3D printing of biological tooth with multiple ordered hierarchical structures

Area of Science:

• Biomaterials Engineering
• Nanotechnology
• Dental Materials Science

Background:

• Natural teeth exhibit complex heterogeneity in composition and hydroxyapatite (HAp) nanostructure between enamel and dentin.
• Replicating this intricate natural microstructure in artificial dental materials remains a significant challenge.

Purpose of the Study:

• To develop a novel fabrication method for multi-material dental crowns that mimics the natural tooth's heterogeneous microstructure.
• To achieve precise control over hydroxyapatite (HAp) nanostructure orientation at the dentinoenamel junction (DEJ).

Main Methods:

• A bottom-up, sequential approach combining shear-induced and magnetic-assisted 3D printing technology was employed.
• Hydroxyapatite (HAp) nanorods were oriented via shear force and magnetic fields to create specific structures in dentin and enamel layers.
• The materials were 3D-printed into a bilayered dental crown with site-specific composition and texture.

Main Results:

• Fabrication of a multi-material dental crown with highly ordered HAp nanostructure, nearly perpendicular at the DEJ.
• The 3D-printed crowns exhibited site-specific composition and texture, closely mimicking natural tooth structure.
• The fabricated material demonstrated outstanding biocompatibility.

Conclusions:

• The developed shear-induced and magnetic-assisted 3D printing approach enables precise multi-level and multi-dimensional texture control for dental restorations.
• This novel technique shows significant potential for designing and fabricating artificial dental crowns that replicate natural tooth heterogeneity and function.