A comparative evaluation of physical properties of CAD/CAM complete denture resins‑ an in vitro study

Abstract

Background In dentistry, there is a growing preference for computer-aided design and computer-aided manufacturing(CAD/CAM) systems over traditional laboratory procedures. However, there is not much literature comparingvarious CAD/CAM materials. Thus, this study aimed to assess and compare the color stability and hardness of gingivaland tooth colored milled and 3D-printed acrylic resins.Materials and methods Four types of CAD/CAM materials were prepared: 3D-printed pink shade (PP), milledpolymenthymethacrylate (PMMA) pink shade (MP), 3D-printed tooth shade (PT) and milled PMMA tooth shade(MT) (n = 6). For hardness, disc shaped samples of 15 mm × 2 mm and for color stability, bar shaped samples of 65mmx10mmx2.5 mm were prepared and polished. Vickers hardness test was performed in a microhardness tester.Color stability test was done by immersing in coffee solution and coca cola for 7 days. Day 0 and day 7 measurementswere recorded using a digital spectrophotometer and the change in color was calculated. For statistical analysis, onewayANOVA and Tukey’s post hoc tests were done.Results For color stability, milled PMMA was superior to 3D-printed resin samples. Milled pink and tooth shade samples had similar color stability, whereas 3D-printed tooth shade samples were more color stable as comparedto pink shade 3D-printed samples. For hardness, milled tooth shade PMMA was the most superior one, followedby 3D-printed tooth shade, whereas pink shade milled PMMA and 3D-printed resin samples had similar hardnessvalues and were inferior to the tooth shade CAD/CAM materials. Conclusion Color stability of milled PMMA is superior to that of 3D-printed resins. Hardness of tooth shade milledand 3D-printed resins is more than that of pink shade milled and 3D-printed resins.