Torquing an upper central incisor with aligners--acting forces and biomechanical principles
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Torquing an upper central incisor with aligners--acting forces and biomechanical principles. / Hahn, Wolfram; Zapf, Antonia; Dathe, Henning; Fialka-Fricke, Julia; Fricke-Zech, Susanne; Gruber, Rudolf; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza.
In: EUR J ORTHODONT, Vol. 32, No. 6, 12.2010, p. 607-613.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Torquing an upper central incisor with aligners--acting forces and biomechanical principles
AU - Hahn, Wolfram
AU - Zapf, Antonia
AU - Dathe, Henning
AU - Fialka-Fricke, Julia
AU - Fricke-Zech, Susanne
AU - Gruber, Rudolf
AU - Kubein-Meesenburg, Dietmar
AU - Sadat-Khonsari, Reza
PY - 2010/12
Y1 - 2010/12
N2 - The forces delivered by aligners during torquing have still not been investigated. The purpose of this study was to measure the forces delivered to an upper central incisor during torquing with three different materials of the same thickness, and to describe the biomechanical principles of torquing with aligners. Five identical appliances were manufactured from each of three materials, all with a thickness of 1.0 mm (Ideal Clear®, Erkodur®, and Biolon®). An upper central incisor, as part of the measuring device, was torqued in defined steps in the vestibular and palatal directions with the respective appliance in place. For statistical analysis, the resulting forces, Fx (forces acting in the palatal and facial directions) and Fz (intrusive force as a side-effect) at a displacement of ±0.15 and ±0.8 mm from the tooth at the gingival margin were calculated. The mean Fx forces for ±0.15 mm displacement ranged from -1.89 N [standard deviation (SD) 0.48] to 0.11 N (SD 0.1). The mean Fz forces were between -0.97 N (SD 0.57) and -0.07 N (SD 0.22). The highest intrusive forces were measured during palatal displacement of the measuring tooth. An influence of direction of displacement on the levels of force was observed, especially for Fz at the greater displacement of ±0.8 mm. In relation to the intended amount of root movement during torquing, aligners tend to 'lift up' and therefore no effective force couple can be established for further root control. The force delivery properties are also influenced by the material used and the shape of the tooth.
AB - The forces delivered by aligners during torquing have still not been investigated. The purpose of this study was to measure the forces delivered to an upper central incisor during torquing with three different materials of the same thickness, and to describe the biomechanical principles of torquing with aligners. Five identical appliances were manufactured from each of three materials, all with a thickness of 1.0 mm (Ideal Clear®, Erkodur®, and Biolon®). An upper central incisor, as part of the measuring device, was torqued in defined steps in the vestibular and palatal directions with the respective appliance in place. For statistical analysis, the resulting forces, Fx (forces acting in the palatal and facial directions) and Fz (intrusive force as a side-effect) at a displacement of ±0.15 and ±0.8 mm from the tooth at the gingival margin were calculated. The mean Fx forces for ±0.15 mm displacement ranged from -1.89 N [standard deviation (SD) 0.48] to 0.11 N (SD 0.1). The mean Fz forces were between -0.97 N (SD 0.57) and -0.07 N (SD 0.22). The highest intrusive forces were measured during palatal displacement of the measuring tooth. An influence of direction of displacement on the levels of force was observed, especially for Fz at the greater displacement of ±0.8 mm. In relation to the intended amount of root movement during torquing, aligners tend to 'lift up' and therefore no effective force couple can be established for further root control. The force delivery properties are also influenced by the material used and the shape of the tooth.
KW - Acrylic Resins
KW - Biomechanical Phenomena
KW - Dental Stress Analysis
KW - Humans
KW - Incisor
KW - Maxilla
KW - Orthodontic Appliance Design
KW - Orthodontic Appliances, Removable
KW - Statistics, Nonparametric
KW - Tooth Movement Techniques
KW - Torque
KW - Journal Article
U2 - 10.1093/ejo/cjq007
DO - 10.1093/ejo/cjq007
M3 - SCORING: Journal article
C2 - 20462912
VL - 32
SP - 607
EP - 613
JO - EUR J ORTHODONT
JF - EUR J ORTHODONT
SN - 0141-5387
IS - 6
ER -