Influence of printing orientation, material-printer-workflow system, and glazing on the surface roughness and color stability of 3D-printed resins for permanent crowns.

AIM: To evaluate the effects of printing orientation, material-printer-workflow system, and glazing on the surface roughness and color stability of permanent 3D-printed crown resins.

MATERIALS AND

METHODS

A total of 180 specimens were fabricated using three material-printer-workflow systems (VS, VarseoSmile Crown Plus; SA, Saremco Print Crowntec; CC, Ceramic Crown, SprintRay) with three printing orientations (0°, 45°, and 90°), and two surface conditions (glazed and non-glazed). Specimens were printed, finished, polished, treated (glazed/non-glazed), and subjected to 300 h of artificial accelerated aging. Surface roughness and color stability were measured by atomic force microscopy and spectrophotometry, respectively. Statistical analyses included ANCOVA, ANOVA, and post hoc Bonferroni tests (α = 0.05).

RESULTS

Before aging, surface roughness differed among the non-glazed systems at all orientations (all P < 0.05), whereas printing orientation affected only non-glazed SA (P = 0.024). Glazing reduced surface roughness and color change in all material-printer-workflow systems. After aging, printing orientation affected surface roughness in non-glazed SA and CC (both P < 0.001) and glazed VS (P < 0.001), but not color change (all P ≥ 0.05). CC consistently exhibited the highest post-aging surface roughness.

CONCLUSIONS

Roughness differed among material-printer-workflow systems, with orientation effects in selected groups. Glazing improved aging-related surface and color stability under the tested conditions. The highest post-aging mean Ra remained below 0.2 µm, but glazed mean ΔE00 values (2.03-2.38) exceeded the acceptability threshold of 1.8.

CLINICAL SIGNIFICANCE: The findings inform the selection of material-printer-workflow systems and glazing protocols for 3D-printed restorations. Glazing improved aging-related surface and color stability under the tested laboratory conditions. Post-aging mean Ra remained below the cited 0.2-µm plaque-retention threshold, but glazed mean ΔE00 values were above the acceptability threshold of 1.8.