In recent years, lithium disilicate glass-ceramics have attracted considerable attention from dental ceramics researchers owing to their exceptional semi-translucency, mechanical strength, and biocompatibility. Nevertheless, insufficient printing precision may result in clinical complications such as restoration misfit and secondary caries. Currently, strategies for improving the printing accuracy of highly transparent ceramic materials primarily focus on optimizing process parameters, modifying ceramic slurry rheology, and tailoring powder refractive index; however, these approaches are still plagued by limitations including marginal accuracy improvement, processing complexity, and residual components.
Recently, a team led by Professor Gaoqi Wang from University of Jinan proposed, for the first time, a composite powder design strategy based on synergistic optical parameter regulation. By incorporating carbon powder with a high extinction coefficient and zinc oxide powder with a matched refractive index into the lithium disilicate matrix, they not only reduced printing error by 92% and increased flexural strength by 43.1% to 297.28 MPa, but also endowed the material with sustained antibacterial efficacy against Streptococcus mutans and Escherichia coli for over 5 days, achieving an antibacterial rate exceeding 85%. The study revealed a synergistic mechanism wherein carbon powder restricts light scattering through its high extinction coefficient, while zinc oxide compensates for curing depth and promotes sintering densification, thereby systematically elucidating a multi-objective optimization method integrating "optical design-printing precision-mechanical performance-antibacterial functionality".
This research not only resolves the trade-off between precision and curing depth in photopolymerization-based manufacturing of highly transparent ceramics but also lays a solid foundation for advancing 3D printing technology and its clinical applications.
The team published their work in Journal of Advanced Ceramics on March 18, 2026.
"Carbon powder limits the scattered light in a certain area through high extinction coefficient., while zinc oxide compensates for the curing depth and imparts antibacterial functionality. The synergistic effect of the two materials breaks through the bottleneck where high-transparency ceramics cannot simultaneously achieve both precision and performance," said Professor Gaoqi Wang from the School of Mechanical Engineering at University of Jinan, whose research primarily focuses on ceramic additive manufacturing technology and equipment, as well as the design and manufacturing of medical devices.
This composite design reduces the printing error of lithium disilicate glass-ceramics by 92%, achieving a three-point flexural strength of 297.28 MPa, Vickers hardness of 6.122 GPa, and fracture toughness of 3.74 MPa·m1/2, with mechanical properties superior to most reported 3D-printed counterparts. The antibacterial efficacy against Streptococcus mutans and Escherichia coli meets the clinical requirements for long-term bacterial inhibition in oral applications. "From the perspective of optical regulation mechanisms, this strategy not only resolves the precision issues caused by light scattering but also achieves simultaneous enhancement of strength and toughness through the sintering aid effect and compressive stress effect of zinc oxide," stated Wang, making the digital manufacturing of functionally integrated dental ceramics feasible.
Further research reveals the mechanism of the composite powders: carbon powder is completely oxidized and removed during the debinding process, without affecting the intrinsic transparency of the material (transmittance > 50%); zinc oxide may promote crystallization and inhibit abnormal grain growth by forming the Zn2SiO4 phase. However, more in-depth research is needed to explore the clinical applicability of this material. Professor Wang also proposed that future work will focus on the long-term stability of the composite slurry, evaluation of multi-scale mechanical properties, and in vivo antibacterial durability verification.
This work was supported by the National Natural Science Foundation of China (Project Nos. 52475263, 52175408), the Shandong Higher Education Youth Innovation and Technology Support Program (Project No. 2023KJ110), the University of Jinan Interdisciplinary Convergence Construction Project 2024 (Project No. XKJC-202406), and the Taishan Scholar Engineering Special Funding (2022-2027).
About Author
Gaoqi Wang, Professor/PhD Supervisor at University of Jinan, Head of Shandong Provincial University Youth Innovation Team. Research interests: ceramic additive manufacturing technology and equipment, medical device design and manufacturing. Serves as Youth Committee Member of Tribology Branch, Chinese Mechanical Engineering Society, and Youth Editorial Board Member of Additive Manufacturing Frontiers and other journals. Has led over 10 research projects including National Natural Science Foundation of China (General Program and Youth Program), China Postdoctoral Science Foundation, and Shandong Provincial Natural Science Foundation. As first or corresponding author, has published over 30 SCI-indexed papers in high-level journals such as Journal of Advanced Ceramics, Additive Manufacturing, Additive Manufacturing Frontiers, Journal of the European Ceramic Society, and Journal of Manufacturing Processes. Holds over 20 authorized national invention patents and received 3 provincial/ministerial-level science and technology awards.
Fan Zhang, Master's Student, School of Mechanical Engineering, University of Jinan. Research interests: 3D printing of lithium disilicate glass-ceramics.
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC's 2024 IF is 16.6, ranking in Top 1 (1/33, Q1) among all journals in "Materials Science, Ceramics" category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
