Evaluation of clinical reliability of transfer trays created by a three dimensional printer

Objective: The aim of this study was to evaluate the clinical reliability of the bracket transfer trays which were fabricated using a 3D printer. Materials and Methods: In this study 139 brackets of 5 patients (2 male and 3 female) were included. The digital models of the patients were obtained by a 3D intraoral scanner (TRIOS, 3Shape Dental Systems, Copenhagen, Denmark). Brackets were positioned in their ideal position on the tooth surface using Orthoanalyzer (3Shape Dental Systems, Copenhagen, Denmark) software on the digital models. Transfer trays were designed by appliance designer software and then fabricated by a three dimensional printer (Envisiontech Vida 3D Printer, Gladbeck, Germany). The brackets were placed in the grooves in the tray and bonded using light cured resin (Transbond XT, 3M, Unitek Monrovia, California, USA). After that, the arches of the patients were re-scanned. The digital models where the brackets were positioned in the ideal position and the models obtained by scanning after bracket bonding procedure were superimposed and the differences were examined three dimensionally (GOM Software 2018 Hotfix 6, Braunschweig, Germany). Kruskal-Wallis test was used to evaluate the differences, and then the tooth groups were compared with Mann-Whitney U test. Results: When the total values were examined, the difference in the torque value of the premolar tooth group was found 1.25° on average and the result increased above the limit of 1°. When the vertical, mesiodistal, buccolingual and torque values were examined, there was a significant difference in the premolars compared to the other groups (p <0,05). When the lower jaw was examined, there was a significant difference in vertical, buccolingual, torque and tip values in canines compared to the molars (p <0,05). The difference in the mean torque value for premolars is above the clinically acceptable range. When the upper jaw was evaluated, there was a significant difference in vertical, buccolingual and torque values in the premolars compared to the molars (p <0,05). The mean torque and rotation values in the premolars are above the clinically acceptable range. Conclusion: The difference in the torque value of the premolars was above the clinically acceptable range. It was found that the change in the vertical direction in linear measurements was more than the mesiodistal and buccolingual directions. In angular measurements, it was found that the change in torque values were higher than tip and rotation values. Keywords: Indirect Bonding, 3D Dental Model, Transfer Tray, Transfer Accuracy