title: Fracture analysis of randomized implant-supported fixed dental prostheses.
abstract: OBJECTIVE
  Fractures of posterior fixed dental all-ceramic prostheses can be caused by one or more factors including prosthesis design, flaw distribution, direction and magnitude of occlusal loading, nature of supporting infrastructure (tooth root/implant), and presence of adjacent teeth. This clinical study of implant-supported, all-ceramic fixed dental prostheses, determined the effects of (1) presence of a tooth distal to the most distal retainer; (2) prosthesis loading either along the non-load bearing or load bearing areas; (3) presence of excursive contacts or maximum intercuspation contacts in the prosthesis; and (4) magnitude of bite force on the occurrence of veneer ceramic fracture.
  
  
  METHODS
  89 implant-supported FDPs were randomized as either a three-unit posterior metal-ceramic (Au-Pd-Ag alloy and InLine POM, Ivoclar, Vivadent) FDP or a ceramic-ceramic (ZirCAD and ZirPress, Ivoclar, Vivadent) FDP. Two implants (Osseospeed, Dentsply) and custom abutments (Atlantis, Dentsply) supported these FDPs, which were cemented with resin cement (RelyX Universal Cement). Baseline photographs were made with markings of teeth from maximum intercuspation (MI) and excursive function. Patients were recalled at 6 months and 1-3 years. Fractures were observed, their locations recorded, and images compared with baseline photographs of occlusal contacts.
  
  
  CONCLUSIONS
  No significant relationship existed between the occurrence of fracture and: (1) the magnitude of bite force; (2) a tooth distal to the most distal retainer; and (3) contacts in load-bearing or non-load-bearing areas. However, there was a significantly higher likelihood of fracture in areas with MI contacts only.
  
  
  CONCLUSIONS
  Because of the absence of a periodontal ligament, this clinical study demonstrates that there is a need to evaluate occlusion differently with implant-supported prostheses than with natural tooth supported prostheses. Implant supported prostheses should have minimal occlusion and lighter contacts than those supported by natural dentition.
  K23 D2007-46.
authors.affiliation: Department of Restorative Dental Sciences, University of Florida, Gainesville, FL, United States. Electronic address: jesquivel@dental.ufl.edu.
authors.forename: Josephine F
authors.initials: JF
authors.lastname: Esquivel-Upshaw
authors.affiliation: Department of Restorative Dental Sciences, University of Florida, Gainesville, FL, United States.
authors.forename: Alex
authors.initials: A
authors.lastname: Mehler
authors.affiliation: Department of Restorative Dental Sciences, University of Florida, Gainesville, FL, United States.
authors.forename: Arthur E
authors.initials: AE
authors.lastname: Clark
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, FL, United States.
authors.forename: Dan
authors.initials: D
authors.lastname: Neal
authors.affiliation: Department of Restorative Dental Sciences, University of Florida, Gainesville, FL, United States.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Anusavice
mesh_terms: D000328:Adult; D000368:Aged; D000538:Aluminum Silicates / Q000737:chemistry; D001732:Bite Force; D002484:Cementation / Q000379:methods; D002516:Ceramics / Q000737:chemistry; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003776:Dental Porcelain / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003801:Dental Veneers; D003779:Denture Design; D003830:Denture, Partial, Fixed; D005260:Female; D005500:Follow-Up Studies; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D007574:Jaw Relation Record / Q000379:methods; D008297:Male; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008875:Middle Aged; D023861:Photography, Dental / Q000379:methods; D019279:Resin Cements / Q000737:chemistry; D016037:Single-Blind Method; D016019:Survival Analysis; D055815:Young Adult; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D015921:Dental Implants; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; C483701:Rely X Unicem; D019279:Resin Cements; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; C078519:leucite; D015019:Yttrium; C023506:Glass ceramics; D015040:Zirconium
keywords: Ceramic–ceramic FDP; Failure analysis; Fractography; Metal–ceramic FDP; Occlusal contact; Occlusion