Transfer trays for indirect bonding of fixed orthodontic appliance

Aim: Comparison of manually produced silicone transfer tray for indirect bonding and modern digital process where the brackets placement as well as transfer tray are digitally designed and tray is 3D-printed. Decide whether the trays are appropriate in clinical practice. Material and method: 2 types of transfer trays for indirect bracket bonding were made in 25 models of the maxilla: silicone tray of V-Posil Putty Fast (VOCO) and 3D-printed tray made of IBT Resin (Formlabs). Using software GOM Inspect 2018 we compared the position of 500 brackets prior to and after application of transfer tray. Results: When using 3D-printed tray the brackets deviated from their original site by 0.14 ±0.12źmm mesiodistally, 0.2 ±0.16źmm in height, 0.17 ±0.17źmm vestibuloorally, 0.98 ±0.69°in inclination, 1.3 ±0.86°in torque, and 0.72 ±0.42°in rotation. When using silicone tray the deviations were 0.29 ±0.15źmm mesiodistally, 0.34 ±0.12 in height, 0.3 ±0.16źmm vestibuloorally, 1.05 ±0.73°in inclination, 1.37 ±0.85°in torque, and 0.79 ±0.41°in rotation. Conclusion: Both types of transfer trays used in the study are sufficiently accurate for clinical use of indirect bonding of fixed appliance. In most parameters the accuracy of both trays was comparable, however, 3D-printed tray shows significantly smaller deviations in linear parameters. Silicone tray transferred higher proportion of brackets within clinically acceptable limits (deviation up to 2źmm) in vestibulooral direction and height. Both trays are least accurate in transfer of bracket torque.