Accuracy of computer-aided indirect bonding using hard resin trays

Objective Many computer-aided solutions for indirect bonding have been proposed to increase the accuracy of bracket placement. The purpose of this study is to evaluate the accuracy of bracket placement using hard three-dimensional (3D) printed transfer trays. Method: Virtual bracket placement was performed on digitally scanned upper arches; transfer trays were virtually designed and 3D-printed using hard resin material. The transfer trays were used to indirectly bond one hundred brackets on the patients’ upper arches. The actual bracket positions were scanned after bonding, and virtual versus actual models were superimposed to measure linear and angular deviations from the planned positions. Result: The mean linear transfer errors were 0.315 ±0.025 mm mesiodistally and 0.366 ±0.014 mm occlusogingivally, with brackets tending toward distal and incisal positions. Angular errors averaged 1.632° ±0.091° for tip and 1.245° ±0.069° for rotation, showing directional bias toward clockwise tipping and mesial-in rotation compared to the planned positions. Conclusion: Indirect bonding with 3D-printed hard trays provides clinically acceptable accuracy in transferring bracket positions from the virtual setup to the patient’s dentition in both linear and angular dimensions