An in vitro comparative analysis of color stability and surface polish between 3D printed ceramic and zirconia milled crowns

Abstract

Introduction: The growing use of digital dentistry has introduced 3D-printed ceramics as an alternative to conventionally milled zirconia crowns. However, concerns remain regarding their aesthetic longevity and surface quality. Evaluating color stability and surface polish is essential to determine their clinical reliability and long-term performance in restorative dentistry.

Objectives: This study aims to comparatively evaluate the color stability and surface polish of 3D-printed ceramic and zirconia-milled crowns at different stages, including pre- and post-polishing and after immersion in artificial saliva and acidic media, to assess their durability, aesthetic performance, and suitability for long-term clinical applications.

Methods: In this study, the prepared first maxillary molar was duplicated in epoxy resin to create consistent replicas of the reference tooth. These replicas were then used as a standardized base for designing crowns in both ceramic and zirconia, facilitating a controlled comparative analysis of color stability and surface polish between the two crown materials. The specimens were polished (standard polishing) and Color changes (ΔE) were measured in Coca-Cola and artificial saliva at the immediate post-production, post-polishing, and post-immersion stages. Comparison of the outcomes of ceramic and zirconia crowns was done by statistical analyses.

Results: The study evaluated the color stability and surface polish of zirconia-milled and 3D-printed ceramic crowns. Zirconia crowns demonstrated superior color stability, with ΔE values ranging from 0.56 to 3.86, showing minimal discoloration in artificial saliva and mild changes in acidic conditions. In contrast, 3D-printed ceramic crowns exhibited higher discoloration, with ΔE values reaching up to 4.03, likely due to inherent porosity. Regarding surface polish, zirconia showed consistent and smoother post-polishing values (2.3–5.6 µm), while 3D-printed ceramics displayed greater variability (2.3–7.8 µm). Overall, zirconia provided more predictable aesthetic performance, durability, and surface smoothness compared to 3D-printed ceramic crowns.

Conclusions: This study compares zirconia milled crowns and 3D-printed ceramics in terms of color stability and surface polish. Zirconia showed superior aesthetics and smoother surfaces, while 3D-printed ceramics were more prone to discoloration and variability. Despite advantages in cost and fabrication speed, 3D-printed ceramics remain less reliable for long-term, high-stress restorations.