Can low-fusing glass application affect the marginal misfit and bond strength of Y-TZP crowns?

Abstract

To evaluate the effect of different surface treatments on the marginal misfit and retentive strength between Y-TZP crowns and an epoxy resin. Forty (40) epoxy resin (G10) abutments (height: 5mm, conicity: 60, finish line: large chamfer) with equal dimensions were milled and included in polyurethane to simulate the periodontal ligament. Next, 40 Y-TZP crowns (thickness: 1mm) were milled (Cerec inLab) and randomly divided into four groups (n=10) according to the surface treatment: GS(glaze spray), GP(glaze powder/liquid), P(zirconia primer) and RS(tribochemical silica coating).The conditioned surfaces were cemented with dual self-adhesive cement, light cured and submitted to thermomechanical cycling (2x106, 100N, 4Hz, 5º/55ºC). Marginal misfit was analyzed by a stereomicroscope and SEM. Retentive strength test was performed (1mm/min) until crown debonding. Glaze layer thickness was also performed to GS and GP groups. Marginal misfit data were analyzed by Kruskal Wallis and Dunn tests; one-way ANOVA and Tukey (5%) analyzed the tensile strength data. The marginal misfit of the GS (48.6±19.9μm) and GP (65.4±42.5μm) were statistically lower than the RS (96±62.9μm) and P (156±113.3μm) (p=0.001).The retentive strength of the GP (470.5±104.1N) and GS (416.8±170.2N) were similar to the P (342.1±109.7N), but statistically higher than those of the RS (208.9±110N). The GS and GP glaze layer was 11.64μm and 9.73μm respectively. Thus, glaze application promoted lower marginal discrepancy and higher retentive strength values than conventional techniques.

Can the silane heat treatment influence the bond durability between resin cements and a dental ceramic?

“…Failure analysis revealed that all fractures occurred at the adhesive area. These results are consistent with the results in published literature that have demonstrated a higher incidence of adhesive or mixed fractures with the microtensile bond strength test compared with conventional tests of adhesive resistance, which present a higher incidence of cohesive fractures [7,10,12]. Some authors have demonstrated an effective bond strength when only heat treatment of silane is performed [8,[13][14].…”

“…The statistical difference in results between the thermocycled and non-thermocycled groups suggests that cement adhesion is significantly influenced by aging. This has also been observed in several previous studies in which ceramics are thermocycled, even when a loss of some specimens has occurred during this process [9,[17][18].…”

“…During the adhesive cementation of a ceramic restoration, several factors may influence adhesion to the dental structure [7,9]. After cementation, two interfaces are obtained, one between the resin cement and ceramic restoration and another between the resin cement and the tooth [7,9]. In this study, the bond strength of the interface formed between the ceramic and resin cement was evaluated using the microtensile bond strength test.…”

“…In this study, the bond strength of the interface formed between the ceramic and resin cement was evaluated using the microtensile bond strength test. This test was selected due to its improved reliability in dental tissues and ceramic adhesion tests compared with other methods [9]. In addition, it also allows the evaluation of numerous specimens with small adhesive surface areas Note: * Uppercase letters represent statistical differences in the vertical (column) and lower case letters represent statistical differences horizontally (rows).…”

Bond and topography evaluation of a Y-TZP ceramic with a superficial low-fusing porcelain glass layer after different hydrofluoric acid etching protocols

“…However, the adhesion between this dental ceramic and the tooth, one of the decisive factors for achieving longevity of the restoration [3][4][5] it is not established and it is a critical factor 6 because the hydrofluoric acid (HF) have almost no effects on zirconia due to the fact that this material is highly crystalline, without a vitreous content 4,7-12 . Therefore, it was necessary to develop some different surface treatments options to zirconia, trying to promote micro retentions and/or make the surface chemically reactive to an adhesive system 12 . These surface treatment options were sandblasting with aluminum oxide particles 13 , laser irradiation 14 , sandblasting with aluminum oxide coated by silica particles 3,15 , the use of metal primers 10,13,14 , plasma selective infiltration 15 and a low-fusing porcelain glass layer application [16][17][18][19] was tried.…”