Effects of Surface Abrasion With Airborne‐Particles and Surface Etching With Hydrofluoric Acid on Color Difference and Translucency of Nano‐Hybrid Ceramic
Hyuk‐Joon Lee, Jin‐Won Jang, Zee‐Hoon Park, Ji‐Hwan KimABSTRACT
Objectives
To evaluate the effects of alumina airborne‐particle abrasion, glass‐bead airborne‐particle abrasion, and hydrofluoric acid etching of intaglio surfaces on the color difference and translucency of a nano‐hybrid ceramic after cementation to resin abutment specimens, and to analyze the relationships between surface roughness and these parameters.
Methods
Thirty nano‐hybrid ceramic discs were allocated to alumina airborne‐particle abrasion (hereinafter called as AL), glass‐bead abrasion (hereinafter called as GB), or 9.5% hydrofluoric acid etching (hereinafter called as ET) ( n = 10, respectively). Surface roughness (Ra) was measured with a 3D confocal laser microscope. Treated specimens were cemented to 3D‐printed resin abutment specimens with the same translucent resin cement, and CIELAB coordinates were recorded using a spectrophotometer with black and white backgrounds to calculate CIEDE2000 color difference (Δ E 00 ) and translucency parameter (TP 00 ). Surface microstructures and elemental compositions were assessed by field‐emission scanning electron microscopy (hereinafter abbreviated as FE‐SEM) and energy‐dispersive x‐ray spectroscopy (hereinafter abbreviated as EDS). Data were analyzed using one‐way or Welch ANOVA with post hoc tests and Pearson correlation ( α = 0.05).
Results
Ra decreased in the order of AL>GB > ET ( p < 0.001). ET (with the lowest Ra) showed greater Δ E 00 and lower TP 00 than AL and GB ( p < 0.001), though no significant correlations between Ra and either Δ E 00 or TP 00 were found in it. However, in AL and GB, larger ΔE 00 and lower TP 00 correlated with higher Ra ( p < 0.05). Etched (ET) surfaces showed distinct open micro‐porosity and reduced Si with increased F and Na.
Conclusions
Hydrofluoric acid etching of the nano‐hybrid ceramic intaglio surface resulted in greater color difference and lower translucency after cementation than alumina or glass‐bead airborne‐particle abrasion. Surface roughness was associated with Δ E 00 and TP 00 only in the airborne‐particle abrasion groups.
Clinical Significance
For nano‐hybrid ceramic restorations, the intaglio surface‐conditioning method can influence post‐cementation color difference and translucency. Under the present in vitro conditions, alumina and glass‐bead airborne‐particle abrasion produced smaller color differences and higher translucency than the evaluated hydrofluoric acid‐etching protocol, suggesting that these treatments may be more favorable when shade matching and translucency preservation are clinically prioritized.