The relationship between gingivitis and colonization by Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in children

Background: Porphyromonas ging ivalis and Actinobacillus actinomycetemcomit ans are closely associated with the onset and severity of adult periodontal disease. However, little is known regarding the colonization by, and host antibody response to, these microorganisms in children. Methods: Plaque and sera were obtained from 40 healthy children, 2 to 18 ye ars old. Gingival health was assessed by the periodontal disease index (PDI ), papillary bleeding score (BS) and the modified total papillary margin at tachment index (M-PMA). P. gingivalis and A. actinomycetemcomitans in plaqu e samples were detected by slot immunoblotting (SIB). Serum antibody levels against these microorganisms were evaluated using ELISA. Results: More than 60% of the children had detectable levels of P. gingival is in their plaque. Those having detectable levels had more gingival inflam mation than those having none; however, these differences were significant only in children over the age of 12 years (PDI, BS). In contrast, while 75% of the children had detectable A. actinomycetemcomitans, there were signif icant differences in gingival inflammation associated with colonization in children from 3 to 7 years of age (PDI) and over 12 years of age (M-PMA). S erum antibody levels to P. gingivalis were inversely correlated with gingiv al inflammation in all age groups, while A. actinomycetemcomitans titers we re positively correlated with gingival inflammation only in the children ov er 12 years. No significant relationship between the presence of either A. actinomycetemcomitans or P. gingivalis and antibodies to them was found. Conclusions: Our findings show that P. gingivalis and A. actinomycetemcomit ans are readily detected as early as 3 years of age and that their presence is associated with the onset and severity of gingivitis.