Department of Physics and Chemistry, São Paulo State University, Ilha Solteira, Brazil.
J Appl Oral Sci. 2009 Nov-Dec;17(6):570-3. doi: 10.1590/s1678-77572009000600006.
This study evaluated the glass transition temperature (Tg) and degree of conversion (DC) of a light-cured (Fill Magic) versus a chemically cured (Concise) orthodontic composite.
Anelastic relaxation spectroscopy was used for the first time to determine the Tg of a dental composite, while the DC was evaluated by infrared spectroscopy. The light-cured composite specimens were irradiated with a commercial LED light-curing unit using different exposure times (40, 90 and 120 s).
Fill Magic presented lower Tg than Concise (35-84 masculineC versus 135 masculineC), but reached a higher DC.
The results of this study suggest that Fill Magic has lower Tg than Concise due to its higher organic phase content, and that when this light-cured composite is used to bond orthodontic brackets, a minimum energy density of 7.8 J/cm(2) is necessary to reach adequate conversion level and obtain satisfactory adhesion.
本研究评估了光固化（Fill Magic）和化学固化（Concise）正畸复合材料的玻璃化转变温度（Tg）和转化率（DC）。
首次使用粘弹性松弛光谱法来确定牙科复合材料的 Tg，而通过红外光谱法来评估 DC。用光固化复合试件，使用不同的暴露时间（40、90 和 120 s），用商业 LED 光固化装置进行照射。
Fill Magic 的 Tg 低于 Concise（35-84 摄氏度对 135 摄氏度），但达到了更高的 DC。
本研究结果表明，由于 Fill Magic 具有更高的有机相含量，因此其 Tg 低于 Concise，当使用这种光固化复合材料粘结正畸托槽时，需要 7.8 J/cm(2)的最小能量密度才能达到足够的转化率并获得满意的粘结效果。
