Avaliação da microbiota gengival e subgengival de seres humanos por PCR

Abstract

The indigenous microbiota plays an important role in health and disease. The human oral cavity is a complex biological system in which members of a diverse microbial community interact with themselves as well as with host structures and components. Members of this community change along lifetime and are diverse in different parts of the world, due to specific population habits and genetic characteristics. In order to understand better the alterations of the oral microbiotaassociated with age, we investigated the presence of the periodontopathogens Agregatibacter actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Tannerella forsythia and Treponema denticola, by PCR, in gingival/subgingival specimens obtained from 237 subjects with no clinical evidence of gingival/ periodontal lesions: 14 children before teeth eruption/A, 47 children 3-5years old/B, 42 individuals from 7-10 years of age/C, 34 adolescents/D, 20 individuals with age ranging from 20-45 years/E, 19 adults older than 45 years/F, 48 edentulous individuals with no total prosthesis/G and 13 individuals with tooth implant/H. A. actinomycetemcomitans, E. corrodens, F. nucleatum, P. gingivalis, P. intermedia, P. nigrescens, T. forsythia and T. denticola were detected in specimens obtained from 116/48,9%, 79/33,3%, 155/65,4%, 0/0%, 2/0,8%, 21/8,8%, 46/19,4%and 36/15,2% individuals, respectively. A. actinomycetemcomitans and F. nucleatum were the only organisms found in all groups studied. In the group A, only these organisms were observed. P. intermedia was identified in the groups C and E only. Individuals with tooth implant had a periodontopathogen profile similar to that found in adults of the groups E and F and a higher organism diversity when compared with edentulous ones. Synergistic associations were found between F. nucleatum/T.forsythia, F. nucleatum/P. nigrescens, F. nucleatum/E. corrodens and F.nucleatum/A. actinomycetemcomitans. Mutual antagonist relationships were detected among T. denticola/P. intermedia/P.nigrescens, T. forsythia/ P. intermedia, P. intermedia/F. nucleatum. Antagonist associations between T. denticola/F. nucleatum, T. denticola/ E. corrodens, T. denticola/A. actinomycetemcomitans, T. forsythia/F.nucleatum, T. forsythia/E. corrodens, T. forsythia/A. actinomycetemcomitans, P. intermedia/E. corrodens, P. intermedia/A. actinomycetemcomitans, P. nigrescens/T. forsythia, P. nigrescens/F. nucleatum, P. nigrescens/E. corrodens and P. nigrescens/A. actinomycetemcomitans were observed. In conclusion, oral microbiotais more diverse after teeth eruption, probably due to environmental alterations induced by this event and to alimentary changes that occur simultaneously. Synergistic associations observed between F. nucleatum and four out of the six periodontopathogens detected reinforces the hypothesis that this organism plays animportant role in the development and maintenance of the oral microbiota. This investigation is the first study that employs PCR to analyse the oral microbiota constitution in different age groups in a Brazilian population and, also, to study the association between periodontopathogens in individuals with no evident periodontal20 lesions.