The Influence of Surface Finishing Processes on Surface Roughness and Stainability of CAD/CAM Composite Material Following Coffee Storage: an in Vitro Study

Abstract

Introduction: Color changes and surface degradation can significantly affect the durability and aesthetic characters of indirect restorations. Chairside polishing procedures impact the surface topography and light scattering characters of CAD/CAM materials. Additionally, acidic and pigmented beverages can cause hydrolytic deterioration of the polymer matrix, worsening these surface alterations.

Aim: The current research was to assess the influence of various surface finishing processes on surface roughness and color stability of a CAD/CAM composite following immersion in coffee solution.

Materials and methods: A total of 21 samples of a CAD/CAM composite (Brilliant Crios) were milled to dimensions of 14 × 12 × 1.5 mm. The samples were randomly allocated into three groups (n=7): Group (C), The control group was not given any surface treatment. Group (F), the finishing group, which was only subjected to finishing, and Group (FP), which subjected to finishing and polishing using a chairside polishing kit. All samples were kept in a coffee solution for 48 hours. Measurement of color change and surface roughness of the samples before and following immersion in the coffee was done using a contact profilometer and a spectrophotometer, respectively.

Results: Regarding surface roughness, the variation across groups was statistically significant. There was a non-significant variation between the control and finish & polish groups, indicating that polishing successfully restored the baseline smoothness. Conversely, the variation across groups was statistically non-significant regarding color change, with all values remaining within clinically acceptable thresholds (ΔE < 3.3). Furthermore, a weak, non-significant correlation was found between color change and surface roughness.

Conclusions: CAD/CAM composite (Brilliant Crios) material exhibited greater color stability and less surface roughness following a complete polishing protocol compared to finishing alone. However, surface roughness did not significantly dictate the color stability of the material following coffee immersion.

Clinical implication: Proper polishing procedures are essential for optimizing both the color and surface roughness of CAD/CAM composite restorations, thereby minimizing aesthetic degradation.