title: Two-year evaluation indicates zirconia bridges acceptable alternative to PFMs.
abstract: OBJECTIVE
  The aim of this in-vivo study was to evaluate the 2-year clinical performance of zirconia computer-aided design/computer-aided manufacturing (CAD/CAM)-generated bridges.
  
  
  METHODS
  A total of 16 three- or four-unit Lava zirconia bridges were done on 15 subjects. The bridges were cemented using RelyX™ Unicem Self-Adhesive Universal Resin Cement. Evaluation was done at 6-month, 1-year, and 2-year recall visits. Evaluation criteria were color stability and matching, marginal integrity, marginal discoloration, incidence of caries, changes in restoration-tooth interface, changes in surface texture, postoperative sensitivity, maintenance of periodontal health, changes in proximal and opposing teeth, and maintenance of anatomic form. In each of these parameters, the bridges were rated in one of three possible categories: "A" (alpha)--ideal; "B" (bravo)--acceptable; and "C" (charlie)--unacceptable.
  
  
  RESULTS
  After 2 years, 100% of the bridges were rated "A" for color stability and matching, marginal discoloration, incidence of caries, changes in restoration-tooth interface, changes in surface texture, postoperative sensitivity, and change in proximal or opposing teeth. In the parameter of marginal integrity, 6.25% of the bridges were rated "B;" the remaining 93.75% were rated "A." Maintenance of periodontal health was rated "B" for 6.25% of the bridges and "A" for 93.75%. At 2 years, 12.5% of the bridges rated "C" in maintenance of anatomic form and 87.5% rated "A."
  
  
  CONCLUSIONS
  The overall clinical outcome was that the CAD/CAM-generated zirconia bridges were clinically acceptable.
authors.affiliation: Gavel Center for Restorative Dental Research, Tufts University School of Dental Medicine, Boston, Massachusetts, USA.
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Perry
authors.forename: Gerard
authors.initials: G
authors.lastname: Kugel
authors.forename: Shradha
authors.initials: S
authors.lastname: Sharma
authors.forename: Susana
authors.initials: S
authors.lastname: Ferreira
authors.forename: Britta
authors.initials: B
authors.lastname: Magnuson
mesh_terms: D000328:Adult; D001672:Biocompatible Materials; D002484:Cementation; D017076:Computer-Aided Design; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D003830:Denture, Partial, Fixed; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D008670:Metals; D016896:Treatment Outcome; D015040:Zirconium
chemical_list: D001672:Biocompatible Materials; D008670:Metals; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide