Research Information System
Journal of Prosthetic Dentistry, vol.134, no.3, 2025 (SCI-Expanded, Scopus)
Statement of problem: Additive manufacturing of zirconia has demonstrated promise. Nonetheless, the impact of build orientation and firing processes on the topography, staining susceptibility, and translucency of additively manufactured zirconia after coffee thermocycling (CTC) is unclear. Purpose: The purpose of this in vitro study was to assess the influence of build orientation and firing processes on the surface roughness (Ra), stainability, and translucency stability of additively manufactured zirconia in comparison with those manufactured subtractively. Material and methods: Forty disk-shaped zirconia specimens were fabricated additively (INNI Cera) or subtractively (IPS e.max ZirCAD LT [SM-L] and IPS e.max ZirCAD MT [SM-M]). Additively manufactured specimens were divided by build orientation into horizontal (AMH), diagonal (AMD), and vertical (AMV) groups and further subdivided based on firing processes: simultaneous debinding and sintering (1) or separate debinding and sintering (2) (n=5). The specimens were polished and evaluated at baseline and after 10 000 cycles of CTC. Ra measurements were made with a noncontact optical profilometer. Color coordinates were recorded with a digital spectrophotometer, and changes in color (ΔE00) and relative translucency (RTP) were calculated using the CIEDE2000 formula. Data for ΔE00 were assessed with 1-way analysis of variance and Tukey tests, and RTP and Ra data were analyzed with generalized linear model analysis and Bonferroni-corrected post hoc tests (α=.05). Results: Ra and RTP were affected by the interaction between manufacturing protocol and CTC, while manufacturing protocol affected ΔE00 (P≤.047). AMV-1 and AMV-2 had higher Ra at baseline and after CTC (P≤.043). AMH-1 showed lower stainability compared with SM-M (P=.049). Regardless of the time interval, SM-M had the highest RTP, followed by SM-L (P<.001). After CTC, RTP values were higher than those at baseline (P=.047). Conclusions: AMH exhibited the smoothest surfaces, whereas AMV showed clinically unacceptable Ra. The color change observed in AM specimens after CTC was within acceptable limits, while the increase in translucency of SM zirconia was perceptible based on previously reported thresholds.