Candida cells were adjusted to a density of 3 × 106 cells/mL in BHIbroth and 2 mL of these microbial suspensions were added to the coated(0, 2, 4 and 8% C. citratus oil) silicone rubber pieces for 7 days at 37 °Cin 24-well plates under aerobic conditions. Then, the biofilm formationwas determined by crystal violet staining (O'Toole, 2011) as describedbefore. Biofilm formation on the silicone rubber surface without anycoating (neither C. citratus oil-hypromellose ointment coating nor hypromellose ointment coating (vehicle alone)) was used as a positivecontrol and set as 100%. Decrease (%) in biofilm formation relative tothe positive control, was calculated using equation (1). Biofilm formation on the silicone rubber surface without any microorganism was usedas a negative control.