Accuracy of Two Indirect Bonding Transfer Methods: A Three-Dimensional, In-vivo analysis

Abstract

Background: Recent literature has suggested that indirect bonding results in more accurate bracket placement. However, this more ideal positioning is of no use to the orthodontist unless the indirect bracket set-up is transferred accurately to the patient's dentition. This study aims to investigate the positional integrity of the indirect bonding transfer method of two commercially available tray types. Materials and Methods: Eighteen patients were randomly assigned to either a transparent tray light-cure or an opaque tray chemical-cure indirect bonding system. A total of 129 teeth were analyzed for the transparent tray group and 99 teeth for the opaque tray group. An intraoral scanner was used to generate three-dimension .stl models of each indirect set-up ("pre-transfer"� model) and each corresponding in-vivo bracketed patient arch ("post-transfer"� model). A comparison software was used to superimpose these models based on a surface best-fit algorithm. Bracket position differences were measured in three translational and three rotational planes of space to the nearest 1 �m. Statistical analysis was performed to compare the pre- and post-transfer bracket position, to detect any directional patterns of error, and to compare the transparent and opaque tray systems. Results: The indirect bonding transfer was found to be accurate for the data as a whole and for each tray type individually (p<0.0001). Final bracket position tended to be slightly more buccal and more occlusal for both groups compared to the set-up. This error was clinically insignificant but was more pronounced for the opaque tray group. Conclusions: Both indirect bonding methods transfer bracket position accurately in actual clinical use.