An Original Theoretical Model of the Microbiome-Mediated Pathogenesis of Severe Childhood Dental Caries in West African Populations

The oral microbiome's role in severe early childhood caries is characterised in European and North American populations, but the specific microbial communities, ecological shifts, and host-microbiome interactions mediating ECC in West African children with distinct dietary patterns require original theoretical and empirical investigation. This study developed and empirically grounded an original theoretical model of microbiome-mediated ECC pathogenesis in West African children, with data from Nigerian children in Enugu and Kano States. A combined theoretical and experimental methodology was employed. Systematic review of ECC microbiome literature (62 publications from 2018 to 2024) was combined with original 16S rRNA amplicon sequencing of oral microbiome samples from 30 ECC-active, 30 ECC-free, and 30 caries-free controls in each zone (180 samples total). Carious dentine and saliva samples were collected. Alpha and beta diversity analysis, LEfSe differential abundance, and network co-occurrence analysis were performed. Results confirmed enrichment of Streptococcus mutans and Lactobacillus fermentum in ECC-active children in both zones. A novel enrichment of Scardovia wiggsiae was identified in the most severe ECC cases, a finding not previously reported in West African children. Dietary fermentable carbohydrate load significantly predicted S. mutans enrichment. Zone-specific microbiome signatures were identified, with northern children showing higher Streptococcus sobrinus enrichment. The original Microbiome-ECC Pathogenesis Model for West Africa integrates these findings with host immunity and dietary exposure inputs. Recommendations include a multi-country West African ECC microbiome consortium.

Keywords: early childhood caries, oral microbiome, West Africa, 16S rRNA sequencing, Scardovia wiggsiae