Effect of Air Polishing Procedure with Glycine and Bicarbonate Powders on Glass Ceramic and Composite Resin Surfaces

Objective: To evaluate the effect produced by air-polishing procedure using glycine and sodium bicarbonate-based powder on different restorative materials' surfaces. Methods: There were used a nanofilled and nanohybrid composite resins and a glass-ceramic. Ten disks (n=10) of each material were made (6.5 mm × 0.5 mm). They were divided in 2 groups of 5 specimens each to be airpolished with sodium bicarbonateand glycine. The polishing procedure was performed at an angulation of 60°, 10 mm working distance, 10s and 4 bar pressure. A profilometer working at 0.5 mm/s was employed to evaluate roughness and a scanning electron microscope was used to evaluate surface morphology. Roughness was measured in all specimens before being polished to serve as control. All values were analyzed using ANOVA and Tukey test (p<0.05). Results: Two-way ANOVA indicated that the factors “Restorative Material”, “Polishing Powder” (p<0.0001) and also interaction between them were statistically significant. Nanohybrid composite treated with sodium bicarbonate (0.62 ± 0.20 µm) showed significantly higher roughness values than its control (0.37 ± 0.17)and also than the nanocomposite (0.16 ± 0.01 µm) and feldspathic ceramic (0.17 ± 0.05 µm) after treated with the same material (p<0.05). After treated with glycine the nanohybrid composite presented significantly lower roughness values (0.22 ± 0.07 µm) than when treated with sodium bicarbonate (p<0.05), and also it was not different from the nanocomposite (0.19 ± 0.05) and feldspathic ceramic (0.14 ± 0.02) after treated with the same material. Conclusion: Sodium bicarbonate produced higher roughness values on the nanohybrid surface, and it also produced more morphological alterations on the two composite resins employed.