The acquisition of Porphyromonas gingivalis was examined in a cross-se
ctional study of 198 subjects from 0 to 18 years of age using a PCR-ba
sed assay. P. gingivalis was detected in the oral cavities of 37% of s
ubjects and at similar frequencies among subjects of all ages. These d
ata indicate that P. gingivalis may be acquired in the first days of l
ife.