High Performance Dental Ceramics Through Additive Manufacturing
Summary
Nearly half of all Americans are dissatisfied with the color or appearance of their teeth, yet the path to a confident smile remains lengthy and highly inefficient. Dental veneers offer one of the most effective and straight forward options, with around 8% of Americans opting for veneers. Traditional approaches such as milling are time-consuming, and waste a significant amount of material. Additionally this route requires multiple office visits and additional time for labs to process and produce the final product. For patients with more complex definitions, these timelines can stretch even further putting additional pressure on dentists and suppliers.
This project aims to address this issue by exploring the feasibility of additive manufacturing, specifically DLP, for the production of dental veneers. Rather than cutting/milling down a block of material, DLP builds the part layer by layer, enabling greater geometric precision, reduced material waste, and potential for same day workflows. The central question driving this research is whether or not we can match both the aesthetics and mechanical performance benchmarks required for clinical use, while meaningfully improving upon the inefficiencies current practices bring.
Technical Approach/Methodology
Glass frits are first reduced into a fine and controlled particle size using a planetary ball mill to improve packing density, dispersion, and final sintering behavior. These powders are then incorporated into a photocurable resin that contains photoinitiators, monoacrylates, dispersing agents, and more to create a printable glass slurry that can be processed by Digital Light Processing (DLP).
One key technical challenge of this project is optimizing the slurry to be compatible with DLP printing while also containing a high enough solids loading that can eventually produce a high density final part. The printed green bodies will then be subjected to a heating profile that first burns out the organic resin through debinding, and then sintered to densify and crystallize the remaining glass powder into a dense, ceramic structure. This process allows for the sustainable and efficient fabrication of mechanically strong, dimensionally precise, and aesthetically pleasing ceramic components suitable for dental applications.
Outcomes
The overall outcome for this project was to provide a more efficient, less wasteful, more accessible alternative to subtractive milling. Our original deliverable for this project was a 3D printed bar of dental-grade glass ceramic. We were going to conduct fracture toughness, hardness, tensile, and compressive tests on this bar to verify if it held up to relevant ISO standards for dental applications. In order to do this, we also had to develop a reproducible and repeatable manufacturing process to 3D print the glass ceramic, and post process to output a densified product successfully. Over the course of our project, we were able to successfully carry out our 4 main procedural tasks. Firstly, we were able to mill down a glass powder to a specific particle size. Secondly, we were able to formulate a resin from literature that can be synthesized into a glass-resin. Thirdly, we were able to optimize printing parameters to successfully print a solid tab. Lastly, we were able to successfully decompose the polymer matrix from the printed tabs using a debinding program and crystallize the samples using a different heating profile.
Our printed tabs fell short of a fully dense printed ceramic body. However, we were able to demonstrate that a glass ceramic can be printed in general, showing promise for using DLP printing as an additional method of dental manufacturing.