title: Guidelines for positioning external hexagon implants in screw-retained multiple prostheses using rotational abutment-type components.
abstract: OBJECTIVE
  This study measured the maximum angulation between 2 implants allowed by the internal walls of the component in screw-retained multiple prostheses using rotational abutment-type components.
  
  
  METHODS
  Thirty specimens of 3 different brands (Conexão; Neodent; and SIN), consisting of titanium rotational abutments connected to external hexagon abutment analogs with standard platforms, were divided into 3 groups. The specimens were internally filled with polyester resin, screw retained, torque, and sectioned to assess the space existing between the internal wall of the rotational abutment component, edge, and vertex of the hexagon. The measurements were performed using 3-dimensional equipment.
  
  
  RESULTS
  When the implant hexagons were oriented edge-to-edge, groups 1, 2, and 3 presented 40.75, 45.00, and 31.89 degrees, respectively. Vertex-to-vertex hexagon orientation showed 9.79, 18.18, and 3.27 degrees for groups 1, 2, and 3, respectively.
  
  
  CONCLUSIONS
  The maximum mean angulation in the mesio/distal direction between the 2 implants with hexagon-oriented vertex-to-vertex is 10.41 degrees, and hexagon-oriented edge-to-edge is 39.54 degrees. This study suggests guidelines for positioning external hexagon implants for interference-free screw-retained multiple prostheses using rotational abutment-type components.
authors.affiliation: *Graduate Student, Department of Prosthodontics, Fluminense Federal University School of Dentistry, Rio de Janeiro, Brazil. †Assistant Professor, Department of Prosthodontics, Fluminense Federal University School of Dentistry, Rio de Janeiro, Brazil. ‡Assistant Professor, Department of Prosthodontics, Laboratory of Applied Biotechnology, Fluminense Federal University School of Dentistry, Rio de Janeiro, Brazil. §Associate Professor, Department of Prosthodontics, Fluminense Federal University School of Dentistry, Rio de Janeiro, Brazil. ‖Chairman, Department of Prosthodontics, Laboratory of Applied Biotechnology, Fluminense Federal University School of Dentistry, Rio de Janeiro, Brazil.
authors.forename: Andre
authors.initials: A
authors.lastname: da Costa Salgado
authors.forename: Aldir Nascimento
authors.initials: AN
authors.lastname: Machado
authors.forename: Waldimir
authors.initials: W
authors.lastname: Carvalho
authors.forename: Eliane Porto
authors.initials: EP
authors.lastname: Barboza
authors.forename: Cresus Vinicius
authors.initials: CV
authors.lastname: Depes de Gouvêa
mesh_terms: D001863:Bone Screws; D000044:Dental Abutments; D015921:Dental Implants; D017408:Guidelines as Topic; D006801:Humans
chemical_list: D015921:Dental Implants