Aim: Three-dimensional (3D) printers used in dentistry allow the fabrication of restorations with varying layer thicknesses, which can affect the mechanical properties of the material. This study aims to evaluate, under in vitro conditions, the effect of different layer thicknesses (10 µm, 25 µm, 50 µm) on the shear bond strength (SBS) of samples produced using a permanent resin material with 3D printing. Materials and Methods: In our study, specimens of permanent resin (Crowntec, Saremco) with different layer thicknesses (10 μm, 25 μm and 50 μm) were produced using a 3D printer (Asiga MAX UV, Asiga). The surface of the prepared specimens was sandblasted. After sandblasting, the surface roughness (Ra, Sa) of the specimens was measured with an optical profilometer. Then, self-adhesive resin cement was bonded to the surfaces of the specimens in a transparent mold as specified in ISO 29022:2013 standards. After aging, SBS testing was performed to determine the bond quality between the luting cement and 3D printed resin specimens. The fracture types after the bond test were examined under a microscope. The Kruskal–Wallis test was used to analyze the data (p 0.05) between the surface roughness values of the specimens prepared with different layer thicknesses on the 3D printer after sandblasting. There was no statistically significant difference between the SBS value (10 μm: 20.94 MPa, 25 μm: 20.88 MPa, 50 μm: 19.99 MPa) of the specimens produced at different layer thicknesses (p>0.05). Cohesive type fracture was observed on the surface of the specimens after shear bond strength test. Conclusion: Although the layer thickness varied among the 3D printed specimens, there was no difference between the SBS values.
Öztürk et al. (Tue,) studied this question.