Figure 8

Quantification of hydroxyl radical spin adducts generated via LED irradiation of titanium specimens (Ti) immersed in 3% H2O2 or pure water. Analysis was performed using the electron spin resonance spin-trapping technique using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap agent. The yield of DMPO-OH, a spin-adduct of hydroxyl radicals, (a) after treatment for 15 s and (b) 5 min. Irradiation with 365 nm LED of titanium specimens immersed in 3% H2O2 [H(+)L(+)] for 15 s generated 81.6 µM DMPO-OH, whereas other treatments generated only trace levels (<0.2 µM DMPO-OH). Values and error bars indicate the mean and standard deviation, respectively (n = 3). Different letters above the columns refer to significant differences (p < 0.01) between different groups. H(−)L(−), treatment with pure water in a light-shielding box; H(+)L(−), treatment with 3% H2O2 in a light-shielding box; H(−)L(+), 365-nm LED irradiation of sample in pure water; H(+)L(+), 365-nm LED irradiation of sample in 3% H2O2.