title: The effect of time on the adhesion of light-body to heavy-body Express in the two-step reline polyvinylsiloxane impression technique.
abstract: Often times light-body wash (LB) cannot be added to the heavy-body putty (HB) within 30 minutes when utilizing the two-step reline impression technique. The purpose of this study was to add the LB to the HB at times greater than 30 minutes and test the tensile bond strength. A split aluminum mold which created a bonding area of 1.13 cm2 and tray were filled with Express HB. After HB set the Express LB in a tray was added at varying times. The split molds were then separated and samples tested on the Instron. Ten groups with five samples/group (determined by a pilot study) were made. The times which the LB was added to the set HB and tested were: A) Immediately (one-step procedure); B) 10 minutes and contaminated with saliva (negative control); C) 10 minutes; D) 30 minutes; E) 45 minutes; F) 1 hour; G) 3 hours; H) 24 hours; I) 115 hours; and J) Freshened after 3 months. The results of this study indicate that saliva-contaminated samples were weaker than all other groups (P less than or equal to 0.01) and as far as tensile bond strength between materials is concerned, there appears to be no detrimental effect in tensile bond strength between HB and LB when delaying the application of the light-body material (P less than or equal to 0.01).
authors.affiliation: Department of Operative Dentistry, University of Missouri-Kansas City.
authors.forename: J H
authors.initials: JH
authors.lastname: Purk
authors.forename: S H
authors.initials: SH
authors.lastname: Hung
authors.forename: R P
authors.initials: RP
authors.lastname: Chappell
authors.forename: R L
authors.initials: RL
authors.lastname: Casper
authors.forename: J D
authors.initials: JD
authors.lastname: Eick
mesh_terms: D001840:Dental Bonding; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D011145:Polyvinyls; D012833:Siloxanes; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane