title: Five-year results of a randomized controlled clinical trial comparing zirconia and titanium abutments supporting single-implant crowns in canine and posterior regions.
abstract: OBJECTIVE
  To test the survival rates, and the technical and biological complication rates of customized zirconia and titanium abutments 5 years after crown insertion.
  
  
  METHODS
  Twenty-two patients with 40 single implants in maxillary and mandibular canine and posterior regions were included. The implant sites were randomly assigned to zirconia abutments supporting all-ceramic crowns or titanium abutments supporting metal-ceramic crowns. Clinical examinations were performed at baseline, and at 6, 12, 36 and 60 months of follow-up. The abutments and reconstructions were examined for technical and/or biological complications. Probing pocket depth (PPD), plaque control record (PCR) and Bleeding on Probing (BOP) were assessed at abutments (test) and analogous contralateral teeth (control). Radiographs of the implants revealed the bone level (BL) on mesial (mBL) and distal sides (dBL). Data were statistically analyzed with nonparametric mixed models provided by Brunner and Langer and STATA (P < 0.05).
  
  
  RESULTS
  Eighteen patients with 18 zirconia and 10 titanium abutments were available at a mean follow-up of 5.6 years (range 4.5-6.3 years). No abutment fracture or loss of a reconstruction occurred. Hence, the survival rate was 100% for both. Survival of implants supporting zirconia abutments was 88.9% and 90% for implants supporting titanium abutments. Chipping of the veneering ceramic occurred at three metal-ceramic crowns supported by titanium abutments. No significant differences were found at the zirconia and titanium abutments for PPD (meanPPDZrO2 3.3 ± 0.6 mm, mPPDTi 3.6 ± 1.1 mm), PCR (mPCRZrO2 0.1 ± 0.3, mPCRTi 0.3 ± 0.2) and BOP (mBOPZrO2 0.5 ± 0.3, mBOPTi 0.6 ± 0.3). Moreover, the BL was similar at implants supporting zirconia and titanium abutments (mBLZrO2 1.8 ± 0.5, dBLZrO2 2.0 ± 0.8; mBLTi 2.0 ± 0.8, dBLTi 1.9 ± 0.8).
  
  
  CONCLUSIONS
  There were no statistically or clinically relevant differences between the 5-year survival rates, and the technical and biological complication rates of zirconia and titanium abutments in posterior regions.
authors.affiliation: Division of Fixed Prosthodontics, University of Berne, Berne, Switzerland.
authors.forename: Anja
authors.initials: A
authors.lastname: Zembic
authors.forename: Adrian
authors.initials: A
authors.lastname: Bösch
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
authors.forename: Irena
authors.initials: I
authors.lastname: Sailer
mesh_terms: D000328:Adult; D003442:Crowns; D003481:Cuspid; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D008297:Male; D015996:Survival Rate; D014025:Titanium; D015040:Zirconium
chemical_list: D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide