Surface pretreatment and cement influence on bond strength of three-dimensional printed permanent restorations

Context: Indirect permanent restorations re-establish strength, aesthetics, and function in compromised teeth. Three-dimensional (3D) printing has expanded to permanent restorations. Cementation and surface pretreatment critically influence adhesion and longevity, yet optimal protocols for 3D-printed restorations remain insufficiently established. Aims: Evaluate the influence of surface pretreatment, cement type, and their combined effects on tensile bond strength (TBS), surface topography, and roughness of a definitive 3D-printed resin. Materials and Methods: One hundred and eighty cubic specimens were 3D-printed with VarseoSmile Crown Plus. For surface pretreatment analysis, specimens were bonded with adhesive resin cement (ARC) after one of four protocols: No pretreatment (Control), Al 2 O 3 airborne-particle abrasion (Air), diamond bur instrumentation (Bur), or polishing (Polished). Surface morphology and roughness parameters (Sq, Sp, Sv, Sz, and Sa) were characterized by digital microscopy and a scanning electron microscope. For cement type comparison, additional groups were prepared using Bur pretreatment combined with ARC, self-adhesive resin cement (SaRC), or resin-modified glass ionomer cement (RmGIC). All bonded pairs ( n = 15 per group) underwent macro-tensile testing in a universal testing machine at a crosshead speed of 1 mm/min. Statistical Analysis: One-way ANOVA was conducted. Bonferroni post hoc testing was performed for pairwise comparisons, with a significance level set at α =0.05 for all tests. Results: TBS was significantly influenced by pretreatment ( P < 0.001), with Bur producing the highest values and Polished the lowest (44.47 ± 37.24); no differences were observed among Control (180.53 ± 101.77), Air (155.92 ± 54.17), and Bur (238.87 ± 68.62). Surface analysis revealed significant differences only for Sv ( P = 0.023), while Sq, Sp, Sz, and Sa remained comparable ( P > 0.05). Cement type strongly affected TBS ( P < 0.001), with ARC + silane achieving the highest values (238.87 ± 68.62), followed by SaRC (105.93 ± 20.70) and RmGIC (19.53 ± 18.61). Conclusions: Cement type influenced critically on the TBS of the 3D permanent restoration; ARC protocols incorporating silane offered superior outcomes. None of the surface pretreatment protocols enhanced significantly TBS, and minimally influenced surface roughness.