Microbial Community Succession on Developing Lesions on Human Enamel

Objectives: White spot lesions were generated in vivo on human teeth that were predetermined to be extracted for orthodontic purposes.  This in vivo model was used in a longitudinal cohort study to investigate shifts in the microbial community composition associated with the development of enamel caries.  Methods: The bacterial microbiota on sound enamel and on developing carious lesions were identified using the Human Oral Microbe Identification Microarray (HOMIM), which permits the detection of about 300 of the approximate 700 predominant bacterial species in the oral cavity.  Results: After only 7 weeks, 87% of targeted teeth developed white spot lesions (8 individuals, 16 teeth).  The microbial community composition of the plaque over white spot lesions differed significantly as compared to sound enamel.  Twenty-five bacterial taxa, including Streptococcus mutans, Atopobium parulum, Dialister invisus, and species of Prevotella and Scardovia, were significantly associated in plaque on initial enamel lesions.  In contrast, 14 bacterial taxa, including species of Fusobacterium, Campylobacter, Kingella, and Capnocytophaga, were significantly associated in plaque on sound enamel.  Conclusions: The bacterial community composition associated with the progression of enamel lesions is specific and much more complex than previously believed.  The in vivo model of generating lesions on teeth destined for extraction in conjunction with HOMIM analyses represent an opportunity to study succession of supragingival microbial communities associated with caries development and to study efficacy of prophylactic and restorative treatments.