Evaluating dimensional accuracy of additively manufactured zirconia and the impact of porosity variations: Part 2.

STATEMENT OF PROBLEM

Subtractive manufacturing (SM) of zirconia crowns, while effective, involves considerable material waste and the risk of introducing defects. Additive manufacturing (AM), or 3-dimensional (3D) printing, offers a promising alternative with potential for reduced waste and enhanced customization.

PURPOSE

The purpose of this in vitro study was to investigate the thickness and diameter of 3D printed zirconia specimens with a novel design, exploring the impact of customized porosity and texture on accuracy.

MATERIAL AND METHODS

Sixty 3D printed zirconia specimens were manufactured via stereolithography (SLA). The disks were divided across 4 groups with different porosity levels, from none to high porosity. Measurements of thickness and diameter were made with digital calipers, and microstructural changes were examined using a scanning electron microscope (SEM). The data were analyzed using the Kruskal-Wallis test followed by pairwise Mann-Whitney U tests (α=.05).

RESULTS

The Kruskal-Wallis test revealed no significant differences in thickness measurements across groups with customized porosities (P=.960), indicating consistent vertical dimensional accuracy. However, diameter measurements showed marginal differences among groups (P=.070), suggesting that porosity variations may have a minor impact on horizontal dimensional accuracy. Median diameter values ranged from 4.96 ±0.08 mm to 5.01 ±0.03 mm, with thickness values remaining consistent at approximately 12 mm across all groups. An analysis of the SEM images provided visual confirmation of the designed porosities, highlighting their distinct configurations and the structural integrity of the printed zirconia.

CONCLUSIONS

Additive manufacturing shows potential for creating 3D printed zirconia crowns with precise, custom porosity. However further refinement is needed to match the reliability and accuracy of traditional manufacturing methods.