Effect of Acidic Beverage on Color Stability, Microhardness, Surface Roughness and Solubility of Different Novice Restorative Materials: An in Vitro Study

Abstract

Background

Resin-based restorative materials are continuously exposed to chemical challenges in the oral environment. Frequent consumption of acidic beverages may compromise their esthetic appearance and mechanical performance through degradation of the resin matrix and filler–matrix interface. Although several contemporary restorative materials have been introduced with improved optical and mechanical characteristics, comparative evidence regarding their resistance to acidic degradation remains limited.

Objective

To evaluate and compare the effect of acidic beverage exposure on color stability, surface microhardness, surface roughness, and solubility of four contemporary resin-based restorative materials: Vittra APS Unique, Neo Spectra™ ST, Beautifil II LS, and Palfique Omnichroma.

Materials and Methods

This in vitro experimental study was performed using sixty standardized disc-shaped specimens (n = 15/group) fabricated from four commercially available restorative materials. Following polymerization and finishing, the specimens were subjected to cyclic immersion in Coca-Cola, with storage in artificial saliva between immersion cycles to simulate the oral environment.

Color stability was assessed using a spectrophotometer based on CIE Lab* coordinates. Surface microhardness was measured using a Vickers hardness tester, surface roughness was evaluated with a contact profilometer, and solubility was determined using a precision analytical balance according to standardized procedures. Statistical analysis was performed using one-way analysis of variance followed by appropriate post hoc comparisons, with statistical significance established at p < 0.05.

Results

Significant differences were observed among the restorative materials for color stability, surface microhardness, and solubility (p < 0.05), whereas surface roughness did not differ significantly among the groups (p > 0.05). Neo Spectra™ ST demonstrated superior color stability and the lowest solubility following acidic exposure. Beautifil II LS exhibited the highest surface microhardness, while Palfique Omnichroma showed the lowest hardness values together with the greatest solubility. Vittra APS Unique demonstrated intermediate performance across the evaluated parameters.

Conclusion

Acidic beverage exposure adversely affected the esthetic and mechanical properties of all evaluated restorative materials. Among the tested composites, Neo Spectra™ ST demonstrated the most balanced overall performance under acidic conditions, whereas Beautifil II LS exhibited superior hardness retention. Vittra APS Unique and Palfique Omnichroma showed comparatively greater susceptibility to acidic degradation. These findings may assist clinicians in selecting restorative materials for patients with frequent consumption of acidic beverages.