Methods: Adhesive containing HEMA, acidic functional monomer and UDMA was prepared. Percent of CQ was chosen experimentally and added to adhesive. Each co-initiator was added to adhesive that already contained CQ. The degree of conversion after 20sec of light cure was defined and calculated
Results: 0.4% of CQ was chosen as optimal quantity for better results of the DC of adhesive (table 1).
Table 1 - Quantity of CQ and corresponding DC of adhesive
|
Quantity of CQ |
|||||
0.10% |
0.20% |
0.30% |
0.40% |
0.50% |
0.60% |
|
DC of adhesive, % |
48 |
52 |
54 |
57 |
57 |
57 |
The all co-initiators were added to the adhesion solution that previously contained 0.4% of CQ (table 2).
Table 2 - Quantity of different co-initiators and corresponding DC
EDB |
0.1% |
0.2% |
0.3% |
0.4% |
0.5% |
0.6% |
DC, % |
48 |
52 |
57 |
58 |
58 |
58 |
Irgacure 819 |
0.5% |
1.0% |
2.0% |
3.0% |
3.5% |
4.0% |
DC, % |
67 |
70 |
74 |
75 |
75 |
75 |
Lucirin TPO |
0.5% |
1.0% |
1.5% |
2.0% |
2.5% |
3.0% |
DC, % |
64 |
69 |
72 |
73 |
73 |
73 |
DPIHP |
0.4% |
0.6% |
0.8% |
1.0% |
1.2% |
1.5% |
DC, % |
54 |
62 |
72 |
74 |
74 |
74 |
Conclusions: Addition of Ethyl-4-dimethylaminobenzoate to CQ-contains system did not show improvement in DC of adhesive. Whereas, addition of the Irgacure 819, or Lucirin TPO, or DPIHP to the CQ-contains system revealed dramatic improvements in DC of the adhesive. Thus, using these co-initiators may increase significantly the mechanical properties of adhesives and as result of this has excellent potential to improving adhesion properties of the dental adhesives.