Mechanical analysis of three-unit metal-free fixed dental prostheses produced in different materials with CAD/CAM technology.

Abstract

The aim of this study was to evaluate the mechanical analysis of different three-unit metal-free fixed dental prostheses (FDPs) produced by computer-aided design (CAD)/computer-aided manufacturing (CAM). A hundred stainless steel die models of a mandibular left first premolar and a mandibular left first molar were prepared. The specimens were divided into five CAD/CAM material groups (n = 20): Group ZIR, a cubic zirconia (DD cube ONE®); Group FRC, FRC resin material (Trinia); Group PEEK, a PEEK material (KERA® starPEEK); Group PEKK, a PEKK material (Pekkton® ivory); and Group COMP, a polymer composite material (BreCAM.HIPC). Compression test was applied to the specimens, and then the results were analyzed statistically using one-way ANOVA and Tukey's tests. In addition, deformation analyses in FDPs were compared with finite element method (FEM). After the compression test, the damage to FDPs was evaluated with a scanning electron microscopy. Although ZIR (2461 ± 93.70N) showed high fracture load values, FRC (1571 ± 35.96N) material was found to be advantageous in terms of toughness. These were followed by PEEK (1398 ± 38.26N), PEKK (1227 ± 44.25N), and COMP (829 ± 32.33N), respectively. A ductile fracture was observed in PEEK, PEKK, and FRC due to their elastic structures. The deformation properties examined by the FEM were found to be similar to the compression test. CAD/CAM high-performance polymers and cubic zirconia material can be used in three-unit FDPs. In three-unit FDPs, the use of FRC material can be advantageous due to both biomechanics and lightness. Metal-free CAD/CAM materials may offer new possibilities in three-unit FDPs.