Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Orthodontics

Aim: to compare the digital 3d printed window transfer tray and the conventional thermoformed tray regarding the accuracy of transferring the attachments, bond failure and chair side time Methodology: A randomized controlled trial was performed the two different bonding techniques, 6 subjects were recruited in this study with 144 attachments. In the control group, the orthodontic attachments were bonded to working models and scanned with an intraoral scanner to make STL file of the working model. The transfer tray was then fabricated in order to transfer the orthodontic attachments in to the patient{u2019}s mouth. While in the intervention group, the teeth were scanned with the same intraoral scanner to produce the digital model on which the virtual attachments are placed using the OrthoAnalyzer software. The tray was designed and printed with windows opened gingivally. The attachments were fitted into their positions through the windows of the tray. Then intraoral scanning for both groups was done to obtain STL models after bonding. Superimposition of the pre and post STL models was done using 3Shape OrthoAnalyzer software to measure the linear deviations (mesio-distal, occluso-gingival and bucco-lingual) and angular deviations (tip, torque and rotation).Results: There was no statistically significant difference between both techniques for overall accuracy of transfer in all linear and angular deviation except for bucco-lingual linear deviation which revealed higher accuracy of transfer for 3D printed technique than vacuum formed tray. The attachment failure rate was higher in vacuum formed tray than 3d printed window tray that had zero bond failure in all attachments. Chair side time difference between the two indirect bonding techniques was statistically insignificant

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