IADR Abstract Archives
Monomer conversion in dual-cured core build-up materials
Methods: The materials tested were Clearfil DC Core Automix (CD), Cosmecore DC (CM), LuxaCore DC (LX) and MultiCore DC Flow (MC). Clearfil Core New Bond (CN, chemically-cured) and Clearfil Photo Core (CP, light-cured) were used as a control. Specimens (Ø: 4mm, d: 1mm, n=4 ) prepared without light-exposure were tested after 10, 20, 30min and 1h storage in dark and dry conditions (37oC). Specimens light-cured immediately after mixing (700mW/cm2 intensity, 20s exp) served as reference. The amount of remaining C=C bonds (%RDB) was measured on bottom surfaces by ATR-FTIR spectroscopy. Two-way ANOVA and multiple comparison tests were used to evaluate the statistically significant differences (a: 0.05).
Results: The %RDB values (mean/SD) are given below (same superscripts indicate mean values with no statistically differences, p<0.05):
|
TIME |
CD |
CM |
LX |
MC |
|
10 min |
97.52 (1.55) |
92.46 (0.75) |
56.11 (0.75)b |
59.92 (0.43) |
|
20 min |
64.27 (1.50) |
79.15 (1.14) |
53.73 (1.32)b,c,1 |
55.91 (0.26)e,f,1 |
|
30 min |
51.69 (0.97)a,2 |
67.60 (1.46) |
51.34 (1.70)c,d,2 |
54.64 (0.65)e,f,2 |
|
1 h |
49.73 (1.32)a,3 |
63.37 (0.95) |
50.04 (1.05)d,3 |
51.92 (1.05)f,3 |
|
LC |
50.57 (0.68)a,4 |
51.53 (0.39)4 |
48.17 (0.51) |
56.03 (0.33)e |
CD and LX reached the level of irradiated specimens.
Conclusions: Some dual-cured core build-up materials demonstrate a very slow chemically initiation mechanism, that leads to low conversion at areas distal to the activating light, providing thus a weak core structure during the early setting stages.