Effects of PMA (A and C) and EMA (B and D) on S. mutans and S. sobrinus cell viability. A total of (A and B) 2.77 × 106 CFU of S. mutans and (C and D) 2.85 × 106 CFU of S. sobrinus were treated with 0, 2.5, 25, and 250 μM PMA and cross-linked. After PMA and EMA treatments, bacterial cells were plated on Mitis-Salivarius agar plates and counted. The mean and S.D. values of independent triplicate data are shown.