Method: Degree of conversion (%DC) was monitored using the Fourier Transform Infrared Spectroscopy (FTIR). A Teflon device with a central orifice correspondent to the posts geometry was produced to simulate the root canal. The device consists of 5 rings (2mm in height each) that enable measure %DC in 10, 8, 6, 4 and 2 mm of the posts, and a last ring (1mm in height and 1.5mm of central orifice) where self-adhesive resin cement was set. The device was placed on spectrometer sample holder; cement was manipulated according manufactory instructions and after chemical polymerization (3 minutes) it was light-activated. Halogen and LED light was tested. Data were submitted to homogeneity analysis and 3-Way Anova test (p<0.05)
Result: Table 1 shows means and standard deviation of %DC for fiberglass post and polymerization lights. Great depths showed smaller %DC for all posts.
Table 1. Means and standard deviation of DC(%)
Depth (mm) |
Fiber Post |
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Exacto nº3 |
White Post nº3 |
D.T. Translucent nº3 |
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Light |
Light |
Light |
||||
Halogen |
LED |
Halogen |
LED |
Halogen |
LED |
|
2 |
46.2±10.8Aa |
38.4±8.9BCa |
36.6±6.7BCa |
39.3±4.8Ba |
32.3±4.8Ca |
40.3±6.4ABa |
4 |
44.8±14.5 Aa |
36.1±4.2Ba |
27.8±3.3Cb |
32.1±2.8BCb |
28.9±4.1Ca |
30.0±5.8BCb |
6 |
36.7±6.7Ab |
36.7±5.5Aa |
25.4±5.5Bb |
29.3±3.5Bb |
31.8±2.9ABa |
29.6±7.3Bb |
8 |
36.9±5.5Ab |
34.5±5.7Aa |
16.1±5.9Cc |
20.2±8.6BCc |
25.9±6.4ABa |
20.9±1.5BCc |
10 |
30.5±10.4Ab |
33.3±7.1Aa |
17.2±8.1Cc |
21.3±6.0BCc |
29.4±3.4ABa |
26.2±5.1Bbc |
Different letters (capital letters. comparison among rows; lower case letters. comparison among columns) indicate statistical difference (p<0.05).
Conclusion: Translucent fiberglass posts are able to transmit light to cure self-adhesive resin cement and the length of the post interfered negatively in the cement polymerization.