title: Influence of film thickness on joint bend strength of a ceramic/resin composite joint.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the influence of different film thicknesses of resin composite luting agents on the joint bend strength of a ceramic/resin interface.
  
  
  METHODS
  Mirage FLC (Chamelon Dental Products) and Vita Cerec (Coltène AG) duo cement were used in combination with the ceramic materials, Mirage and Vita Cerec blocks. Cement layers with thicknesses of 20 microns, 50 microns, 100 microns and 200 microns were light-cured with a high-intensity curing light. Ten specimens of each ceramic/cement combination and thickness provided a total of 80 complete test specimens. Each specimen was placed in a four-point bending jig mounted in a universal tensile testing machine and underwent loading. A paired two-tailed Student's 1-test was used to evaluate differences between different series of film thicknesses and resin cement combinations.
  
  
  RESULTS
  Within each ceramic/cement combination, the bond strength values were significantly lower for the 20 micron film then the thicker films.
  
  
  CONCLUSIONS
  Taking into account the physical and clinical properties of resin-based luting agents, available knowledge indicates that a marginal gap on the order of 50-100 microns seems to optimize performance.
authors.affiliation: Department of Prosthetic Dentistry, Faculty of Odontology, Umeå, Sweden. Margareta.Molin@protetik.umu.se
authors.forename: M K
authors.initials: MK
authors.lastname: Molin
authors.forename: S L
authors.initials: SL
authors.lastname: Karlsson
authors.forename: M S
authors.initials: MS
authors.lastname: Kristiansen
mesh_terms: D002484:Cementation / Q000379:methods; D002516:Ceramics; D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods; D003738:Dental Cements; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D008422:Materials Testing / Q000295:instrumentation; D008689:Methacrylates; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D019279:Resin Cements; D013718:Tensile Strength
chemical_list: C087274:Cerec Cement; D003188:Composite Resins; D003738:Dental Cements; D008689:Methacrylates; C080875:Mirage; C070605:Mirage-Bond; D019279:Resin Cements; D003776:Dental Porcelain; C074543:Cerec