Effect of Erosive and Abrasive Challenges on the Glaze Layer

Objectives: To evaluate the impact of erosive and abrasive challenges on the glaze layer applied on indirect restorative materials for surface roughness (Ra), surface loss (PS) and surface topography (T).
Methods: Samples (6mm x 7mm x 1.3mm), of LuxaCam Zircon HT - Plus (LC) and IPS e.max CAD (IPS) were tested in different moments: after Sintering (S), Glazing (G) and Surface challenges [Erosion (E), Abrasion (A) and Erosion/Abrasion (EA)]. E protocol consisted of immersing samples in 5 ml of 0.06M HCl, pH 1.2, for 30 hours and A protocol was performed with brushing machine, soft bristle brushes and slurry with 400.000 cycles (load of 200 grams). Ra and SL (n = 10) were evaluated with optical profilometry and T with SEM (n=3). Data were submitted to analysis of variance (ANOVA) and Tukey test (p <0.05).
Results: Regarding Ra, LC presented higher Ra than IPS (p <0.05) for all tested groups. E decreased glaze Ra (p <0.05), while A and EA increased it (p <0.05). Regarding PS, LC presented PS higher than IPS (P = 0.03). A and EA challenges generated higher PS than E (p = 0.00). SEM images showed that the smothest surface was detected for E and the most irregular, for A and EA. The application of G promoted a smother surface than S.
Conclusions: It is concluded that all the glaze layers properties tested were altered by the surface challenges, however the glaze layer applied on zirconia was more susceptible to these.