en Restorative Dentistry Restorative Dentistry Original article Original article <div style="text-align: justify;"><span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Background and Aim</span></span></span></b><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">:</span></span></span></b> <span style="font-size:9.0pt"><span style="font-family:" verdana="">This study aimed to assess the alterations in microhardness of Clearfil Universal Bond Quick (CUBQ), G-Premio Bond (GPB), and Scotchbond Universal (SBU) immediately, 24 hours, and 6 months after curing. </span></span>&nbsp;</span></span><br> <span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Materials and Methods: </span></span></span></b><span style="font-size:9.0pt"><span style="font-family:" verdana="">In this in vitro study, a composite disc was fabricated. A putty/wash impression was made from the disc to serve as a mold. CUBQ, GPB, and SBU adhesives were applied in the mold, and after allowing 3 hours for the solvent to evaporate, they were cured by a LED curing unit for 20 seconds. Ten specimens were fabricated from each adhesive. The microhardness of the specimens was measured by a microhardness tester immediately, 24 hours, and 6 months after curing. Data were analyzed by repeated measures ANOVA (alpha=0.05).</span></span>&nbsp;</span></span><br> <span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Results: </span></span></span></b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#0e101a">The mean microhardness of the three adhesives was significantly different immediately after curing (P<0.001), and CUBQ showed significantly higher microhardness than GPB (P<0.001) and SBU (P=0.004). The difference in microhardness of the three adhesives was not significant after 24 hours and 6 months (P>0.05).</span></span></span><span style="font-size:9.0pt"><span style="font-family:"Verdana",sans-serif"></span></span></span></span><br> <span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Conclusion:</span></span></span></b> <span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#0e101a">The present results showed that the microhardness of all three tested universal adhesives increased with time.</span></span></span></span></span><br> &nbsp;</div> Composite Resins, Dentin-Bonding Agents, Hardness 257 262 http://jrdms.dentaliau.ac.ir/browse.php?a_code=A-10-1417-2&slc_lang=en&sid=1 Mohsen Rezaee dr.rezaee.m@gmail.com 100319475328460013361 100319475328460013361 No Department of Operative Dentistry, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran Armin Darabi armin.darabi@gmail.com 100319475328460013362 100319475328460013362 No Dentist, Private Dentistry Practice, Tehran, Iran Narges Panahandeh nargespanahandeh@yahoo.com 100319475328460013363 100319475328460013363 Yes Dental Research Center, Research Institute of Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, IranMedical Sciences, Tehran, Iran.