THE ORAL GRAM-NEGATIVE ANAEROBIC MICROFLORA IN YOUNG-CHILDREN - LONGITUDINAL CHANGES FROM EDENTULOUS TO DENTATE MOUTH

Eruption of primary teeth has a great influence on the oral environmen t by providing suitable niches for bacterial colonization. The composi tion of oral gram-negative anaerobic microflora was investigated in 21 young children (mean age 32 months) with primary dentition. The bacte rial findings of samples were compared with those of the same children collected at their edentulous infant period (mean age 3 months). Duri ng the primary dentition period, 2 samples were collected from each ch ild: a sample with dental floss from gingival margin of 2 teeth and st imulated saliva pooled with a mucosal swab sample. Both samples were c ultured aerobically and anaerobically using nonselective and selective media. Prevotella melaninogenica, nonpigmented Prevotella spp., Fusob acterium nucleatum group and Capnocytophaga spp. were found in all chi ldren at the older age, whereas they occurred in edentulous mouth in 7 6%, 62%, 67% and 19%, respectively. The occurrence of Prevotella loesc heii increased from 14% to 90%, Prevotella intermedia from 10% to 67%, Leptotrichia spp. from 24 to 71%, Campylobacter (Wolinella) spp. from 5 to 43% and Eikenella corrodens from 5 to 57%. Only the occurrence o f Bacteroides gracilis and Veillonella spp. remained at about the same level. Species not isolated from the edentulous mouth, such as Prevot ella denticola, Fusobacterium spp. other than the K nucleatum group an d Selenomonas spp. were now detected in 71%, 71% and 43% of the childr en. The stability of the colonizing P. melaninogenica strain(s) in the oral cavity was determined by using ribotyping; 1-2 isolates per chil d from the edentulous infant period of 9 children and 3-15 isolates pe r child from their primary dentition period were analyzed. The P. mela ninogenica population proved to be intraindividually very heterogeneou s, but one child had the same ribotype both in the infant and child pe riod. Although a stable colonization seems to be possible already in t he edentulous mouth, new species or strains colonizing oral surfaces c reate a multiform gram-negative anaerobic microflora in young children with primary dentition.