Abstract
<title>Abstract</title> <p>Purpose This study aimed to evaluate and compare the shear bond strength (SBS) of a 3D-printed cobalt-chromium (Co-Cr) alloy fabricated via selective laser melting (SLM) versus a conventionally cast alloy when bonded with different luting cements. Materials and Methods A total of 72 cylindrical metal specimens (5 × 5 mm) were prepared and assigned to two main groups based on the fabrication method: Selective Laser Melting (SLM, n = 36) and Traditional Casting (Cast, n = 36). Each main group was further subdivided into three distinct subgroups (n = 12 each) according to the luting agent utilized: Group ZP (zinc phosphate cement), Group GIC (conventional glass ionomer cement), and Group RMGI (resin-modified glass ionomer cement). Following cementation, specimens underwent shear testing to determine the SBS values in megapascals (MPa). Data analysis was performed using independent-samples t-tests and one-way ANOVA followed by Games-Howell post-hoc comparisons. Results The mean SBS were (group SLM\ZP: 7.77, group SLM\ GIC: 5.46, group SLM\ RMGI: 8.99) MPa and (group Cast \ZP: 6.58, group Cast \ GIC: 5.42, group Cast \ RMGI: 8.96) MPa. Statistical analysis revealed that the SLM-fabricated alloy exhibited significantly higher SBS values when bonded with zinc phosphate cement compared to the cast alloy (P < 0.001). However, no statistically significant differences were observed between the two fabrication methods when using either GIC (P = 0.52) or RMGI (P = 0.75). Regardless of the fabrication technique, RMGI demonstrated the highest bond strength, followed by zinc phosphate, while conventional GIC recorded the lowest values (P < 0.001). Conclusions Within the limitations of this in vitro study, the SLM-fabricated Co-Cr alloy exhibited superior bond strength when paired with resin-modified glass ionomer cement compared to conventional glass ionomer and zinc phosphate cements. Furthermore, the selective laser melting technique significantly enhanced the mechanical retention of zinc phosphate cement compared to conventional casting.</p>