Evaluating the conversion degree of temporary restorative materials produced by different 3-dimensional printer technologies

Purpose: The purpose of this in vitro study was to evaluate the DC of interim restorative materials produced using different 3D printer technologies and to compare them with conventionally manufactured polymethyl methacrylate (PMMA). Material and methods: Stereolithography (SLA), digital light processing (DLP), and liquid crystal display (LCD) 3D printers were used as experimental groups and conventional (C) method was used as the control. Six different 3D printers (DWS, Formlabs, Asiga, Mega, Vega, and Photon) were included. The 3D-printed specimens were designed in a rectangular prism geometry (10×4×2.5 mm) using a computer-aided design (CAD) software program (Materialise 3-matic) and printed with a layer thickness of 50 μm in the horizontal direction (n=15). Fourier transform infrared spectroscopy (FT-IR) spectra were measured in 3 steps: the liquid state of the resins, after washing, and after final polymerization. For the conventional method, FT-IR spectra were assessed in 2 steps: immediately after mixing the liquid and powder and after polymerization. Statistical analysis of the data was performed with 1-way ANOVA followed by the post hoc Tukey HSD test (α=.05). Results: There was no statistically significant difference in DC values between the 3D printed groups (P>.05). There was a statistically significant difference only between Formlabs (FL) and the conventional (C) in terms of DC (P=.042). Conclusions: Three-dimensionally printed interim resin materials showed comparable results with those of the conventional group. The DC was not affected by different 3D printing technologies. Keywords: 3D Printer, Additive Manufacturing, Interim Restorations, Degree of Conversion