Recently, novel antibacterial substances have been developed and added to available dentifrices. Isopropyl methylphenol (IPMP) exerts an antibacterial effect on a wide range of bacteria with biosafety, and thus, is a component recently added in the disinfectants of dentifrices. Accordingly, this study aimed to evaluate the antibacterial effect of a commercially-available IPMP-containing toothpaste on Streptococcus mutans. The antibacterial effects of different concentrations (0, 0.1, 1.0, and 10%) of the dentifrice were examined via colony-forming, biofilm formation, and dispersion assays.

The results of this study demonstrated that bacterial colonization was inhibited in culture media containing 10% dentifrice, and biofilm formation was suppressed even at relatively low dentifrice concentrations (0.1 and 1.0%), however, the removal of the biofilm that had already formed was difficult. Hence, the evaluated dentifrice was considered effective for appropriate oral care. However, the ingredients responsible for this effect need to be identified and compared with other commercial products.

Nucleotide-binding oligomerization domain 1, which is constitutively expressed in human dental pulp fibroblast-like cells (hDPFs), plays a role in pulpal immune responses by sensing γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP) from bacteria. Matrix metalloproteinase-1 (MMP-1) is an important enzyme that degrades type I collagen, an extracellular matrix component, and is involved in the destruction of dental pulp tissue. In the present study, we investigated the involvement of the ERK1/2 signaling pathway in MMP-1 production by iE-DAP-stimulated hDPFs. iE-DAP was not cytotoxic against hDPFs and did not affect their proliferation. A stimulation with iE-DAP enhanced MMP-1 production and ERK1/2 phosphorylation. The ERK1/2 signaling pathway was involved in the production of MMP-1 by iE-DAP-stimulated hDPFs. These results suggest that the induction of MMP-1 production by iE-DAP-stimulated hDPFs exacerbates pulpitis by promoting the degradation of surrounding collagen.

Nucleotide-binding oligomerization domain 2, which is constitutively expressed in human dental pulp fibroblast-like cells (hDPFs), plays a role in pulpal immune responses by sensing muramyl dipeptide (MDP) from bacteria. Matrix metalloproteinase-3 (MMP-3) is abundantly expressed in acute pulpitis and acts as a mediator of the healing of dental pulp as an anti-inflammatory and regenerative factor. In the present study, we investigated the involvement of the ERK1/2 signaling pathway in MMP-3 production by MDP-stimulated hDPFs. MDP was not cytotoxic against hDPFs and did not affect their proliferation. A stimulation with MDP enhanced MMP-3 production and ERK1/2 phosphorylation. The ERK1/2 signaling pathway was involved in the production of MMP-3 by MDP-stimulated hDPFs. These results suggest that the induction of MMP-3 production by MDP-stimulated hDPFs has an anti-inflammatory function by degrading inflammatory cytokines.

Bacterial attachment to tooth surfaces via acquired pellicles is important in the mechanism of caries development. Streptococci are the initial colonizers on the tooth surface. Dental plaque maturation occurs when late-established bacteria bind and grow on the outside of the early-established bacteria. Phytochemicals are part of the plant defense system, and a variety of antimicrobial components are known to exist. However, the effects of complexes containing multiple phytochemicals on the initial settlement of bacteria in dental plaque are not known.

In this study, we prepared a complex of three Phytochemicals (IP2). Then we investigated the inhibitory effects of a complex of three different phytochemicals on the growth of five types of early-occupying bacteria constituting dental plaque. As a result, there was a large inhibitory effect on the number of all colonies.

Nano Biomedicine 10 (1) ;9-14, 2018

The photo in Fig.2 (pp.11) was proofreading by mistake. This photo is the same EST experimental protocol on similar experiment by the same technical researchers. Therefore, the correct photo will be replaced this time.