Childhood Caries Increased With Concurrent Streptococcus mutans and Scardovia wiggsiae

Objectives: To examine the association between caries experience and bacterial load in children from Queensland, Australia, attending community dental clinics.
Methods: Salivary samples were collected from 158 6-7 year old children with caries, who are enrolled into an on-going multi-centre trial. Bacterial DNA was extracted and the prevalence and bacterial load of 14 species determined using a custom-made quantitative polymerase chain reaction array. Caries experience was assessed by the number of decayed, missing, and filled teeth using WHO criteria.
Results: Ten of the species (Actinomyces odontolyticus, Actinomyces viscosus, Capnocytophaga gingivalis, Neisseria flava, Scardoiva wiggsiae, Streptococcus mitis, Streptococcus mutans, Streptococcus sanguinis, Streptococcus salivarius/thermophilus and Veillonella dispar) were highly prevalent, the other four (Bifidobacterium dentium, Lactobacillus casei/paracasei/zeae, Lactobacillus acidophilus, and Streptococcus sobrinus) less so. S. mutans and S. wiggsiae occurred concurrently in 49% of the children. A further 26% recorded S. mutans alone, 14% S. wiggsiae alone, and 11% recorded neither. The mean caries experience of children positive for S. mutans and S. wiggsiae concurrently (5.31 ± 3.34) was higher than for those positive for either S. mutans alone (3.65 ± 2.47), S. wiggsiae alone (3.09 ± 2.05), or those negative for both species (2.83 ± 2.12) (p=0.027, p=0.010, p=0.007 respectively). It was only for each of the species S. mutans and S. wiggsiae that there was a positive correlation between caries experience and bacterial load (r=0.407, p<0.001 and r=0.258, p=0.001 respectively).
Conclusions: The high rate of detection of S. wiggsiae in combination with S. mutans, and the associations with childhood caries experience, may reflect cooperation between these two species. This study is supported by the CRC Oral Health and GC Corporation.