Influence of additively manufactured PEEK and titanium and milled zirconia substructures on the translucency of ceramage and G-CAM veneering composites: An in vitro study

Context The esthetic outcome of implant-supported restorations depends on the optical interaction between substructure and veneering materials. With the increasing use of additively manufactured (AM) abutments, evidence regarding their optical behavior remains limited. Aims To evaluate the influence of AM polyetheretherketone (PEEK), AM titanium, and CAD/CAM-milled zirconia substructures on the translucency of two veneering composites, Ceramage and G-CAM. Settings and Design This in vitro study followed a 3 × 2 factorial design assessing the effects of three substructure materials and two veneering composites on the translucency parameter (TP). Methods and Material Sixty disk-shaped specimens (n = 10/group) were fabricated. Substructure disks (10 mm × 2 mm) of AM PEEK, AM titanium, or milled zirconia were veneered with either Ceramage or G-CAM to a thickness of 2 mm. TP was measured using a spectrophotometer over standard black and white backgrounds. Statistical Analysis Used TP values were analyzed using two-way analysis of variance (ANOVA) to evaluate the main effects and interaction between substructure material and veneering composite type, followed by Tukey’s honestly significant difference post-hoc test, with significance set at P < 0.05. Results Mean TP values ranged from 0.20 to 0.50. The zirconia–Ceramage combination demonstrated the highest translucency (0.50 [±] 0.01), while titanium–Ceramage showed the lowest (0.20 [±] 0.01). PEEK–Ceramage (0.40 [±] 0.02) and titanium–G-CAM (0.42 [±] 0.01) exhibited intermediate translucency. Two-way ANOVA revealed significant main effects for substructure material (P < 0.001) and veneering composite (P < 0.001), as well as a significant interaction between these factors (P < 0.001). Differences among all groups were statistically significant (P < 0.001). Conclusions Both substructure material and veneering composite significantly affect translucency. Zirconia veneered with Ceramage provided superior optical performance, while AM PEEK exhibited moderate translucency. Within the limitations of this in vitro study, CAD/CAM composite veneers enhanced translucency over metallic substructures, suggesting a potential esthetic advantage in implant prosthodontics that warrants further clinical investigation.