RESUMO
Background: Porcelain fracture or chipping is one of the limitations of all ceramic restorations. This study investigated the shear bond strength (SBS) of composite resins to lithium disilicate ceramics using universal bondings and different methods of surface preparation. Materials and Methods: In this experimental study, 72 specimens of e.max computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic blocks were divided into six groups of 12 according to surface treatment: Group I-Hydrofluoric (HF) acid etching + All-Bond Universal bonding (ABU), Group II-Bur roughening (BR) + HF + ABU, Group III-BR + HF + Bis-Silane (Si) + ABU, Group IV-Sandblasting (SB) + ABU, Group V-SB + HF + ABU, Group VI-SB + HF + Si + ABU. After bonding of composite resin to the prepared ceramic surface and storage of samples in distilled water for 24 h, SBS test was done using the universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed using the analysis of variance and Tukey's post hoc test (α = 0.05). Results: The mean values of SBS in six studied groups were 6.65 ± 2.78 MPa, 8.56 ± 2.69 MPa, 8.49 ± 2.14 MPa, 3.13 ± 1.66 MPa, 7.94 ± 2.4 MPa, and 10.04 ± 2.47 MPa, respectively. The mean values of SBS were significantly different (P < 0.001). The highest value of SBS was observed in Group VI and the lowest in Group IV. Conclusion: Ceramic sandblasting followed by HF etching, Bis Si, and ABU resulted in a higher SBS of composite resins to lithium disilicate ceramics.
RESUMO
Background: The goal of this study is to determine the effect of different sandblasting particles and dental adhesive systems on the repair strength of dimethacrylate-based composite resins. Materials and Methods: In this in-vitro study, 96 specimens of X-trafil composite blocks were prepared and divided into eight groups (n = 12). Four groups were sandblasted with Aluminum Oxide (AL) and four other groups with Bio-Active Glass particles (BAG). A two-component silane was applied on the surface of all the samples after phosphoric acid etching and rinsing. Two groups of the sandblasted specimens were treated with Clearfil SE Bond (CSB) and the other two groups were treated with Single Bond Universal (SBU) and new composite was bonded to the prepared surfaces. Half of the specimens in each group were thermocycled. Shear force was applied to the bonded composite using a universal testing machine with a crosshead speed of 0.5 mm/min and mean shear bond strength (MSBS) was calculated (MPa). The data was analyzed using Kruskal-Wallis and Man-Whitney U-tests with the significance level of 0.05. Results: Significant differences were observed between different groups (P < 0.001). The highest and the lowest MSBS of the thermocycled samples were reported 18.88 MPa with application of AL and SBU and 11.46 MPa with the application of AL and CSB, respectively. No significant difference was observed with application of BAG particles after thermocycling. Conclusion: Effect of AL on repair shear bond strength of composite resins is affected by bonding type. Bonding type did not affect repair shear bond strength of BAG. Thermocycling reduced bond strength in all groups.
RESUMO
Background. This experimental study sought to assess the biocompatibility of Resil, an experimental epoxy resin-based sealer, in comparison with AH26 and AH-Plus sealers in rats. Methods. Twelve male Wistar rats weighing 400 to 500 grams were evaluated in this experimental study. Four polyethylene tubes containing Resil, AH-Plus, AH26 sealers, and an empty tube were implanted subcutaneously in rats. The degree of inflammation, type of inflammatory cells present, foreign body reaction, quality of connective tissue, and presence of fibrotic capsule were evaluated histopathologically at 7 and 30 days after implanting the tubes to assess the biocompatibility of sealers. Data were analyzed using the Chi-square test. Results. At 7 days, the degree of inflammation in Resil group was almost similar to AH26 group, and 66.7% of rats showed moderate inflammation. AH-Plus group showed less inflammation than Resil and AH26 (50% of rats showed low degree of inflammation), At 30 days, the inflammatory status of all groups was the same, and 83.3% of rats showed very low degree of inflammation. The inflammatory response during the experiment decreased from day 7 to day 30 in all groups. The neutrophil count (P=0.00), fibrotic capsule (P=0.01) and the amount of granulation tissue (P=0.05) significantly decreased from day 7 to day 30 in Resil group. Conclusion. Resil sealer showed appropriate biocompatibility at 7 and 30 days after subcutaneous implantation in rats, comparable to AH26 and AH-Plus. Clinical studies are required to confirm these results.
RESUMO
Introduction: Dentin hypersensitivity (DH) is one of the most common complaints of patients referred to a dental office, so this study aimed to compare the effectiveness of combined diode laser and GLUMA bonding therapy with combined diode laser and 5% sodium fluoride varnish in patients with DH. Methods: Sixty patients were divided into three groups (bonding, laser-bonding, laser-varnish), and before the intervention, the amount of DH was measured with the visual analogue scale (VAS) scale. In the bonding group, GLUMA Desensitizer solution was applied and then air-dried. In the bonding-laser group, first bonding was used, and then the affected tooth was irradiated with a diode laser. In the varnish-laser group, 5% sodium fluoride varnish was coated and then the laser was irradiated with the said method. DH was measured immediately after the treatment and then 2, 7 and 30 days after the treatment. Results: Laser-varnish treatment was not different from laser-bonding treatment at all measurement times (P=1). Laser-varnish and bonding treatment were not significantly different up to one week after the intervention, but on the 30th day after the intervention, the difference in pain was significant (P=0.01). There was no significant difference in laser-bonding treatment up to one week after the intervention, but on the 30th day after the intervention, the difference in pain was significant (P=0.003). Conclusion: The combined treatment with GLUMA bonding and the 660 nm diode laser is effective in reducing DH and this is more effective than GLUMA bonding alone in the long term. However, it does not have a significant advantage over the combined varnish-laser method, but it seems that due to its ease of use, it can be a suitable alternative to the varnish-laser method.
