title: Effects of micromovement on the changes in stress distribution of partially stabilized zirconia (PS-ZrO2) dental implants and bridge during clenching: a three-dimensional finite element analysis.
abstract: OBJECTIVE
  This investigation aims to evaluate the changes in stress magnitudes and distributions on Partially Stabilized Zirconia (PS-ZrO(2)) dental implants and bridges and on the mandible caused by fibrous encapsulations during clenching.
  
  
  METHODS
  Four 3.26 mm diameter PS-ZrO(2) dental implants with lengths of 12 mm were modelled and placed in the second premolar and first molar region on both sides of the mandible model. A rigid zirconia bridge with a thickness of 0.5 mm connects the PS-ZrO(2) dental implants placed in the second premolar and first molar. Four periodontal ligament (PDL) case studies were examined: PDL in the second premolars; PDL in the first molars; PDL in both the second premolars and first molars; and no PDL present.
  
  
  RESULTS
  The results reveal the magnitudes and distributions of stresses on the dental implants and connecting bridges were governed by the PDLs. A significant drop in stress levels were recorded when the PDL encapsulates the roots of the dental implants. Of the four PDL case studies, it was found that when the PDLs are present in both the second premolars and first molars the lowest stress magnitudes are generated. The analysis also revealed that, during the healing process after implant insertion and the result of fibrous encapsulation, the dental implant system will experience a varying amount of stress levels.
  
  
  CONCLUSIONS
  This study was intended to produce more insight into the influence of the PDL on the changes in stress distribution on the dental implant system during clenching.
authors.affiliation: Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, PR China. ahchoi@hotmail.com
authors.forename: Andy H
authors.initials: AH
authors.lastname: Choi
authors.forename: Jukka
authors.initials: J
authors.lastname: Matinlinna
authors.forename: Besim
authors.initials: B
authors.lastname: Ben-Nissan
mesh_terms: D002102:Cadaver; D019245:Compressive Strength; D003722:Dental Alloys / Q000737:chemistry; D015921:Dental Implants; D003799:Dental Stress Analysis / Q000379:methods; D003830:Denture, Partial, Fixed; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D008422:Materials Testing; D003765:Models, Dental; D009068:Movement; D009119:Muscle Contraction; D010513:Periodontal Ligament / Q000502:physiology*; D013718:Tensile Strength; D015040:Zirconium / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D015921:Dental Implants; D015040:Zirconium; C028541:zirconium oxide