Does ErbiumiYttrium-Aluminum-Garnet Laser to Enamel improve the Performance of Etch-and-rinse and Universal Adhesives?

AIM: This study aims to evaluate the effect of erbium: Yttrium-aluminum-garnet (Er:YAG) laser irradiation on the enamel microshear bond strength (µSBS), followed by the utilization of etch-and-rinse and universal adhesive systems. MATERIALS AND METHODS: A total of 32 molars were sectioned in the mesiodistal direction producing 64 samples that were randomized into two groups (n = 32): single bond 2 (SB2) (etch-and-rinse system; 3M), SB universal (SBU) (universal etching system; The SB2 and SBU groups were then divided into two subgroups (n = 16): (i) enamel was irradiated with an Er:YAG laser (λ = 2.94 µm, 60 mJ, 10 Hz), and (ii) enamel served as a control. The samples were restored with TPH3 (Dentsply), stored in artificial saliva for 24 hours, and subjected to a micro-shear test. RESULTS: Kruskal-Wallis (p < 0.05) and Mann-Whitney U tests indicated no significant differences in uSBS between the groups, and the fractures were predominately at the resin-enamel interface. CONCLUSION: The previous irradiation of enamel with Er:YAG laser does not interfere with the performance of simplified two-step etch-and-rinse and universal adhesive systems. CLINICAL SIGNIFICANCE: The increasing use of Er:YAG laser is important to evaluate the influence of this irradiation on the adhesion of restorative materials. Thus, to obtain the longevity of the restorative procedures, it is necessary to know the result of the association of the present adhesive systems to the irradiated substrate.

Effect of Dental Prophylaxis Techniques on the Surface Roughness of Resin Composites.

AIM: The aim of this study is to evaluate the effect of dental prophylaxis techniques on surface roughness of composite resins. MATERIALS AND METHODS: A total of 36 nanohybrid resin composite test specimens were fabricated and divided into three groups (n = 12). They were kept in distilled water at 37°C for 24 hours and submitted to the finishing and polishing technique. For the prophylactic techniques, in group G1, a mixture of pumice stone and distilled water was used with the aid of a rubber cup; in group G2, Herjos-F prophy paste was used with a rubber cup; and in group G3, a bicarbonate jet spray was used. Afterward, all the samples were repolished using the Soflex pop-on disks. A roughness meter was used to measure surface roughness at three points in time: Before the prophylactic techniques (1st evaluation), afterward (2nd evaluation), and following repeat polishing (3rd evaluation). RESULTS: It was found that roughness values changed significantly between the 1st and 2nd evaluations (p < 0.05) and between the 2nd and 3rd evaluations (p < 0.05), showing that the change in roughness depended on the type of prophylactic treatment. Roughness was significantly higher after the bicarbonate jet (p < 0.05). CONCLUSION: Prophylaxis using the sodium bicarbonate jet significantly altered the roughness of nanoparticle-reinforced resin. CLINICAL SIGNIFICANCE: Dental prophylaxis is the most common practice employed to remove bacterial plaque and other coatings. However, one side effect of the cleaning may be a rougher surface subject to degradation and staining. The correct use of prophylactic devices and avoiding prolonged use on resin restorations reduce surface roughness.

Influence of Different Etching Modes on Bond Strength to Enamel using Universal Adhesive Systems.

INTRODUCTION: The adhesive systems and the techniques currently used are designed to provide a more effective adhesion with reduction of the protocol application. The objective of this study was to evaluate the bond strength of universal adhesive systems on enamel in different etching modes (self-etch and total etch). MATERIALS AND METHODS: The mesial and distal halves of 52 bovine incisors, healthy, freshly extracted, were used and divided into seven experimental groups (n = 13). The enamel was treated in accordance with the following experimental conditions: FUE-Universal System - Futurabond U (VOCO) with etching; FUWE - Futurabond U (VOCO) without etching; SB-Total Etch System - Single Bond 2 (3M); SBUE-Universal System - Single Bond Universal (3M ESPE) with etching; SBUWE - Single Bond Universal (3M ESPE) without etching; CLE-Self-etch System - Clearfil SE Bond (Kuraray) was applied with etching; CLWE - Clearfil SE Bond (Kuraray) without etching. The specimens were made using the composite spectrum TPH (Dentsply) and stored in distilled water (37 ± 1°C) for 1 month. The microshear test was performed using the universal testing machine EMIC DL 2000 with the crosshead speed of 0.5 mm/minute. The bond strength values were analyzed using statistical tests (Kruskal-Wallis test and Mann-Whitney test) with Bonferroni correction. RESULTS: There was no statistically significant difference between groups (p < 0.05), where FUE (36.83 ± 4.9 MPa) showed the highest bond strength values and SBUWE (18.40 ± 2.2 MPa) showed the lowest bond strength values. The analysis of adhesive interface revealed that most failures occurred between the interface composite resin and adhesive. CONCLUSION: The universal adhesive system used in dental enamel varies according to the trademark, and the previous enamel etching for universal systems and the self-etch both induced greater bond strength values. CLINICAL SIGNIFICANCE: Selective enamel etching prior to the application of a universal adhesive system is a relevant strategy for better performance bonding.