Influence of Sandblasting on Bonding Strength to Intact Enamel: Roughness, Surface Energy, and Micro-Shear Bond Strength Analysis

Objectives: The study aimed to evaluate the enamel roughness, surface energy, and micro-shear bond strength due to sandblasting with 53 μm aluminum oxide, etching with 37% phosphoric acid, and sandblasting plus etching. Methods: One hundred bovine teeth were used in this study. Samples were prepared with one of three different treatments: G I; intact enamel ( IE ), G II; enamel treated with 37% phosphoric acid ( AE ), G III; enamel surface conditioned with 53 μm Al2O3 particles ( SB ), and G IV; enamel treated with alumina oxide particle followed by phosphoric acid etching ( SBAE ). The surface roughness was measured using a Zeiss Axio Imager M1m + phase view Profilometry (Non-contact roughness measurement) and a Portable Surface Roughness Tester (Surftest SJ-310; Mitutoyo America, Aurora, IL) for contact roughness measurement. All samples were subjected to surface energy tests using Data Physics Instruments (USA Corp). Finally, a cylinder of Filtek™ Supreme Ultra composite resin was bonded to treated enamel surface using Scotchbond™ Universal Adhesive or bottle 3 Adper™ Scotchbond™ Multipurpose. All samples were subjected to a micro-shear test using a Chatillon TCD200 (Johnson scale co. INC, Lane Pine Brook, NJ. 07058).Results: A one-way ANOVA test revealed that the average surface roughness (Ra) and surface energy tests differed significantly between groups. Ra values of the treated enamel surfaces ranged between 0.2 to 0.7μm in the non-contact roughness test. Ra values in the contact roughness test ranged between 0.08 to 0.6μm. The roughness data showed a significant difference between groups (P < 0.001). The higher roughness values were obtained by SB and SBAE groups. Roughness and contact angle influenced the μSBS. The bonding strength of Scotchbond™ Universal Plus Adhesive to enamel sandblasted-plus-acid-etched enamel demonstrated high μSBS values compared to other groups. The μSBS values of the six groups ranged from 32 to 8.7 MPa. The bonding strength was significantly different between groups (P < 0.001). There was no significant difference between G5 (SB) and G6 (AE) using bottle 3 Adper™ Scotchbond. All the groups showed various mixed failures, adhesive and cohesive failure based on the types of the adhesive system. Significance: Sandblasting plus acid etching increase enamel roughness with a significant influence on various liquids' wettability. Compared to other groups, samples subjected to airborne particles showed significantly higher bond strengths of composite restorations using Scotchbond™ Universal Plus Adhesive.