A avaliação da resistência de união de uma resina fresada e uma resina impressa ao cimento 4-meta/mma-tbb

Abstract

Objective: To evaluate the bond strength of a milled resin and a 3D-printed resin to a 4-META/MMA-TBB cement. Materials and Methods: Blocks measuring 14.5 × 14.5 × 2 mm (n = 12) were fabricated using a nanohybrid ceramic resin (Grandio® blocs) for milling and a 3D printing resin (V-Print DentBase®). The specimens were polished with silicon carbide papers of decreasing grit sizes (#600, #800, and #1200), cleaned in distilled water using an ultrasonic bath for 360 seconds, and then dried. Subsequently, the specimens were embedded in chemically activated acrylic resin inside PVC tubes. Silicone matrices with an internal diameter of 1 mm were adapted to the specimen surfaces with the aid of wax. A 4-META/MMA-TBB cement was manipulated according to the manufacturer’s instructions and inserted into the matrices, producing five cement cylinders (Ø = 1 mm; h = 2 mm) on the surface of each specimen, totaling 12 cylinders per group. The samples were stored in an incubator at 37 °C for 24 hours. Afterwards, a micro-shear bond strength test was performed using a stainless-steel wire (Ø = 0.25 mm) at a crosshead speed of 0.5 mm/min and a 100 kgF load cell. Additional analyses were carried out to assess surface roughness (Ra, Rq, and Rz), wettability, and surface/interface characteristics using scanning electron microscopy (SEM). Results: The groups untreated with aluminum oxide blasting showed a high rate of pre-test failures. Among the surface-treated groups, no significant differences in bond strength were observed between the milled and printed resins. Surface roughness values were higher for the milled resin after surface treatment. No significant differences in contact angles were found among the tested groups. Discontinuities at the cement–restorative material interface were observed in the SEM images. Conclusion: Based on the results, the 4-META/MMA-TBB cement exhibited low bond strength to both the milled and printed resins under the surface treatments performed.

Objective: To evaluate the bond strength of a milled resin and a 3D-printed resin to a 4-META/MMA-TBB cement. Materials and Methods: Blocks measuring 14.5 × 14.5 × 2 mm (n = 12) were fabricated using a nanohybrid ceramic resin (Grandio® blocs) for milling and a 3D printing resin (V-Print DentBase®). The specimens were polished with silicon carbide papers of decreasing grit sizes (#600, #800, and #1200), cleaned in distilled water using an ultrasonic bath for 360 seconds, and then dried. Subsequently, the specimens were embedded in chemically activated acrylic resin inside PVC tubes. Silicone matrices with an internal diameter of 1 mm were adapted to the specimen surfaces with the aid of wax. A 4-META/MMA-TBB cement was manipulated according to the manufacturer’s instructions and inserted into the matrices, producing five cement cylinders (Ø = 1 mm; h = 2 mm) on the surface of each specimen, totaling 12 cylinders per group. The samples were stored in an incubator at 37 °C for 24 hours. Afterwards, a micro-shear bond strength test was performed using a stainless-steel wire (Ø = 0.25 mm) at a crosshead speed of 0.5 mm/min and a 100 kgF load cell. Additional analyses were carried out to assess surface roughness (Ra, Rq, and Rz), wettability, and surface/interface characteristics using scanning electron microscopy (SEM). Results: The groups untreated with aluminum oxide blasting showed a high rate of pre-test failures. Among the surface-treated groups, no significant differences in bond strength were observed between the milled and printed resins. Surface roughness values were higher for the milled resin after surface treatment. No significant differences in contact angles were found among the tested groups. Discontinuities at the cement–restorative material interface were observed in the SEM images. Conclusion: Based on the results, the 4-META/MMA-TBB cement exhibited low bond strength to both the milled and printed resins under the surface treatments performed.