Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 11 4 2014 08 15 389 97 Soodabeh Sadat Sajadi Assistant Professor, Department of Orthodontics, Arak University of medical science, Arak, Iran. Gholamreza Eslami Amirabadi Assistant Professor, Department of Orthodontics, Dental School, Shahed University, Tehran, Iran. Sepideh Sajadi Assistant Professor, Department of Endodontics, Arak University of medical science, Arak, Iran. 2015 10 16 Bond failure of brackets during orthodontic treatment is a common problem; which results in treatment interference, increased treatment time and prolonged clinical time for rebonding of failed brackets. The purpose of this study was to evaluate the effects of Coca-Cola and a non-alcoholic beer on the shear bond strength and adhesive remnant index (ARI) of orthodontic metal brackets in vitro.Eighty intact human premolars were divided into two experimental groups of Coca-Cola and non-alcoholic beer (Istak), and a control group of artificial saliva. Over a period of thirty days, the test groups were immersed in the respective soft drinks for 5 minutes, twice a day. For the remainder of the time, they were kept in artificial saliva at 37°C. The control group was stored in artificial saliva during the experiment. All samples were subjected to shearing forces using Universal Testing Machine. ARI was determined with a stereomicroscope at ×12 magnification. The data of shear bond strength were statistically analyzed by one-way ANOVA and Tukey's Post-Hoc test and the data of ARI scores were analyzed by Kruskal-Wallis test.No significant difference was observed in ARIs of the three groups (P≤ 0.552). The shear bond strength of Coke group was significantly lower than that of the two other groups (P≤ 0.035); but there was no significant difference between the shear bond strength of Istak and the control group (P≤ 0.999).Coca-Cola decreased the shear bond strength of orthodontic brackets. https://fid.tums.ac.ir/index.php/fid/article/view/432 https://fid.tums.ac.ir/index.php/fid/article/download/432/408