title: Strains in the marginal ridge during occlusal loading.
abstract: BACKGROUND
  The marginal ridge is considered fundamental to the ability of the tooth to resist functional and parafunctional occlusal loads without damage. Despite this role, very little is known of patterns of stress and strain in marginal ridges under load. This study investigated strains in proximal enamel of mandibular premolars using finite element analysis (FEA) and strain gauge measurements.
  
  
  METHODS
  A three-dimensional FEA model of a human mandibular premolar was developed using commercial FEA software, and strains were computed in response to loads simulating clenching and chewing functions. Strains were measured in extracted premolars using strain gauges mounted on the proximal surfaces, under similar occlusal loading conditions.
  
  
  RESULTS
  Strains in the vicinity of contact areas and marginal ridges were lower than near the cemento-enamel junction and on buccal and lingual surfaces. The magnitude of proximal strains increased with oblique loading on cuspal inclines. Finite element analysis results correlated well with strain gauge measurements and can be used to predict strain directions and magnitudes.
  
  
  CONCLUSIONS
  At least for mandibular premolars, the marginal ridges are not highly stressed areas during simulated occlusal loading.
authors.affiliation: School of Dental Science, The University of Melbourne, Victoria. j.palamara@dent.unimelb.edu.au
authors.forename: J E A
authors.initials: JE
authors.lastname: Palamara
authors.forename: D
authors.initials: D
authors.lastname: Palamara
authors.forename: H H
authors.initials: HH
authors.lastname: Messer
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid / Q000033:anatomy & histology / Q000502:physiology*; D001732:Bite Force; D002012:Bruxism / Q000503:physiopathology; D003198:Computer Simulation; D003743:Dental Enamel / Q000033:anatomy & histology / Q000502:physiology*; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D008409:Mastication / Q000502:physiology; D008954:Models, Biological; D013314:Stress, Mechanical; D019237:Tooth Cervix / Q000033:anatomy & histology / Q000502:physiology; D019228:Tooth Crown / Q000033:anatomy & histology / Q000502:physiology*; D016474:Weight-Bearing