eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2015-12-25 12 3 2319 2324 10.13005/bbra/1907 4033 article Seyed Mohammad Mousavi 1 Parinaz Saeidi Ghorani 2 Pedram Javidi 3 Nazanin Berahman 3 Morteza Moattari 4 Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Orthodontist. Postgraduate Student of Orthodontics, Faculty of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Postgraduate Student of Endodontics, Faculty of Dentistry, Tehran Azad University of Medical Sciences, Tehran, Iran. Acrylic resin is widely used in manufacturing removable orthodontic appliances. Nevertheless water sorption and dimensional changes are some of the drawbacks of this material that can affect the accuracy of the appliance. The aim of this study was to evaluate the effects of Corega® solution on dimensional changes of orthodontic appliances in comparison with two conditions including dry and water environment. Sixty six acrylic resin specimens were made in quadrangular metal mold. Then the length, width and diameter of each specimen were measured with digital caliper with measurement accuracy of 0.01 mm. Specimens were randomly divided into three groups. The samples in these three groups were kept in dry environment, water and Corega® solution respectively. Different dimensions of the specimens were blindly measured after 18 hours, 48 hours and 1 week by two independent evaluators.Dry environment had the highest amount of dimensional change and was significantly different from water and Corega® solution over those three evaluated periods of time. No significant difference was seen between dimensional changes in water and Corega® solution. Also data analysis showed that acrylic resin’s dimensional change in dry environment over different periods of time is not statistically significant. Orthodontic appliances should be kept in water or Corega® solution and Corega® solution is the superior choice due to its antibacterial effects.   https://www.biotech-asia.org/vol12no3/the-effect-of-time-and-three-different-storage-environments-on-the-dimensional-stability-of-acrylic-removable-orthodontic-appliances/ Acrylic resin; Removable orthodontic appliance; Corega