IgG antibody levels to Porphyromonas gingivalis and clinical measures in children

The ecological proportion of indigenous bacterial populations in saliva is correlated with oral health status

To obtain deeper insights into the etiology of oral disease, an understanding of the composition of the surrounding bacterial environments that lead to health or disease is required, which is attracting increasing attention. In this study, the bacterial compositions in the saliva of 200 subjects aged 15-40 years were depicted as peak patterns by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes. The subjects were classified into three clusters by partitioning around medoids clustering based on their T-RFLP profiles, and the clinical oral health parameters of the clusters were compared. The clustering of the T-RFLP profiles in this study was mainly based on differences in the abundance distribution of the dominant terminal restriction fragments (TRFs) detected in most of the subjects. Predicted from the sizes of the TRFs, the characteristically more predominant members of each were Prevotella and Veillonella species in cluster I; Streptococcus species in cluster II and Neisseria, Haemophilus or Aggregatibacter species and Porphyromonas species in cluster III. The parameters associated with periodontal disease were significantly different among the clusters. Clusters I and II had a higher percentage of sites of periodontal pockets greater than 4 mm than cluster III, and cluster I contained sites exhibiting bleeding on probing more often than cluster II or III; no significant differences were observed in other parameters. These results suggest that the abundance distribution of commensal bacteria in saliva is correlated with periodontal health, and might be involved in the susceptibility of an individual to periodontal disease.

Molecular analysis of the subgingival microbiota in health and disease

This investigation provides molecular analyses of the periodontal microbiota in health and disease. Subgingival samples from 47 volunteers with healthy gingivae or clinically diagnosed chronic periodontitis were characterized by PCR-denaturing gradient gel electrophoresis (DGGE) with primers specific for the V2-V3 region of the eubacterial 16S rRNA gene. A hierarchical dendrogram was constructed from band patterns. All unique PCR amplicons (DGGE bands) were sequenced for identity. Samples were also analyzed for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis by multiplex PCR. Associations of patient age, gender, and smoking status together with the presence of each unique band and putative periodontal pathogens with disease were assessed by logistic regression. Periodontal pockets were colonized by complex eubacterial communities (10 to 40 distinct DGGE bands) with substantial individual variation in the community profile. Species diversity in health and disease was determined by the Shannon-Weaver index of diversity and compared by the Mann-Whitney U test. Sequence analyses of DGGE amplicons indicated the occurrence of many nontypical oral species and eubacteria previously associated with this environment. With the exception of T. forsythensis, the putative pathogens were not detected by DGGE. Multiplex PCR, however, detected T. forsythensis, A. actinomycetemcomitans, and P. gingivalis in 9% 16%, and 29% of the patients with disease, respectively. The presence of A. actinomycetemcomitans was significantly associated with disease (P < 0.01). Statistical analyses indicated that the presence of Treponema socranskii and Pseudomonas sp. was a significant predictor of disease (P < 0.05) and that there was no significant difference (P > 0.05) in terms of eubacterial species diversity between health and disease.

The Relationship BetweenPorphyromonas gingivalisInfection and Local and Systemic Factors in Children

BACKGROUND

Porphyromonas gingivalis (P. gingivalis) is a major pathogen related to periodontitis. There are few reports on the prevalence and effect of P. gingivalis in children. The purpose of the present study was to describe in children the level of DNA-P gingivalis in subgingival plaque and the IgG serum reactivity to P. gingivalis (IgG-Pg), and examine their relationship to demographic, systemic, and oral variables.

METHODS

Thirty-four children, aged 1.83 to 13.42 years, were included in the study; 16 with no systemic disease and 18 with systemic conditions. The demographic data for caries incidence, plaque and gingival indices, probing depth, and alveolar bone height were recorded. The IgG-Pg and DNA-Pg levels were determined by enzyme-linked immunosorbent assay and DNA-DNA hybridization, respectively. The relationships between the IgG-Pg and DNA-Pg values to the demographics, oral parameters, and systemic conditions were examined.

RESULTS

IgG-Pg was evident in 53% of the children and DNA-Pg in 47%. IgG-Pg values significantly correlated positively with age, plaque index, and bone height. DNA-Pg values had statistically significant positive correlations with age. IgG-Pg and DNA-Pg values correlated with probing depth among children with systemic diseases. Neither the IgG-Pg nor the DNA-Pg values had a significant correlation to systemic conditions. Multiple regression analyses indicated that only age remained significantly related to IgG-Pg and DNA-Pg values.

CONCLUSIONS

P. gingivalis can be found in significant levels in the plaque of young children and elicits an immune reaction that increases with age and may be related to incipient signs of periodontal disease. Plaque DNA-Pg and serum IgG-Pg levels correlate significantly.