Effect of packing types on the dimensional accuracy of denture base resin cured by the conventional cycle in relation to post-pressing times.
This study investigated the dimensional stability of denture bases influenced by packing methods, in relation to post-pressing times, in the Clássico acrylic resin which was prepared according to manufacturer recommendations. Forty maxillary wax bases were made and randomly assigned into 2 groups of 20 specimens each according to the conventional and RS system packing methods. In each method, the specimens were subdivided into immediate, 6, 12 and 24 h post-pressing times. The dough of the acrylic resin was packed in metallic flasks and processed in a water bath curing cycle at 74 masculine C for 9 h. After cooling at room temperature, the bases were removed from the flasks, finished and fixed on stone casts with instantaneous adhesive. The resin base-stone cast sets were transversally sectioned into 3 sections and the base-stone gap measured at 5 points in each section. The data were submitted to ANOVA and Tukey's test, which showed that the RS system had a smaller base distortion compared to conventional packing, with the exception of the 24-h post-pressing time. There was a statistically significant difference between the packing methods only in section C (posterior palatal zone). In the conventional packing method, the immediate and 6 h times demonstrated values with no statistically significant difference between them, as well as between the 12 and 24 h post-pressing times.
Department of Prosthodontics, School of Dentistry of Piracicaba, UNICAMP, Piracicaba, SP, Brazil. rconsani@merconet.com.br
Rafael Leonardo Xediek
RL
Consani
Saide Sarckis
SS
Domitti
Marcelo Ferraz
MF
Mesquita
Simonides
S
Consani
D000180:Acrylic Resins / Q000737:chemistry*; D000269:Adhesives / Q000737:chemistry; D003735:Dental Casting Technique; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing; D003819:Denture Bases; D006801:Humans; D008422:Materials Testing; D008437:Maxilla; D008689:Methacrylates / Q000737:chemistry; D003765:Models, Dental; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011312:Pressure; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D000269:Adhesives; D003764:Dental Materials; D008689:Methacrylates; D014867:Water; C038690:Loctite; D019904:Polymethyl Methacrylate