Mechanical Properties of 3D-Printed Occlusal Splint Materials

Abstract

Data regarding the mechanical properties of three-dimensionally (3D) printed materials for occlusal splint manufacturing are scarce. The aim of the present study was to evaluate the flexural strength and surface hardness of modern 3D-printed occlusal splint materials and compare them with two control groups, namely, milled and conventional cold-polymerized occlusal splint materials. A total of 140 rectangular specimens were manufactured for the present study. The specimens were prepared in accordance with the International Organization for Standardization standards (ISO 20795-1:2013). Five 3D-printed (NextDent Ortho Rigid, Dental LT Clear, Dentona Flexisplint, Cosmos Bite Splint, and ProArt Print Splint), one milled (ProArt CAD Splint), and one cold-polymerized (ProBase Cold) occlusal splint materials were used to determine flexural strength and surface hardness values. The three-point flexure test was used for the determination of flexural strength values, while Vickers hardness was measured to determine surface hardness. Ten specimens (n = 10) of each material were tested using these procedures. One-way ANOVA and Tukey’s post-hoc test were used to analyze the obtained results (α = 0.05). The values of flexural strength ranged from 46.1 ± 8.2 MPa to 106 ± 8.3 MPa. The Vickers hardness values ranged from 4.9 ± 0.5 VHN to 20.6 ± 1.3 VHN. Significant differences were found among the tested materials (p < 0.0001). The milled and cold-polymerized materials yielded higher values for both flexural strength (only one 3D-printed resin had comparable results to cold-polymerized acrylics) and surface hardness. There are differences in the mechanical properties of the various tested occlusal splint materials. The flexural strength of most of the 3D-printed materials and their surface hardness values are still inferior when compared to the milled or cold-polymerized materials.

Biaxial Flexural Strength of Printed Splint Materials

“…Elution, deterioration, relaxation, accelerated crack growth, visco-elastic effects, and decreased wear resistance are all potential outcomes that might be brought about by these causes [31,[44][45][46]. Despite the fact that previous studies have demonstrated that the mechanical qualities of 3D printed materials are often inferior to those of milled materials, the technology of additive manufacturing represents a promising field for dentistry [47]. Within the scope of future studies, it is possible to incorporate a more extensive range of materials into a clinical environment (in vivo) in order to investigate the durability and clinical acceptance of these materials.…”

Influence of Post-Processing on the Degree of Conversion and Mechanical Properties of 3D-Printed Polyurethane Aligners

“…While there is a growing body of work examining the mechanical properties of materials used in the additive manufacturing of occlusal splints [ 30 , 31 ], there remains a significant gap in the literature regarding how post-curing methods influence the mechanical properties of orthodontic aligner materials.…”