en Restorative Dentistry Restorative Dentistry Original article Original article <div> <table align="center" hspace="0" vspace="0"> <tbody> <tr> <td style="padding: 0cm 12px; text-align: justify;" valign="top"><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><b> </b><span style="font-size:9.0pt"><span style="font-family:" verdana="">The use of traditional camphorquinone (CQ) photo-initiators in dental composites may cause undesirable yellow discoloration. An alternative photo-initiator called lucirin trimethylbenzoyl-diphenyl-phosphine oxide (TPO) was recently introduced which exhibits minimal color change (&Delta;E). This study evaluated the color change of TPO-containing composites cured by different types of light-curing units, after accelerated artificial aging (AAA). &nbsp;</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">Materials and Methods:</span></span></span></b><span style="font-size:9.0pt"><span style="font-family:" verdana=""> In this in vitro experimental study, specimens were fabricated from Tetric N-Ceram and Vit-l-escence TPO-containing composites with 10 mm diameter and 2 mm thickness (n=10) and light-cured by Bluephase G2 polywave and Bluephase C5 monowave curing units. The samples were polished with Sof-Lex discs and underwent initial colorimetry by a spectrophotometer after 24 hours. Aging was performed for 384 hours in a weathering chamber and final colorimetry was then performed. The results were analyzed by two-way ANOVA. </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">Results:</span></span></span></b><span style="font-size:9.0pt"><span style="font-family:" verdana=""> The interaction effect of light curing unit and composite type on &Delta;E was not significant (P=0.53). <a name="_Hlk136523865">The mean &Delta;E of Vit-l-escence and Tetric N-Ceram cured with Bluephase G2 and Bluephase C5 light-curing units was 1.67&plusmn;0.48 and 1.62&plusmn;0.45, and 2.59&plusmn;0.29 and 2.69&plusmn;0.26, respectively. </a>Tetric N-Ceram demonstrated significantly greater &Delta;E than Vit-l-escence (P=0.001). Light curing units had no significant difference in &Delta;E (P=0.80).</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="">The &Delta;E of TPO-containing composites does not depend on the type of light curing unit but depends on the type of composite. Aging caused discoloration of the composites but this discoloration was clinically acceptable (&Delta;E<3. 3). &nbsp;</span></span></span></span></td> </tr> </tbody> </table> </div> <div style="text-align: justify;"></div> Aging, Composite Resins, Curing Lights, Dental, Photoinitiators, Dental 249 256 http://jrdms.dentaliau.ac.ir/browse.php?a_code=A-10-1097-3&slc_lang=en&sid=1 Negar Madihi negarmadihi@gmail.com 100319475328460011470 0009000483480923 No School of Dentistry, Tehran Medical Science Islamic Azad University, Tehran, Iran Maryam Hoorizad ganjkar Mahoorizad@yahoo.com 100319475328460011471 0000000229639022 Yes Operative Dentistry Department, School of Dentistry, Tehran Medical Science Islamic Azad University, Tehran, Iran Negin Nasoohi neginnasoohi@yahoo.com 100319475328460011472 0000000209812721 No Operative Dentistry Department, School of Dentistry, Tehran Medical Science Islamic Azad University, Tehran, Iran Ali Kaboudanian Ardestani alikaboudanian@gmail.com 100319475328460011473 0000000316625665 No School of Dentistry, Tehran Medical Science Islamic Azad University, Tehran, Iran