Parham Pedram; Hannane Ghadirian; Sepideh Arab
Abstract
Background: Splinting anterior teeth is a way to fix them after orthodontics treatments. Occlusal trauma from functional or parafunctional forces can cause stress increase and movements of teeth especially while having bone loss.
Methods: Six anterior teeth with different bone levels were designed in ...
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Background: Splinting anterior teeth is a way to fix them after orthodontics treatments. Occlusal trauma from functional or parafunctional forces can cause stress increase and movements of teeth especially while having bone loss.
Methods: Six anterior teeth with different bone levels were designed in SolidWorks (2010), the models were then transferred to ANSYS Workbench 12.1. The models were loaded with 187 N force on the incisal edges of two incisors. Results: Stress on canine was 0.45 MPa in normal bone height and increased to 0.60 MPa in five millimeters of anterior teeth bone loss. Labial displacement was less in normal alveolar bone height while it was increased in all those teeth with five millimeter of bone loss.
Conclusions: Splinting distribute the forces between teeth and the stress production on canine increase while it splinted with low level bone incisors. Anterior teeth also showed tipping movements in reply to increased forces.
Atefe Saffar Shahroudi; Amir-Hossein Mirhashemi; Hassan Noroozi; Hannane Ghadirian; Tahereh Hosseinzadeh Nik
Abstract
One of the most important characteristic of dentition is dental arch form. In orthodontic treatment, it is crucial to understand each individual dental arch for diagnosis and treatment planning and try to preserve it throughout the treatment to achieve a higher stability. Additionally, it is important ...
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One of the most important characteristic of dentition is dental arch form. In orthodontic treatment, it is crucial to understand each individual dental arch for diagnosis and treatment planning and try to preserve it throughout the treatment to achieve a higher stability. Additionally, it is important to maintain a wellestablished coordination between maxillary and mandibular dental arch to have a perfect functional occlusion. In orthodontics up to now, different definitions have been proposed for human dental arch form and methods for coordinating dental arches. The aim of this study was to gather and compare these concepts. The available data were categorized and discussed in five different domains: Arch Form (history and recent concepts), Factors affecting dental arch form, Characterization of arch form, Coordination of upper and lower arches and arch wire selection and arch form.
Allahyar Geramy; Hannane Ghadirian
Abstract
Aim: Bent root forms are always a challenging point in an orthodontic treatment. The main aim of this study has been to assess the stress effects of a dilaceration in apical third of an upper central incisor in orthodontic movement.Materials and Methods: Three FEM models of an upper central incisor were ...
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Aim: Bent root forms are always a challenging point in an orthodontic treatment. The main aim of this study has been to assess the stress effects of a dilaceration in apical third of an upper central incisor in orthodontic movement.Materials and Methods: Three FEM models of an upper central incisor were designed with cortical and spongy bone, PDL, and teeth. The only difference between 3D models was the anatomy of the apical fourth of their root. A 30-deg (the first model) and a 60-degree (the second model) dilaceration in the apical fourth of the root were designed in a labial direction. The calculation was in ANSYS Workbench Ver. 11.0. A 1.0 N labio-palatal force was applied in 45 degrees to the horizontal plane in the labial side of the crown. Von mises stress was evaluated along a path of nodes starting at the mid root area at labial moving towards the apex and continuing to reach the mid root lingual region on root surface.
Results: The apical stress did not show a dramatic increase in dilacerated form models starting from 0.11 MPa in normal model to 0.17 MPa in a 60-degree dilacerations model. Moving away from the apex, the stress findings increased which was noticeable between the normal model (0.48 MPa) and the 60-degree model (2.11 MPa).Conclusion: Based on the findings of this FEN! study, It was shown that the increase in the stress in areas away from the apex can be interpreted as the reason to the start of the external root resorption. There may be other models of the pointed apex root forms to show an increase in the apical area stress which was not the case in this model.
