title: Are implants more reliable than severely compromised endodontically treated teeth as abutments for zirconia-based FPDs? : In vitro results of long-term preclinical load simulation.
abstract: OBJECTIVE
  The aim was to study the impact of the defect size of endodontically treated incisors compared to dental implants as abutments on the survival of zirconia two-unit anterior cantilever-fixed partial dentures (2U-FPDs) during 10-year simulation.
  
  
  METHODS
  Human maxillary central incisors were endodontically treated and divided into three groups (n = 24): I, access cavities rebuilt with composite core; II, teeth decoronated and restored with composite; and III as II supported by fiber posts. In group IV, implants with individual zirconia abutments were used. Specimens were restored with zirconia 2U-FPDs and exposed to two sequences of thermal cycling and mechanical loading.
  
  
  METHODS
  Kaplan-Meier; log-rank tests.
  
  
  RESULTS
  During TCML in group I two tooth fractures and two debondings with chipping were found. Solely chippings occurred in groups II (2×), IV (2×), and III (1×). No significant different survival was found for the different abutments (p = 0.085) or FPDs (p = 0.526). Load capability differed significantly between groups I (176 N) and III (670 N), and III and IV (324 N) (p < 0.024).
  
  
  CONCLUSIONS
  Within the limitations of an in vitro study, it can be concluded that zirconia-framework 2U-FPDs on decoronated teeth with/without post showed comparable in vitro reliability as restorations on implants. The results indicated that restorations on teeth with only access cavity perform worse in survival and linear loading.
  
  
  CONCLUSIONS
  Even severe defects do not justify per se a replacement of this particular tooth by a dental implant from load capability point of view.
authors.affiliation: Department of Prosthetic Dentistry, Center of Dentistry, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany. micha.naumann@gmx.de
authors.forename: M
authors.initials: M
authors.lastname: Naumann
authors.forename: C
authors.initials: C
authors.lastname: Hohmann
authors.forename: A
authors.initials: A
authors.lastname: Happe
authors.forename: F
authors.initials: F
authors.lastname: Beuer
authors.forename: R
authors.initials: R
authors.lastname: Frankenberger
authors.forename: R
authors.initials: R
authors.lastname: Seemann
authors.forename: M
authors.initials: M
authors.lastname: Rosentritt
mesh_terms: D003442:Crowns; D000044:Dental Abutments; D015921:Dental Implants; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003779:Denture Design; D003830:Denture, Partial, Fixed; D006801:Humans; D066298:In Vitro Techniques; D007180:Incisor; D011176:Post and Core Technique; D014082:Tooth Fractures / Q000209:etiology; D019553:Tooth, Nonvital; D015040:Zirconium
chemical_list: D015921:Dental Implants; D015040:Zirconium; C028541:zirconium oxide