title: Accuracy and dimensional stability of extended-pour and conventional alginate impression materials.
abstract: BACKGROUND
  The authors conducted a study to determine if two irreversible hydrocolloid impression materials (Cavex ColorChange, Cavex Holland BV, Haarlem, Netherlands; Jeltrate Plus Antimicrobial Dustless Alginate Impression Material, Dentsply Caulk, Milford, Del.) stored for five days were dimensionally accurate.
  
  
  METHODS
  The authors modified Ivorine teeth (Columbia Dentoform, Long Island City, N.Y.) on a Dentoform model (1560 series model, Columbia Dentoform) to allow measurements of tooth and arch width. They made impressions and generated casts immediately and at five additional times. They recorded tooth and arch widths on the casts and compared the measurements with those for the standard model.
  
  
  RESULTS
  Compared with measurements for the model, the greatest measured difference in casts was 0.003 inches for Cavex ColorChange (extended-pour alginate) and 0.005 inches for Jeltrate Plus Antimicrobial Dustless Alginate Impression Material (conventional alginate). The percentage of dimensional change ranged from -0.496 to 0.161 percent for the extended-pour alginate and from -0.174 to 0.912 percent for the conventional alginate.
  
  
  CONCLUSIONS
  Results of analysis of variance and paired t tests indicated that when generated immediately and at day 5, casts produced from both impression materials were not statistically different from the standard model (P < .05).
  
  
  CONCLUSIONS
  When stored properly, both alginate materials can produce accurate impressions at day 5 for diagnostic casts and for fabrication of acrylic appliances.
authors.affiliation: professor, Department of General Practice, School of Dentistry, VirginiaCommonwealth University, Lyons Building, Richmond, VA 23298-0566, USA. taimbery@vcu.edu
authors.forename: Terence A
authors.initials: TA
authors.lastname: Imbery
authors.forename: Joshua
authors.initials: J
authors.lastname: Nehring
authors.forename: Charles
authors.initials: C
authors.lastname: Janus
authors.forename: Peter C
authors.initials: PC
authors.lastname: Moon
mesh_terms: D000464:Alginates / Q000737:chemistry; D000704:Analysis of Variance; D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique; D003764:Dental Materials / Q000737:chemistry; D006801:Humans; D006813:Humidity; D008422:Materials Testing; D003765:Models, Dental / Q000592:standards*; D009930:Organic Chemicals / Q000737:chemistry; D015203:Reproducibility of Results; D013696:Temperature; D013997:Time Factors
chemical_list: D000464:Alginates; D003760:Dental Impression Materials; D003764:Dental Materials; D009930:Organic Chemicals; C050135:cavex; C043594:Jeltrate