Sulcal-surface carious lesions in singly infected, coinfected, or uninfected animals. Sulcal-surface caries scores are presented as mean values ± standard deviations (n = 11). Scores are recorded as stages of carious lesion severity according to Larson's modification of Keyes' scoring system: Ds, initial lesion (surface enamel white, broken and/or dry); Dm, moderate lesion (dentin exposed); Dx, extensive lesion (dentin soft or missing). Asterisks indicate that the values for different experimental groups are significantly different from each other (P, <0.05).