Effect of Grit-blasting and Primer on Bond Strength of 3D-printed Permanent Restorations

Purpose: To investigate the microtensile bond strength of two different resin cements with primer combinations and grit-blasting on 3D-printed permanent resins. Methods: Sixteen specimens were designed using computer-aided design software, and resin blocks were created in 10 x 10 x 5 mm dimensions. The specimens of 3D-printed restorations were divided into eight groups (n = 2). The groups are 1-) G-Cem One (GCO) with G-Multi Primer (GMP), 2-) Panavia V5 (PV5) with Clearfil ceramic primer plus (CCPP), 3-) GCO with GMP and adhesive enhancement primer (AEP), 4-) PV5 with CCPP and Panavia tooth primer (PTP), 5-) Grit-blasting and G-Cem One (GCO) with G-Multi Primer (GMP), 6-) Gritblasting and Panavia V5 (PV5) with Clearfil ceramic primer plus (CCPP), 7-) Gritblasting and GCO with GMP and adhesive enchament primer (AEP), 8-) Gritblasting and PV5 with CCPP and Panavia tooth primer (PTP). Grit-blasting groups, air abraded for 10 s at a 45 ° angle at a distance of 10 mm with a pressure of 1.5 bar. Subsequent to this, surfaces that have undergone the same treatment process are then cemented together. The build-ups were sectioned into beams (1 mm x 1 mm x 10 mm) under water cooling using a low-speed saw (n = 12). To obtain microtensile bond strength (µTBS) specimens following water storage at 37 °C for 24 h. Bonded specimens were subjected to shear load using a load cell of 60 N in a Universal Testing Machine until failure at a cross-head speed of 0.5 mm/min. The bond strength was calculated using force values obtained during tests (τ = F/A). Following debonding, the failure types were examined under a stereomicroscope at ×30 magnification and classified as adhesive, cohesive in 3D-printed permanent restoration, or mixed. Results: With regard to surface preparation, there were statistically significant differences in µTBS values between the subgroups of the G CEM groups (Gr 1, 3, 5, 7) and the Panavia groups (Gr 2, 4, 6, 8) (p = 0.001; p < 0.05). No statistically significant difference between the control groups was observed in µTBS values (p = 0.627; p > 0.05). The µTBS of group 3 were higher than group 4 (p = 0.001; p < 0.05). 1. It has been demonstrated that grit-blasting enhances the µBTS of 3-D printed permanent resins, with a considerable increase in bond strength in the grit-blasting in comparison to the control groups. 2. The µBTS values for 3-D printed resin were observed to be higher when additional primers were used compared to the control groups. 3. The additional primer groups GCO + GMP exhibited significantly higher µBTS values. Clinical significance Understanding the complex interactions between adhesive resins and 3D-printed composites may be critical to guiding the production of new materials that enhance adhesion. In particular, 3D-printed resin materials can better withstand chewing forces in the mouth and extend their clinical life.