Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 10 5 2013 10 15 461 5 Javad Chalipa Assistant Professor, Department of Orthodontics, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Sadegh Ahmad Akhondi Professor, Dental Research Center, Dentistry Research Institute, Department of Orthodontics, Tehran University of Medical Sciences, Tehran, Iran. Sepideh Arab Assistant Professor, Department of Orthodontics, Qazvin University of Medical Sciences, Qazvin, Iran. Mohammad Javad Kharrazifard Post Graduated Student of Epidemiology, Dental Research Center, Tehran University of Medical Sciences, Tehran, Iran. Maryam Ahmadyar General Dental Practitioner, Tehran, Iran. 2015 10 16 The purpose of this study was to evaluate the shear bond strength (SBS) of orthodontic brackets bonded with two types of nano-composites in comparison to a conventional orthodontic composite.Sixty extracted human first premolars were randomly divided into 3 groups each containing 20 teeth. In group I, a conventional orthodontic composite (Transbond XT) was used to bond the brackets, while two nano-composites (Filtek TM Supreme XT and AELITE Aesthetic Enamel) were used in groups II and III respectively. The teeth were stored in distilled water at 37°C for 24 hours, thermocycled in distilled water and debonded with a universal testing machine at a crosshead speed of 1 mm/min. The adhesive remnant index (ARI) was also evaluated using a stereomicroscope.AELITE Aesthetic Enamel nano-composite revealed a SBS value of 8.44±2.09 MPa, which was higher than Transbond XT (6.91±2.13) and Filtek TM Supreme XT (6.04±2.01). Statistical analysis revealed a significant difference between groups II and III (P < 0.05). No significant difference was found between groups I and III, and between groups I and II (P > 0.05). Evaluation of ARI showed that Transbond XT left fewer adhesive remains on teeth after debonding.Results of this study indicate that the aforementioned nano-composites can be successfully used for bonding orthodontic brackets. https://fid.tums.ac.ir/index.php/fid/article/view/603 https://fid.tums.ac.ir/index.php/fid/article/download/603/578