Three-Dimensional Accuracy of Clear Aligner Attachment Reproduction Using a Standardized In-House Protocol: An In Vitro Study

초록

This in vitro study aimed to quantitatively evaluate the accuracy of reproducing attachments for clear aligner therapy (CAT) using a standardized in-house fabrication protocol and to analyze discrepancies across maxillary tooth types. A custom attachment was designed on a symmetrical master model, and 30 experimental models were fabricated by three-dimensional (3D) printing, template construction, and bonding. Following scanning and superimposition, dimensional, angular, and positional deviations were quantified and statistically analyzed (p < 0.05). Results showed minor mean discrepancies but a consistent pattern of under-reproduction, most evident in the mesial and distal wall angles, as well as in the gingival bevel angle and attachment height. A significant trend was observed in the occlusal bevel, demonstrating marked extrusion in the anterior region that decreased posteriorly. Positional errors were minimal mesiodistally but substantial in the lingual and occlusal directions, with magnitudes varying by tooth type. In conclusion, this study identified consistent, predictable inaccuracies in a simulated in-house attachment reproduction protocol. These findings indicate that similar deviations may occur clinically, potentially affecting the predictability of CAT.

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