Abstract
Purpose
Torque control in lingual orthodontics is key to obtain optimal esthetic results. The aim of this in vitro experimental study was to verify the efficiency of the ligature–archwire–slot system in torque control using a customized lingual appliance.
Methods
An idealized cast with eight extracted human teeth was created and a set of customized lingual brackets was obtained. Tests were performed with the following wires: 0.016″ × 0.022″ nickel-titanium (NiTi), 0.016″ × 0.024″ stainless steel (SS), 0.017″ × 0.025″ βIII titanium (βIIITi), 0.0182″ × 0.0182″ βIIITi, 0.018″ × 0.025″ SS, 0.018″ × 0.025″ NiTi, 0.018″ × 0.025″ βIIITi, and three types of ligatures were tested using a universal testing machine to calculate the efficiency in torque control. A blind statistical analysis was performed.
Results
Based on post hoc multiple comparisons, differences were found for two of the three ligatures when using the 0.016″ × 0.022″ NiTi wires (p < 0.001 for both ligatures). When considering all ligatures, 0.018″ × 0.025″ SS and 0.018″ × 0.025″ βIIITi were significantly different from all other wires (p < 0.001 in all cases). With a moment of 5 Nmm, the 0.016″ × 0.022″ NiTi wire developed median angles of 26.7, 29.8, and 38.7° with the three ligatures, respectively, while the 0.018″ × 0.025″ SS developed median angles of 12.9, 10.7, and 12.7°, respectively.
Conclusions
The ligature type and geometry did not affect the efficiency of torque control, except for the 0.016″ × 0.022″ NiTi wire. The wires generating the greatest moments were the 0.018″ × 0.025″ SS and 0.018″ × 0.025″ βIIITi.
Zusammenfassung
Zweck
Die Torquekontrolle in der lingualen Kieferorthopädie ist ein Schlüsselfaktor, um optimale ästhetische Ergebnisse zu erzielen. Ziel dieser experimentellen In-vitro-Studie war es, die Effizienz des Ligatur-Bogen-Slot Systems bei der Torquekontrolle mit einer individualisierten Lingualapparatur zu überprüfen.
Methoden
Ein idealisiertes Modell mit 8 extrahierten menschlichen Zähnen wurde erstellt und ein Satz individualisierter lingualer Brackets wurde angefertigt. Es wurden Tests mit den folgenden Drähten durchgeführt: 0,016″ × 0,022″ Nickel-Titan (NiTi), 0,016″ × 0,024″ Edelstahl (SS), 0,017″ × 0,025″ βIII-Titan (βIIITi), 0,0182″ × 0,0182″ βIIITi, 0,018″ × 0,025″ SS, 0,018″ × 0,025″ NiTi, 0,018″ × 0,025″ βIIITi. Drei Arten von Ligaturen wurden mit einer Universalprüfmaschine getestet, um das Ausmaß der Torquekontrolle zu berechnen. Eine blinde statistische Analyse wurde durchgeführt.
Ergebnisse
Basierend auf post hoc durchgeführten Mehrfachvergleichen wurden bei der Verwendung der 0,016″ × 0,022″ NiTi-Drähte (p < 0,001 für beide Ligaturen) Unterschiede für 2 der 3 Ligaturen nachgewiesen. Bei Betrachtung aller Ligaturen unterschieden sich 0,018″ × 0,025″ SS und 0,018″ × 0,025″ βIIITi signifikant von allen anderen Drähten (p < 0,001 in allen Fällen). Bei einem Drehmoment von 5 Nmm entwickelte der 0,016″ × 0,022″ NiTi-Draht Medianwinkel von 26,7, 29,8 bzw. 38,7° mit den 3 Ligaturen, der 0,018″ × 0,025″ SS-Draht erzielte dagegen Medianwinkel von 12,9, 10,7 bzw. 12,7°.
Schlussfolgerungen
Ligaturtyp und Geometrie hatten – mit Ausnahme des 0,016″ × 0,022″ NiTi-Drahts – keinen Einfluss auf die Effizienz der Torqueübertragung. Die Drähte, welche die größten Drehmomente erzeugten, waren 0,018″ × 0,025″ SS und 0,018″ × 0,025″ βIIITi.
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Acknowledgements
We would like to thank and remember Professor Marco Capurro: his great contribution as a man, a teacher and a researcher will last in our hearts. We also would like to thank 3M Oral Care for the kind support, assistance and the materials provided for the experiments.
Funding
This research did not receive any specific grant from funding agencies in public, commercial or not-for-profit sectors.
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R. Stradi has a consultancy agreement with 3M Unitek. M. Migliorati, D. Poggio, S. Drago, A. Lagazzo, F. Barberis and A. Silvestrini-Biavati declare that they have no competing interests.
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Migliorati, M., Poggio, D., Drago, S. et al. Torque efficiency of a customized lingual appliance. J Orofac Orthop 80, 304–314 (2019). https://doi.org/10.1007/s00056-019-00190-w
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DOI: https://doi.org/10.1007/s00056-019-00190-w