title: Photoelastic analysis of stresses transmitted by universal cast to long abutment on implant-supported single restorations under static occlusal loads.
abstract: OBJECTIVE
  The aim of this study was to compare the stresses resulting from cemented or screw-retained dental prostheses using universal cast to long abutment by the photoelastic method.
  
  
  METHODS
  A photoelastic resin model was fabricated to simulate a segment of the mandibular arch with resin replicas of a first premolar and a second molar, and two 3.75 × 11-mm implants replacing the second premolar and the first molar. Vertical static loads were individually applied on the occlusal surface of the premolar and the molar (5 kgf) and simultaneously on both crowns (10 kgf).
  
  
  RESULTS
  Results found variable stress patterns around each implant and concentrated stresses in the individually loaded crowns. Force transfer characteristics of each situation and quantification of the isochromatic fringes were evaluated.
  
  
  CONCLUSIONS
  Within the limitations of this study and based on the results obtained for implant-supported prosthesis with internal hexagon connection/universal cast to long abutment, it could be concluded that single adjacent screw-retained prosthetic restorations lead to higher stresses around the implants when compared with cement-retained restorations.
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Fábio Afrânio de
authors.initials: FA
authors.lastname: Aguiar
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Tiossi
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Macedo
authors.forename: Maria da Gloria Chiarello de
authors.initials: Mda G
authors.lastname: Mattos
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
authors.forename: Renata Cristina Silveira
authors.initials: RC
authors.lastname: Rodrigues
mesh_terms: D001031:Apatites / Q000737:chemistry; D001641:Bicuspid; D001696:Biomechanical Phenomena; D001732:Bite Force; D002484:Cementation / Q000379:methods; D002858:Chromium Alloys / Q000737:chemistry; D003442:Crowns; D059605:Dental Implant-Abutment Design; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention / Q000295:instrumentation; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006801:Humans; D008334:Mandible; D016876:Metal Ceramic Alloys / Q000737:chemistry; D003765:Models, Dental; D008963:Molar; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D001031:Apatites; D002858:Chromium Alloys; D016876:Metal Ceramic Alloys; C506670:d.SIGN ceramic; D003776:Dental Porcelain