Prospects for the development of probiotics and prebiotics for oral applications

There has been a paradigm shift towards an ecological and microbial community-based approach to understanding oral diseases. This has significant implications for approaches to therapy and has raised the possibility of developing novel strategies through manipulation of the resident oral microbiota and modulation of host immune responses. The increased popularity of using probiotic bacteria and/or prebiotic supplements to improve gastrointestinal health has prompted interest in the utility of this approach for oral applications. Evidence now suggests that probiotics may function not only by direct inhibition of, or enhanced competition with, pathogenic micro-organisms, but also by more subtle mechanisms including modulation of the mucosal immune system. Similarly, prebiotics could promote the growth of beneficial micro-organisms that comprise part of the resident microbiota. The evidence for the use of pro or prebiotics for the prevention of caries or periodontal diseases is reviewed, and issues that could arise from their use, as well as questions that still need to be answered, are raised. A complete understanding of the broad ecological changes induced in the mouth by probiotics or prebiotics will be essential to assess their long-term consequences for oral health and disease

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Abstract The chemomechanical excavation approach fits the "adhesive cavity" design criteria by producing a rounded internal outline of cavity walls. However, such a relatively new and conservative approach should be at least as effective as conventional bur excavation in the removal of residual caries. Objectives: The aim of the present study was to test the effect of Carisolv TM chemomechanical excavation on caries removal and residual cariogenic bacteria as compared with conventional bur excavation using simple chair-side methods. Methods and Materials: A total 15 patients (mean age 42.7±11.3), presenting with a number of isolated class V carious lesions, were selected for the study. The carious lesions in each patient were randomly assigned to one of the excavation methods: (i) caries removal with Carisolv TM (n=22), (ii) conventional excavation with a bur (n=24). The carious lesions were measured before and after excavation by laser fluorescence, using DIAGNOdent ® , and the presence of cariogenic bacteria was evaluated using a microbial assay (Replica test). Results: Both methods yielded similar results in DIAGNOdent ® readings (9.9 and 7.9 for chemomechanical and bur excavation, respectively) and microbial assay (2.8 and 2.9% for chemomechanical and bur excavation, respectively). No significant difference was observed between the two excavation methods (p>0.05). Conclusions: This suggests that the efficacy of chemomechanical excavation in carious removal and cariogenic bacterial reduction equals that of conventional bur excavation. Short title: Chemomechanical effect on cariogenic bacteri

Effect of Silver Nanoparticles on Blue Light Phototoxicity against <i>Fusobacterium nucleatum</i>

A previous study showed that sub-lethal exposure of blue light caused cell membrane damage in Fusobacterium nucleatum (Fn). The aim of the present study was to test the combined effect of blue light and silver nanoparticles against Fn. Bacterial suspensions were exposed to blue light (400–500 nm) with or without silver nanoparticles (10 nm). Exposed and non-exposed samples were studied for malodor production (Odor judge scores), VSC levels (Halimeter), reactive oxygen species (ROS) production (fluorimeter), and bacterial cell membrane damage (fluorescence microscopy). The results showed that combining blue light exposure and silver nanoparticles significantly reduced malodor and VSC production by Fn concomitant with increased ROS levels and bacterial cell membrane damage. These results suggest that silver nanoparticles may increase blue light phototoxicity against Fn

Blue Light Enhances Fluoride Anticariogenic Activity against <i>Streptococcus mutans</i>

Previous studies have shown that sub-lethal exposure of blue light caused increased bacterial cell membrane permeability. We hypothesized that combining blue light exposure with other antibacterial agents may increase their efficacy. The aim of the present study was to test the combined effect of blue light and sodium fluoride against dental caries pathogen Streptococcus mutans. Sm biofilms were exposed to blue light (400–500 nm) with or without sodium fluoride. Exposed and non-exposed samples were studied for acid production (lactate assay kit), acid tolerance (ATPase assay kit) and bacterial cell membrane damage (fluorescence microscopy). Results showed that the combined treatment significantly reduced the virulence of Sm concomitant with an increase in bacterial cell membrane permeability. Taken together, these results suggest that adjacent blue light exposure may increase fluoride caries preventive properties