title: An in vitro evaluation of titanium, zirconia, and alumina procera abutments with hexagonal connection.
abstract: OBJECTIVE
  The purpose of this study was to assess the precision at the implant interface of titanium, zirconia, and alumina Procera abutments with a hexagonal connection for single-tooth restorations.
  
  
  METHODS
  Twenty Procera abutments were produced with commercially pure titanium, 20 with zirconia, and 20 with alumina using computer-assisted design and manufacture (CAD/CAM). The rotational freedom of the abutments was assessed to detect the precision of fit of each abutment on the top of the implant hexagon.
  
  
  RESULTS
  Significant differences relative to rotational freedom were found between groups: the titanium group and the zirconia group did not differ significantly, but both demonstrated significantly smaller mean rotational freedoms than the alumina group (P < .05). Rotational freedom was less than 3 degrees for all abutments.
  
  
  CONCLUSIONS
  The hexagonal misfit of the Procera abutment on the implant hexagon may be implicated in screw joint loosening. In the present study, all types of CAD/CAM Procera abutments consistently showed less than 3 degrees of rotational freedom in a situation where the abutment was connected to an implant by a hexagonal external connection.
authors.affiliation: Department of Clinical Odontostomatology, University of Padova Institute of Clinical Dentistry, Padova, Italy. paolovigolo@virgilio.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Vigolo
authors.forename: Fulvio
authors.initials: F
authors.lastname: Fonzi
authors.forename: Zeina
authors.initials: Z
authors.lastname: Majzoub
authors.forename: Giampiero
authors.initials: G
authors.lastname: Cordioli
mesh_terms: D000537:Aluminum Oxide; D017076:Computer-Aided Design; D000044:Dental Abutments; D015921:Dental Implants; D003764:Dental Materials; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D016876:Metal Ceramic Alloys; D012399:Rotation; D014025:Titanium; D015040:Zirconium
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D016876:Metal Ceramic Alloys; C077451:Procera; D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide; C028541:zirconium oxide