Dental caries is the most common disease in the human mouth. Streptococcus mutans is the primary cariogenic bacteria. Propolis is a nontoxic natural product with a strong inhibitory effect on oral cariogenic bacteria. The polyphenol-rich extract from propolis inhibit S. mutans growth and biofilm formation, as well as the genes involved in virulence and adherence, through the inhibition of glucosyltransferases. However, because the chemical composition of propolis is highly variable and complex, the mechanism of its antimicrobial action and the active compound are controversial and not completely understood. Caffeic acid phenethyl ester (CAPE) is abundant in the polyphenolic compounds from propolis, and it has many pharmacological effects. In this study, we investigated the antibacterial effects of CAPE on common oral cariogenic bacteria (Streptococcus mutans, Streptococcus sobrinus, Actinomyces viscosus and Lactobacillus acidophilus) and its effects on the biofilm-forming and cariogenic abilities of S. mutans. CAPE shows remarkable antimicrobial activity against cariogenic bacteria. Moreover, CAPE also inhibits the formation of S. mutans biofilms and its metabolic activity in mature biofilms. Furthermore, CAPE can inhibit the key virulence factors of S. mutans associated with cariogenicity, including acid production, acid tolerance and its ability to produce extracellular polysaccharides without affecting bacterial viability at subinhibitory levels. In conclusion, CAPE appears to be a new agent with anticariogenic potential, not only via inhibition of the growth of cariogenic bacteria.

Dental caries is one of the most common oral diseases in the world. This study was tantamount to investigate the combinatory effects of an amelogenin-derived peptide (called QP5) and fluoride on the remineralization of artificial enamel caries. The peptide QP5 was synthesized and characterized, and the binding capability of the peptide on hydroxyapatite (HA) and demineralized tooth enamel surface was analysed. Then, the mineralization function of the peptide and fluoride was studied through the spontaneous mineralization testing and remineralization on enamel caries in vitro. First, the novel peptide QP5 could bind on the hydroxyapatite and demineralized tooth enamel surfaces. Second, QP5 can transitorily stabilize the formation of amorphous calcium phosphate and direct the transformation into hydroxyapatite crystals alone and in combination with fluoride. In addition, compared to blocks treated by peptide QP5 alone or fluoride, the sample blocks showed significantly higher surface microhardness, lower mineral loss and shallower lesion depth after treatment with a combination of QP5 and fluoride at high or low concentrations. The peptide QP5 could control the crystallization of hydroxyapatite, and combinatory application of peptide QP5 and fluoride had a potential synergistic effect on the remineralization of enamel caries.

BackgroundHuman saliva is a protein-rich, easily accessible source of potential biomarkers for the diagnosis of oral and systemic diseases. However, little is known about the changes in salivary proteome associated with aging of patients with dental caries. Here, we applied isobaric tags for relative and absolute quantitation (iTRAQ) in combination with multiple reaction monitoring mass spectrometry (MRM-MS) to characterize the salivary proteome profiles of subjects of different ages, presenting with and without caries, with the aim of identifying age-related biomarkers for dental caries.MethodsUnstimulated whole saliva samples were collected from 40 caries-free and caries-susceptible young adults and elderly individuals. Salivary proteins were extracted, reduced, alkylated, digested with trypsin and then analyzed using iTRAQ-coupled LC–MS/MS, followed by GO annotation, biological pathway analysis, hierarchical clustering analysis, and protein–protein interaction analysis. Candidate verification was then conducted using MRM-MS.ResultsAmong 658 salivary proteins identified using tandem mass spectrometry, 435 proteins exhibited altered expression patterns in different age groups with and without caries. Of these proteins, 96 displayed age-specific changes among caries-susceptible adults and elderly individuals, and were mainly associated with salivary secretion pathway, while 110 age-specific proteins were identified among healthy individuals. It was found that the age factor caused significant variations and played an important role in both healthy and cariogenic salivary proteomes. Subsequently, a total of 136 target proteins with complex protein–protein interactions, including 14 age-specific proteins associated with caries, were further successfully validated using MRM analysis. Moreover, non-age-specific proteins (histatin-1 and BPI fold-containing family B member 1) were verified to be important candidate biomarkers for common dental caries.ConclusionsOur proteomic analysis performed using the discovery-through-verification pipeline revealed distinct variations caused by age factor in both healthy and cariogenic salivary proteomes, highlighting the significance of age in the great potential of saliva for caries diagnosis and biomarker discovery.Electronic supplementary materialThe online version of this article (10.1186/s12967-018-1669-2) contains supplementary material, which is available to authorized users.

Objectives Initial dental caries often occurs in clinic. Reduction of cariogenic bacteria and promotion of remineralization are effective ways to control them. This study was to develop bifunctional anticaries peptides with antibacterial and remineralizing properties. Methods We designed peptides TDH19, TNH19, and TVH19 and selected one through comparing their minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) against Streptococcus mutans and their reaction on mineralization. Then the bifunction of the selected peptide was studied through: (a) effects on S. mutans biofilm, (b) remineralizing effects on initial lesions and (c) stability in saliva and cytocompatibility to human oral keratinocytes (HOKs). Results TVH19 showed the lowest MIC and MBC and a better mineralizing ability. It inhibited new biofilm formation and reduced the viability of old biofilm (p < 0.05). Treating initial caries with TVH19 led to greater recovery of surface microhardness, shallower lesion depth, and higher mineral content (p < 0.05). No significant differences were observed between TVH19 and NaF samples (p > 0.05). TVH19 was stable in saliva and had little effect on HOKs. Conclusions The novel bifunctional anticaries peptide TVH19 was developed with remarkable antibacterial activity and the potential to enhance remineralization of initial caries.

No abstract

No abstract

A novel biomimetic peptide inspired by salivary statherin was developed and exhibited beneficial potentials in promoting remineralization of hydroxyapatite on tooth enamel surface, providing a desirable alternative restorative strategy against dental caries.

1,3-Propanediol was synthesized via the hydrogenation of dimethyl malonate over a Cu/SiO2 catalyst. The reaction network and active sites were revealed for the first time.