title: Influence of preparation form, luting space setting and cement type on the marginal and internal fit of CAD/CAM crown copings.
abstract: OBJECTIVE
  To evaluate the influence of two different tooth preparation forms, two luting space settings and two cement types on the marginal and internal adaptation of all-ceramic crown copings produced using Cerec3 CAD/CAM system.
  
  
  METHODS
  Forty working stone dies were made from two metal master casts (1. Tooth 36: with anatomic occlusal reduction, 2. Tooth 36: with flat occlusal reduction). Forty crown copings were milled using Vita In-Ceram 2000 YZ: 20 with an luting space settings of 0 = 100 microm and 20 with -50 = 50 microm. Copings were cemented using two cements (zinc phosphate cement, P21: Panavia21), then embedded and sectioned bucco-lingually and mesio-distally. Widths of marginal and internal gaps were measured using a light microscope at magnification of 40X. Data were submitted to one-way ANOVA, and statistical significance was set at p < 0.05.
  
  
  RESULTS
  Copings with flat occlusal reduction and luting space settings of 100 pm had a better internal and marginal fit compared with copings with anatomic occlusal reduction and luting space settings of 50 microm, regardless of the cement used. P21 showed a significantly better fit compared with zinc phosphate cement.
  
  
  CONCLUSIONS
  The presented Cerec3 CAD/CAM system can provide a marginal and internal adaptation which is comparable to that of conventional cast and conventional all-ceramic crowns.
authors.affiliation: Department of Prosthodontics and Geriatric Dentistry, Tishreen University, Latakia, Syria. rim.hmaidouch@charite.de
authors.forename: R
authors.initials: R
authors.lastname: Hmaidouch
authors.forename: P
authors.initials: P
authors.lastname: Neumann
authors.forename: W-D
authors.initials: WD
authors.lastname: Mueller
mesh_terms: D000704:Analysis of Variance; D002484:Cementation / Q000379:methods*; D017076:Computer-Aided Design; D003442:Crowns; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D006801:Humans; D003765:Models, Dental; D008963:Molar; D010710:Phosphates; D017755:Prosthesis Fitting; D019279:Resin Cements; D018709:Statistics, Nonparametric; D019231:Tooth Preparation, Prosthodontic / Q000379:methods*; D015036:Zinc Phosphate Cement
chemical_list: C093719:Panavia TPN-S; D010710:Phosphates; D019279:Resin Cements; D003776:Dental Porcelain; D015036:Zinc Phosphate Cement