Intra-familial comparison of supragingival dental plaque microflora using the checkerboard DNA-DNA hybridisation technique.

Objective: The aims of the present study were to correlate the quantified supragingival plaque bacteria between mothers and their children and identify possible microbial associations.

Design: A total of 86 mothers and their 4- to 6-year-old and 12- to 16-year-old children participated. Pooled supragingival plaque samples were obtained from interproximal sites between teeth 16/15, 25/26, 35/36 and 46/45 in mothers and older children and teeth 55/54, 64/65, 74/75 and 85/84 in younger children. All the samples were individually analysed for their content of 18 bacterial strains using checkerboard DNA-DNA hybridisation (whole genomic probes). Microbial associations were sought using cluster analysis (dendrogram) for all three age groups together, while community ordination techniques were used for each of the three groups separately.

Results: Three complexes were formed from the dendrogram in addition to associations between these complexes and remaining bacterial strains. Principal component analysis results were similar in all three groups. The correlation analyses of bacterial counts between mothers and their children showed a significant association for most of the bacterial strains (p<0.05 or 0.01).

Conclusions: Supragingival plaque microbiota are correlated between mothers and their children. In addition, similar supragingival plaque microbial associations are present in family members..