title: Effect of thermal cycling and disinfection on microhardness of acrylic resin denture base.
abstract: The purpose of this study was to investigate the effect of thermal cycling and disinfection on the microhardness of acrylic resins denture base. Four different brands of acrylic resins were evaluated: Onda Cryl, QC 20, Classico and Lucitone. Each brand of acrylic resin was divided into four groups (n = 7) according to the disinfection method (microwave, Efferdent, 4% chlorhexidine and 1% hypochlorite). Samples were disinfected during 60 days. Before and after disinfection, samples were thermal cycled between 5-55 °C with 30-s dwell times for 1000 cycles. The microhardness was measured using a microhardener, at baseline (B), after first thermal cycling (T1), after disinfection (D) and after second thermal cycling (T2). The microhardness values of all groups reduced over time. QC-20 acrylic resin exhibited the lowest microhardness values. At B and T1 periods, the acrylic resins exhibited statistically greater microhardness values when compared to D and T2 periods. It can be concluded that the microhardness values of the acrylic resins denture base were affected by the thermal cycling and disinfection procedures. However, all microhardness values obtained herein are within acceptable clinical limits for the acrylic resins.
authors: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Araçatuba, UNESP - Univ Estadual Paulista , Araçatuba, São Paulo , Brazil. goiato@foa.unesp.br
authors: Marcelo Coelho
authors: MC
authors: Goiato
authors: Daniela Micheline
authors: DM
authors: Dos Santos
authors: Gabriella Trunckle
authors: GT
authors: Baptista
authors: Amália
authors: A
authors: Moreno
authors: Agda Marobo
authors: AM
authors: Andreotti
authors: Stéfan Fiuza de Carvalho
authors: SF
authors: Dekon
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002710:Chlorhexidine; D003819:Denture Bases; D004202:Disinfectants; D004203:Disinfection / Q000379:methods; D006244:Hardness; D008422:Materials Testing; D008872:Microwaves; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D004202:Disinfectants; D002710:Chlorhexidine