The More Streptococcus mutans, the More Caries on Approximal Surfaces

Abstract

The relationship between the presence of S. mutans and caries on approximal tooth surfaces was studied in a group of 28 children who were 13 yr old at baseline. Surfaces (700) in the pre-molar and molar regions were studied. Sampling of S. mutans was performed with a toothpick method at the beginning of the study and after 1 and 2 yr. From bite-wing radiographs, the approximal surfaces were recorded as caries-free, decayed or restored. Progression of lesions during the 2 yr was also studied. More new caries lesions and progressive caries lesions were found on surfaces positive for S. mutans than on surfaces without, and the more S. mutans, the more lesions. Of the surfaces with positive S. mutans findings at all 3 sampling occasions 52% became carious or had caries in a progressive form. Among the surfaces with no detectable S. mutans, the corresponding figure was 8%. Of the 530 surfaces diagnosed as intact at the start of the study 80 became carious over the 3-yr period. Sixty-nine of these were S. mutans-positive at the 1st and/or 2nd sampling.