title: Clinical Evaluation and Patient Satisfaction of Single Zirconia-Based and High-Noble Alloy Porcelain-Fused-to-Metal Crowns in the Esthetic Area: A Retrospective Cohort Study.
abstract: OBJECTIVE
  The aim of this study was to assess clinical survival, complications, and patient satisfaction with single zirconia-based crowns (ZC) or high-noble alloy PFM crowns (HC) in esthetic areas.
  
  
  METHODS
  The study was a retrospective cohort study with up to 3.8 years follow-up (mean 2.5 years). Patients who met the inclusion criteria were reviewed. Survival rates, complications, satisfaction rates (color and form), and overall satisfaction (visual analogue scale, VAS) were evaluated by follow-up examination. Chi-square test (survival, complication, and satisfaction rate) and unpaired t-test (overall satisfaction: VAS) were used to test the difference between the ZC and HC groups. Survival rates and complications were assessed both at subject-level (patient as statistical unit) and at tooth-level (tooth as statistical unit).
  
  
  RESULTS
  One hundred and thirteen patients met the inclusion criteria; 95 patients (ZC: 45, HC: 50) with 132 crowns (ZC: 61, HC: 71) were enrolled in the study. The overall survival rate was 93.3% for ZC crowns and 96.0% for HC crowns at subject-level and 93.4% for ZC crowns and 97.2% for HC crowns at tooth-level (p = 0.56 and 0.30, respectively). Veneer chipping was the most frequently seen complication. One HC crown lost retention because of poor cementation. One patient in the ZC group showed progression of periodontal disease. No significant difference of complications was found between the two groups at subject-level and tooth-level (p = 0.37 and 0.34, respectively). The overall satisfaction (VAS) was 8.18 for ZC crowns and 8.46 for HC crowns (p = 0.34).
  
  
  CONCLUSIONS
  The results of the study showed that a high survival rate could be achieved in both ZC and HC groups. Chipping of the veneering porcelain was the most frequently seen event that led to short-term (less than 3 years) failure and complications. The patients' rating of ZC crowns was not superior to HC crowns. Well-designed studies with high evidence level and large sample size are still needed to further explore the clinical success of ZC and HC crowns.
authors.affiliation: Department of Oral and Maxillofacial Implantology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Jun-Yu
authors.initials: JY
authors.lastname: Shi
authors.affiliation: Graduate School of Dentistry, Dalian Medical University, Dalian, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Oral and Maxillofacial Implantology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ni
authors.affiliation: Department of Prosthodontics, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China. Ziyuan1588@163.com.
authors.forename: Zi-Yuan
authors.initials: ZY
authors.lastname: Zhu
mesh_terms: D000497:Alloys; D003442:Crowns; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D004955:Esthetics, Dental; D006801:Humans; D016876:Metal Ceramic Alloys; D017060:Patient Satisfaction; D012189:Retrospective Studies; D015040:Zirconium
chemical_list: D000497:Alloys; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide
keywords: Zirconia-based crown; complication; patient satisfaction; survival rates