title: Pressure dynamics in the trays caused by differences of the various impression materials and thickness of the relief in the maxillary edentulous model.
abstract: OBJECTIVE
  The purpose of this study is to compare the pressure dynamics in the trays caused by differences in the various impression materials and in the thickness of the relief provided for the trays.
  
  
  METHODS
  In this study, two types of polyvinylsiloxane elastomers, one type of polyether elastomer and one type of alginate impression material were used. Pressure sensors were embedded at eight locations in a model of an edentulous maxilla, and used a simulation model covered with a pseudomucosa. For each impression material, the measurement was performed five times for each of the three types of trays, and the mean values were determined. Statistical analysis was carried out using one-way analysis of variance and the Tukey's HDS method, and the various pressure sensor values for each of the impression materials were compared 10s and 20s after the start of the measurement. Additionally, we compared differences among the three types of trays after 20s.
  
  
  RESULTS
  The pressure values for sensors placed in the relief region tended to become uniform. Furthermore, we saw a tendency for the pressure to increase at the alveolar crests of the first molars on the left and right and at the posterior border of the palate, all of which support the denture, when relief was provided.
  
  
  CONCLUSIONS
  The above results suggest that making the final impression for the denture using the selective pressure technique, with consideration given to the pressure dynamic, may lead to a good outcome in terms of preservation of the alveolar ridge.
authors.affiliation: Nihon University Graduate School of Dentistry at Matsudo, Japan; Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan. Electronic address: iwasaki.masatoshi@gmail.com.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan.
authors.forename: Misao
authors.initials: M
authors.lastname: Kawara
authors.affiliation: Nihon University Graduate School of Dentistry at Matsudo, Japan; Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan.
authors.forename: Sayumi
authors.initials: S
authors.lastname: Inoue
authors.affiliation: Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Komiyama
authors.affiliation: Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iida
authors.affiliation: Department of Oral Function and Rehabilitation, Nihon University School of Dentistry at Matsudo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Asano
mesh_terms: D000539:Alveolar Process; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D020724:Elastomers; D007575:Jaw, Edentulous; D008437:Maxilla; D003765:Models, Dental; D011145:Polyvinyls; D011312:Pressure; D012833:Siloxanes
chemical_list: D003760:Dental Impression Materials; D020724:Elastomers; D011145:Polyvinyls; D012833:Siloxanes
keywords: Impression material; Impression pressure; Removable denture; Selective pressure impression