https://publish.kne-publishing.com/index.php/fid <p><strong><em>Frontiers in Dentistry (Formerly known as :Journal of Dentistry of Tehran University of Medical Sciences (JDT))</em></strong>&nbsp;is the first Iranian dental journal in English.&nbsp;<strong><em>FD</em></strong>&nbsp;is an Open Access,&nbsp;Peer-Reviewed bimonthly journal published by Dental Research Center (DRC) of Tehran University of Medical Sciences which is a dynamic, rapidly growing research center.</p> <p>The Journal aims to publish novel and high quality relevant information written by peers to researchers and readers involved in all fields of dentistry, oral health sciences and related&nbsp;<span dir="LTR">interdisciplinaries,&nbsp;</span>strives to keep pace with the rapid growth of publications, and move on to the edge of knowledge in this field.</p> <p><strong data-stringify-type="bold">All the manuscripts should be submitted through the Journal Primary Website at <a href="https://fid.tums.ac.ir/index.php/fid/about/submissions">https://fid.tums.ac.ir/index.php/fid/about/submissions</a></strong></p> Tehran University of Medical Sciences en-US Frontiers in Dentistry 2676-296X https://publish.kne-publishing.com/index.php/fid/article/view/17839 <p><strong>Objectives:</strong> Repair of composite resin restorations is a challenge specially when the restoration undergoes aging; thus, this study aimed to assess the effect of aging and different surface treatments on the repair microshear bond strength of IPS Empress Direct nanohybrid composite resin.</p> <p><strong>Materials and Methods: </strong>This in vitro, experimental study evaluated 48 IPS Empress Direct composite resin samples in two groups of aged and nonaged (n=24). The samples in both groups were finished and polished with Sof-Lex discs. Composite samples in the aged group were subjected to 5000 thermal cycles. The two groups were then divided into two subgroups (n=12) for surface roughening by a diamond bur or sandblasting with aluminum oxide particles. Composite cylinders were then bonded to the composite samples, and underwent microshear bond strength test in a universal testing machine. Data were analyzed by two-way ANOVA and t-test (alpha=0.05).</p> <p><strong>Results: </strong>The results showed no significant difference in the microshear bond strength of bur and sandblasted subgroups, irrespective of aging (P&gt;0.05). In the aged subgroups, however, irrespective of the method of surface treatment, the bond strength was significantly lower than that in the subgroups that did not undergo the aging process (P&lt;0.05).</p> <p><strong>Conclusion: </strong>Micromechanical retention is the most reliable method to achieve a high repair bond strength in IPS Empress Direct composite resin. Surface roughening by bur is safe and cost-effective, and can be used instead of sandblasting for composite restoration repair.</p> Maryam Hoorizad Ganjkar Negin Nasoohi Mahshad Lesani Neda Sanaee Copyright (c) 2025 Frontiers in Dentistry 2025-02-10 2025-02-10 10.18502/fid.v22i6.17839