Effect of Electrical Discharge Machining on Dental Y-TZP Ceramic-Resin Bonding

Abstract

Purpose The study determined (i) the effects of electrical discharge machining (EDM) on the shear-bond strength (SBS) of the bond between luting resin and zirconia ceramic and (ii) zirconia ceramic's flexural strength with the three-point bending (TPB) test. Methods Sixty 4.8 mm × 4.8 mm × 3.2 mm zirconia specimens were fabricated and divided into four groups (n = 15): SBG: sandblasted + silane, TSCG: tribochemical silica coated + silane, LTG: Er:YAG laser treated + silane, EDMG: EDM + silane. The specimens were then bonded to a composite block with a dual-cure resin cement and thermal cycled (6000 times) prior to SBS testing. The SBS tests were performed in a universal testing machine. The SBS values were statistically analyzed using ANOVA and Tukey's test. To determine flexural strength, sixty zirconia specimens were prepared and assigned to the same groups (n = 15) mentioned earlier. After surface treatment TPB tests were performed in a universal testing machine (ISO 6872). The flexural strength values were statistically analyzed using ANOVA and Tukey's test (α = 0.05). Results The bond strengths for the four test groups (mean ± SD; MPa) were as follows: SBG (Control), 12.73 ± 3.41, TSCG, 14.99 ± 3.14, LTG, 7.93 ± 2.07, EDMG, 17.05 ± 2.71. The bond strength of the EDMG was significantly higher than those of the SBG and LTG (p < 0.01). The average flexural strength values for the groups SBG (Control), TSCG, LTG and EDMG were 809.47, 800.47, 679.19 and 695.71 MPa, respectively (p > 0.05). Conclusions The EDM process improved the SBS. In addition, there was no significant adverse effect of EDM on the flexural strength of zirconia. © 2016 Japan Prosthodontic Society