The enhanced ZrO2 produced by DLP via a reliable plasticizer and its dental application.

Digital light processing (DLP) is considered as one of the most promising additive manufacturing technologies to process ceramics. However, the potential defects produced in the debinding and sintering process extremely restrict ceramic application. In this work, a plasticizer which effectively inhibits defects of the green body in debinding process was investigated. The effects of plasticizer (Polyethylene glycol 200) on the rheological behavior and curing property of the slurry were discussed. In addition, the debinding process and the mechanical of zirconia parts with different PEG200 contents were studied. Adding 20 vol% PEG200 could efficiently suppress the defects in debinding process, and the flexural strength increased from 302 ± 15 to 1210 ± 25 MPa of the ZrO2 ceramic sintered at 1600 °C. The superior biocompatibility and mechanical property reveal that the DLP zirconia has a promising application prospect of biology dental ceramic prostheses.

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

For decades, titanium has been the preferred material for dental implant fabrication. However, metallic ions and particles can cause hypersensitivity and aseptic loosening. The growing demand for metal-free dental restorations has also promoted the development of ceramic-based dental implants, such as silicon nitride. In this study, silicon nitride (Si3N4) dental implants were fabricated for biological engineering by photosensitive resin based digital light processing (DLP) technology, comparable to conventionally produced Si3N4 ceramics. The flexural strength was (770 ± 35) MPa by the three-point bending method, and the fracture toughness was (13.3 ± 1.1) MPa · m1/2 by the unilateral pre-cracked beam method. The elastic modulus measured by the bending method was (236 ± 10) GPa. To confirm whether the prepared Si3N4 ceramics possessed good biocompatibility, in vitro biological experiments were performed with the fibroblast cell line L-929, and preferable cell proliferation and apoptosis were observed at the initial stages. Hemolysis test, oral mucous membrane irritation test, and acute systemic toxicity test (oral route) further confirmed that the Si3N4 ceramics did not exhibit hemolysis reaction, oral mucosal stimulation, or systemic toxicity. The findings indicate that Si3N4 dental implant restorations with personalized structures prepared by DLP technology have good mechanical properties and biocompatibility, which has great application potential in the future.

Application prospect of silicon nitride ceramics in dental implants / 口腔疾病防治

@#Silicon nitride has high fracture toughness and compressive strength similar to human bone. It meets the basic mechanical requirements of implants and has good biocompatibility. The micrometer/nanometer morphology surface characteristics of silicon nitride give it good osteogenic activity and antibacterial properties, which are helpful to reduce the incidence of periimplant inflammation. Therefore, silicon nitride has good application potential in dental implants. In orthopedics, silicon nitride implants have been used in spine repair and joint implantation. However, there is a lack of research on silicon nitride as dental implant material. The evaluation of the osteogenic and antibacterial properties of silicon nitride bioceramics prepared using different sintering additives and sintering processes, the antibacterial properties of silicon nitride on different dominant oral pathogens, and the osteogenic activity and antibacterial properties of silicon nitride materials implanted into the jaw need to be further studied. Combined with the latest research results at home and abroad, this review discusses the application potential of silicon nitride materials in dentistry.