Previous studies have shown the oral microbiome stays stable unless it is disturbed by medication, disease, low pH, or significant changes in diet. Dysbiosis of the oral microbiome by colonization of aciduric and acidophilic bacteria is associated with dental caries. In a clinical study published in 2015 in the Journal of Dental Research Johansson et al aimed to “evaluate the tooth microbiota in adolescents with high prevalence of caries and who never had access to dental care and the microbiota of another population who had systematic dental care and preventive measures from early childhood and who remained caries free or had a low prevalence of caries.”1
Participants consisted of 17-year-old adolescents from Sweden that had access to dental care. They were recruited from a Public Dental Health Clinic with 28 being caries free with no sign of disease and 36 had high caries risk. In Romania, school children aged 14-15 (n=14) with limited dental care, receiving treatment only directed at pain relief, were selected for microbial analysis.
The children selected from Romania were approximately 2.5 years younger than the group selected from Sweden, on average the Romanian children also had 1 less tooth than the Swedish adolescents. The Romanian children had a significantly higher prevalence of caries than the Swedish adolescents, even when compared to the high-risk caries Swedish group. S. mutans were detected in 86% of the Romanian children, while 50% of the children had S. mutans and S. sobrinus. The Swedish cohort had a 48% incidence of S. mutans and 0% had S. mutans and S. sobrinus.
Though the microbial composition between the cohorts was significantly different, a core microbiome of 24 taxa was identified. S. sobrinus and S. mutans were strongly associated with increased caries rates. Additionally, an interesting feature of this study was that the Romanian children received minimal dental care and could be considered as a representation of the oral microbiome unaltered by oral hygiene practices and fluoride exposure. Romanian children did not brush regularly, if at all indicating the composition of their biofilms were more mature.
Notably, most caries studies have focused on caries in the primary dentition, whereas this study expands the knowledge to permanent teeth, keeping in mind that pellicle and colonizing bacteria differ between the primary dentition and permanent dentition.
In this study both S. sobrinus and S. mutans were highly associated with caries, with a conspicuously high prevalence of S. sobrinus alone in the Romanian children. Interestingly, 15% of the Romanian cohort and 30% of the Swedish cohort had no detectable S. mutans. As a matter of fact, S. mutans were less frequent and S. sobrinus was rarely detected among the Swedish cohort that received regular dental care and anticaries preventative treatments from early childhood. These findings suggest that regular dental care from early childhood may reduce the bacterial load of S. mutans.
The authors conclude by stating, systematic, long-term dental care appears to affect the microbiota in a population over time.”
Have you considered the complexity of determining which bacterium are most associated with dental caries? Do you offer services that provide an analysis of your patient’s oral microbiome? Do you think services that provide a breakdown of the patient’s oral microbiome are helpful in treating patients?
- Johansson I, Witkowska E, Kaveh B, Lif Holgerson P, Tanner AC. The Microbiome in Populations with a Low and High Prevalence of Caries. J Dent Res. 2016;95(1):80-86. doi:10.1177/0022034515609554
