Methods: Titanium nanoparticle (20nm) was synthesized by sol-gel method and incorporated in dental polymeric matrix (BisGMA: TEGDMA: UDMA 40:40:20 m/m, and BAPO photoiniciator) at 0,5% and 5%.A sample of the uncured paste of each composite was smeared on FTIR-ATR selenite crystal and polymerized by Led light source (1200 mW/cm2) for 60s, in situ. Degrees of conversion of polymeric matrix without filler (M), dental composite with 0.5% titanium nanoparticle (M0.5%) and dental composite with 5% titanium nanoparticle (M5%) were analyzed in the uncured and cured samples after 20, 40, 60 and 80s by real-time Attenuated Total Reflection Infrared spectroscopy (FTIR-ATR), resolution of 4cm-1 and 20 scans.
Results: After 20s of light polymerization, the sample M had a DC of 34%; M0.5% of 38% and M5% of 2%. After 80s M5% had the lower degree of conversion: 34% against 43% for M and 45%, for M0.5% respectively.
Conclusion: The increased absorption and scattering of light of the titanium nanoparticles decreased the transmittance of the composite. Optical characteristic of nanofiller in dental composite is a factor that affected the degree of conversion.