11 new 3D-printing materials tested for dental use

Dental Tribune International

Fri. 5. April 2024

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PERUGIA, Italy: In recent years, the landscape of dental prosthesis fabrication has seen a significant shift with the advent of additive manufacturing technologies. This innovative approach has not only revolutionised design and manufacturing processes, but also introduced a plethora of new polymer materials tailored for dental applications.

Researchers in Italy have recently investigated the dynamic mechanical properties and in vitro biocompatibility of 11 new 3D-printing dental materials designed for the fabrication of temporary crowns and bridges and denture bases to assess their suitability for clinical use. They found that the materials showed potential for absorbing typical masticatory loads.

The study measured the viscoelastic properties of the materials by subjecting them to a dynamic load and analysing their deformation and energy dissipation behaviour under controlled temperature and frequency conditions (dynamic mechanical analysis) to understand their behaviour under loads mimicking those of the oral cavity. It also tested their cytotoxicity by culturing human oral mucosa cells on discs of the materials.

The study’s insights into the dynamic mechanical behaviour and biological interactions of these materials underscore the complex considerations involved in selecting suitable materials for dental prostheses. It found that the elastic modulus (a measure of material stiffness) of the materials varied with frequency of the applied force. The mechanical properties at higher frequencies (11–101 Hz) were more consistent, having no significant changes in stiffness or measurement uncertainty, indicating that the materials maintained their structural integrity and strength; however, when subjected to low frequencies, resembling natural masticatory forces (1–11 Hz), the materials were more flexible and less likely to break, but also exhibited a decrease in strength. At this frequency, there was significant variability, suggesting these results might be unreliable. These findings point towards a potential reduction in the durability and reliability of these materials when subjected to the varying forces within the oral cavity.

The biological assessment found a significant reduction in cell viability after 3 and 24 hours of exposure to these materials, indicating a need for cautious evaluation of these materials’ long-term interactions with oral tissue. This reduction in cell viability, however, showed some signs of recovery after 24 hours, suggesting a potential decrease in cytotoxicity over time.

The research team suggested further exploration of the behaviour of these materials in artificial saliva to better simulate oral conditions and investigation into their use for temporary tooth- or mucosa-supported prostheses, including their resistance to microbial attacks and biofilm accumulation, particularly by Candida species. Further microscopic analyses were also suggested in order to identify any microfractures or structural changes after mechanical testing.

The understanding of these materials’ varying behaviour under dynamic loading conditions and their interactions with biological tissue provides a foundation for further research and development in the field of materials science, ultimately aiming to enhance the performance and safety of dental prostheses fabricated using additive manufacturing technologies.

The study, titled “Dynamic mechanical and biological characterization of new 3D-printed polymeric dental materials: A preliminary study”, was published online on 15 March 2024 in Prosthesis.