The prevalence of spirochetes in the subgingival microbiota of Tanzanian and Dutch children.

The subgingival microflora of 71 Tanzanian and 77 Dutch prepurberty children was analyzed by dark-field microscopy. Spirochetes were observed in almost every Tanzanian child and in 66% of the Dutch children. The predominant spirochetes were small and medium sized; large spirochetes were infrequently observed in the rural Tanzanian children and at the bleeding sites of the Dutch children. Further differences in the %s of cocci, rods and fusiforms indicated that the subgingival microflora of Tanzanian children is different from that of Dutch children. Generally, spirochetes occurred at higher %s and frequency at bleeding sites than at non-bleeding sites in both populations. However, the non-bleeding sites in the Tanzanian children had a higher prevalence of spirochetes than the bleeding sites in Dutch children. It is concluded that spirochetes are members of the normal flora of prepuberty children, that in children gingivitis is associated with increased proportions of spirochetes and that the presence of spirochetes in the gingival crevice is not dependent upon gingival inflammation.