title: Effect of damping properties on fracture resistance of root filled premolar teeth: a dynamic finite element analysis.
abstract: OBJECTIVE
  To evaluate the ex vivo effects of damping on stress concentration in root filled premolar teeth.
  
  
  METHODS
  Damping ratios of maxillary premolar teeth that had undergone root canal treatment were tested in a laboratory model. In addition, two-dimensional finite element (FE) models were established for dynamic analysis.
  
  
  RESULTS
  The mean-damping ratio was significantly lower in premolar teeth that had undergone root canal preparation (8.50 +/- 0.53%) than in unprepared teeth (14.42 +/- 2.17%) (P < 0.05). However, root filling had a significant positive effect on the damping ratio of the tooth (10.84 +/- 1.70%) (P < 0.05). When the damping ratio was taken into consideration, FE analysis revealed that peak stresses in the apical one-third of the root on the buccal side were reduced by 31.8% when mastication forces were applied on the palatal cusp and occlusal fossa.
  
  
  CONCLUSIONS
  Pulp tissue plays an important role in providing protective effects when teeth are subjected to a dynamic load. However, root filled teeth do not provide such protective effects.
authors: Graduate Institute of Biomedical Materials and Engineering, Taipei Medical University, Taipei, Taiwan.
authors: K-L
authors: KL
authors: Ou
authors: C-C
authors: CC
authors: Chang
authors: W-J
authors: WJ
authors: Chang
authors: C-T
authors: CT
authors: Lin
authors: K-J
authors: KJ
authors: Chang
authors: H-M
authors: HM
authors: Huang
mesh_terms: D000328:Adult; D001641:Bicuspid; D003782:Dental Pulp / Q000502:physiology*; D003799:Dental Stress Analysis / Q000379:methods*; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D008409:Mastication; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D019227:Tooth Apex / Q000503:physiopathology; D014082:Tooth Fractures / Q000517:prevention & control*; D019553:Tooth, Nonvital / Q000503:physiopathology*; D014732:Vibration; D014783:Viscosity; D055815:Young Adult