Abstract
Objectives- To evaluate the effect of glazing on the flexural strength of high translucent zirconia after different surface treatments.
Methods- Ninety specimens were prepared from high translucent 3Y-TZP blocks (VITA YZ® HT, VITA Zahnfabrik, Bad Säckingen, Germany) as per ISO standard 6872:2015 (3 mm × 4 mm × 30 mm). After sintering, specimens were divided into three groups (n=30): control CP (non-glazed), DG (glaze I) and IG (glaze II). Glaze materials were applied on one surface of the specimen and sintered according to the manufacturer’s instructions. Specimens were subjected to four-point bending test to measure the flexural stress and flexural extension. Surface characterisation were performed using scanning electron microscopy, energy-dispersive x-ray spectroscopy and confocal microscopy. Descriptive fractographic analysis of surfaces were conducted to observe the point of failure and fracture pattern. Data were analysed with two-parameter Weibull analysis and Kruskal-Wallis test with Dunn’s post hoc test.
Results- Group CP (647.17, 1σ = 74.71 MPa) presented higher flexural strength values compared to group DG (541.20, 1σ = 82.91 MPa) and group IG (581.10, 1σ = 59.41 MPa). Characteristic strength (σƟ) from Weibull analysis also observed higher (660.67 MPa) values for the control specimens. Confocal microscopy revealed that glazed surfaces were much rougher than control surfaces. Descriptive fractographic analysis revealed that there was no correlation between point of failure initiation and flexural strength.
Significance- Glazing significantly decreased the flexural strength and flexural extension of high translucent monolithic 3Y-TZP; however, the values for the glazed specimens were within clinically acceptable limits.