Analysis of corrosion, surface roughness, and ıon release of orthodontic brackets in simulated gastric acid and saliva

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.