Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 17 0 2020 10 19 3230 3230 Shabnam Milani Department of Pediatric Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Bahman Seraj Department of Pediatric Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Zahra Khoshlafz Private Practice, Hamadan, Iran Niusha Abazarian Department of Pediatric Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2019 07 15 2020 06 08 Objectives: Achieving durable restorations with adequate strength in severely damaged primary anterior teeth in children is a priority. The aim of this study was to investigate the effect of dentin pretreatment with chlorhexidine on push-out bond strength of composite restorations. Materials and Methods: In this in vitro experimental study, 56 extracted primary anterior teeth were randomly divided into 4 groups: (1) saline and total-etch bonding agent, (2) chlorhexidine and total-etch bonding agent, (3) saline and self-etch bonding agent, and (4) chlorhexidine and self-etch bonding agent. After the application of bonding agents, the post space was filled with Z250 composite resin. Following thermocycling of the samples, the push-out test was performed using a universal testing machine, and the results were analyzed with two-way ANOVA. Results: The mean push-out bond strength values in groups 1 to 4 were 5.7, 8.39, 5.35, and 7 MPa, respectively. Chlorhexidine groups had significant differences with saline groups in bond strength (P<0.05) but there was no statistically significant difference between the self-etch and total-etch bonding agents in the groups (P>0.05). Conclusion: Both types of bonding agents (self-etch and total-etch) exhibited favorable results in radicular dentin of primary anterior teeth; however, pre-treatment with chlorhexidine increased the push-out bond strength of composite restorations in primary anterior teeth. https://fid.tums.ac.ir/index.php/fid/article/view/3230 https://fid.tums.ac.ir/index.php/fid/article/download/3230/1818