Journal of Research in Dental and Maxillofacial Sciences

en Flexural Strength and Microshear Bond Strength of Conventional and Flowable Composite Resins to Dentin Restorative Dentistry Restorative Dentistry Original article Original article <div style="text-align: justify;">Background and Aim: This study aimed to evaluate the flexural strength (FS) and microshear bond strength (µSBS) of conventional and flowable composite resins to dentin. Materials and Methods: This in vitro study was conducted on composite specimens fabricated from Filtek Z250 and Clearfil AP-X Esthetics (CE) conventional, and Clearfil AP-X Esthetics Flow (CEF) and Clearfil AP-X Flow (CF) flowable composite resins in 4 groups (n=10). The specimens underwent a 3-point bending test for measurement of their FS. For assessment of µSBS, dentin discs with 2 mm thickness were obtained from the coronal third of the crowns of 20 extracted premolars. Composite resins were bonded to dentin discs in Tygon tubes (1 mm height, 0.7 mm internal diameter) using Tetric N-Bond 5th generation bonding agent, and a universal testing machine measured their µSBS. Data were analyzed by ANOVA and Tukey test (alpha=0.05). Results: Z250 showed a significantly higher FS than CEF (P=0.002); no other significant difference was found in FS. The two conventional composites (P=0.847) and the two flowable composites (P=0.575) had no significant difference with each other in µSBS. However, the conventional composites had a significantly higher µSBS than the flowable composites (P<0.001). Conclusion: The FS of CEF was significantly lower than that of Z250, and comparable to that of other tested composite resins. All tested composites had a FS higher than 80 MPa recommended by ISO-4049 for restorations under occlusal forces. Both CEF and CF showed significantly lower µSBS than the tested conventional composite resins.</div> Composite Resins, Dental Bonding, Flexural Strength 144 151 http://jrdms.dentaliau.ac.ir/browse.php?a_code=A-10-1417-4&slc_lang=en&sid=1 Sina Farahiparizi sina.f.p.sf@gmail.com 100319475328460014742 100319475328460014742 No Dental Research Center, Research Institute of Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Kasra Tabari kasratabari54@gmail.com 100319475328460014743 100319475328460014743 No Department of Restorative Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hasan Torabzadeh 5htorabzadeh@gmail.com 100319475328460014744 100319475328460014744 No Dental Research Center, Research Institute of Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Narges Panahandeh nargespanahandeh@yahoo.com 100319475328460014745 100319475328460014745 Yes Dental Research Center, Research Institute of Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.