الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Introduction: The objective of this trial was to compare the differences between two types of indirect bonding techniques regarding accuracy of transfer orthodontic attachments in all 3 planes of space using 3D scanning and superimposition, bond failure of orthodontic attachment and chairside time. Materials and methods: A randomized controlled trial compared between the digital 3D printed transfer tray versus thermoformed transfer tray techniques was performed, 12 patients with fully erupted full set of permanent teeth including the permanent maxillary second molars, with mild to moderate crowding, with good oral hygiene and no signs of caries, large restorations, abnormalities of crown morphology or gingival inflammation were recruited in this study. 144 attachments were bonded to the maxillary teeth from central to first molar for both groups. For the thermoformed transfer tray group, after placement of the attachments on the working model using water soluble glue regarding the vertical and horizontal reference lines, the tray was vacuum-formed over the model using soft vacuum sheet 1 mm thickness. While for the 3d printed tray group, the tray was designed using 3Shape Appliance Designer software and 3d printed in flexible resin. The attachments were transferred to the patient’s dentition using the two techniques. Pre-operative and post-operative scans were superimposed to assess the transfer accuracy. The number of failed attachments was recorded and the chair side time was recorded using stopwatch. Results: regarding mesio-distal deviation (X-axis), bucco-lingual deviation (Z-axis), torque and rotational differences, there was no significant difference between both groups (as P-value > 0.05). While for the occluso-gingival deviation (Y-axis) and the tip difference, group II (intervention) was significantly less accurate than group I (control) (as P-value < 0.05). There were no significant differences between the two groups regarding attachment failure and chair side time (as P-value <0.05). Conclusion: Both 3D printed tray technique and thermoformed transfer tray technique showed accurate attachment transfer lying within the clinically acceptable range of deviation (0.5 mm and 2o respectively) in all three planes. Attachment failure rate and chair side time were proven to be comparable between the two indirect bonding techniques.