To determine H2O2 levels, 15 g of fresh pulp tissue was
homogenized in 20 mL of 5% trichloroacetic acid, filtered through
two layers of Miracloth (Textil Planas Oliverassa, Manresa, Spain)
and centrifuged at 20,000 g for 15 min at 4 C H2O2 content was
determined using the Bioxytech H2O2-560 (OXIS International Inc.,
Portland, OR USA) colourimetric assay following the manufacturer’s
instructions.