High-throughput DNA sequencing of microbiota at interproximal sites

The oral microbiota has been deeply studied by high-throughput sequencing techniques. This has helped scientists to understand the microbial differences between health and disease conditions. However, although the interproximal regions have one of the highest caries rates in the oral cavity, information about the bacterial composition at those sites is scarce. In this study, we used 16S rRNA Illumina sequencing to describe the microbiota associated to interproximal regions at two time points. In addition, dental plaque samples at the vestibular and lingual surfaces from the same teeth were also analysed at the same timepoints, and compared with the bacterial composition at interproximal sites.Interproximal-associated microbiota was found to be similar to the already described bacterial communities in other mouth niches and appeared to be quite constant in diversity and composition through time. Streptoccocus, Veillonella, Rothia, Actinomyces, Neisseria, Haemophilus and Fusobacterium were the most abundant genera in this oral region. Statistical analyses showed that the microbiota from interproximal sites was more similar to that sampled from the vestibular surfaces of the same teeth than to the lingual surfaces. Interestingly, many potentially cariogenic bacteria were over-represented in the interproximal regions in comparison with dental plaque samples from the vestibular and lingual sites, which may contribute to the high caries risk at these sites.