Objective: The main purpose of this study was to evaluate and compare the fit between thermoformed and direct-printed aligners. Materials and Method: Three types of aligners(N=36) were manufactured from the same reference STL file: thermoformed aligners were manufactured using (n=12) Zendura Flx™ (BayMaterials, Fremont, CA), and (n=12) Essix ACE™ (Dentsply Sirona, Sarasota, FL) and Direct-Printed aligners were printed with Tera Harz™ TC-85DAP 3-D Printer UV Resin . The samples (N=36) were sprayed with an opaque scanning spray, scanned, imported to Geomagic® Control X™ metrology software, and superimposed on the reference STL file using the “Best Fit Alignment” algorithm. Distances between the aligner meshes and the reference STL file were measured at 9 anatomical landmarks. The average measurements and standard deviations between aligners and reference models at each anatomical landmark were examined to compare the accuracy of fit between t he three types of aligners. Results: Mean absolute discrepancies in the Zendura Flx™ aligners ranged from 0. 076 ± 0.057 mm to 0.260 ± 0.35 mm and in the Essix ACE™ aligners ranged between 0.188 ± 0.27 mm to 0.457 ± 0.35mm, while in the direct printed aligners they ranged from 0.079 ±0.054 mm to 0.224 ± 0.021 mm. Root mean square (RMS) values, representing overall trueness, ranged from 0.209mm ± 0.094mm (Essix ACE) to 0.140 ± 0.020mm (Direct-Printed). Permutation tests identified significant differences between thermoformed aligners and direct-printed aligners at 6 out of the 9 bilateral landmarks and overall (RMS) Conclusions: This study showed greater trueness and precision of direct-printed aligners than thermoformed aligners.
|Advisor:||Kim, Ki B.|
|Commitee:||McCray, Julie F., Hayes, Andrew M.|
|School:||Saint Louis University|
|School Location:||United States -- Missouri|
|Source:||MAI 82/9(E), Masters Abstracts International|
|Subjects:||Dentistry, Materials science|
|Keywords:||Accuracy of fit, Clear aligners, Direct-printed aligners, Thermoforming|
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