In vitro comparison of bond strengths of different adhesive systems used in attachment application in clear aligner treatments

The aim of this research is to evaluate in vitro the bond strengths of four different adhesive systems used in attachment application in clear aligner treatments, which are becoming increasingly common in orthodontic practice. In the study, 128 molar teeth with extraction indication were used. Following extraction, teeth were stored in sample jars containing distilled water and thymol crystals (0.1% w/vol) to inhibit bacterial growth. Samples were stored in the dark and at room temperature. Scotchbond Universal Bond (3M Unitek, USA) was applied to the prepared teeth, 3M Filtek Supreme Flowable adhesive, G-Premio Universal Bond (GC Corporation, Japan) was applied to the attachment spaces to be applied to the relevant teeth in the attachment template, and GC Ortho Connect Flow adhesive was applied to the attachment spaces to be applied to the relevant teeth in the attachment template. GC Corporation, Japan), G-Premio Universal Bond (GC Corporation, Japan) and the attachment spaces to be applied to the relevant teeth in the attachment template. Tetric EvoCeram (Ivoclar Vivadent, Liechtenstein) adhesive was placed and 4 working groups were formed. For the polymerization of adhesives, a high-intensity LED light source (Valo, Opal Orthodontics by Ultradent, USA) was used and illuminated for a total of 6 seconds. Bond strength tests were performed on a Universal testing device (LLOYD Instron, Foreham Hampshire, England) where the force was loaded at a speed of 1 mm/min until the attachments were separated from the tooth surface. Average bond strength values were evaluated statistically using analysis of variance. After the bond strength test, the amount of residual adhesive on the enamel surface was evaluated with the naked eye. Among the composites we evaluated, 3M Filtek Supreme (Group 1) and GC Ortho Connect Flow (Group 2) are nanohybrid flowable composites. Values of 22.03 Mpa and 21.38 Mpa were found for Group 1 and Group 2. In addition to flowable composites, our research group also includes the packable composites GC G-aenial A'Chord (Group 3) and Tetric EvoCeram (Group 4). The values obtained for Groups 3 and 4 are 27.41 Mpa and 25.96 Mpa. When all groups of the research are compared, it is clearly seen that higher bond strength values are obtained from packable composites than flowable composites. However, no statistically significant difference was found between the maximum bond strength values according to the groups. No significant relationship was found between the distribution of ARI scores and the groups. It was clearly seen that the adhesives used in the research had sufficient bond strength to be used in clear aligner treatments. Higher bond strength values were obtained from packable composites, but flowable composites were found to be more advantageous in terms of application times. Key words: Adhesives used in attachment application, Bond strength, Transparent plate treatments