NORMAL MICROBIOTA ON THE TEETH OF PRESCHOOL-CHILDREN

Plaque samples from nine healthy, preschool children were gathered fro m the labial and lingual surfaces of primary maxillary and mandibular incisors and the occlusal fissures of primary maxillary first molars o ver a 16 mth period. Samples were dispersed, serially diluted and cult ivated on non-selective and a variety of selective media. Representati ve colony types were counted, subcultured and microorganisms identifie d using morphological, physiological, serological and acid end-product analyses. Non-parametric statistical methods, including a permutation analysis, were used to analyse the data. The communities on each surf ace were much more complex than has been reported previously. Streptoc occus was the dominant genus at each surface except for the lower inci sor where Actinomyces dominated. Neisseriae was more dominant than vei llonellae at all dental surfaces. Gram-negative rods and filaments inc luding Haemophilus, Fusobacterium, Capnocytophaga, Leptotrichia and Po rphyromonas species were also present on all surfaces at varying level s and persistence. This investigation has shown that many potential or al pathogens, both dental and periodontal, are components of the comme nsal oral microbiota of preschool children and exist in the absence of overt disease.