title: Influence of chemical and mechanical polishing on water sorption and solubility of denture base acrylic resins.
abstract: Influence of polishing methods on water sorption and solubility of denture base acrylic resins was studied. Eighty samples were divided into groups: Classico (CL), and QC 20 (QC) - hot water bath cured; Acron MC (AC), and Onda Cryl (ON) - microwave cured; and submitted to mechanical polishing (MP) - pumice slurry, chalk powder, soft brush and felt cone in a bench vise; or chemical polishing (CP) - heated monomer fluid in a chemical polisher. The first desiccation process was followed by storage in distilled water at 37 +/- 1 degrees C for 1 h, 1 day, 1, 2, 3 and 4 weeks. Concluding each period, water sorption was measured. After the fourth week, a second desiccation process was done to calculate solubility. Data were submitted to analysis of variance, followed by Tukey test (p<or=0.05). Means of water sorption (%) and solubility (%), respectively, were: CL-MP: 1.92 and 0.02; CL-CP: 1.98 and 0.52; QC-MP: 2.31 and -0.05; QC-CP: 2.32 and 0.25; AC-MP: 2.45 and -0.07; AC-CP: 2.43 and 0.41; ON-MP: 2.32 and -0.06; ON-CP: 2.34 and 0.27. Mechanical polishing promoted significantly lower solubility of acrylic resins; initially, water sorption values were higher for chemically polished samples, however, after 4 weeks all groups were similar.
authors.affiliation: Department of Prosthodontics, Paranaense University (UNIPAR), Umuarama, PR, Brazil.
authors.forename: Juliana Saab
authors.initials: JS
authors.lastname: Rahal
authors.forename: Marcelo Ferraz
authors.initials: MF
authors.lastname: Mesquita
authors.forename: Guilherme Elias Pessanha
authors.initials: GE
authors.lastname: Henriques
authors.forename: Mauro Antonio Arruda
authors.initials: MA
authors.lastname: Nóbilo
mesh_terms: D000042:Absorption; D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D002119:Calcium Carbonate / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000295:instrumentation / Q000379:methods*; D003819:Denture Bases; D003890:Desiccation; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008872:Microwaves; D017640:Silicates / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; C488492:QC 20 (denture base resin); D017640:Silicates; D014867:Water; C075051:Acron MC; D002119:Calcium Carbonate; C005144:pumice