Flexural strength, flexural modulus and microhardness of milled vs. fused deposition modeling printed Zirconia; effect of conventional vs. speed sintering

Maher S Hajjaj; Rana A A Alamoudi; Walaa A Babeer; Waleed Y Rizg; Ahmad A Basalah; Saeed J Alzahrani; Hanin E Yeslam

doi:10.1186/s12903-023-03829-8

Flexural strength, flexural modulus and microhardness of milled vs. fused deposition modeling printed Zirconia; effect of conventional vs. speed sintering

BMC Oral Health. 2024 Jan 7;24(1):38. doi: 10.1186/s12903-023-03829-8.

Authors

Maher S Hajjaj^{1

2}, Rana A A Alamoudi³, Walaa A Babeer⁴, Waleed Y Rizg^{5

6}, Ahmad A Basalah⁷, Saeed J Alzahrani⁸, Hanin E Yeslam⁸

Affiliations

¹ Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia. mhajjaj@kau.edu.sa.
² Advanced Technology Dental Research Laboratory, King Abdulaziz University, P.O. Box 80209, Jeddah, 21589, Saudi Arabia. mhajjaj@kau.edu.sa.
³ Prosthodontic Master Student, Department of Oral and Maxillofacial Rehabilitation, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
⁴ Department of Oral and Maxillofacial Rehabilitation, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
⁵ Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
⁶ Center of Innovation in Personalized Medicine (CIPM), 3D Bioprinting Unit, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
⁷ Mechanical Engineering Department, College of Engineering and Architecture, Umm Al Qura University, Makkah, Saudi Arabia.
⁸ Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.

Abstract

Background: Various methods can be used for creating zirconia dental restorations, including 3-dimensional (3D) printing and computer-aided design/ computer-aided manufacturing (CAD/CAM) milling. The fused deposition modeling (FDM) printing method for zirconia presents numerous advantages, albeit research on the mechanical properties of these materials and resultant restorations remains scarce. Such developments are undeniably intriguing and warrant further investigation. The objective of the present study was to evaluate the impact of the sintering firing cycle (Conventional vs. Speed sintering) on the flexural strength, flexural modulus, and Vickers Microhardness of milled vs. FDM printed zirconia.

Methods: A total of 60 bars (2 × 5 × 27 mm) were fabricated for flexural strength testing, along with 40 discs (12 × 1.5 mm) for Vickers microhardness testing. Half of the specimens underwent conventional sintering, while the other half underwent a speed sintering cycle. The flexural strength and modulus were determined by a three-point bending test in a universal testing machine. The microhardness of the specimens was evaluated using a Vickers microhardness tester. Statistical analysis was performed using a two-way ANOVA test with a post-hoc Tukey test (p < 0.05).

Results: CAD/CAM milled zirconia had significantly higher flexural strength and modulus than FDM-printed zirconia. The sintering process did not significantly affect the flexural strength or modulus of milled or FDM-printed zirconia. The milled speed sintering group had significantly higher values in the Vickers microhardness test compared to the other groups.

Conclusions: The mechanical properties of FDM-printed zirconia specimens were not found to be comparable to those of milled zirconia. Speed sintering cycle may produce milled zirconia restorations with similar flexural strength and modulus to conventional sintering, and even higher Vickers Microhardness values.

Keywords: 3D printing; CAD/CAM; FDM; Mechanical properties; Prosthodontics; Restorative dentistry; Sintering cycle; Zirconia.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Analysis of Variance
Computer-Aided Design*
Flexural Strength*
Humans
Printing, Three-Dimensional

Substances

zirconium oxide

Grants and funding

G: 254-165-1443/Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Saudi Arabia