Method: Three experimental groups were prepared by mixing different ratios of powdered (polymethylmethacrylate and sodium fluoride; 9:1, 8:2 and 7:3 wt) with liquids (methylmethacrylate and 2-hydroxyethylmethacrylate), camphorquinone and DMAEMA. Different concentrations (10%, 20%) of acetone were added to decrease the viscosity of the experimental materials. FTIR was used to measure degree of conversion (DC%) and ion selective electrode to measure fluoride release. Data were analysed using Mann-Whitney test (p<0.05).
Result:
After 80 second light curing all groups with 20% acetone achieved higher DC% than 0% acetone except 7:3 (p<0.05). Fluoride release at day 1 was greater with 20% acetone for all groups except 7:3 (p<0.05). All groups continued to release fluoride at day 70 with 20% acetone groups releasing higher fluoride compared to those with 0% acetone.
Experiments
|
Groups (acetone% wt) |
|||||||||
9:1 |
8:2 |
7:3 |
||||||||
0% |
10% |
20% |
0% |
10% |
20% |
0% |
10% |
20% |
||
DC% at 80sec. |
48 (3.4)a |
54 (6.6)a |
59 (0.5) |
40 (10.6) |
52 (4.8)b |
55 (1.8)b |
53 (3.6)c |
54 (1.5)c |
55 (4.5)c |
|
Fluoride release (µg/cm2/day) |
Day (1) |
122 (22) |
149 (22)d |
176 (17)d |
308 (21) |
457 (32)e |
457 (28)e |
505 (163)fg |
579 (48)f |
497 (46)g |
Day (70) |
0.3 (0.1)h |
0.5 (0.3)hi |
1.2 (0.3)i |
1.6 (0.3)j |
1.1 (0.5)j |
6.3 (1.6) |
3.1 (1.8) |
8.0 (4.5)k |
8.7 (2.1)k |
|
Median (IQR). Superscript letters indicate no significant difference.
Conclusion: Acetone may be a suitable solvent to reduce the viscosity of the acrylic resin as it has no significant detrimental effect on either degree of conversion or fluoride release.