Influence of surface treatment on bond strength to printed resin
Digital Dentistry, 3D-printing, surface treatment, cementation
The objective of this study was to evaluate the influence of different surface treatment protocols on a printed resin and a conventional resin in the bond strength to a flowable resin through the microshear bond strength test. Discs of a conventional composite resin (Z100, 3M Oral Care) and discs of a printed resin (Biocrown, Makertech Labs) were produced (2mm thickness and 8mm diameter), embedded in acrylic cylinders, and polished to #2000 grit. Six surface treatments were evaluated: S+Si+SBU - Sandblasting with 50μm aluminum oxide, 4bar (S, Bio-Art), silane (Si, Relyx Ceramic Primer, 3M Oral Care), and Single Bond Universal adhesive (SBU, 3M Oral Care); S+SBU - only S and SBU adhesive; SBU - only SBU adhesive; S+Si+SBUP – S, Si, and Scotchbond Universal Plus adhesive (SBUP, 3M Oral Care); S+SBUP – only S and SBUP adhesive; and SBUP – only SBUP adhesive. Each treatment was performed on 8 discs of each of the tested resins. On each surface, four specimens of 0.8mm diameter of a flowable composite resin (Filtek Supreme Flowable, 3M Oral Care) were bonded. The microshear bond strength test was conducted, and the data were analyzed by two-way ANOVA. Fracture patterns were analyzed using a laser scanning confocal microscope. The printed resin, in general, showed slightly lower bond strength than the conventional resin (p<0.01). The four surface treatments that included the sandblasting step with aluminum oxide showed significantly higher bond strength values (p<0.01) than those that did not receive such treatment. Fracture pattern analysis showed that the sandblasted groups had a higher percentage of cohesive fractures than adhesive fractures. Surface treatments with different adhesives or with prior silane application did not show significant differences. It is concluded that prior sandblasting with aluminum oxide has a positive impact on the bond strength of both printed and conventional resins.