title: Internal adaptation and some physical properties of methacrylate-based denture base resins polymerized by different techniques.
abstract: This study evaluated the internal adaptation, porosity, transverse and impact strength of three denture base polymers: (1) conventional heat-polymerized, (2) microwave-polymerized, and (3) injection-molded resins. Internal adaptation was measured by weighing a vinyl polysiloxane film reproducing the gap between the denture base and the metallic master model of an edentulous maxilla. The measurements were performed immediately after finishing and after 30-day storage in water. Porosity was evaluated by weighing each specimen in air and in water using an analytical scale balance. Transverse strength test (three-point bending test) was performed using a universal machine under axial load, at a crosshead speed of 5 mm/min. Impact strength test (Charpy's test) was performed with a 40 kJ/cm load. Data were analyzed by ANOVA and Tukey test (alpha = 0.05). Internal adaptation, porosity, transverse and impact strength varied according to the type of acrylic resin and the processing technique. The injection-molded resin showed better internal adaptation compared with the conventional heat-polymerized and the microwave-polymerized resins, particularly after 30 days, but there was no relevant improvement of porosity, transverse and impact strength.
authors.affiliation: Department of Prosthodontics, Pontifical Catholic University of Campinas, Campinas, SP, Brazil. solimar@puc-campinas.edu.br
authors.forename: Solimar M
authors.initials: SM
authors.lastname: Ganzarolli
authors.forename: José A Nunes
authors.initials: JA
authors.lastname: de Mello
authors.forename: Rosemary S
authors.initials: RS
authors.lastname: Shinkai
authors.forename: Altair A
authors.initials: AA
authors.lastname: Del Bel Cury
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis / Q000737:chemistry*; D003819:Denture Bases; D008422:Materials Testing; D019563:Mechanics; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D016062:Porosity
chemical_list: D000180:Acrylic Resins; D008689:Methacrylates; D011108:Polymers