3D‐Printed Strong Dental Crown with Multi‐Scale Ordered Architecture, High‐Precision, and Bioactivity

• Published in: Advanced science Vol. 9; no. 5; pp. e2104001 - n/a
• Main Authors: Zhao, Menglu, Yang, Danlei, Fan, Suna, Yao, Xiang, Wang, Jiexin, Zhu, Meifang, Zhang, Yaopeng
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.02.2022; John Wiley and Sons Inc; Wiley
• Subjects: 3-D printers; 3D printing; Composite materials; Compressive Strength; Crowns; Dental crowns; Dental enamel; Durapatite; finite element method; Flexural Strength; Fourier transforms; hierarchical architecture; Hydroxyapatite; Mechanical properties; Microscopy; Nanocrystals; Nanowires; Printing, Three-Dimensional; Rheology; Shear stress; Viscoelasticity; Viscosity; Yield stress; hydroxyapatite; finite element method; hierarchical architecture; 3D printing; mechanical properties
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202104001

Mimicking the multi‐scale highly ordered hydroxyapatite (HAp) nanocrystal structure of the natural tooth enamel remains a great challenge. Herein, a bottom‐up step‐by‐step strategy is developed using extrusion‐based 3D printing technology to achieve a high‐precision dental crown with multi‐scale highly ordered HAp structure. In this study, hybrid resin‐based composites (RBCs) with “supergravity +” HAp nanorods can be printed smoothly via direct ink writing (DIW) 3D printing, induced by shear force through a custom‐built nozzle with a gradually shrinking channel. The theoretical simulation results of finite element method are consistent with the experimental results. The HAp nanorods are first highly oriented along a programmable printing direction in a single printed fiber, then arranged in a layer by adjusting the printing path, and finally 3D printed into a highly ordered and complex crown structure. The printed samples with criss‐crossed layers by interrupting crack propagation exhibit a flexural strength of 134.1 ± 3.9 MPa and a compressive strength of 361.6 ± 8.9 MPa, which are superior to the corresponding values of traditional molding counterparts. The HAp‐monodispersed RBCs are successfully used to print strong and bioactive dental crowns with a printing accuracy of 95%. This new approach can help provide customized components for the clinical restoration of teeth. Biomimetic dental crown based on hydroxyapatite (HAp)‐monodispersed resin‐based composites (RBCs) is constructed by shear‐induced approach and path control using direct ink writing 3D printing. HAp‐monodispersed RBCs inks can be printed smoothly with programmable high orientation through a new type of custom‐built nozzle. Printed high‐precision crowns with multi‐scale highly ordered structure exhibit outstanding mechanical properties and excellent bioactivity for dental restoration.