抄録
In order to clarify how St. mutans is established in the oral cavity and transferred to other hosts, dental plaque from 78 pairs of mothers and children was examined. Bio-typing of the isolated St. mutans was performed according to a biochemical test. As a result St. mutans was isolated in 52 mother-and-child pairs(67%); 32 pairs(41%) had the same biotype of St. mutans in both mothers and children.
