Tridimensional finite element analysis of teeth movement induced by different headgear forces.
BACKGROUND
This study aimed to simulate the actions of low-pull (LP), high-pull (HP), and combined pull (CP) headgears (HGs) and to analyze tooth movement tendencies through finite element analysis.


METHODS
Tomographic slices of a human maxilla with complete permanent dentition were processed by reconstruction software, and the triangular surface mesh was converted into non-uniform rational B-spline (NURBS) curves. An HG facial bow was also modulated in 3D. The teeth and bone were considered to have isotropic and linear behavior, whereas the periodontal ligament was considered to have non-linear and hyperelastic behavior. Data regarding the application points, directions and magnitudes of forces were obtained from the literature and from a dolichofacial patient with class II, division 1 malocclusion, who was treated with a CP HG.


RESULTS
The CP HG promoted 37.1 to 41.1 %, and the HP HG promoted 19.1 to 31.9 % of LP distalization. The HP HG presented the highest intrusion, and the LP HG presented the highest extrusion of the first molar. The LP HG contracted the distal side, and the HP and CP HGs contracted the lingual and distobuccal roots of the second molar to a lesser degree.


CONCLUSIONS
The LP HG promotes the greatest distalization, followed by the CP and HP HGs; the LP HG causes greater extrusion of the first molar, and the HP HG causes greater intrusion of the first molar. The LP HG causes greater contraction of the second molar than the HP HG.
Orthodontic Graduation Program, Brazilian Dental Association (ABO) and Pontifícia Universidade Católica do Paraná, Curitiba, Paraná, Brazil.
Ivan Toshio
IT
Maruo
Orthodontic Graduation Program, Brazilian Dental Association (ABO), Ponta Grossa, Paraná, Brazil.
Hiroshi
H
Maruo
Orthodontic Graduation Program, Brazilian Dental Association (ABO) and Pontifícia Universidade Católica do Paraná, Curitiba, Paraná, Brazil.
Armando Yukio
AY
Saga
Orthodontic Graduation Program, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Dauro Douglas
DD
de Oliveira
Post Graduation Program in Numerical Methods in Engineering, Federal University of Paraná, Curitiba, Brazil.
Marco André
MA
Argenta
Graduate Program in Orthodontics, Pontifícia Universidade Católica do Paraná, School of Life Sciences, R. Imaculada Conceição, 1155, Curitiba, Brazil. tanakaom@gmail.com.|Post-Doctoral fellowship at The Center for Advanced Dental Education, Saint Louis University, Saint Louis, MO, USA. tanakaom@gmail.com.
Orlando Motohiro
OM
Tanaka
D000539:Alveolar Process / Q000502:physiology; D001696:Biomechanical Phenomena; D054893:Cone-Beam Computed Tomography / Q000379:methods; D019229:Dentition, Permanent; D005115:Extraoral Traction Appliances; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008312:Malocclusion, Angle Class II / Q000628:therapy; D008437:Maxilla / Q000000981:diagnostic imaging / Q000502:physiology; D008953:Models, Anatomic; D008954:Models, Biological; D008963:Molar / Q000000981:diagnostic imaging / Q000502:physiology; D016382:Orthodontic Appliance Design; D010513:Periodontal Ligament / Q000502:physiology; D012886:Skull / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques / Q000295:instrumentation* / Q000379:methods*; D014092:Tooth Root / Q000502:physiology
Extraoral traction appliances; Finite element analysis; Tooth movement