http://www.jrdms.dentaliau.ac.ir J Res Dentomaxillofac Sci 2019; 4 (1) H Kazemi,et al, 26 In-Vitro Comparative Study of the Effect of Four Finishing and Polishing Tools on Sur- face Roughness of a Microhybrid Resin S Nemati Anarakiu 1 ,H Kazemi 2 , Z GHafari 3 , Z Naser 4 , T Bitaraf *5 1- Assistant professor, Restorative Dept, faculty of Dentistry,Tehran medical sciences, Islamic Azad University, Tehran, Iran. 2- Assistant professor, Restorative Dept, Dental implant research center faculty of Dentistry,Tehran medical sciences, Islamic Azad University, Tehran, Iran. 3- Dentist, Tehran, Iran 4- Dentist, Boston, Massachusetts, United States. 5- Assistant professor, Dental Implant Research Center, Dental Faculty, Tehran Medical Sciences, Islamic Azad Univer- sity, Tehran, Iran ABSTRACT ARTICLE INFO Article History Received: March 2018 Accepted: April 2018 ePublished: May 2019 Corresponding author: Assistant professor, Dental Implant Re- search Center, Dental Faculty, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran , taherehbitaraf@ yahoo.com Background and Aim: The complications of unwanted surface roughness of com- posite restorations are highly common due to the increasing use of this restorative ma- terial. Therefore, the present study was designed to compare the effect of four fnish- ing and polishing (F&P) tools on surface roughness of microhybrid resin composites. Materials and Methods: This experimental study was performed on 42 samples of CLEARFIL™ AP-X microhybrid composite, which were divided into four groups of different F&P methods and one control group as follows: control (n=2), Flexi-D discs (n=10), Flexi-D + diamond polishing paste (n=10), Intensive twisted rubber polisher (n=10), and Rubber Polisher Teco (n=10). The samples were examined by proflometry. Surface roughness (Ra) of each specimen was measured at three points, and the mean value was considered as surface roughness. The results were analyzed by analysis of variance (ANOVA) and post hoc statistical tests. Results: The surface roughness of composite discs in an ascending order was as fol- lows: control (0.048±0.014 µm), Flexi-D disc (0.179±0.132 µm), Intensive twist- ed rubber polisher (0.233±0.105 µm), Flexi-D disc with diamond polishing paste (0.232±0.141 µm), and Rubber Polisher Teco (0.251±0.087 µm; P=0.001). The dif- ference between the two groups of Flexi-D disc with diamond polishing paste and Rubber Polisher Teco was not statistically signifcant (P=0.742). The level of surface roughness in Flexi-D samples was signifcantly lower than that of the other samples (P<0.05). Conclusion: It seems that the Flexi-D disc is the best F&P tool for microhybrid resin composites. Keywords: Dental Polishing / Instrumentation, Composite Resin, Surface Properties, Ma- terials Testing J Res Dentomaxillofac Sci 2019;4(2):26-31. DOI: 10.29252/jrdms.4.2.26 Original Article Introduction: The surface roughness of restorative materials is one of the problems that can cause plaque and bacteria to accumulate, eventually leading to un- healthy surfaces with consequences such as dis- coloration and gingival and periodontal infam- mation. (1-3) Also, increased staining of composite restorations will ultimately have a signifcant effect on their aes- thetics. The maximum acceptable roughness is 0.2 μm for restorative materials; at this level, there will be no bacterial adhesion. Higher surface roughness will cause bacterial adhesion and plaque accumula- tion, increasing the risk of decay and periodontitis. (1-3)