An In vitro Comparative Evaluation of Flexural Strength of Monolithic Zirconia after Surface Alteration Utilising Two Different Techniques

Abstract

Introduction: Chairside surface alteration like grinding is often done by clinicians for adjustment of zirconia restorations. To restore the surface of the prostheses, either polishing or glazing is done. However, there is a controversy which of the surface restoration technique helps regain strength of the restoration. Aim: This study was conducted to evaluate the effects of chairside surface alteration on flexural strength of Monolithic zirconia. Materials and Methods: Rectangular zirconia samples (n=30) were prepared by CAD-CAM and divided into three groups. One was control group with no alteration (n=10), second was ground and polished (n=10) and third was ground and reglazed (n=10). Flexural strength testing was performed with a three-point bend test on a universal testing machine. The collected data was statistically analysed for normal distribution using D'Agostino and Pearson omnibus normality test, one-way ANOVA and Tukeys multiple comparison test (p<0.05). Results: The mean flexural strength of the reglazed group was significantly higher (648.7 MPa) as compared to the control (507 MPa) or the polished groups (588.5 MPa). Conclusion: Statistically, reglazing increased the flexural strength as compared to polishing.

Keywords

• computer aided design
• dental polishing
• dental porcelain
• tensile strength
• zirconium oxide