Tabriz University of Medical Sciences Journal of Dental Research, Dental Clinics, Dental Prospects 2008-210X 17 4 2023 12 30 Effect of at-home and in-office bleaching on microleakage of class V composite resin restorations using different types of universal adhesives: An in vitro study 211 215 10.34172/joddd.2023.40820 EN Mehdi Abed Kahnamouei https://orcid.org/0000-0002-0458-6366 Soodabeh Kimyai https://orcid.org/0000-0003-0703-5479 Katayoun Katebi https://orcid.org/0000-0002-6595-6359 Mohammad Esmaeel Ebrahimi Chaharom https://orcid.org/0000-0002-8163-8510 Mehdi Daneshpooy https://orcid.org/0000-0002-1549-2488 Mahmoud Bahari https://orcid.org/0000-0002-1774-7659 Mahshid Moradi https://orcid.org/0009-0000-1853-7955 Journal Article 10.34172/joddd.2023.40820 2023 10 09 2023 12 05 Background. When bleaching agents contact dental structures, they act on restorative materials and adhesive interfaces. This study investigated the effect of "at-home" and "in-office" bleaching on the microleakage of composite resin restorations performed with different universal adhesives in self-etch and etch-and-rinse modes. Methods. Class V cavities were prepared in 132 premolars. The samples were divided into four groups (n=33). All Bond Universal adhesive was used in the first and second groups, and G-Premio Bond adhesive was used in the third and fourth groups. The total-etch mode was used in the first and third groups, and the self-etch mode was used in the second and fourth groups. The samples were divided into three subgroups (n=11). In the first subgroup, home bleaching was used, and in the second subgroup, office bleaching was used. In the third subgroup, bleaching was not performed. The specimens were examined under a stereomicroscope for microleakage. Ordinal regression analysis was applied (P<0.05). Results. The adhesive type, application method, and margin type significantly affected microleakage (P<0.05). The amount of microleakage in All Bond Universal adhesive was significantly higher than in G-Premio Bond adhesive. The chance of microleakage in the self-etch mode was almost twice as high as in the etch-and-rinse mode. The bleaching method did not significantly affect microleakage (P>0.05). Conclusion. Based on the results of the microleakage test, bleaching after composite resin restorations did not significantly affect the microleakage of Class V restorations.