Influence of nonhazardous postprocessing solutions and surface treatments on the surface roughness and color stability of resins used for additively manufactured definitive restorations.

Statement Of Problem Knowledge of the surface roughness and color stability of definitively intended additively manufactured (AM) resins when different postprocessing cleaning solutions and surface treatments are applied is limited.Purpose The purpose of this in vitro study was to evaluate the effect of postprocessing cleaning solution and surface treatment (polishing and coffee thermocycling) on the surface roughness and color stability of resins intended for AM definitive restorations. In addition, the color coordinates were compared with an A1 shade tab.Material And Methods Sixty specimens were AM from 2 different resins, a glass-filler reinforced composite resin (AM-CR) and urethane acrylate-based resin (AM-UA), for definitive restorations. The specimens were divided into 3 groups based on the postprocessing cleaning solution (n=10): 96% ethanol, water-based solvent, and methyl ether solvent. The surface roughness (Ra) and color coordinates were measured before polishing, after polishing, and after coffee thermocycling for 5000 cycles. Color difference values (ΔE00) were calculated, and color coordinates were compared with a reference shade tab (α=.05).Results AM-CR had a lower Ra with ethanol than methyl ether solvent before polishing (P=.006). AM-UA had the lowest Ra with ethanol and the highest Ra with water-based solvent before polishing (P≤.001). Irrespective of material and postprocessing solution, Ra decreased after polishing (P≤.001). AM-CR had the highest ΔE00 with methyl ether solvent after polishing and after coffee thermocycling (P≤.002). AM-CR had the lowest ΔE00 with ethanol after coffee thermocycling (P≤.003).Conclusions Resin type, postprocessing cleaning solution, and surface treatment affected the surface roughness and color stability of AM resins intended for definitive restorations.