Multifactorial Evaluation of Color Changes in Material Assemblies Used for Hybrid Abutment Crowns: Role of Ceramics, Surface Treatments, and Resin Cements.

PURPOSE: This study aimed to evaluate the individual and combined effects of titanium surface treatment (ST), ceramic material (CM), and resin cement (RC) on the color stability of material assemblies used for hybrid abutment crowns following artificial aging.

MATERIALS AND

METHODS

Titanium discs (n = 160; 10 mm × 3 mm) were produced and allocated to four ST protocols: untreated control, 50 µm Al2O3 sandblasting, 110 µm Al2O3 sandblasting, and tribochemical silica coating (CoJet). Ceramic components were fabricated using lithium disilicate (LS) and zirconia-reinforced lithium disilicate (ZLS) ceramics and cemented with either an opaque self-curing RC (Multilink Hybrid Abutment Cement) or an opaque dual-curing RC (Panavia V5). Color differences (ΔE 00) were measured using a spectrophotometer before and after 5000 thermocycles. Group differences were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. To evaluate the independent and interactive effects of ST, CM, and RC, a three-way factorial analysis of variance (ANOVA) was performed.

RESULTS

Significant differences in ΔE 00 values were observed among the experimental groups (p < 0.001). The greatest color change was recorded in ZLS specimens bonded with self-curing RC to 50 µm Al2O3-treated titanium surfaces, whereas the lowest color change was observed in specimens bonded with dual-curing RC to untreated titanium surfaces. Three-way ANOVA demonstrated that ST had a significant main effect on overall color change (p < 0.001, ηp 2 = 0.362), whereas CM and RC showed no significant independent effects (p > 0.05). However, significant interactions between surface treatment and CM, surface treatment and RC, and the three-way interaction indicated that the influence of ceramic type and cement system on color stability depended on the titanium ST.

CONCLUSION

ST demonstrated the largest independent effect on the color stability of material assemblies used for hybrid abutment crowns after artificial aging. However, the final optical outcome was also influenced by significant interactions among ST, CM, and RC.