title: Clinical results of lithium-disilicate crowns after up to 9 years of service.
abstract: OBJECTIVE
  The purpose of this prospective study was to evaluate the clinical outcome of anterior and posterior crowns made of a lithium-disilicate glass-ceramic framework material (IPS e.max Press, Ivoclar Vivadent).
  
  
  METHODS
  A total of 104 single crowns were placed in 41 patients (mean age, 34 ± 9.6 years; 15 male, 26 female). Eighty-two anterior and 22 posterior crowns were inserted. All teeth received a 1-mm-wide chamfer or rounded shoulder preparation with an occlusal/incisal reduction of 1.5-2.0 mm. The minimum framework thickness was 0.8 mm. Frameworks were laminated by a prototype of a veneering material combined with an experimental glaze. Considering the individual abutment preconditions, the examined crowns were either adhesively luted (69.2 %) or inserted with glass-ionomer cement (30.8 %). Follow-up appointments were performed 6 months after insertion, then annually. Replacement of a restoration was defined as failure.
  
  
  RESULTS
  Four patients (10 crowns) were defined as dropouts. For the remaining 94 crowns, the mean observation time was 79.5 months (range, 34-109.7 months). The cumulative survival rate according to Kaplan-Meier was 97.4 % after 5 years and 94.8 % after 8 years. Applying log rank test, it was shown that the location of the crown did not significantly have an impact on the survival rate (p = 0.74) and that the cementation mode did not significantly influence the occurrence of complications (p = 0.17).
  
  
  CONCLUSIONS
  The application of lithium-disilicate framework material for single crowns seems to be a reliable treatment option.
  
  
  CONCLUSIONS
  Crowns made of a lithium-disilicate framework material can be used clinically in the anterior and posterior region irrespective of an adhesive or conventional cementation when considering abutment preconditions.
authors.affiliation: Department of Prosthodontics, Implantology and Biomaterials, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany. mgehrt@ukaachen.de
authors.forename: Maren
authors.initials: M
authors.lastname: Gehrt
authors.forename: Stefan
authors.initials: S
authors.lastname: Wolfart
authors.forename: Nicole
authors.initials: N
authors.lastname: Rafai
authors.forename: Sven
authors.initials: S
authors.lastname: Reich
authors.forename: Daniel
authors.initials: D
authors.lastname: Edelhoff
mesh_terms: D000328:Adult; D002484:Cementation / Q000379:methods; D002516:Ceramics / Q000737:chemistry; D003442:Crowns; D000044:Dental Abutments; D003738:Dental Cements / Q000737:chemistry; D003774:Dental Plaque Index; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003801:Dental Veneers; D005260:Female; D005500:Follow-Up Studies; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D010512:Periodontal Index; D011446:Prospective Studies; D019279:Resin Cements / Q000737:chemistry; D012390:Root Canal Therapy; D013499:Surface Properties; D016019:Survival Analysis; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D016896:Treatment Outcome
chemical_list: D003738:Dental Cements; D005899:Glass Ionomer Cements; C508050:IPS e.max Press; D019279:Resin Cements; C493120:lithia disilicate; D003776:Dental Porcelain; C023506:Glass ceramics