Functional Active Microbiome in Supragingival Biofilms in Health and Caries

The oral microbiome is unique at inter and intra-individual levels at various sites due to physical and biological factors. This study aimed to compare the bacterial composition of supragingival biofilms collected from enamel sites with different caries activity, from active and inactive-caries subjects, and from caries-free (CF) subjects. Twenty-two individuals (aged between 13 and 76 years old; med = 23.5 years old) were allocated into 3 groups: caries-active (CA) (n = 10), caries-inactive (CI) (n = 6), and CF (n = 6). From the CA group, 3 sites were sampled: CA (active non-cavitated lesion), CI (inactive non-cavitated lesion), and sound enamel surface (S). From the subjects of the CI group, biofilm from a CI lesion was collected (INCL), while for the CF subjects, a pool of biofilm from sound enamel surfaces was sampled. The total RNA was extracted, and cDNA libraries were prepared and pairedend sequenced (Illumina HiSeq 3,000). Final dental biofilm samples analysed from CA was 16 (ANCL-CA = 6, INCL-CA = 4, S-CA = 6); from CI, 3 (INCL-CI = 3); and from CF, 6 (S-CF = 6) (some samples were lost by insufficient genetic material). Read sequences were processed and analysed using the Metagenomics RAST server. High-quality sequences (3,542,190) were clustered into operational taxonomic units (97% identity; SILVA SSU), representing 915 genera belonging to 29 phyla (higher abundant: Actinobacteria, Firmicutes, Bacteroidetes, and Fusobacteria). The presence of a core microbiome was observed (123 shared genera). The alpha diversity analysis showed less bacterial diversity in disease (S-CA) compared to health (S-CF). The dominant genera included Actinomyces, Corynebacterium, Capnocytophaga, Leptotrichia, Veillonella, Prevotella, Streptococcus, Eubacterium, and Neisseria. Veillonella and Leptotrichia were related with disease and Prevotella with health. Corynebacterium, Capnocytophaga, and Actinomyces clustered together presenting high abundance in health and disease. The Metric Multidimensional Scaling Ordination analysis shows that sites from active subjects (ANCL-CA, INCL-CA, and S-CA) are closer to each other than either INCL-CI subjects or S-CF subjects. In conclusion, supragingival bacterial communities presented intra-individual similarities, but inter-individual diversity and difference in bacterial composition reveal that the subject’s caries activity status matters more than sites

Contemporary operative caries management:consensus recommendations on minimally invasive caries removal

The International Caries Consensus Collaboration (ICCC) presented recommendations on terminology, on carious tissue removal and on managing cavitated carious lesions. It identified 'dental caries' as the name of the disease that dentists should manage, and the importance of controlling the activity of existing cavitated lesions to preserve hard tissues, maintain pulp sensibility and retain functional teeth in the long term. The ICCC recommended the level of hardness (soft, leathery, firm, and hard dentine) as the criterion for determining the clinical consequences of the disease and defined new strategies for carious tissue removal: 1) Selective removal of carious tissue - including selective removal to soft dentine and selective removal to firm dentine; 2) stepwise removal - including stage 1, selective removal to soft dentine, and stage 2, selective removal to firm dentine 6 to 12 months later; and 3) non-selective removal to hard dentine - formerly known as complete caries removal (a traditional approach no longer recommended). Adoption of these terms will facilitate improved understanding and communication among researchers, within dental educators and the wider clinical dentistry community. Controlling the disease in cavitated carious lesions should be attempted using methods which are aimed at biofilm removal or control first. Only when cavitated carious dentine lesions are either non-cleansable or can no longer be sealed, are restorative interventions indicated. Carious tissue is removed purely to create conditions for long-lasting restorations. Bacterially contaminated or demineralised tissues close to the pulp do not need to be removed. The evidence and, therefore these recommendations, supports minimally invasive carious lesion management, delaying entry to, and slowing down, the destructive restorative cycle by preserving tooth tissue, maintaining pulp sensibility and retaining the functional tooth-restoration complex long-term