Table 2.

Scale for assessing antimicrobial activity of materials.

Characteristics of Strain Growth	Effect	Symbol of the Effect
Growth inhibition around zone >1 mm and under film	Very good activity	+++
Growth inhibition around zone <1 mm or no growth inhibition around zone and growth inhibition under sample	Good activity	++
No growth inhibition around zone and slight growth inhibition under sample	Low activity	+
No growth inhibition around zone No growth inhibition under sample	Lack of activity	−