Abstract
This study aims to assess the ion release (Ni, Cr) and surface roughness of metal (M), self-ligating (SL), and ceramic (C) orthodontic brackets after exposure to simulated gastric acid (pH 1.5, pH 3.0) and artificial saliva (pH 7.0). A total of 198 brackets, metal brackets (M) (n = 66) self-ligating (SL) (n = 66), and ceramic brackets (C) (n = 66) were used in this study. Gastric solutions mimicking human gastroesophageal reflux with a pH of 1, 5 or 3 and as a control group pH of 7 (artificial saliva) were used. All specimens were immersed in test solutions for 30 min, 24 h, and 1 month (n = 22 per group). Inductively coupled plasma-mass spectrometry (ICP-MS) measured ion release, while an optical profilometer assessed surface roughness. Data were analyzed using One-way ANOVA and t-tests (p < 0.05). Ni and Cr ion release peaked at 24 h and decreased by 1 month (p < 0.05). SL brackets released the most ions, particularly in acidic conditions (p < 0.05). Surface roughness was highest at 24 h, then decreased (p < 0.001), with M brackets showing the greatest roughness and C brackets the lowest (p < 0.001). M and SL brackets had the highest roughness at pH 1.5, while C brackets peaked at pH 3.0 (p < 0.001). Acidic conditions significantly impact ion release and surface roughness. Ceramic brackets may be advantageous for patients with reflux disease, offering reduced corrosion and surface alterations.