Objective This study examined the effectiveness of different functional monomers in universal adhesives on zirconia/resin composite bond strength both before and after thermocycling. Four universal adhesives (G-premio bond universal, GPU; Clearfil Tri-S bond universal, CTB; Optibond Universal, OBU; Tetric N-bond universal; TNU), one adhesive (single bond 2; SB2), and one ceramic primer (Clearfil ceramic primer plus, CCP) were used in this study. Materials and Methods Zirconia discs were prepared and embedded in acrylic. Specimens were polished and sandblasted with alumina. The specimens were randomly divided into two groups (24 hours and the thermocycled), and each group was divided into six subgroups (n = 10), according to zirconia surfaces treatments: no Tx, CCP + SB2, GPU, CTB, OBU, TNU. An Ultradent mold was located on top of the treated zirconia surface. The resin composite was filled into the mold and then light-cured. A universal testing device was used to determine the shear bond strength. Statistical Analysis The data were statistically analyzed using one-way ANOVA and Tukey's test. Results After water storage for 24 hours, the shear bond strengths were GPU > CCP + SB2 = CTB = OBU = TNU > no Tx (p < 0.05). After thermocycling, the shear bond strengths were CCP + SB2 = GPU = CTB = TNU > OBU > no Tx (p < 0.05). Conclusion The universal adhesives containing 10-MDP exhibited the best performance in the shear bond strength of the zirconia/resin composite interface both before and after thermocycling.

This study examined the effectiveness of resin infiltration in inhibiting microleakage from artificial white-spot lesions (AWL) in enamel. Fifty sound extracted premolars were selected and randomly divided into five groups (n = 10 each). Group 1 included sound teeth. In contrast, an AWL was created in all specimens in groups 2 to 5, as follows—Group 2: AWL with no treatment; Group 3: AWL treated with resin infiltration; Group 4: AWL treated with resin infiltration and 5,000 cycles of thermocycling; Group 5: AWL treated with resin infiltration and 10,000 cycles of thermocycling. All specimens were then coated with nail varnish, except for a 4 × 4 mm2 area on the buccal surface (the measurement area), immersed in 2% methylene blue solution, and sectioned buccolingually. Microleakage was evaluated with a stereomicroscope. Data were analyzed by using the Kruskal-Wallis test and Bonferroni post-hoc correction. Application of resin infiltrant reduced microleakage in AWL. No microleakage was seen in Group 3, and differences between Groups 3, 4, and 5 were not significant (P > 0.05). The resin infiltration technique appears to aid in sealing enamel AWL and may help provide long-term protection against microleakage in enamel AWL.

The aim was to assess the effect of powder to liquid ratio (PLR) on setting time, fluoride release, and compressive strength of conventional glass ionomer cements (GICs) containing pre-reacted spherical glass fillers (SPG). GICs were prepared by mixing SPG with Fuji IX Universal liquid using PLR of 1:1, 1.5:1, 2:1, 2.5:1, 3:1. Setting time decreased from 221 to 51 s upon rising PLR. Increasing PLR decreased cumulative fluoride release (33 to 13 ppm). Diffusion coefficient of fluoride of experimental GICs (1.6–1.8×10−8 cm2/s) was comparable with that of Fuji IX Universal (1.6×10−8 cm2/s). Compressive strength of PLR 2:1 to 3:1 (93–140 MPa) were comparable with that of Fuji IX Universal (124 MPa). These results demonstrated that rising powder ratio reduced setting time, fluoride release, and compressive strength of GICs. However, the setting time and strength experimental GICs with PLR greater than 2:1 were in the acceptable range of the ISO standard.

The aim of this study was to specifically explore the effects of morpholine on chemical surface treatments of aged resin composites contaminated with saliva to new resin composite repair strength. One hundred and thirty five resin composite specimens were fabricated and thermocycled to replicate an aged resin composite. These aged resin composites were randomly separated into nine groups (n = 15) depending on the various surface contaminants and surface treatment techniques. These groups were as follows: group 1—no surface treatment; group 2—no saliva + adhesive agent; group 3—no saliva + morpholine + adhesive agent; group 4—no saliva + morpholine; group 5—saliva; group 6—saliva + adhesive agent; group 7—saliva + morpholine + adhesive agent; group 8—saliva + morpholine; and group 9—saliva + phosphoric acid + adhesive agent. A mold was covered on the top of the specimen center and then filled with resin composite. The shear bond strengths and failure modes were examined. The collected data was analyzed using one-way ANOVA, and the significance level was determined using Tukey’s test. Group 5 (3.31 ± 0.95 MPa) and group 6 (4.05 ± 0.93 MPa) showed the lowest bond strength statistically, while group 3 (23.66 ± 1.35 MPa) and group 7 (22.88 ± 1.96 MPa) showed the most significantly high bond strength. The bond strength in group 2 (16.41 ± 1.22 MPa) was significantly different from that in group 1 (9.83 ± 1.13 MPa), group 4 (10.71 ± 0.81 MPa), and group 8 (10.36 ± 1.53 MPa), while group 9’s (17.31 ± 1.48 MPa) SBS was not significantly different. In conclusion, the application of morpholine on aged resin composite with or without contamination with saliva prior to the application of the adhesive agent increased the bond strength of aged resin composite repaired with new resin composite (p < 0.05).

The ability to release and recharge fluoride is a property of glass ionomer cement materials, which is an advantage for patients with a high caries risk. The purpose of this study was to evaluate the amount of released and recharged fluoride in recent uncoated high-viscosity glass ionomer cement (Ketac^TM Universal Aplicap^TM) with different surface coatings and at different time points. In total, 135 cylindrical-shaped specimens were equally divided into the following three groups: Ketac^TM Universal Aplicap^TM, Ketac^TM Molar Aplicap^TM, and Ketac^TM Fil Plus Aplicap^TM. The different coatings performed on each group were as follows: uncoated, coated with Ketac^TM Glaze, and coated with G-Coat Plus^TM. The amounts of released and recharged fluoride were measured at 24 h and at weeks 1, 2, 3, and 4. The recharging agent was a 1.23% APF gel. Ketac^TM Universal Aplicap^TM showed the highest released fluoride at all time points and the highest recharged fluoride at weeks 1, 2, and 3. Both the Ketac^TM Glaze- and G-Coat Plus^TM-coated specimens presented significantly lower released and recharged fluoride ions than the uncoated group at all time points (p < 0.001). Coating with G-Coat Plus^TM significantly decreased the released and recharged fluoride compared to the coating with Ketac^TM Glaze at almost all time points (p < 0.05), except for weeks 1 and 2. The application of coating agents reduced the amount of released and recharged fluoride by the Ketac^TM Universal Aplicap^TM.

To assess color and translucency change (∆E00 and ∆TP) of 3D-printed (Varseosmile crown plus, VS) and milled resin-ceramic hybrid material (Cerasmart, CS) compared to enamel (E) when immersed in distilled water (DW) and coffee (C). Sixty VS, CS, and E specimens were immersed in DW and C for 30 days. Statistics analysis using t-test and one-way ANOVA at p≤0.05. ∆E00 of VS, CS, and E significantly increased when immersed in coffee (p<0.001, p<0.001 and p=0.01, respectively). E has more ∆E00 than VS and CS (p<0.001). The translucency of VS and CS was reduced after water and coffee immersion. The translucency of E was increased after immersion in water and coffee. ∆TP of VS, CS, and E were not different between immersion in water and coffee at p=0.08, p=0.43 and p=0.72, respectively. Therefore, DW and C have distinct effects on the ∆E00 and ∆TP among VS, CS and E.