title: Damage of lithium-disilicate all-ceramic restorations by an experimental self-adhesive resin cement used as core build-ups.
abstract: OBJECTIVE
  This in vitro study aimed to predict the potential of fracture initiation after long-term incubation (LTI) of lithium-disilicate restorations due to a hygroscopic expansion of self-adhesive resin cement (SARC) used as core build-up material.
  
  
  METHODS
  Human maxillary central incisors were divided into four groups (n = 10). Teeth were endodontically treated and decoronated. Specimens were restored in a one-stage post-and-core procedure using experimental dual-curing SARC. Three application protocols to build up the core were compared as follows: I, auto-polymerisation; II, dual curing including 40 s light-initiated polymerisation; and III, an open matrix technique in a dual-curing mode. In group IV, a chemical-curing composite core build-up material served as control. For all specimens, a 2-mm ferrule design was ensured. Full anatomic lithium-disilicate crowns were adhesively luted. One-year LTI in 0.5 % chloramine solution at 37 °C was performed. Restorations were examined after 3, 6, 9 and 12 month of storage. Survival rates were calculated using log-rank statistics (p = 0.05).
  
  
  RESULTS
  Fifty per cent of lithium-disilicate crowns of groups I and II showed visible crack propagation after 9 months of incubation, while one crown failed in group III. No failure was observed in group IV. The survival rates differed significantly (p = 0.017).
  
  
  CONCLUSIONS
  SARC used to build up the core of severely damaged endodontically treated teeth does have the potential to cause fracture of lithium-disilicate crown restorations.
  
  
  CONCLUSIONS
  Hygroscopic expansion of self-adhesive resin cements used as a core build-up material might have an adverse impact on longevity of glass-ceramic crowns.
authors.affiliation: Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, CharitéCentrum 3, Charité - Universitätsmedizin Berlin, Aßmannshauser Str. 4-6, 14197, Berlin, Germany, guido.sterzenbach@charite.de.
authors.forename: G
authors.initials: G
authors.lastname: Sterzenbach
authors.forename: G
authors.initials: G
authors.lastname: Karajouli
authors.forename: R
authors.initials: R
authors.lastname: Tunjan
authors.forename: T
authors.initials: T
authors.lastname: Spintig
authors.forename: K
authors.initials: K
authors.lastname: Bitter
authors.forename: M
authors.initials: M
authors.lastname: Naumann
mesh_terms: D002516:Ceramics; D003793:Dental Restoration, Permanent; D006801:Humans; D008094:Lithium; D019279:Resin Cements; D017640:Silicates
chemical_list: D019279:Resin Cements; D017640:Silicates; D008094:Lithium