title: Clinical evaluation of 121 lithium disilicate all-ceramic crowns up to 9 years.
abstract: OBJECTIVE
  The aim of this prospective clinical study was to evaluate the clinical performance of lithium disilicate allceramic crowns for a period from 12 to 156 months.
  
  
  METHODS
  One hundred and twenty five lithium disilicate all-ceramic crowns were placed in 35 patients between 2001 and 2007. One patient who received four all-ceramic crowns was excluded from the study. The remaining 34 patients received 121 all-ceramic crowns and were recalled. Ninety-eight anterior and 23 posterior crowns were inserted. All crowns were applied on vital teeth except for 11 crowns which were placed on endodontically treated teeth. Follow-up appointments were performed 6 months after insertion, then annually. Replacement of a restoration was defined as failure. Marginal integrity, marginal discoloration, secondary caries, sensitivity, color match, and ceramic surface were evaluated following modified California Dental Association/Ryge criteria. The survival rate of the crowns was determined using Kaplan- Meier statistical analysis and log-rank test (P = .05).
  
  
  RESULTS
  Ten crowns were fractured. The cumulative survival rate according to Kaplan-Meier was 87.1% after mean 104.6 months (range 12 to 156 months). Location (anterior vs posterior) of all-ceramic crown did not significantly affect the survival rate according to log-rank test (P = .89). Endodontically treated teeth without post-and-core restorations exhibited a higher failure rate after all-ceramic crown application according to log-rank test (P < .001).
  
  
  CONCLUSIONS
  In this in vivo study, lithium disilicate all-ceramic crowns exhibited a satisfactory clinical performance with an estimated survival probability of 87.1% over 104.6 months and they can be used clinically in the anterior and posterior region. Restoring endodontically treated teeth with post-and-core restorations should be considered before all-ceramic crown application.
authors.forename: Muhittin
authors.initials: M
authors.lastname: Toman
authors.forename: Suna
authors.initials: S
authors.lastname: Toksavul
mesh_terms: D000328:Adult; D000538:Aluminum Silicates; D003442:Crowns; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D000538:Aluminum Silicates; C075815:IPS-Empress ceramic; C493120:lithia disilicate; D003776:Dental Porcelain