Journal of Prosthetic Dentistry, 2026 (SCI-Expanded, Scopus)
Statement of problem: Esthetic properties of additively manufactured (AM) zirconia can be enhanced by extrinsic staining, but data on its surface roughness (Ra) and stain durability under intraoral challenges remain limited. Purpose: This in vitro study aimed to compare the Ra and stain durability of extrinsically stained AM zirconia with those of subtractively manufactured (SM) zirconia and lithium disilicate, following erosive, abrasive, and thermal challenges. Material and methods: Disk-shaped specimens (Ø13×2 mm) were produced using an AM zirconia (INNI Cera BCM W1000, AM-ZR), an SM zirconia (VITA YZ ST, SM-ZR), and an SM lithium disilicate (UP.CAD HT, SM-LD) (N=16). One surface of each specimen was externally stained (B4, VITA AKZENT Plus) and glazed (VITA AKZENT Plus Glaze LT). After initial Ra and color assessments, specimens were randomly assigned into 2 subgroups (n=8). One subgroup per material was first exposed to an erosive challenge (5% hydrochloric acid, pH=2, 91 hours) before all specimens were artificially brushed (5000 cycles) and thermocycled (10 000 cycles). Ra and color coordinate measurements were repeated following each process. To evaluate stain durability, color differences (∆E00) were calculated between successive time intervals as well as between the baseline and final measurements. One-way analysis of variance and Tukey tests were used to compare baseline Ra, and generalized linear model analysis and Bonferroni-corrected post hoc tests were used to assess the effect of material type and time interval on Ra and ΔE00 within erosive challenge subgroups and the effect of material type and erosive challenge on the final Ra and ΔE00 among subgroups (α=.05). Results: SM-ZR specimens had the lowest baseline Ra (P<.001). After thermocycling, in the absence of erosion, SM-LD had the lowest Ra among tested materials, SM-ZR had its highest Ra, and SM-LD had lower Ra compared with baseline (P<.001). Noneroded SM-LD had the lowest final Ra values (P≤.001), except for the eroded SM-ZR (P=.398). Among eroded specimens, AM-ZR had the highest ΔE00 after brushing (P≤.020). In addition, after brushing ΔE00 of noneroded SM-ZR was lower than its final ΔE00 (P=.013). Eroded AM-ZR had higher final ΔE00 than noneroded SM-LD (P=.003). Conclusions: Considering the previously reported clinical perceptibility threshold, AM-ZR had Ra comparable with that of SM-ZR and SM-LD, irrespective of the time interval and erosive challenge condition. The final ΔE00 of all specimens was moderately unacceptable, except for noneroded SM-LD, which exhibited perceptible color change.