Wear of interim resin materials manufactured by 3D printing and CAD/CAM milling following chewing simulation

Recently introduced novel additively manufactured interim resins require in vitro investigation of their mechanical properties. The objective of the study is to assess the wear rates of four different interim resin materials using a chewing simulator for 1.5 months of dynamic loading.

Four interim resin materials were assessed: (1) Liquid crystal displays (LCD) 3D printed (n = 8), (2) Digital light processing (DLP) 3D printed (n = 8) (3) Conventional autopolymerizing bis-acrylic (n = 8), (4) CAD/CAM milled interim resin materials. The specimens underwent 30,000 cycles, approximately equivalent to 1.5 months of chewing simulation. The volumetric loss (mm³) and wear depth (mm) of each specimen was calculated. The Kruskal-Wallis test was used to identify intergroup differences (α = 0.05).

The mean ± SD wear volume losses (mm3) following chewing simulation were 0.1394 ± 0.0810 for conventional resin, 0.1099 ± 0.0873 for milled resin, 0.0980 ± 0.1021 for DLP resin, and 0.0934 ± 0.0788 for LCD resin. Wear volume loss was not significantly different amongst interim materials (P > 0.05). The mean ± SD wear depths (mm) following chewing simulation were 0.4084 ± 0.01440 for conventional resin, 0.4343 ± 0.1115 for milled resin, 0.4546 ± 0.0349 for DLP resin, and 0.3954 ± 0.1051 for LCD resin. Wear depths were not significantly different amongst interim materials (P > 0.05).

3D printed and CAD/CAM milled resins had wear resistance comparable to conventional resin. Wear resistance after chewing simulation offers 3D printed resin a suitable interim restorative material for clinical use.