Effect of torque customization with composite resin bases on the shear bond strength and adhesive remnant patterns of lingual brackets : An in vitro evaluation.

Autor: Kumar SS; Division of Orthodontics and Dentofacial Orthopedics, Department of Dentistry, Jawaharlal Institute of Postgraduate Medical Education and Research, 605006, Puducherry, India., Ramteke S; Division of Orthodontics and Dentofacial Orthopedics, Department of Dentistry, Jawaharlal Institute of Postgraduate Medical Education and Research, 605006, Puducherry, India., Nivethitha B; Division of Orthodontics and Dentofacial Orthopedics, Department of Dentistry, Jawaharlal Institute of Postgraduate Medical Education and Research, 605006, Puducherry, India., Madhan B; Division of Orthodontics and Dentofacial Orthopedics, Department of Dentistry, Jawaharlal Institute of Postgraduate Medical Education and Research, 605006, Puducherry, India. madhanb@hotmail.com.
Jazyk: angličtina
Zdroj: Journal of orofacial orthopedics = Fortschritte der Kieferorthopadie : Organ/official journal Deutsche Gesellschaft fur Kieferorthopadie [J Orofac Orthop] 2024 Dec 06. Date of Electronic Publication: 2024 Dec 06.
DOI: 10.1007/s00056-024-00559-6
Abstrakt: Purpose: This study evaluated the effect of torque customization of lingual brackets with resin-modified bases on their shear bond strength (SBS), adhesive remnant index (ARI), and bond failure patterns (BFP).
Methods: The sample comprised 200 lingual lower incisor brackets (DTC® ORG, DTC Medical Apparatus, Hangzhou, China); 40 brackets were tested as-received and 4 groups with 40 brackets each were customized for -10, -20, +10 and +20° torque respectively with light-cured composite resin (Transbond XT™, 3M Unitek, Monrovia, CA, USA) bases. All brackets were bonded to bovine mandibular incisors. Their SBS were estimated in a universal testing machine (INSTRON®, Norwood, MA, USA) with a gingivally directed force applied at the incisal bracket-adhesive interface with 1 mm/min crosshead speed. Their ARI and BFP were evaluated under 20× magnification.
Results: The SBS was 19.9 ± 7.6 MPa for noncustomized brackets, 20.1 ± 9.0 and 18.7 ± 8.2 MPa for brackets with 10 and 20° of negative torque, and 16.6 ± 5.68 and 19.45 ± 5.84 MPa for brackets with 10 and 20° of positive torque, respectively. The differences were not statistically significant (p = 0.097). Teeth with the -20° brackets exhibited higher median ARI scores than noncustomized brackets (1.5 vs 2, p = 0.018). Adhesive-cohesive bond failure with nearly axial split was more frequent in noncustomized brackets than customized ones, the reverse being true for adhesive-cohesive failure with nearly vertical split (p < 0.05). Truly cohesive bond failures were seen only in brackets with positive torque.
Conclusions: Torque customization with a resin base is an acceptable strategy for metal orthodontic brackets as it does not affect their SBS. However, their BFP differed from noncustomized brackets, depending on the type of torque introduced.
Competing Interests: Declarations. Conflict of interest: S.S. Kumar, S. Ramteke, B. Nivethitha and B. Madhan declare that they have no competing interests. Ethical standards: This in vitro study was approved by the Postgraduate Research Monitoring Committee (JIP/DENT/PGJR/2019, dated 30 October 2019) and was exempted from review by the Institute Animal Ethics Committee (JIP/Dean(R)/Multi-centric/59/2020, dated 19 June 2020) of Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry-605006, India.
(© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)
Databáze: MEDLINE
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