title: Initial force systems during bodily tooth movement with plastic aligners and composite attachments: A three-dimensional finite element analysis.
abstract: OBJECTIVE
  To describe, using a three-dimensional finite element (FE) model, the initial force system generated during bodily movement of upper canines with plastic aligners with and without composite attachments.
  
  
  METHODS
  A CAD model of an upper right canine, its alveolar bone and periodontal ligament, thermoformed plastic aligner, and two light-cured composite attachments were constructed. A FE model was used to analyze the effects of imposing a distal movement condition of 0.15 mm on the aligner (simulating the mechanics used to produce a distal bodily movement) with and without composite attachments.
  
  
  RESULTS
  In terms of tension and compression stress distribution, without composite attachments a compression area in the cervical third of the distal root surface and a tension area in the apical third of the mesial surface were observed. With composite attachments, uniform compression areas in the distal root surface and uniform tension area in the mesial root surface were observed. Compression areas in the active surfaces of the composite attachments were also observed. In terms of movement patterns, an uncontrolled distal inclination, with rotation axis between the middle and cervical root thirds, was observed without composite attachment. Distal bodily movement (translation) was observed with composite attachment.
  
  
  CONCLUSIONS
  In a three-dimensional FE analysis of a plastic aligner system biomechanically supplementary composite attachments generate the force system required to produce bodily tooth movement; the absence of biomechanically supplementary composite attachments favors the undesired inclination of the tooth during the translation movements.
authors.affiliation: a  Associate Professor of Biomechanics, Department of Orthodontics, Universidad Autónoma de Manizales, Manizales, Colombia.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Gomez
authors.forename: Fabio Marcelo
authors.initials: FM
authors.lastname: Peña
authors.forename: Valentina
authors.initials: V
authors.lastname: Martínez
authors.forename: Diana C
authors.initials: DC
authors.lastname: Giraldo
authors.forename: Carlos Iván
authors.initials: CI
authors.lastname: Cardona
mesh_terms: D000539:Alveolar Process / Q000473:pathology; D001696:Biomechanical Phenomena; D003188:Composite Resins / Q000737:chemistry; D017076:Computer-Aided Design; D003481:Cuspid / Q000473:pathology*; D003764:Dental Materials / Q000737:chemistry; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016382:Orthodontic Appliance Design; D010513:Periodontal Ligament / Q000473:pathology; D010969:Plastics / Q000737:chemistry; D011312:Pressure; D013314:Stress, Mechanical; D019237:Tooth Cervix / Q000473:pathology; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D014092:Tooth Root / Q000473:pathology
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D010969:Plastics
keywords: Bodily movement; Finite element; Plastic aligners