Effect of Simulated Tooth Brushing on Surface Roughness, Gloss, and Color Stability of Milled and Printed Permanent Restorative Materials.

Abstract

Objectives: This in vitro study evaluated the effects of simulated toothbrushing on surface roughness, gloss, and color stability of milled and printed resin-based and lithium disilicate materials for permanent dental restorations.

Materials and methods: Five materials were tested, including CAD/CAM prepolymerized resin blocks, a ceramic material, a resin composite and a newly FDA-cleared 3D-printed resin for permanent crowns. Specimens underwent a controlled brushing protocol simulating 5 years of brushing (50,000 cycles). Surface roughness (R_a), gloss (GU), and color stability (ΔE) were measured at baseline and after 10,000, 30,000, and 50,000 cycles using an optical profilometer, glossmeter, and spectrophotometer. Scanning electron microscopy (SEM) analyzed surface morphology post-brushing.

Results: Ceramic materials exhibited superior resistance to surface roughness and gloss loss, maintaining high esthetic properties (p < 0.001). In contrast, 3D-printed resin materials showed notable increases in surface roughness and gloss reduction, reflecting a higher susceptibility to wear. Resin composites demonstrated variable performance, with direct-use composites performing worse than their CAD/CAM milled counterparts. Glossed ceramic materials exhibited clinically acceptable color changes, while all other groups exceeded thresholds, posing potential esthetic challenges.

Conclusions: Milled materials, particularly ceramics, demonstrated superior durability and esthetic retention. Optimization is needed for 3D-printed resin materials to enhance their mechanical and esthetic properties for long-term use. These findings guide material selection for durable, esthetic dental restorations.