Strength and Adaptation of Stereolithography-Fabricated Zirconia Dental Crowns: An In Vitro Study

Purpose: To evaluate the physical and mechanical properties of zirconia ceramic manufactured with stereolithography and to quantitatively analyze the internal and marginal adaptation of the zirconia ceramic dental crowns. Materials and Methods: A resin-based zirconia suspension with a solid content of 45 vol% was prepared. Zirconia dental crowns (n = 5) for the maxillary right first molar were designed and manufactured. Physical and mechanical properties-including density, sintering shrinkage, flexural strength, Weibull parameters, phase composition, and microstructure-of the stereolithography-manufactured zirconia crowns were evaluated. A three-dimensional subtractive analysis technique was used to evaluate the internal and marginal adaptation. Results: The stereolithography-manufactured zirconia (n = 22) achieved a flexural strength of 812 +/- 128 MPa and a Weibull modulus of 7.44. Quantitative analysis of the fabricated zirconia crowns showed a cement space of 63.40 +/- 6.54 mu m in the occlusal area, 135.08 +/- 10.55 mu m in the axial area, and 169.58 +/- 18.13 mu m in the marginal area. Conclusion: Within the limits of this study, the strength of the stereolithography-manufactured zirconia was adequate for fabricating dental crowns. However, internal and marginal adaptation are not yet ideal for clinical application.