title: Basic investigation of the laminated alginate impression technique: Setting time, permanent deformation, elastic deformation, consistency, and tensile bond strength tests.
abstract: OBJECTIVE
  Laminated alginate impression for edentulous is simple and time efficient compared to border molding technique. The purpose of this study was to examine clinical applicability of the laminated alginate impression, by measuring the effects of different Water/Powder (W/P) and mixing methods, and different bonding methods in the secondary impression of alginate impression.
  
  
  METHODS
  Three W/P: manufacturer-designated mixing water amount (standard), 1.5-fold (1.5×) and 1.75-fold (1.75×) water amount were mixed by manual and automatic mixing methods. Initial and complete setting time, permanent and elastic deformation, and consistency of the secondary impression were investigated (n=10). Additionally, tensile bond strength between the primary and secondary impression were measured in the following surface treatment; air blow only (A), surface baking (B), and alginate impression material bonding agent (ALGI-BOND: AB) (n=12).
  
  
  RESULTS
  Initial setting times significantly shortened with automatic mixing for all W/P (p<0.05). The permanent deformation decreased and elastic deformation increased as high W/P, regardless of the mixing method. Elastic deformation significantly reduced in 1.5× and 1.75× with automatic mixing (p<0.05). All of these properties resulted within JIS standards. For all W/P, AB showed a significantly high bonding strength as compared to A and B (p<0.01).
  
  
  CONCLUSIONS
  The increase of mixing water, 1.5× and 1.75×, resulted within JIS standards in setting time, suggesting its applicability in clinical setting. The use of automatic mixing device decreased elastic strain and shortening of the curing time. For the secondary impression application of adhesives on the primary impression gives secure adhesion.
authors.affiliation: Nihon University Graduate School of Dentistry at Matsudo, Removable Prosthodontics, 2-870-1 Sakaecho-nishi Matsudo, Chiba 271-8587, Japan. Electronic address: maay10006@g.nihon-u.ac.jp.
authors.forename: Aya
authors.initials: A
authors.lastname: Kitamura
authors.affiliation: Department of Removable Prosthodontics, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-nishi Matsudo, Chiba 271-8587, Japan. Electronic address: kawai.yasuhiko@nihon-u.ac.jp.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kawai
mesh_terms: D000464:Alginates; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D003764:Dental Materials; D004548:Elasticity; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D055585:Physical Phenomena; D011208:Powders; D013718:Tensile Strength; D013997:Time Factors; D014867:Water
chemical_list: D000464:Alginates; D003738:Dental Cements; D003760:Dental Impression Materials; D003764:Dental Materials; D006603:Hexuronic Acids; D011208:Powders; D014867:Water; D020723:Glucuronic Acid
keywords: Alginate impression material; Consistency; Elastic deformation; Setting times; Tensile bond strength