Background: Fluoridated acrylic resin material can present more stable properties when compared with
conventional one.The most widely used fluoride –containing substance added to dental resin materials is sodium
fluoride (Naf). This study evaluated the effect of Naf in different concentration to the acrylic resin denture base
material and its effect on tensile strength ,modules of elasticity with long –term water immersion (after 4 months
immersion in de-ionized water)
Materials and methods: Eighty specimens from dumbbells shaped metal pattern for tensile strength test were
preparedaccording to ISO 527: 1993 plastic –Determination tensile properties ,in dimensions(60mm, 12mm, 3 ±
0.2mm) length, width and depth respectively were allocated to two groups according to water immersion there
were 40 specimens before immersion and 40 specimens after water immersion for 4 months in de-ionized water(the
de-ionized water was changed every day),these two groups were sub divided in to four groups according to the
concentration of Naf,Naf powder were added to monomer of acrylic in concentrations of 1%,2%and 5% Naf .0%
Naf(control group) ,then mixing were done with polymer according to manufacture instructions ,the conventional
flasking ,packing procedure were used following that (fast cycle). For tensile strength test the measuring was done
by Instron machine, the values of modulus of elasticity were obtained from tensile test.
Results: Results showed that the addition of sodium fluoride to acrylic resin material werelower the tensile strength
and modules of elasticity with highly significant differences p<0.01 when compared to control group regardless the
concentration of Naf,But after immersion (for 4 month ) the tensile strength and modules of elasticity increased in
comparison to groups before immersion (with highly significance differences p <0.01 ), highly significance differences
(p <0.0)were found between groups after and before immersion in all concentrations except for tensile strength
between 1%Naf and 2%Naf after immersion there was no significant differences(p>0.05), and for modules of
elasticity between control and 1%Naf, 1% Naf and 2%Naf( after immersion ),there was only significant differences
between them(p<0.05).
Conclusions: Addition of fluoride to acrylic resin material lower the tensile strength and modules of elasticity when
compared to control group regardless the concentration of Naf, But after immersion (for 4 months ) the tensile
strength and modules of elasticity increased in comparison to groups before immersion (with highly significance
differences p <0.01) |