title: Outcome of zirconia single crowns made by predoctoral dental students: a clinical retrospective study after 2 to 6 years of clinical service.
abstract: BACKGROUND
  Zirconia has established its role as a reliable ceramic material for fixed prostheses.
  
  
  OBJECTIVE
  The purpose of this retrospective study was to evaluate the outcome of zirconia single crowns made by predoctoral students after 2 to 6 years of clinical service.
  
  
  METHODS
  A cohort of 88 patients treated with zirconia single crowns (mean 3 crowns per patient, range 1 to 12 crowns) from 2007 to 2010 by predoctoral dental students was identified. The patients were invited to attend a clinical examination.
  
  
  RESULTS
  Sixty-six participants (75%) took part in the clinical follow-up (30 women and 36 men; mean age 60.4 years, range 19 to 81 years). Altogether, 190 teeth with single crowns were examined, and the mean follow-up time was 3.88 years (1.85 to 6.04 years). The most common complications were chipping of veneering porcelain (4%) and loss of cementation (4%). The success rate of the zirconia single crowns after 2 to 6 years was 80% and the survival rate 89%.
  
  
  CONCLUSIONS
  Zirconia crowns can be successfully used in predoctoral dental education. The success rate of zirconia single crowns after 2 to 6 years was 80% and the survival rate was 89%, in accordance with previous studies.
authors.affiliation: Senior Lecturer, Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Oulu; and Medical Research Center, Oulu, Oulu University Hospital and University of Oulu, Finland. Electronic address: ritva.napankangas@oulu.fi.
authors.forename: Ritva
authors.initials: R
authors.lastname: Näpänkangas
authors.affiliation: Research Assistant, Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Oulu; and Medical Research Center, Oulu, Oulu University Hospital and University of Oulu, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Pihlaja
authors.affiliation: Professor, Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Oulu; and Medical Research Center, Oulu, Oulu University Hospital and University of Oulu, Finland.
authors.forename: Aune
authors.initials: A
authors.lastname: Raustia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002484:Cementation / Q000379:methods; D015331:Cohort Studies; D017076:Computer-Aided Design; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry*; D003774:Dental Plaque Index; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D004497:Education, Dental; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010512:Periodontal Index; D011476:Prosthodontics / Q000193:education; D012189:Retrospective Studies; D013335:Students, Dental; D013499:Surface Properties; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide