Microbiome Shifts in the Supragingival Biofilm in Orthodontic Patients

Orthodontic treatment increases risk of caries and periodontal disease. To evaluate whether introduction of fixed appliances induces dysbiotic shifts in the supragingival biofilm, we conducted a longitudinal study of adolescent orthodontic patients using next-generation sequencing methods. Twenty four patients had clinical measures and plaque samples collected before bonding and at 1, 6 and 12 weeks thereafter. Overall, gingival health worsened over time relative to baseline. Plaque and saliva samples have distinct microbiomes. Alpha diversity did not change significantly over time. Biofilm taxonomic diversity significantly decreased in RNA from baseline pre-treatment to one week post-bonding, African-Americans show distinct characteristics of their microbiome relative to other ethnic populations. Initial evidence suggests that in healthy individuals, a dysbiotic shift in both phylogenetic diversity and metatranscriptomic activity of supragingival oral biofilm occurs after the introduction of fixed orthodontic appliances. Further study is needed to determine significance, reveal therapeutic targets and assess for novel interventions.