title: Quality of impressions using hydrophilic polyvinyl siloxane in a clinical study of 249 patients.
abstract: OBJECTIVE
  This study aimed to evaluate the clinical success of a hydrophilic polyvinyl siloxane impression material for fixed dental restorations under various clinical conditions.
  
  
  METHODS
  A total of 1,466 preparations for fixed restorations in maxillary and mandibular anterior and posterior teeth were evaluated. The study contained inlay, onlay, crown, veneer, post, and adhesive-wing preparations and implants for gold, porcelain-fused-to-metal, and ceramic restorations. The preparation finish line relative to the crest of the marginal gingiva, type of restoration, and position of the teeth were recorded. Three categories were established to rate impression quality: perfect impressions, with an absence of any voids or bubbles and perfect reproduction of the preparation finish line, were rated Criteria I; acceptable impressions, with minimal defects (< or = 2 mm) not involving the preparation finish line, were rated Criteria II; and unacceptable impressions, with larger voids or bubbles (> 2 mm) or defects involving the preparation finish line, were rated Criteria III.
  
  
  RESULTS
  Overall, 96.86% of the final impressions were clinically acceptable, 89.43% of which were rated Criteria I and 7.43% of which were rated Criteria II. Only 3.14% of the impressions were unacceptable and rated Criteria III. A significant influence on impression quality was found when the preparation finish line was more than 2 mm subgingival (P < .004), as well as when a beveled preparation was used (P < .004). The position of the teeth (P > .404) had no significant effect.
  
  
  CONCLUSIONS
  Surface-activated polyvinyl siloxane impression material offers high predictability to avoid bubbles and voids in the final impression.
authors.affiliation: Clinical Department of Prosthetic Dentistry, Innsbruck Medical University, Innsbruck, Austria. ulrike.beier@uklibk.ac.at
authors.forename: Ulrike Stephanie
authors.initials: US
authors.lastname: Beier
authors.forename: Ingrid
authors.initials: I
authors.lastname: Grunert
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kulmer
authors.forename: Herbert
authors.initials: H
authors.lastname: Dumfahrt
mesh_terms: D003760:Dental Impression Materials; D003761:Dental Impression Technique / Q000592:standards*; D006801:Humans; D011145:Polyvinyls; D012833:Siloxanes; D018709:Statistics, Nonparametric
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane