Accuracy of zirconia crowns manufactured by stereolithography with an occlusal full-supporting structure: An in vitro study

Rong Li; Tan Xu; Yong Wang; Yuchun Sun

doi:10.1016/j.prosdent.2022.01.015

Accuracy of zirconia crowns manufactured by stereolithography with an occlusal full-supporting structure: An in vitro study

J Prosthet Dent. 2023 Dec;130(6):902-907. doi: 10.1016/j.prosdent.2022.01.015. Epub 2022 Feb 16.

Authors

Rong Li¹, Tan Xu², Yong Wang³, Yuchun Sun⁴

Affiliations

¹ Doctoral student, Center of Digital Dentistry, Department of Prosthodontics, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health, Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Disease, Beijing, PR China.
² Engineer, Porimy 3D Printing Technology Co. Ltd, Kunshan, PR China.
³ Professor, Center of Digital Dentistry, Department of Prosthodontics, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health, Beijing Key Laboratory of Digital Stomatology & National Clinical Research Center for Oral Disease, Beijing, PR China.
⁴ Professor, Center of Digital Dentistry, Department of Prosthodontics, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health, Beijing Key Laboratory of Digital Stomatology & National Clinical Research Center for Oral Disease, Beijing, PR China. Electronic address: kqsyc@bjmu.edu.cn.

PMID: 35183363
DOI: 10.1016/j.prosdent.2022.01.015

Abstract

Statement of problem: Additive manufacturing is emerging as an alternative method of fabricating dental restorations, but the support design needs to be optimized.

Purpose: The purpose of this in vitro study was to evaluate the 3-dimensional trueness and adaptations of zirconia crowns manufactured by stereolithography (SLA) with an occlusal full-supporting structure, compared with those SLA-printed with pillar supports, and those made by milling.

Material and methods: A zirconia abutment was prepared, and an anatomic contour crown was designed. The crowns were manufactured by SLA and milling (n=6). For SLA manufacturing, a full-supporting base and pillar supports were designed. The 3-dimensional (3D) trueness of the fabricated crowns was characterized by 3D deviation analysis. The adaptations of crowns in the SLA-base and milling groups were measured by using a triple-scan method. Color-difference maps and the root mean square (RMS) values were used to characterize the 3D trueness. One-way analysis of variance (ANOVA) and Tukey post hoc test were used to analyze the difference in RMS values among the 3 groups, and Student t test was used to analyze the difference in cement-gap width between the milling group and the SLA group with the full-supporting base (α=.05).

Results: The 3D deviation analysis showed that in the external area, the RMS value of the SLA-pillar group was significantly higher than that of the SLA-base and the milling groups (P<.05). In the intaglio area, the milling group showed a lower RMS value than the 2 SLA groups (P<.05). The color-difference maps showed the SLA-base group had smaller positive errors at the cusp inclines than the SLA-pillar group. No statistically significant difference was found in adaptations between the SLA-base and milling groups (P>.05).

Conclusions: The occlusal full-supporting base provided improved support in fabricating the crowns, and no remnants were left after removal. The zirconia crowns manufactured by SLA with an occlusal full-supporting structure had good external 3D trueness and clinically acceptable adaptation.

MeSH terms

Computer-Aided Design*
Crowns
Dental Prosthesis Design
Stereolithography*

Substances

zirconium oxide