Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 4 2018 08 19 214 221 EN Maryam Khoroushi Professor, Department of Restorative Dentistry, Dental Materials Research Center, Torabinejad Dental Research Center, Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran Fatemeh Keshani Assistant Professor, Department of Restorative Dentistry, Dental Materials Research Center, Department of Restorative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran. Moeen Hosseini Shirazi Assistant Professor, Department of Prosthodontics and Implantology, School of Dentistry, Babol University of Medical Sciences, Mazandaran, Iran Mehdi Esmaeili Dentist, Private Practice, Isfahan, Iran 2017 05 16 2018 05 02 Objectives: The aim of this study was to compare the microleakage in normal and caries-affected dentin (CAD) and to investigate the effect of three hemostatic agents on the microleakage of Class V composite resin restorations in CAD. Materials and Methods: Ninety-six Class V non-beveled cavities were prepared in 48 third molars at 1 mm below the cementoenamel junction (CEJ) in the cervical margin with the occlusogingival size of 2 mm, mesiodistal dimension of 3 mm, and a depth of 1.5 mm. Next, the teeth were divided into 8 groups (n=12): G1-4 included normal dentin (N) substrate, while G5-8 were exposed to mineralization/demineralization cycles to produce CAD substrate. Groups 1 and 5 were the controls. ViscoStat was used in groups 2 and 6, ViscoStat Clear was used in groups 3 and 7, while trichloroacetic acid (TCA) was used in groups 4 and 8. The cavities were restored with composite resin. The samples were sectioned after thermocycling and immersion in 2% fuchsin for 24 hours. The degree of dye penetration was evaluated under a stereomicroscope at 40× magnification. Data were evaluated using Kruskal-Wallis and Mann-U-Whitney tests in SPSS 15 software (α=0.05). Results: Significant differences were recorded on the mean microleakage of different groups (P=0.047). There was a significant difference in the mean dentinal microleakage between N and CAD groups (P=0.014). The dentinal microleakage in group 3 was significantly higher than that in groups 4 to 8. Conclusions: According to the results, CAD showed less microleakage in comparison with intact dentin. ViscoStat Clear caused a greater microleakage than did ViscoStat or TCA. https://fid.tums.ac.ir/index.php/fid/article/view/1902 https://fid.tums.ac.ir/index.php/fid/article/download/1902/1013