title: A 15-year clinical comparative study of the cumulative survival rate of cast metal core and resin core restorations luted with adhesive resin cement.
abstract: OBJECTIVE
  The aim of this study was to compare the core survival rates (CSRs) of cast metal versus resin core restorations luted with adhesive resin cement, as well as to determine the risk factors for core failure.
  
  
  METHODS
  Nine hundred ninety-one patients (2,124 cores) who received either cast metal or resin cores luted with adhesive resin cement at the Fixed Prosthodontic Clinic of Okayama University Dental Hospital between April 1988 and December 1991 and whose structured clinical core record was filled appropriately comprised the study subjects. The clinical core record included information regarding patient age, sex, core restoration type, tooth location, tooth type, remaining coronal dentin, and root canal form. CSRs, as well as causes for failure, were analyzed 15 years postinsertion. Since 381 patients lacked data regarding predictors for core failure, a subsample of 610 patients (1,053 cores) was used for the subsequent risk factor analysis.
  
  
  RESULTS
  The cumulative CSR of resin cores (78.7%) was significantly higher than that of cast metal cores (55.4%; log-rank test, P < .0001). The Cox proportional hazards test revealed that sex (male, P < .0001), absence of remaining coronal dentin (P = .0057), core restoration type (cast metal, P = .0186), and higher age at core insertion (P = .0380) were significant predictors for core failure. The incidence of complications, such as core loosening (P = .0016) and tooth extraction (P < .0001), was significantly higher in cast metal cores.
  
  
  CONCLUSIONS
  Cast metal cores were associated with a significantly lower CSR than resin cores, and significant risk factors for core failure were sex (male), absence of remaining coronal dentin, core restoration type (cast metal), and higher age at core insertion.
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Hikasa
authors.forename: Yoshizo
authors.initials: Y
authors.lastname: Matsuka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Mine
authors.forename: Hajime
authors.initials: H
authors.lastname: Minakuchi
authors.forename: Emilio Satoshi
authors.initials: ES
authors.lastname: Hara
authors.forename: Bart
authors.initials: B
authors.lastname: Van Meerbeek
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yatani
authors.forename: Takuo
authors.initials: T
authors.lastname: Kuboki
mesh_terms: D000328:Adult; D000368:Aged; D002484:Cementation / Q000379:methods*; D015331:Cohort Studies; D003188:Composite Resins; D003442:Crowns; D004245:DMF Index; D019232:Dental Restoration Failure; D003830:Denture, Partial, Fixed; D005260:Female; D005500:Follow-Up Studies; D006047:Gold Alloys; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011176:Post and Core Technique; D016016:Proportional Hazards Models; D012044:Regression Analysis; D019279:Resin Cements; D012307:Risk Factors
chemical_list: D003188:Composite Resins; D006047:Gold Alloys; D019279:Resin Cements