The effect of bleaching on surface roughness and gloss of different CAD/CAM ceramic and hybrid ceramic materials.

OBJECTIVE: To assess the effect of bleaching on surface roughness and gloss of different CAD/CAM ceramic materials.

METHODS: The ceramic materials included IPS e.max CAD (lithium disilicate), VITA ENAMIC (polymer infiltrated ceramic), and Celtra Duo CAD (zirconia reinforced lithium silicate). Samples of each material were randomly divided into four groups ( n  = 10); a control group immersed in distilled water, the second and third groups were treated with 20% carbamide peroxide (20% CP) and 35% carbamide peroxide (35% CP) bleaching agents for 4 h/day and 60 min/day respectively for 7 days. The fourth group was treated with 40% hydrogen peroxide (40% HP) applied twice, each turn for 20 min. After treatment, the surface roughness (using 3D non-contact profilometry) and surface gloss were assessed followed by imaging with a scanning electron microscope. The data were analyzed using multiple linear regression and Kruskal-Wallis one-way ANOVA tests (α = 0.05).

RESULTS: The surface roughness ( p  = 0.157) and gloss ( p  = 0.073) of IPS e.max CAD were not significantly affected by the different bleaching treatments. Similarly, no significant effect on surface roughness ( p  = 0.162) and gloss ( p  = 0.965) were shown for Celtra Duo CAD. On the other hand, VITA ENAMIC was significantly affected when treated with 20% CP and 35% CP showing increased roughness ( p  = 0.001) and gloss ( p  = 0.008).

CONCLUSIONS: Home bleaching treatments (20% CP and 35% CP) significantly affected the surface roughness and gloss of VITA ENAMIC while IPS e.max CAD and Celtra Duo CAD were not affected by the different bleaching treatments.