title: Zirconia and titanium implant abutments for single-tooth implant prostheses after 5 years of function in posterior regions.
abstract: OBJECTIVE
  To verify, in a medium-term follow-up, whether or not zirconia (Zr) abutments show similar survival outcomes as titanium (Ti) abutments in posterior areas.
  
  
  METHODS
  A two-stage surgical protocol was used. Each patient was followed for 5 years after the definitive prosthesis insertion. Clinical and radiographic parameters were assessed at the yearly follow-up visit, and prosthetic complications were recorded. Statistical analysis (Wilcoxon signed rank test) was used to compare any difference in biologic and radiographic parameters between implants and the natural contralateral teeth. Descriptive statistics were used to analyze the changes over time (from baseline to the last follow-up) of clinical and radiographic parameters.
  
  
  RESULTS
  A total of 85 patients with a single posterior tooth gap were treated with 85 implants supporting 47 Ti and 38 Zr abutments, respectively. All-ceramic (38) and metal-ceramic (47) single crowns were fabricated. Four patients were classified as dropouts. Eighty-one implants supporting 44 Ti and 37 Zr abutments completed the 5-year follow-up examination. No implant, reconstruction, or abutment failures were recorded. Therefore, the prosthetic survival after 5 years of function was 100% for all the abutments and restorations. No significant differences in biologic and radiographic indexes were found between Ti and Zr abutments when compared with each other and with the natural teeth after 5 years. No significant marginal bone loss was found between the baseline and the last follow-up, both for Zr and Ti abutments.
  
  
  CONCLUSIONS
  The medium-term survival of Zr abutments in posterior regions was comparable with that of Ti abutments. Long-term evaluations are needed to confirm this finding.
authors: Department of Prosthodontics, Dental Clinic, School of Dentistry, University of Milan, Milan, Italy. diego.lops@guest.unimi.it
authors: Diego
authors: D
authors: Lops
authors: Eriberto
authors: E
authors: Bressan
authors: Matteo
authors: M
authors: Chiapasco
authors: Alessandro
authors: A
authors: Rossi
authors: Eugenio
authors: E
authors: Romeo
mesh_terms: D000328:Adult; D000368:Aged; D002516:Ceramics; D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain; D019232:Dental Restoration Failure / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D014025:Titanium; D016896:Treatment Outcome; D015040:Zirconium
chemical_list: D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide