title: Stress distribution around maxillary implants in anatomic photoelastic models of varying geometry. Part II.
abstract: BACKGROUND
  Insufficient buccal bone volume can be a significant problem when loading dental implants in the maxilla. Increased potential for buccal fenestration and dehiscence can result in an exposed implant surface, mucosal irritation, decreased support, and potential implant failure.
  
  
  OBJECTIVE
  The objective of this study was to model the stress distribution around maxillary implants by comparing simulated occlusal loading of maxillary implants in a 2-dimensional photoelastic anatomic model and a dry skull model.
  
  
  METHODS
  Two model systems were used. First, a 2-dimensional photoelastic anatomic frontal skull sectional model was prepared in the first molar region. Left and right maxillary metal cylinder implant analogues inclined at 0 and 25 degrees to the sagittal plane were loaded in simulated intercuspation. Second, a dry skull lined with a photoelastic coating on the buccal aspect over an embedded cylinder implant was prepared in the first molar region. Principal stress concentration was photographed on axial and nonaxial implant loading.
  
  
  RESULTS
  On simulated intercuspal loading, maximum stress concentration occurred at the buccal concavity in both the 2-dimensional anatomic photoelastic and skull models. There was no stress concentration at the apices of the maxillary implants in the 2-dimensional model. On lateral loading of the skull model, stress was distributed along the entire buccal aspect of bone adjacent to the implant, with a higher concentration at the buccal concavity.
  
  
  CONCLUSIONS
  Preservation of buccal supporting bone volume is desirable to obtain a physiological modeling response and to enhance the facial plate. Insufficient bone volume may result in buccal fenestration or dehiscence, which can precipitate mucosal irritation, decreased support, and potential implant failure.
authors.affiliation: The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. grossmd@post.tau.ac.il
authors.forename: M D
authors.initials: MD
authors.lastname: Gross
authors.forename: J
authors.initials: J
authors.lastname: Nissan
mesh_terms: D001718:Birefringence; D015519:Bone Density; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D003799:Dental Stress Analysis; D004548:Elasticity; D006801:Humans; D008437:Maxilla / Q000502:physiology*; D008443:Maxillary Sinus / Q000502:physiology; D008953:Models, Anatomic; D003765:Models, Dental; D008963:Molar / Q000502:physiology; D012886:Skull; D016474:Weight-Bearing
chemical_list: D015921:Dental Implants