Influence of various metal oxides on mechanical and physical properties of heat-cured polymethyl methacrylate denture base resins.
OBJECTIVE
To evaluate the effect of various metal oxides on impact strength (IS), fracture toughness (FT), water sorption (WSP) and solubility (WSL) of heat-cured acrylic resin.


METHODS
Fifty acrylic resin specimens were fabricated for each test and divided into five groups. Group 1 was the control group and Group 2, 3, 4 and 5 (test groups) included a mixture of 1% TiO2 and 1% ZrO2, 2% Al2O3, 2% TiO2, and 2% ZrO2 by volume, respectively. Rectangular unnotched specimens (50 mm × 6.0 mm × 4.0 mm) were fabricated and droptower impact testing machine was used to determine IS. For FT, compact test specimens were fabricated and tests were done with a universal testing machine with a cross-head speed of 5 mm/min. For WSP and WSL, discshaped specimens were fabricated and tests were performed in accordance to ISO 1567. ANOVA and Kruskal-Wallis tests were used for statistical analyses.


RESULTS
IS and FT values were significantly higher and WSP and WSL values were significantly lower in test groups than in control group (P<.05). Group 5 had significantly higher IS and FT values and significantly lower WSP values than other groups (P<.05) and provided 40% and 30% increase in IS and FT, respectively, compared to control group. Significantly lower WSL values were detected for Group 2 and 5 (P<.05).


CONCLUSIONS
Modification of heat-cured acrylic resin with metal oxides, especially with ZrO2, may be useful in preventing denture fractures and undesirable physical changes resulting from oral fluids clinically.
Department of Comprehensive Dentistry, Dental School, University of Texas Health Science Center at San Antonio, Texas, USA. ; Department of Prosthodontics, Dental School, Gazi University, Ankara, Turkey.
Neset Volkan
NV
Asar
Hamdi
H
Albayrak
Turan
T
Korkmaz
Ilser
I
Turkyilmaz
Metal-oxide; Polymer; Reinforcement; Water sorption and solubility