title: Influence of Metal and Ceramic Abutments on the Stress Distribution Around Narrow Implants: A Photoelastic Stress Analysis.
abstract: OBJECTIVE
  This study aimed to compare, through photoelastic analysis, the distribution of stresses around narrow implants with external hexagon (EH) and Morse taper (MT) connections, when single crowns made with metal and ceramic abutments were used.
  
  
  METHODS
  Six photoelastic models were prepared, simulating the use of narrow EH and MT implants replacing a lateral incisor. These 2 groups received 3 different abutments: prefabricated metal abutments, customized metal abutments, and customized zirconia abutments. All crowns were identical and made with a leucite reinforced glass-ceramic. Vertical loads of 0 to 100 N were applied on the palatal surface of the crowns, and the photoelastic stress fringes developed in each model were captured in a high-definition video, and digital photographs were taken at 100 N.
  
  
  RESULTS
  The abutment type and material influenced the stress distribution patterns around narrow implants with EH and MT connections. Stresses were generated mainly around the apical and lingual regions of the implants.
  
  
  CONCLUSIONS
  For both connections, the prefabricated metal abutments presented better stress distribution around the implants when compared to customized metal and zirconia abutments because low stress levels were developed in smaller areas around the implants.
authors.affiliation: *MSc Student, Graduate Program in Dentistry, Positivo University, Curitiba, PR, Brazil. †PhD Student, Graduate Program in Dentistry, Positivo University, Curitiba, PR, Brazil. ‡Full Professor, Graduate Program in Dentistry, Positivo University, Curitiba, PR, Brazil. §Assistant Professor, Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Gustavo Holtz
authors.initials: GH
authors.lastname: Galvão
authors.forename: João Almeida
authors.initials: JA
authors.lastname: Grossi
authors.forename: João César
authors.initials: JC
authors.lastname: Zielak
authors.forename: Allan Fernando
authors.initials: AF
authors.lastname: Giovanini
authors.forename: Adilson Yoshio
authors.initials: AY
authors.lastname: Furuse
authors.forename: Carla Castiglia
authors.initials: CC
authors.lastname: Gonzaga
mesh_terms: D002516:Ceramics; D003442:Crowns; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D003799:Dental Stress Analysis / Q000379:methods; D004548:Elasticity; D006801:Humans; D008670:Metals
chemical_list: D008670:Metals