Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 16 4 2019 05 29 265 271 EN Sara Valizadeh Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. AND Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Aida Moradi Post graduate Student, Operative Dentistry Department, Dental School, Tehran University of Medical Sciences, Tehran, Iran Mansoureh Mirzaei Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Hooman Amiri Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Mohammad Javad Kharazifard Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran 2018 08 22 2019 03 01 Objectives: The aim of this study was to compare the microshear bond strength (µSBS) of various adhesive systems to dentin. Materials and Methods: In this in vitro experimental study, 60 sound human third molars were divided into four groups. Dentin discs were prepared of middle-third dentin measuring 4 mm in diameter and 2 mm in thickness. Dentin surfaces were bonded with one of the four types of adhesives: (A) Single Bond (3M ESPE), Scotchbond Universal (3M ESPE) in etch and rinse (B) and self-etch (C) modes and (D) Clearfil SE Bond (Kuraray Noritake Dental). After the application of adhesive systems according to the manufacturers’ instructions, composite cylinders (Vit-l-escence) were bonded to dentin surfaces. The μSBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with one-way ANOVA and Tukey’s test (α=0.05). Results: The µSBS was the highest in self-etch Scotchbond Universal (15.8±6.08 MPa) followed by Clearfil SE Bond (15.24±4.6 MPa), etch and rinse Scotchbond Universal (11.68±4.07MPa) and Single Bond (11.24±3.74 MPa). A significant difference was only found between Single Bond and etch and rinse Scotchbond Universal groups (P=0.04). Conclusion: Based on the results of this study, application of Scotchbond Universal in self-etch mode provides a reliable bond to dentin. https://fid.tums.ac.ir/index.php/fid/article/view/2785 https://fid.tums.ac.ir/index.php/fid/article/download/2785/1766