Comparison of a novel 3-dimensional-printed attachment transfer method with conventional methods in clear aligner therapy: An in vitro study


BOR S., ÖZDEN S.

American Journal of Orthodontics and Dentofacial Orthopedics, 2025 (SCI-Expanded, Scopus) identifier identifier

Özet

Introduction: This study aimed to compare the accuracy of a novel 3-dimensional (3D)-printed attachment transfer technique with conventional composite-based methods, evaluating the effect of template material and thickness. Methods: Three transfer methods were investigated: nonflowable composite resin, flowable composite resin, and 3D-printed attachments with a transfer carrier. In the conventional attachment transfer method, 4 different thermoplastic template sheet thicknesses were used: 0.3, 0.5, 0.75, and 0.8 mm. A standardized reference model with 6 digitally planned attachments was used for all groups. Using each method, attachments were transferred to 3D-printed dental models, which were then scanned and superimposed with the reference model. Root mean square and mean distance values were calculated using CloudCompare software (version 2.14;www.danielgm.net/cc/) for surface deviation analysis. Results: Statistically significant differences were observed among the attachment transfer methods (P <0.001, Kruskal-Wallis test). The 3D-printed attachment group exhibited the highest geometric accuracy across all evaluated sites. Pairwise comparisons showed that the 3D-printed group performed significantly better than both composite-based groups (P <0.001, Dunn’s test). Composite viscosity showed no significant effect on transfer accuracy, except for attachments 16 and 23 in mean distance values (P = 0.023-0.031) and attachment 16 in root mean square values (P = 0.043). Template thickness significantly influenced transfer accuracy, with thicker aligners generally producing lower deviation values, particularly between Tristar (0.3 mm) and Track A (0.8 mm) (P <0.05 to P <0.001). Conclusions: The 3D-printed attachment transfer method demonstrated superior accuracy than conventional composite-based methods. Although the thinnest template exhibited greater deviations, accuracy varied among the different templates, suggesting that both material thickness and composition may influence transfer performance. Composite viscosity did not substantially affect transfer accuracy, as both flowable and nonflowable composite resins produced comparable results in most attachment sites.