Influence of powder type, power, angulation and duration in air-polishing on the surface properties of gingiva-colored composites.

BACKGROUND: This study evaluated the effects of air-polishing procedures using sodium bicarbonate, glycine, and erythritol powders on the surface microhardness and roughness of gingiva-colored composites (GCCs). METHODS: Sixty GCC discs were divided into 12 groups to investigate the differences in air polishing applications based on powder type (E = erythritol, S = sodium bicarbonate, G = glycine), power (F = Full, M = Medium), and angulation (45 degrees ; 90 degrees ). Surface microhardness and roughness were assessed at baseline (T0), 5 s (T1), and 10 s (T2). Statistical analyses included Independent Sample T-test, Mann-Whitney U test, ANOVA, and Kruskal-Wallis tests. RESULTS: EF45, EM90, SF45, SF90, SM90, and GF90 groups showed a significant decrease in hardness over time (p < 0.05). Erythritol exhibited greater hardness compared to sodium bicarbonate and glycine at T2 (p < 0.05). Surface roughness increased significantly in the majority of groups at T2 compared to both T0 and T1 (p < 0.05). EM45, EM90, SM90, and GM90 exhibited significantly higher roughness at T2 compared to both T0 and T1 (p < 0.05). Among the powders, sodium bicarbonate caused a higher increase in surface roughness under all conditions. CONCLUSION: Erythritol exhibited the lowest abrasive properties and resulting in lowest hardness loss and roughness increase on the GCC surface. Similarly, the medium power mode and 45 degrees angle caused lower increase in surface hardness and roughness. Based on the tested parameters, if a patient has restorations with GCC, the airflow application protocol can be adjusted according to the findings of this study to achieve optimal results.