title: Standards of teeth preparations for anterior resin bonded all-ceramic crowns in private dental practice in Jordan.
abstract: OBJECTIVE
  To investigate if general dental practitioners (GDPs) in private practice in Jordan follow universal guidelines for preparation of anterior teeth for resin bonded all-ceramic crowns (RBCs).
  
  
  METHODS
  A sample (n=100) of laboratory models containing 208 tooth preparations for IPS Empress and In Ceram, featuring work from different GDPs, was obtained from 8 commercial dental laboratories. Aspects of preparations were quantified and compared with accepted criteria defined following a review of the literature and recommendations of the manufactures' guidelines.
  
  
  RESULTS
  Subgingival margins on the buccal aspect were noticed in 36% of the preparations, 54% demonstrated overpreparation with a tendency to overprepare the teeth on the mesiodistal plane more than buccolingual plane. Twenty percent of samples presented a shoulder finish line while a chamfer margin design was noticed in 39%. Twenty-nine percent and 12% of samples had either a feathered or no clear margin design respectively. Incisal underpreparation was observed in 18% of dies of each type. Only 17% of all preparations were found to follow the recommended anatomical labial preparations while 29% of the RBC preparations were found to have the recommended axial convergence angle. In total, 43% of preparations were found to have the recommended depth of the finish line.
  
  
  CONCLUSIONS
  It was found that relevant guidelines for RBC preparations were not being fully adhered to in private practice in Jordan.
authors.affiliation: Prosthodontics Department, Jordan University of Science and Technology, Irbid, Jordan. ziadd@just.edu.jo
authors.forename: Ziad Nawaf
authors.initials: ZN
authors.lastname: Al-Dwairi
authors.forename: Ahmad Saleh
authors.initials: AS
authors.lastname: Al-Hiyasat
authors.forename: Haitham
authors.initials: H
authors.lastname: Aboud
mesh_terms: D000537:Aluminum Oxide; D002516:Ceramics / Q000627:therapeutic use*; D003442:Crowns; D001840:Dental Bonding / Q000379:methods*; D003776:Dental Porcelain; D019983:Guideline Adherence; D006801:Humans; D007597:Jordan; D007754:Laboratories, Dental; D019239:Practice Patterns, Dentists' / Q000592:standards*; D011331:Private Practice / Q000592:standards; D019231:Tooth Preparation, Prosthodontic / Q000379:methods / Q000592:standards*
chemical_list: D003776:Dental Porcelain; C070870:In-Ceram; D000537:Aluminum Oxide