Familial Oral Microbial Imbalance and Dental Caries Occurrence in Their Children.

Objective: Develop a familial liability index for oral microbial status that reflects an imbalance of oral domains based on the presence of risk indicators in saliva, inter-proximal plaque, tongue, and throat.

Methods: Fifty-six mother-child pairs from Webster and Nicholas counties, West Virginia, USA, participated in this study. Saliva samples were assayed for mutans streptococci (MS), interproximal plaque samples for the BANA Test (BT) species, tongue swabs for BT, and throat swabs for any of the sentinel organisms (Staphylococcus aureus, Streptococcus pyogenes, and yeasts). The corresponding thresholds for a (+) risk indicator were, respectively, ≥10⁵ CFU of MS salivary levels, one or more BT-(+) plaques (>10⁵ CFU/mg of plaque of at least one of BT-(+) species), weak-(+) BT for a tongue swab (>10⁴-<10⁵), and >10⁴ CFU/swab for any of the sentinel markers.

Results: The mean age of mothers and children was 41.6 and 14.6 years. Ninety-one % of both mothers and children had at least one (+) risk indicator. Overall, 76% of mother child-pairs had at least one (+) concordant oral microbial risk indicator. Accordingly, the relative risk (RR) of children having concordant results with their mothers was increased 1.36 (BT-plaque), 1.37 (BT-tongue), 0.94 (sentinel organisms) and 1.13 (MS) times. Principal component analysis revealed distinct sets of oral microbial risk indicators in mothers and children that correlated with dental caries prevalence rates in children.

Conclusions: Mother-child pairs shared similarities of oral microbial risk indicators that allow for the development of a liability index that can elucidate caries in the children.