Three-dimensional stress distribution in the human periodontal ligament in masticatory, parafunctional, and trauma loads: finite element analysis.
BACKGROUND
The presence of the periodontal ligament (PDL) makes it possible to absorb and distribute loads produced during masticatory function and other tooth contacts into the alveolar process via the alveolar bone proper. However, several factors affect the integrity of periodontal structures causing the destruction of the connective matrix and cells, the loss of fibrous attachment, and the resorption of alveolar bone.


METHODS
The purpose of this study was to evaluate the stress distribution by finite element analysis in a PDL in three-dimensional models of the upper central incisor under three different load conditions: 100 N occlusal loading at 45 degrees (model 1: masticatory load); 500 N at the incisal edge at 45 degrees (model 2: parafunctional habit); and 800 N at the buccal surface at 90 degrees (model 3: trauma case). The models were built from computed tomography scans.


RESULTS
The stress distribution was quite different among the models. The most significant values (harmful) of tensile and compressive stresses were observed in models 2 and 3, with similarly distinct patterns of stress distributions along the PDL. Tensile stresses were observed along the internal and external aspects of the PDL, mostly at the cervical and middle thirds.


CONCLUSIONS
The stress generation in these models may affect the integrity of periodontal structures. A better understanding of the biomechanical behavior of the PDL under physiologic and traumatic loading conditions might enhance the understanding of the biologic reaction of the PDL in health and disease.
Poiate
Isis A Venturini P
IA
Department of General Physics, University of São Paulo, São Paulo, SP, Brazil.
de Vasconcellos
Adalberto Bastos
AB
de Santana
Ronaldo Barcellos
RB
Poiate
Edgard
E
D000328:Adult; D001696:Biomechanical Phenomena; D001732:Bite Force; D019245:Compressive Strength; D003198:Computer Simulation; D003743:Dental Enamel / Q000502:physiology; D003769:Dental Occlusion, Traumatic / Q000503:physiopathology*; D003782:Dental Pulp / Q000502:physiology; D003804:Dentin / Q000502:physiology; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D007180:Incisor / Q000502:physiology; D008297:Male; D008310:Malocclusion / Q000503:physiopathology*; D008409:Mastication / Q000502:physiology*; D008437:Maxilla / Q000502:physiology; D008954:Models, Biological; D010159:Palate / Q000502:physiology; D010513:Periodontal Ligament / Q000502:physiology*; D013314:Stress, Mechanical; D013718:Tensile Strength