Colour Stability between In-House 3D-Printed Resin Brackets and Conventionally Aesthetic Brackets: An In Vitro Study

Background: To evaluate colour stability in artificial saliva by mechanically simulating brushing between in-house 3D-printed resin brackets (IH3DBs) and commercially available brackets. Methods: The samples consist of four sets of ten aesthetic brackets each supplied by four different manufacturers: clear Damon, Synovate C, Crystal and in-house 3D printed brackets (IH3DBs). The brackets were immersed in a plastic tank containing artificial saliva maintained at a constant temperature of 37 °C with a 65-minute brushing system. Staining changes at T0 (pre-brushing) and T1 (post-brushing) were measured with a spectrophotometer according to the VITA and Master scale and brightness values. Statistical analysis compared the colour changes with the Wilcoxon test and in case of significance, severity was investigated. The significance level considered was p < 0.05. Results: The IH3DBs shows statistically significant differences for both scales and brightness values. The Damon and the Crystal brackets report a statistically significant difference only for brightness. The Synovate C bracket shows no statistically significant differences. Conclusions: The IH3DB produced chromaticity differences for the VITA and Master scale possibly due to the surface roughness created during the printing process. However, the IH3DBs together with Damon Clear improved brightness, due to the mechanical action of brushing.