title: Titanium-zirconium narrow-diameter versus titanium regular-diameter implants for anterior and premolar single crowns: 3-year results of a randomized controlled clinical study.
abstract: OBJECTIVE
  To test whether titanium-zirconium (Ti-Zr) 3.3 mm diameter implants perform differently from titanium (Ti) 4.1 mm diameter implants with respect to marginal bone level (MBL) and clinical parameters.
  
  
  METHODS
  Forty patients in need of a single-implant crown in the anterior or premolar regions were enrolled in two centres. Following random allocation, either a Ti-Zr or a Ti implant was inserted. Porcelain-fused-to-metal crowns were inserted 6 months after implantation. Implant survival, change in MBL, clinical parameters, change in mid-facial mucosa and papilla levels, and the occurrence of biological and technical complications were assessed at the 3-year follow-up.
  
  
  RESULTS
  At 3 years, 32 of the 40 included patients were examined (15 Ti and 17 Ti-Zr implants). There were no implant failures. From the implant placement to 3 years, the median change in mean MBL amounted to 0.21 mm (mean: -0.31) in the Ti group and 0.10 mm (mean: -0.40) in the Ti-Zr group. There were no significant differences between the groups with respect to the change in MBL, the change in mucosa levels, and the occurrence of complications.
  
  
  CONCLUSIONS
  Ti-Zr implants with 3.3 mm diameter used for the support of single crowns in the anterior and the premolar regions did not differ from Ti implants with 4.1 mm diameter regarding the clinical performance over a 3-year period.
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Alexis
authors.initials: A
authors.lastname: Ioannidis
authors.affiliation: Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA.
authors.forename: German O
authors.initials: GO
authors.lastname: Gallucci
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
authors.affiliation: Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA.|Department of Substitutive Dental Sciences, College of Dentistry, Taibah University, Al Madinah Al Munawwarah, Kingdom of Saudi Arabia.
authors.forename: Sary
authors.initials: S
authors.lastname: Borzangy
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Goran I
authors.initials: GI
authors.lastname: Benic
mesh_terms: D001641:Bicuspid; D003442:Crowns; D019250:Dental Implants, Single-Tooth; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D006801:Humans; D014025:Titanium; D015040:Zirconium
chemical_list: D015040:Zirconium; D014025:Titanium
keywords: bone; complication; crown; dental implants; diameter; fixed partial denture; humans; mucosa; narrow; peri-implantitis; radiographic; randomized controlled trial; survival; titanium; titanium-zirconium