Weight loss and surface roughness of hard chairside reline resins after toothbrushing: influence of postpolymerization treatments.
OBJECTIVE
To evaluate the effect of 2 postpolymerization treatments on toothbrushing wear (weight loss) and surface roughness of 3 autopolymerized reline resins--Duraliner II (D) (Reliance Dental), Kooliner (K) (Coe Laboratories), and Tokuso Rebase Fast (T) (Tokuyama Dental)--and 1 heat-polymerized resin, Lucitone 550 (L) (Dentsply International).


METHODS
Specimens (40 x 10 x 2mm) of each material (n = 24) were prepared and divided into 3 groups: control (no postpolymerization treatment); water bath (immersion in water at 55 degrees C); and microwave (microwave irradiation). Specimens were dried until constant weight was achieved and the surface roughness (Ra) was measured. Tests were performed in a toothbrush machine using 20,000 strokes of brushing at a weight of 200 g, with the specimens immersed in 1:1 dentifrice/water slurry. Specimens were reconditioned to constant weight and the weight loss (mg) and surface roughness were evaluated. Data were analyzed by 2-way analysis of variance and followed by Tukey test (alpha = .05).


RESULTS
In the control group, the weight loss of materials D and T was lower (P < .05) than that of L. No differences among materials were found after postpolymerization treatments (P > .05). The weight loss of material T (control = 0.5 mg) was significantly increased (P < .05) after postpolymerization treatments (water bath = 1.9 mg; microwave = 1.8 mg). For materials K and T, the toothbrushed surface roughness was higher (P < .05) after microwave and waterbath postpolymerization treatments. Material L showed increased surface roughness after microwave postpolymerization treatment.


CONCLUSIONS
The toothbrushing wear resistance of L was not superior to the reline resins. The postpolymerization treatments did not improve the toothbrushing wear resistance of the materials and produced an increased surface roughness for materials L, K, and T.
Mendonça
Márcio José
MJ
West Paraná State University and Paranaense University, Brazil.
Machado
Ana Lúcia
AL
Giampaolo
Eunice Teresinha
ET
Pavarina
Ana Cláudia
AC
Vergani
Carlos Eduardo
CE
D000180:Acrylic Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003802:Dentifrices / Q000737:chemistry; D003819:Denture Bases; D003822:Denture Liners; D003823:Denture Rebasing; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D008872:Microwaves; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D013499:Surface Properties; D014099:Toothbrushing / Q000295:instrumentation; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D003764:Dental Materials; D003802:Dentifrices; D008689:Methacrylates; D011108:Polymers; C503430:Tokuso Rebase Fast; C103362:duraliner II; D014867:Water; C103363:kooliner; C040291:Lucitone