Compressive stress in periodontal ligament under orthodontic movements during periodontal breakdown
| Autor: | C.G. Chiorean, Stefan M. Buru, Raluca Cosgarea, Radu Andrei Moga |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Tooth Movement Techniques Periodontal Ligament Hydrostatic pressure Finite Element Analysis Orthodontics Computed tomography Models Biological Stress (mechanics) 03 medical and health sciences Intrusion 0302 clinical medicine medicine Pressure Periodontal fiber Humans Computer Simulation Voxel size medicine.diagnostic_test 030206 dentistry Periodontium Cone-Beam Computed Tomography Compressive strength Stress Mechanical 030217 neurology & neurosurgery |
| Zdroj: | American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 159(3) |
| ISSN: | 1097-6752 |
| Popis: | Introduction This analysis aimed to assess quantitatively and qualitatively the compressive stress (S3) in periodontal ligament in a gradual periodontal breakdown (0-8 mm) under orthodontic movements. Correlations between the applied forces, the level of bone resorption, the decrease of force magnitude, and S3 increase were also conducted. Methods On the basis of cone-beam computed tomography examinations (voxel size, 0.075 mm), nine 3-dimensional models of the second mandibular premolar with intact periodontium were created and then individually subjected to various levels of horizontal bone loss. Orthodontic forces (intrusion: 0.2 N; extrusion, rotation, tipping: 0.6 N; translation: 1.2 N) were applied on the brackets. Finite elements analysis was performed, and S3 stresses were quantitatively and qualitatively determined. Results Translation and rotation induced the highest stress apically and cervically, whereas intrusion determined the lowest. Apical stress was lower than cervical stress. In intact periodontium, only intrusion and extrusion exhibited S3 stresses lower (apically and cervically) than maximum hydrostatic pressure (MHP) and maximum tolerable stress (MTS). In reduced periodontium, S3 stress (except for intrusion) exceeded MHP and MTS. Conclusions In reduced periodontium, forces of 0.2 N seems safe to be used. Forces of 0.6-1.2 N may produce stresses exceeding both MTS and MHP, endangering the periodontium. S3 failure criterion (despite its widely use) seems not to be adequate for accurate quantitative results when evaluating the stress in the periodontal ligament while remaining adequate for qualitative results. An overall correlation between the applied force, S3 increase, and periodontal breakdown applicable to all 5 movements could not be established—this was possible only for sole movements. |
| Databáze: | OpenAIRE |
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