Periodontal ligament hydrostatic pressure with areas of root resorption after application of a continuous torque moment - A study using identical extracted maxillary human premolars

Ansgar Hohmann, Uwe Wolfram, Martin Geiger, Andrew Boryor, Christian Sander, Rolf Faltin, Kurt Faltin, Franz Guenter Sander

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Objective: To evaluate the risk of root resorption, individual finite element models (FEMs) of extracted human maxillary first premolars were created, and the distribution of the hydrostatic pressure in the periodontal ligament (PDL) of these models was simulated.

Materials and Methods: A continuous lingual torque of 3 Nmm and 6 Nmm respectively was applied in vivo to the aforementioned teeth. After extraction, FEMs of these double-rooted teeth were created based on high-resolution microcomputed tomographics (micro CT, voxel size: 35 microns). This high volumetric resolution made the recognition of very small resorption lacunae possible. Scanning electron micrographs of the root surfaces were created as well. This enabled the investigation of advantages and disadvantages of the different imaging techniques from the viewpoint of the examination of root resorption. Using the FEMs, the same loading conditions as applied in vivo were simulated.

Results: The results of clinical examination and simulations were compared using the identical roots of the teeth. The regions that showed increased hydrostatic pressure (>0.0047 MPa) correlated well with the locations of root resorption for each tooth. Increased torque resulted in increased high-pressure areas and increased magnitudes of hydrostatic pressure, correlating with the experiments.

Conclusion: If hydrostatic pressure exceeds typical human capillary blood pressure in the PDL, the risk of root resorption increases.

Original languageEnglish
Pages (from-to)653-659
Number of pages7
JournalAngle Orthodontist
Volume77
Issue number4
DOIs
Publication statusPublished - Jul 2007

Keywords

  • root resorption
  • hydrostatic pressure in the periodontal ligament
  • finite element method
  • human maxillary first premolars
  • simulation
  • continuous torque
  • FINITE-ELEMENT MODEL
  • ORTHODONTIC FORCE MAGNITUDE
  • PHYSICAL-PROPERTIES
  • TOOTH MOVEMENT
  • CEMENTUM
  • ADOLESCENTS
  • INTRUSION
  • CRATERS
  • STRESS
  • LIGHT

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