title: Evaluation of the marginal accuracy of different all-ceramic crown systems after simulation in the artificial mouth.
abstract: The in vitro marginal fit of five different all-ceramic crown systems (In-Ceram, Empress staining technique, Empress veneering technique, Celay feldspathic system, Celay In-Ceram system) was evaluated before and after cyclic preloading in an artificial mouth. The crowns were adhesively luted to extracted natural maxillary incisors prepared with a 90 degrees shoulder. The results were compared to those for porcelain-fused-to-metal (PFM) crowns with circular porcelain-butt margins which were cemented with zinc phosphate cement. The analysis of the marginal discrepancies showed significant (P < 0.001) differences among the groups. Crown cementation increased the marginal gaps significantly (P < 0.01). Empress staining technique crowns showed the smallest marginal gaps (median 47 microm), followed by conventional In-Ceram crowns (median 60 microm) and Empress veneer technique crowns (median 62 microm). Celay In-Ceram crowns displayed marginal openings with a median of 78 microm, followed by Celay feldspathic crowns with a median of 99 microm. The marginal gap of the PFM control crowns showed a median of 64 microm. Ageing in the chewing simulator had no significant influence on the marginal fit of all specimens. The study indicates that all the tested all-ceramic crowns have clinically acceptable margins. However, in vivo investigations of all all-ceramic crown systems should be made before clinical routine.
authors.affiliation: Department of Prosthodontics, University of Freiburg, Germany. beschnid@zmk2.ukl.uni.freiburg.de
authors.forename: S M
authors.initials: SM
authors.lastname: Beschnidt
authors.forename: J R
authors.initials: JR
authors.lastname: Strub
mesh_terms: D000537:Aluminum Oxide; D000538:Aluminum Silicates; D002484:Cementation / Q000379:methods; D003442:Crowns / Q000706:statistics & numerical data; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain; D006801:Humans; D066298:In Vitro Techniques; D007180:Incisor; D008422:Materials Testing / Q000706:statistics & numerical data; D008437:Maxilla; D017680:Potassium Compounds; D011897:Random Allocation
chemical_list: D000538:Aluminum Silicates; C078572:Celay; C075815:IPS-Empress ceramic; D017680:Potassium Compounds; D003776:Dental Porcelain; C016447:feldspar; C070870:In-Ceram; D000537:Aluminum Oxide