title: Clinical evaluation of all-ceramic crowns fabricated from intraoral digital impressions based on the principle of active wavefront sampling.
abstract: OBJECTIVE
  The aim of the present study was to compare the fit of all-ceramic crowns fabricated from intraoral digital impressions with the fit of all-ceramic crowns fabricated from silicone impressions.
  
  
  METHODS
  Twenty patients agreed to take part in the study to receive two Lava crowns each for the same preparation. One crown was fabricated from intraoral scans using the Lava Chairside Oral Scanner (Lava C.O.S.), and the other crown from a two-step silicone impression. Prior to cementation the fit of both crowns was clinically evaluated by two calibrated and blinded examiners; the marginal fit was also scored from replicas. Data from the replica scores were analysed by Anderson-Darling test, Levene's test and Mann-Whitney test. All tests were performed with alpha-level of 0.05.
  
  
  RESULTS
  Median marginal gap in the conventional impression group was 71microm (Q1:45microm; Q3:98microm), and in the digital impression group 49microm (Q1:32microm; Q3:65microm). Mann-Whitney test revealed a significant difference between the groups (p<0.05). No differences were found regarding the occlusion, and there was a trend for better interproximal fit for the digitally fabricated crowns.
  
  
  CONCLUSIONS
  1. Crowns from intraoral scans revealed significantly better marginal fit than crowns from silicone impressions. 2. Marginal discrepancies in both groups were within the limits of clinical acceptability. 3. Crowns from intraoral scans tended to show better interproximal contact area quality. 4. Crowns from both groups performed equally well with regard to occlusion.
authors.affiliation: 3M ESPE, Espe Platz, 82229 Seefeld, Germany. asyrek@mmm.com
authors.forename: Andreas
authors.initials: A
authors.lastname: Syrek
authors.forename: Gunnar
authors.initials: G
authors.lastname: Reich
authors.forename: Dieter
authors.initials: D
authors.lastname: Ranftl
authors.forename: Christoph
authors.initials: C
authors.lastname: Klein
authors.forename: Barbara
authors.initials: B
authors.lastname: Cerny
authors.forename: Jutta
authors.initials: J
authors.lastname: Brodesser
mesh_terms: D000328:Adult; D002484:Cementation; D017076:Computer-Aided Design; D003442:Crowns; D003760:Dental Impression Materials / Q000737:chemistry; D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007574:Jaw Relation Record; D008297:Male; D008875:Middle Aged; D011145:Polyvinyls / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D016037:Single-Blind Method; D013499:Surface Properties; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D055815:Young Adult; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide