title: Clinical marginal fit of zirconia crowns and patients' preferences for impression techniques using intraoral digital scanner versus polyvinyl siloxane material.
abstract: BACKGROUND
  The use of digital intraoral scanners is increasing; however, evidence of its precision in making crown impressions clinically remains scarce. Patients should also feel more comfortable with digital impressions, but only a few studies evaluating this subject have been performed.
  
  
  OBJECTIVE
  The purpose of this clinical study was to evaluate the marginal fit of monolithic zirconia crowns and patients' preferences for digital impressions versus polyvinyl siloxane (PVS) impressions.
  
  
  METHODS
  Sixteen participants with indications for single molar crowns were included. After crown preparation, digital impressions by intraoral scanner and PVS impressions were made. The participants were asked to complete a 6-item questionnaire with a visual analog scale related to perceptions of each of the following topics: time involved, taste/smell, occlusal registration, size of impression tray/scanner, gag reflex, and overall preference. Computer-aided design and computer-aided manufacturing monolithic zirconia crowns were fabricated from both impressions. The crowns were evaluated intraorally, and a blinded examiner measured the marginal discrepancy of silicone replicas under a stereomicroscope. Intraexaminer reliability was evaluated by calculating the intraclass correlation coefficient. Data for patients' preferences and marginal discrepancies were analyzed using the paired t test (α=.05).
  
  
  RESULTS
  Visual analog scale scores for digital impressions were statistically significantly higher than those for PVS impressions in every topic (P<.05), except for occlusal registration. The results showed excellent reliability of the examiner with an intraclass correlation coefficient of .996. No significant difference was found in marginal discrepancies between the PVS group and the digital group on all sides (P>.05).
  
  
  CONCLUSIONS
  No differences were found in the clinical marginal fit of zirconia crowns fabricated from either digital impressions compared with PVS impressions. Furthermore, patients' satisfaction with digital impressions was significantly higher than with conventional impressions.
authors.affiliation: Graduate student, Esthetic Restorative and Implant Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Nawapat
authors.initials: N
authors.lastname: Sakornwimon
authors.affiliation: Associate Professor and Program Director, Esthetic Restorative and Implant Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand. Electronic address: chalermpollee@gmail.com.
authors.forename: Chalermpol
authors.initials: C
authors.lastname: Leevailoj
mesh_terms: D000328:Adult; D017076:Computer-Aided Design; D003442:Crowns; D003722:Dental Alloys; D003760:Dental Impression Materials; D003761:Dental Impression Technique / Q000295:instrumentation*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D057240:Patient Preference; D011145:Polyvinyls; D012833:Siloxanes; D016037:Single-Blind Method; D011795:Surveys and Questionnaires; D015040:Zirconium
chemical_list: D003722:Dental Alloys; D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane; D015040:Zirconium; C028541:zirconium oxide