title: Clinical performance of a lithia disilicate-based core ceramic for three-unit posterior FPDs.
abstract: OBJECTIVE
  The purpose of this research project was to determine the clinical success rate of a lithia disilicate-based core ceramic for use in posterior fixed partial dentures (FPD) as a function of bite force, cement type, connector height, and connector width.
  
  
  METHODS
  Thirty ceramic FPD core frameworks were prepared using a heat-pressing technique and a lithia disilicate-based core ceramic. The maximum clenching force was measured for each patient prior to tooth preparation. Connector height and width were measured for each FPD. Patients were recalled yearly after cementation for 2 years and evaluated using 11 clinical criteria. All FPDs were examined by two independent clinicians, and rankings from 1 to 4 were made for each criterion (4 = excellent; 1 = unacceptable).
  
  
  RESULTS
  Two of the 30 ceramic FPDs fractured within the 2-year evaluation period, representing a 93% success rate. One fracture was associated with a low occlusal force and short connector height (2.9 mm). The other fracture was associated with the greatest occlusal force (1,031 N) and adequate connector height. All criteria were ranked good to excellent during the 2-year recall for all remaining FPDs.
  
  
  CONCLUSIONS
  The performance of the experimental core ceramic in posterior FPDs was promising, with only a 7% fracture rate after 2 years. Because of the limited sample size, it is not possible to identify the maximum clenching force that is allowable to prevent fracture caused by interocclusal forces.
authors.affiliation: Department of General Dentistry, University of Texas Health Science Center at San Antonio, 78229, USA. esquivelj@uthscsa.edu
authors.forename: Josephine F
authors.initials: JF
authors.lastname: Esquivel-Upshaw
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Anusavice
authors.forename: Henry
authors.initials: H
authors.lastname: Young
authors.forename: Jack
authors.initials: J
authors.lastname: Jones
authors.forename: Charles
authors.initials: C
authors.lastname: Gibbs
mesh_terms: D000328:Adult; D001641:Bicuspid; D001732:Bite Force; D002484:Cementation / Q000379:methods; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003779:Denture Design; D003830:Denture, Partial, Fixed; D005260:Female; D005899:Glass Ionomer Cements; D006801:Humans; D018020:Lithium Compounds; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008963:Molar; D019279:Resin Cements
chemical_list: D005899:Glass Ionomer Cements; D018020:Lithium Compounds; C091610:Protech glass ionomer cement; D019279:Resin Cements; D003776:Dental Porcelain; C103502:Variolink