A biocompatible silicon nitride dental implant material prepared by digital light processing technology

Area of Science:

• Biomaterials Engineering
• Dental Materials Science
• Ceramic Engineering

Background:

• Titanium is the traditional material for dental implants but can cause adverse reactions.
• There is a growing need for metal-free dental restorations.
• Silicon nitride (Si3N4) is an emerging ceramic material for dental applications.

Purpose of the Study:

• To fabricate silicon nitride (Si3N4) dental implants using digital light processing (DLP) technology.
• To evaluate the mechanical properties of the fabricated Si3N4 implants.
• To assess the biocompatibility of Si3N4 dental implants through in vitro and in vivo tests.

Main Methods:

• Fabrication of Si3N4 dental implants via photosensitive resin-based DLP.
• Mechanical testing: three-point bending for flexural strength, unilateral pre-cracked beam for fracture toughness, and bending method for elastic modulus.
• Biocompatibility assessment: in vitro fibroblast cell (L-929) proliferation and apoptosis assays, hemolysis test, oral mucous membrane irritation test, and acute systemic toxicity test.

Main Results:

• Si3N4 dental implants fabricated by DLP exhibited high flexural strength (770 ± 35 MPa), fracture toughness (13.3 ± 1.1 MPa·m1/2), and elastic modulus (236 ± 10 GPa).
• In vitro studies showed preferable fibroblast cell proliferation and apoptosis.
• Hemolysis, oral mucosal irritation, and systemic toxicity tests confirmed the material's safety.

Conclusions:

• DLP technology enables the fabrication of Si3N4 dental implants with excellent mechanical properties.
• The fabricated Si3N4 implants demonstrate good biocompatibility, with no adverse reactions observed in biological tests.
• Personalized Si3N4 dental restorations produced by DLP show significant potential for future dental applications.