@inproceedings{schneider10,
  author = {L. F. Schneider and L. M. Cavalcante and S. A. Prahl and J. Ferracane},
  title = {Trimethylbenzoyl-diphenyl-phosphine Oxide as Photoinitiator in Dental Resins and Composites},
  booktitle = {IADR/AADR/CADR 88th General Session},
  year = {2010 abstract only},
  volume = {89A},
  abstract = {\textit{Objectives}: Since photoinitiator systems for dental resins based on camphorquinone (CQ) present color disadvantages, trimethylbenzoyl-diphenyl-phosphine oxide (TPO) could be a substitute. However, there are remaining considerations about its curing efficiency. The aims of the present investigation were: to characterize the relationship between the photoinitiator absorption spectra and the light spectrum emitted from a QTH light (Absorbed power density, PD$_{\mathit{abs}}$); and to evaluate the kinetics of polymerization and the degree of conversion (DC) at different depths for unfilled and filled dimethacrylate resins.\\[3mm] \textit{Methods}: CQ+EDMAB (control); TPO and TPO+EDMAB were used in 50:50 Bis-GMA/TEGDMA resins. Photoinitiator absorption and QTH-light emission were evaluated using a spectrophotometer, kinetics of polymerization with differential scanning calorimetry (DSC), and DC at top and bottom surfaces of 2\,mm thick discs via FTIR ($n=3$). One way ANOVA/Tukey's ($p<0.05$) was used to analyze the results from DSC and two-way ANOVA/Tukey's ($p<0.05$) for those from FTIR.\\[3mm] \textit{Results}: CQ presented higher PD$_{\mathit{abs}}$ than TPO (364 and 223\,mW/cm$^3$, respectively). The DSC revealed that TPO and TPO+EDMAB produced a faster reaction than CQ+EDMAB. There were no differences for DC among the photoinitiators for unfilled materials, whereas only the combination TPO+EBMAB was able to produce similar DC as CQ+EDMAB for filled materials.\\[3mm] \begin{tabular}{l|cccccc} Group tested & \multicolumn{2}{c}{DC(\%) and $R_P^{\mathit{max}}$ (\%/s) by DSC} & \multicolumn{2}{c}{DC(\%) by FTIR in unfilled resins} & \multicolumn{2}{c}{DC(\%) by FTIR in composites}\\ \hline & DC & $R_P^{\mathit{max}}$& Surface & 2\,mm depth & Surface & 2\,mm depth\\ CQ+EDMAB & $59\pm1^b$ & $3.8\pm0.0^b$ & $70\pm2$ & $73\pm4$ & $54\pm1^a$ & $52\pm3^a$\\ TPO & $62\pm1^a$ & $6.0\pm0.2^a$ & $70\pm3$ & $69\pm1$ & $48\pm2^b$ & $46\pm1^b$\\ TPO+EDMAB & $64\pm2^a$ & $6.6\pm0.4^a$ & $72\pm2$ & $70\pm3$ & $56\pm2^a$ & $51\pm4^a$\\ \hline \multicolumn{7}{l}{\it Different lower case letters in each column means statistically significant differences.} \end{tabular} \vskip2mm \textit{Conclusions}: CQ presented higher PD$_{\mathit{abs}}$ than TPO, but TPO exhibited higher reactivity. DC was similar for unfilled resins. For composites, TPO alone produced lower DC, but the combination TPO+EDBMA produced similar DC as CQ+EDMAB at the surface and 2\,mm deep.},
}