title: Effect of insertion method on knoop hardness of high viscous glass ionomer cements.
abstract: The aim of this study was to assess the Knoop hardness of three high viscous glass ionomer cements: G1 - Ketac Molar; G2 - Ketac Molar Easymix (3M ESPE) and G3 - Magic Glass ART (Vigodent). As a parallel goal, three different methods for insertion of Ketac Molar Easymix were tested: G4 - conventional spatula; G5 - commercial syringe (Centrix) and G6 - low-cost syringe. Ten specimens of each group were prepared and the Knoop hardness was determined 5 times on each specimen with a HM-124 hardness machine (25 g/30 s dwell time) after 24 h, 1 and 2 weeks. During the entire test period, the specimens were stored in liquid paraffin at 37ºC. Significant differences were found between G3 and G1/G2 (two-way ANOVA and Tukey's post hoc test; p<0.01). There was no significant difference in the results among the multiple ways of insertion. The glass ionomer cement Magic Glass ART showed the lowest hardness, while the insertion technique had no significant influence on hardness.
authors.affiliation: Department of Pediatric Dentistry, Dental School, University of São Paulo, São Paulo, SP, Brazil. danielar@usp.br
authors.forename: Daniela Prócida
authors.initials: DP
authors.lastname: Raggio
authors.forename: Clarissa Calil
authors.initials: CC
authors.lastname: Bonifácio
authors.forename: Marcelo
authors.initials: M
authors.lastname: Bönecker
authors.forename: José Carlos P
authors.initials: JC
authors.lastname: Imparato
authors.forename: Anton J de
authors.initials: AJ
authors.lastname: Gee
authors.forename: Willem Evert van
authors.initials: WE
authors.lastname: Amerongen
mesh_terms: D003793:Dental Restoration, Permanent / Q000295:instrumentation*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D013594:Syringes; D013696:Temperature; D013997:Time Factors; D014783:Viscosity
chemical_list: D005899:Glass Ionomer Cements; C515713:Ketac Molar Easymix; C110712:ketac-molar