Objective The aim of this study was to evaluate the effect of neutralizing agents on the shear bond strength of hydrofluoric (HF)–etched porcelain in nonaging and aging conditions. Subjects and Methods One hundred and twenty feldspathic porcelain specimens were prepared and divided into six groups to undergo different surface conditioning methods—group 1: control; group 2: HF; group 3: HF + calcium hydroxide; group 4: HF + calcium carbonate; group 5: HF + calcium gluconate; and group 6: HF + ultrasonic. All samples were immersed in 37°C distilled water for 24 h. Half of the samples were thermocycled in water for 5,000 cycles. The shear bond strength test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. Data were statistically analyzed by two-way ANOVA and Tukey's multiple comparison test at a 95% confidence level. The surface micromorphology and surface elements were analyzed using scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively. Results The shear bond strengths of groups 2–6 were significantly higher than the control group in both aging and nonaging conditions (p < 0.05). There were no significant differences among all of the HF-etched porcelain groups (p > 0.05). SEM images of groups 2–6 illustrated similar patterns of irregularity on the specimen surfaces. Elemental analysis of EDX demonstrated identical elements on surfaces of specimens of groups 2–6. Conclusion Within the limitations of this study, shear bond strength values between HF-etched porcelain, HF-etching followed by application of neutralizing agents, and HF-etching followed by ultrasonic cleaning were not significantly different in both nonaging and aging conditions.

This investigation evaluated the effects of aprotic solvents, i.e., tetrahydrofuran, pyridine, and morpholine, compared with hydrogen peroxide, on the surfaces of fiber-reinforced composite posts with a composite core based on the microtensile bond strength. In total, 150 FRC Postec Plus posts and 150 D.T. Light-Posts were randomly divided into three groups (non-thermocycling, 5000-cycle, and 10,000-cycle thermocycling groups). Each group was divided into five subgroups according to the post-surface treatment: C, non-treatment group; H₂O₂, immersed in 35% hydrogen peroxide; THF, immersed in tetrahydrofuran; PY, immersed in pyridine; and MP, immersed in morpholine. The treated specimens were placed in the bottom of a plastic cap and filled with a composite core material in preparation for the microtensile bond test. The data were evaluated using one-way ANOVA and Tukey’s test (p < 0.05) as well as an independent t-test (p < 0.05). For the surface roughness, white light interferometry was used for measurement, and the mean surface roughness was analyzed via one-way ANOVA and Tukey’s test (p < 0.05). The results showed that, under non-thermocycling conditions, the PY subgroup with D.T. Light-Post had the highest microtensile bond strength, followed by THF, MP, H₂O₂, and the control groups. For FRC Postec Plus, the PY group had the highest microtensile bond strength, followed by MP, THF, H₂O₂, and the control groups. Although the thermocycling conditions decreased the microtensile bond strength in all groups, the PY subgroup still had the highest value. An independent t-test revealed that even under all non-thermocycling and 5000- and 10,000-cycle thermocycling conditions, D.T. Light-Post in the PY subgroup displayed significantly higher microtensile bond strengths than FRC Postec Plus in the PY subgroup. While the surface roughness of the fiber-reinforced composite posts showed that the posts treated with pyridine possessed the highest surface roughness for each material type, In conclusion, as an aprotic solvent, pyridine generates the highest microtensile bond strength between the interfaces of composite cores and fiber-reinforced composite posts.

This study examines the impact of a dual cure activator (DCA) when applied in combination with self-adhesive resin cements on the zirconia. Sixty zirconia were prepared in compliance with the manufacturer’s directions. The specimens were randomly assigned to each group under the dark condition, following DCA and self-adhesive resin cements [RelyX universal resin cement (RXS); Maxcem elite chroma (MAC); Panavia SA cement multi (PSM)]; group 1, RXS; group 2, MAC; group 3, PSM; group 4, DCA + RXS; group 5, DCA + MAC; and group 6, DCA + PSM. The resin composite was fixed to the zirconia, surface-treated, and maintained in a dark container for 30 min. The specimens were kept in an incubator at a temperature of 37 degrees Celsius for 24 h. The universal testing device was employed to compute the shear bond strength (SBS). A stereomicroscope was used to analyze the fractured types. The data were analyzed employing the one-way ANOVA and Tukey’s test. Group 2 had the lowest SBS (4.93 ± 0.53 MPa). Group 1 (11.17 ± 0.86 MPa) and group 3 (11.48 ± 1.17 MPa) were not significantly different in SBS. Group 6 (15.61 ± 0.68 MPa) had the highest SBS but was not significantly different from group 4 (15.45 ± 1.20 MPa). The findings show that treating the zirconia surface with DCA before using the self-curing mode of self-adhesive resin cements is the best way to improve the bond between the zirconia and resin cement.

This study investigated the effectiveness of Tooth Primer and cleaning agents in removing saliva contamination from zirconia as assessed using shear bond strength (SBS). A total of 175 rectangular specimens, 10 mm in diameter and 6 mm in thickness, were randomly divided into seven groups (n = 25 each): group 1, no saliva contamination (control); group 2, saliva-contaminated and not rinsed; group 3, saliva-contaminated and rinsed; group 4, saliva-contaminated, Ivoclean-treated, and rinsed; group 5, saliva-contaminated, Katana Cleaner-treated, and rinsed; group 6, saliva-contaminated, Tooth Primer-treated, and rinsed; and group 7, saliva-contaminated, Tooth Primer-treated, and not rinsed. All zirconia specimens from groups 1–7 were bonded to composite rods with Panavia SA Luting Multi cement. The bonded specimens were subjected to the SBS test using a universal testing machine. To assess the type of failure, the debonded surface was evaluated using a stereomicroscope. The SBS data were analyzed using one-way ANOVA with Tukey’s post-test. The SBS values of groups 2 (0.90 ± 0.20 MPa) and 3 (1.35 ± 0.43 MPa) were significantly lower compared with the other groups (p = 0.00). The SBS value of zirconia decontamination using Ivoclean in group 4 (18.51 ± 3.01 MPa) was significantly lower than that of the control group (22.24 ± 2.37 MPa) (p = 0.00). However, the SBS values of groups 5 (20.92 ± 2.63 MPa), 6 (21.43 ± 2.81 MPa), and 7 (20.87 ± 2.35 MPa) did not significantly differ compared with the control group (22.24 ± 2.37 MPa) (p = 0.369, p = 0.861, p = 0.327, respectively). Moreover, SBS values did not significantly differ among groups 5 to 7 (p = 0.984, p = 1.00, p = 0.976, respectively). Regarding failure mode, groups 2 and 3 exclusively experienced adhesive failures. Groups 1, 4, 5, 6, and 7 exhibited adhesive and mixed failures. In conclusion, Ivoclean, Katana Cleaner, and Tooth Primer effectively mitigated the adverse effects of saliva contamination on the resin cement–zirconia interface. Furthermore, Tooth Primer can be used as a cleaner for saliva-contaminated zirconia surfaces, with or without rinsing.

The current study evaluates the effect of morpholine on saliva-contaminated acrylic resin repaired with light-cured resin composites. Sixty rods of self-curing acrylic resin were fabricated and assigned into four groups of fifteen specimens and surface-treated with saliva, phosphoric acid (PH), morpholine (MR), liquid MMA monomer, and a universal adhesive agent (UA, Singlebond Universal) based on the following techniques: group 1, saliva; group 2, saliva + PH + MMA + UA; group 3, saliva + MMA + UA; and group 4, saliva + MR + MMA + UA. An Ultradent model was placed at the center of the specimen, and then the resin composite was pressed and light-cured for 20 s. A mechanical testing device was used to evaluate the samples’ shear bond strength (SBS) scores. The debonded specimen areas were inspected under a stereomicroscope to identify their failure mechanisms. The data were assessed by employing the one-way ANOVA approach, and the significance level (p < 0.05) was established with Tukey’s test. The greatest SBS scores for group 2 (30.46 ± 2.26 MPa) and group 4 (32.10 ± 2.72 MPa) did not differ statistically significantly from one another. The lowest SBS recorded for group 1 was 1.38 ± 0.87 MPa. All of the fractured samples in group 1 had an adhesive failure profile. Groups 2 and 4 had the greatest percentages of cohesive failures. This study concluded that applying phosphoric acid and morpholine to sandblasted self-curing acrylic resin contaminated with saliva before MMA and universal adhesive agents are applied is the most efficient protocol for stimulating SBS when it is repaired with light-cured resin composites.

Objective This study examined the effect of the number of phosphate-containing primer applications on the shear bond strength (SBS) of zirconia to resin cement. Materials and Methods 315 square specimens (10 × 10 × 4 mm³) were manufactured from Cercon ht presintered zirconia blocks. Alumina particles were used to sandblast zirconia specimens. These specimens were randomly divided into six primer-based groups: No primer application (NP), CLEARFIL CERAMIC PRIMER (C), PANAVIA V5 Tooth Primer (T), M&C PRIMER (MC), Monobond N (MN), and Z-PRIME plus (Z), and then separated into application number (1–4) groups (excluding NP). Each specimen was bonded with resin cement. The SBS was measured using a universal testing machine. The debonded surface was examined with a stereomicroscope. Statistical Analysis The SBSs were analyzed using two-way analysis of variance. Results Applying the primer twice exhibited the highest SBSs in each group, with significant differences in the T, MN, and Z groups. However, the SBS in the MC group was significantly lower on the second application. One-hundred percent adhesive failure was observed in all groups. Conclusion Within the limitations of this study, prior to cementation, the sandblasted zirconia surface should be applied twice with a phosphate-containing primer other than MC to maximize the SBS at the zirconia-resin cement interface. Article published online: 16 July 2024 © 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/) Thieme Medical and Scientific Publishers Pvt. Ltd. A-12, 2nd Floor, Sector 2, Noida-201301 UP, India