanical behaviors and ageing resistance of a super-translucent dental zirconia. J Dent 2017;66:23–31. DOI: 10.1016/j.jdent.2017.09.003.
  21. Anusavice K, Phillips R. Phillip's Science of Dental Materials. St. Louis: Elsevier; 2003.
  22. Denry I, Kelly J. Emerging ceramic-based materials for dentistry. J Dent Res 2014;93(12):1235–1242. DOI: 10.1177/0022034514553627.
  23. Borba M, de Araújo MD, de Lima E, et al. Flexural strength and failure modes of layered ceramic structures. Dent Mater 2011;27(12): 1259–1266. DOI: 10.1016/
  24. Traini T, Gherlone E, Parabita SF, et al. Fracture toughness and hardness of a Y-TZP dental ceramic after mechanical surface treatments. Clin Oral Investig 2014;18(3):707–714. DOI: 10.1007/s00784-013-1018-z.
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