In Vitro Mechanical Evaluation of Prosthodontic Dental Acrylics Fabricated by Conventional and Additive Techniques

Introduction: Acrylic materials have been a staple in dental prosthetics for decades. Developments in manufacturing technology, including additive techniques, have led to the introduction of new types of acrylics, whose mechanical properties require detailed evaluation and comparison with conventional materials. Aim of the study: The aim of the study was to comparatively evaluate selected mechanical properties, such as hardness, impact strength, density, flexural strength, and tensile strength, of three types of acrylic materials used in prosthetics: 3D-printed acrylic, heat-cured acrylic, and cold-cured acrylic, in vitro. Materials and Methods: Three materials were used in the study: 3D-printed acrylic (NextDent Denture 3D+), heat-cured acrylic (made using the cupping method (Villacryl H Plus)), and cold-cured acrylic (made using the pouring method (Villacryl SP)). Ten samples (n = 30) were prepared from each material. Flexural strength, tensile strength, Young's modulus, density, Vickers hardness, and impact strength were tested. Results: The tested materials demonstrated significant differences in mechanical properties. The highest values for impact strength, flexural strength, tensile strength, and density were obtained for 3D-printed acrylic. Hot-cured acrylic achieved the highest hardness values. Cold-cured acrylic, on the other hand, achieved the lowest results, except for the impact strength test, where it achieved intermediate results. Conclusions: The mechanical properties of dental acrylics are significantly dependent on their manufacturing technology. Hot-cured acrylic exhibits the highest hardness, while 3D-printed acrylic is characterized by favorable impact strength, flexural strength, and tensile strength, which may have significant clinical significance in terms of the resistance of dentures to mechanical damage. The study results could provide a basis for introducing this material into clinical practice.