Force system generated by elastic archwires with vertical V bends: a three-dimensional analysis.
Our previous understanding of V-bend mechanics is primarily from two-dimensional (2D) analysis of archwire bracket interactions in the second order. These analyses do not take into consideration the three-dimensional (3D) nature of orthodontic appliances involving the third order.



To quantify the force system generated in a 3D two bracket set up involving the molar and incisors with vertical V-bends.



Maxillary molar and incisor brackets were arranged in a dental arch form and attached to load cells capable of measuring forces and moments in all three planes (x, y, and z) of space. Symmetrical V-bends (right and left sides) were placed at 11 different locations along rectangular beta-titanium archwires of various sizes at an angle of 150degrees. Each wire was evaluated for the 11 bend positions. Specifically, the vertical forces (Fz) and anterio-posterior moments (Mx) were analysed. Descriptive statistics were used to interpret the results.



With increasing archwire size, Fz and Mx increased at the two brackets (P < 0.05). The vertical forces were linear and symmetric in nature, increasing in magnitude as the bends moved closer to either bracket. The Mx curves were asymmetric and non-linear displaying higher magnitudes for molar bracket. As the bends were moved closer to either bracket a distinct flattening of the incisor Mx curve was noted, implying no change in its magnitude.



This article provides critical information on V-bend mechanics involving second order and third order archwire-bracket interactions. A model for determining this force system is described that might allow for easier translation to actual clinical practice.
Division of Orthodontics, Department of Craniofacial Sciences, University of Connecticut Health Center, Farmington, CT, USA.
Madhur
M
Upadhyay
Private Practice, Albuquerque, New Mexico.
Raja
R
Shah
College of Science Technology, Engineering and Mathematics, Biomedical Engineering, Texas A&M University, Texarkana, TX, USA.
Donald
D
Peterson
STEM Innovation Laboratory, Biomedical Engineering, Texas A&M University, Texarkana, TX, USA, and.
Takafumi
T
Asaki
Division of Orthodontics, Department of Craniofacial Sciences, University of Connecticut Health Center, Farmington, CT, USA.
Sumit
S
Yadav
Department of Orthodontics, Melbourne Dental School, University of Melbourne, Melbourne, Australia.
Sachin
S
Agarwal
D003722:Dental Alloys; D003799:Dental Stress Analysis / Q000379:methods; D006801:Humans; D007180:Incisor / Q000502:physiology; D008963:Molar / Q000502:physiology; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel; D013314:Stress, Mechanical; D014025:Titanium
D003722:Dental Alloys; C023988:beta titanium; D013193:Stainless Steel; D014025:Titanium