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@#Caries is a chronic infectious disease that occurs in the hard tissues of teeth. The interaction of oral microorganisms, host, food and time leads to the occurrence and progression of caries. Free sugar is an important food factor in the occurrence of dental caries. This paper reviews the research progress on the relationship between free sugar and caries in recent years, providing a reference for further clarifying the mechanism of the occurrence and progression of caries caused by free sugar and exploring the methods of caries prevention. The cariogenic mechanism of free sugar is multifaceted. Free sugar can not only be used by oral microorganisms in dental plaque biofilms to produce acid and synthesize intracellular and extracellular polysaccharides but also cause an imbalance in oral microecology and enhance gene expression related to the cariogenic toxicity of oral microorganisms. Based on the correlation between free sugar and caries, it is important to limit the intake amount and frequency of free sugar to prevent caries. This can be achieved mainly by formulating public health policies for reducing sugar, creating a low-sugar family environment with good eating habits, using sugar substitutes and using fluoride. There are few studies on the relationship between free sugar and oral microecology. More research is needed to better understand the effect of free sugar on oral microecology and its mechanism and to validate the caries-preventing effect of various sugar reduction measures. We believe such studies would open up new avenues for the effective prevention of caries.
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@#Fibroblast growth factor 8 (FGF8) is a kind of secretory polypeptide that has crucial roles in the development of various tissues and organs. Current studies have found that FGF8 can regulate the differentiation of cranial neural crest cells by activating the mitogen-activated protein kinase (MAPK) signaling pathway and affect the establishment of mandibular arch polarity and the development of craniofacial symmetry by regulating the expression of target genes. Cleft lip with or without cleft palate, ciliopathies, macrostomia and agnathia are four developmental malformations involving the craniofacial region that seriously affect the quality of life of patients. The abnormal FGF8 signal caused by gene mutation, abnormal protein conformation or expression is closely related to the occurrence of craniofacial malformations, but the molecular mechanism and signaling pathway underlying these malformations have not been fully elucidated. Craniofacial development is a complex process mediated by a variety of signaling molecules. In the future, the role of various signaling molecules in craniofacial development and malformations need to be explored to provide a new perspective and vision for the prevention and treatment of these craniofacial malformations.
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@#Dental and craniofacial bone development is a highly coordinated process that is tightly controlled by genetics and influenced by complex environments. The abnormal regulation of many development-related signaling molecules may lead to abnormal tooth development, severe craniofacial bone formation disorders, and developmental deformities. Transforming growth factor-β (TGF-β) is widely expressed in vivo and participates in many cellular biological processes, showing complex regulatory roles in mammalian craniofacial bone growth and tooth development. In tooth development, abnormal TGF-β signaling can lead to the failure of tooth germ formation, and its deletion mutation can directly affect odontoblast differentiation and enamel formation defects. However, the current research on TGF-β mainly focuses on the early stage of tooth development, and a comprehensive and systematic study of TGF-β-related tooth development is lacking. TGF-β signal transduction mainly controls the development of teeth and craniofacial bone by regulating the expression of development-related molecules via the classical Smad-dependent signaling pathway. In addition, the nonclassical mitogen-activated protein kinase (MAPK) pathway also participates in this process. Abnormal TGF-β signaling may cause jaw development disorders, temporomandibular joint dysplasia and inflammation, and cleft palate. Because the specific regulatory mechanism of TGF-β in craniofacial bone development has not been fully elucidated, its specific application in the treatment of related diseases is also greatly limited. This paper describes the new research progress of TGF-β in the development of teeth, jaws, temporomandibular joints and palate as well as related diseases.
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@#Curcumin is a natural medicine with a wide range of sources and low toxicity. It has antibacterial, antifungal, anti-inflammatory and other pharmacological effects. In recent years, curcumin has attracted much attention in the field of prevention and treatment of oral infectious diseases. Single curcumin is easily degraded during application and has poor water solubility and low bioavailability, but it can be used as a natural photosensitizer to mediate photodynamic treatment of oral infections. Photodynamic therapy has high antibacterial efficiency and can better protect the appearance and function of the affected area. This article reviews the research on curcumin-mediated photodynamic therapy for oral infectious diseases. As a natural photosensitizer, curcumin mediates photodynamic therapy and has shown good therapeutic effects against dental caries, endodontics, periodontitis, oral candidiasis and other oral infectious diseases by enhancing antibacterial ability, increasing the production of reactive oxygen species, and inhibiting the formation of biofilms. In-depth exploration of the mechanism of action of curcumin-mediated photodynamic therapy in different oral infectious diseases can provide new strategies for the prevention and treatment of oral infectious diseases.
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Objective@#To investigate the in vitro interaction of amphotericin B (AmB) and fluconazole (FLC) at different time points and provide a reference for clinical combined treatment therapy of polyenes and azoles.@*Methods@#Candida albicans ATCC SC5314 was used in the study. The minimum inhibitory concentration (MIC) of antifungal drugs was determined using the double microdilution broth method. The same amount of DMSO and low concentration drugs were added to the DMSO treatment group at different time points (0, 2, 4, 6 h) to determine whether the solvent background environment affected the growth of Candida albicans. In the experimental group, to observe the effect of low concentration AmB on the antifungal effect of FLC, the experimental group was administered a low concentration of AmB (0.25 μg/mL or 0.125 μg/mL) added to FLC at different time points (0, 2, 4, 6 h), and the same amount of DMSO was added to FLC at different time points in the single drug control group. In the experimental group, to observe the effect of low concentration of FLC on the antifungal effect of AmB, the experimental group was administered a low concentration of FLC (0.06 μg/mL or 0.03 μg/mL) in AmB at different time points (0, 2, 4, 6 h), and the same amount of DMSO was used at different time points as the single drug control group. In the solvent group, the same amounts of DMSO and low concentration drugs were added at different time points. After resuscitation, the colony growth of each solvent control group, single-drug control group and experimental group was observed to evaluate the interaction between drug concentration and time. Compared with the AmB single-drug control group, there was no significant change in the experimental group with added low concentrations of FLC at 0 h (F=0.27, P=0.775), which was 1.74-1.93 times that of the control group at 2-4 h (P < 0.001), and there was no significant difference in colony count after 6 h (P > 0.05). @*Results@# Under the treatment of FLC at an inhibitory concentration (0.25 μg/ml), adding low concentration AMB did not affect the antifungal effect of FLC, and the multiple of colony count differences were not significant (P > 0.05).@*Conclusion@#The interaction between AmB and FLC was time-dependent. At the early stage (0 h), the interaction effect between fluconazole and amphotericin B was not clear. The fungicidal effect of AmB could be weakened when FLC was supplied at 2-4 h, and the effect of FLC on AmB was absent after 6 h.
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@#Oral cancer is one of the most common cancers that occur in the head and neck and can seriously affect the life span and living standard of oral cancer patients. Candida albicans （C. albicans） is the most common opportunistic pathogenic fungus in the oral cavity, shows pathogenicity and easily causes Candida infection when the host′s immune function is low. Recent studies have shown that C. albicans infection is closely related to oral cancer. This paper reviews the epidemiology of C. albicans infection in oral cancer patients, the influence of C. albicans infection on the occurrence and development of oral cancer and research on its mechanism. Existing studies have shown an increased risk of C. albicans infection in oral cancer patients, while C. albicans infection may promote the occurrence and development of oral cancer through mechanisms such as damaging the oral epithelium; producing carcinogens, including nitrosamine and acetaldehyde; and inducing a chronic inflammatory response and T helper cell 17 immune response. However, these mechanisms are still relatively superficial and lack sufficient direct evidence. In the future, additional in-depth studies are still needed to further clarify the cancer-promoting mechanisms of C. albicans and provide new ideas for the prevention and treatment of oral cancer.
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@#D-alanine is a chiral molecule of L-alanine that participates in the formation and regulation of cell wall peptidoglycans, phosphoteichoic acid, spore germination and respiratory metabolism in individual bacteria. D-alanine participates in the formation and regulation of biofilm in bacterial communities. The function and metabolism of D-alanine in bacteria are specific, and the enzymes and genes in its metabolic pathway can be used as drug targeting sites. In this paper, the synthesis, metabolism and function of D-alanine in bacteria were reviewed, and the relationship between D-alanine and pathogenicity of Streptococcus mutans was discussed to provide a theoretical basis for candidate targeting sites of anti-caries drugs. According to existing research results, the enzymes and related genes involved in D-alanine metabolism play important roles in the growth and biofilm formation of Streptococcus mutans, and D-alanine is expected to be a target for the design of anti-caries drugs.
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@#Radioactive caries is the most common complication of head and neck cancer after radiotherapy. It is a rapidly progressing and widespread destructive disease of tooth tissue after radiotherapy. It is currently believed that salivary gland dysfunction and direct damage to teeth by radiation are the main pathogenic factors of radiation caries. In this paper, the pathogenesis of radiation caries, especially the effect of radiotherapy on oral caries-related microorganisms, are reviewed, and future research directions are proposed. Existing research has revealed that the structures of oral microorganisms change significantly after radiotherapy. The number and proportion of some dental caries-related microorganisms such as Streptococcus mutans, Lactobacillus lactis and Candida albicans increased, and their virulence increased. This indicated that the changes in oral microorganisms caused by radiotherapy played an important role in radioactive caries.
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@#Oral infectious diseases include caries, periodontal disease, halitosis, candidiasis albicans and so on. Over the past few decades, probiotics have mainly been studied in the field of the gastrointestinal tract. In recent years, probiotics have begun to be used in the prevention and treatment of various oral diseases and have become a new field in the research of oral disease prevention and control technology. This paper reviews the research progress of probiotics applied in the prevention and treatment of various oral infectious diseases. A review of the literature shows that probiotics can prevent and cure dental caries by inhibiting the growth of Streptococcus mutans and competing with them for nutrition and attachment sites. Probiotics not only inhibit periodontal pathogens and reduce the production of sulfide, they also regulate the body’s immune function to alleviate halitosis and periodontal inflammation. Probiotics can inhibit periodontal caries by inhibiting them. Probiotics can inhibit them mycelial growth of Candida albicans and interfere with its adherence, thus playing a role in the prevention and treatment of oral candidiasis. Current studies have shown that probiotics play an auxiliary role in the treatment of caries, periodontitis, halitosis and oral candidiasis. However, the mechanism of probiotics in the prevention and treatment of oral infectious diseases is still unclear, and the safety of probiotics remains to be further studied. In the future, oral probiotics should be studied with reference to intestinal probiotics to better work to prevent and treat oral diseases.
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Abstract Dental caries is a chronic progressive disease occurring in the tooth hard tissue due to multiple factors, in which bacteria are the initial cause. Both Streptococcus mutans and Streptococcus sanguinis are main members of oral biofilm. Helicobacter pylori may also be detected in dental plaque, playing an important role in the development of dental caries. Objective The aim of this study was to investigate the effect of H. pylori culture supernatant on S. mutans and S. sanguinis dual-species biofilm and to evaluate its potential ability on affecting dental health. Material and methods The effect of H. pylori supernatant on single-species and dual-species biofilm was measured by colony forming units counting and fluorescence in situ hybridization (FISH) assay, respectively. The effect of H. pylori supernatant on S. mutans and S. sanguinis extracellular polysaccharides (EPS) production was measured by both confocal laser scanning microscopy observation and anthrone-sulfuric acid method. The effect of H. pylori supernatant on S. mutans gene expression was measured by quantitative real-time PCR (qRT-PCR) assays. Results H. pylori supernatant could inhibit both S. mutans and S. sanguinis biofilm formation and EPS production. S. sanguinis inhibition rate was significantly higher than that of S. mutans. Finally, S. mutans bacteriocin and acidogenicity related genes expression were affected by H. pylori culture supernatant. Conclusion Our results showed that H. pylori could destroy the balance between S. mutans and S. sanguinis in oral biofilm, creating an advantageous environment for S. mutans, which became the dominant bacteria, promoting the formation and development of dental caries.
Subject(s)
Streptococcus mutans/physiology , Streptococcus sanguis/physiology , Helicobacter pylori/physiology , Biofilms , Dental Plaque/microbiology , Plankton/growth & development , Polysaccharides, Bacterial/metabolism , Streptococcus mutans/genetics , Streptococcus sanguis/genetics , Time Factors , Colony Count, Microbial , Gene Expression , Helicobacter pylori/genetics , In Situ Hybridization, Fluorescence , Microscopy, Confocal , Dental Caries/microbiology , Real-Time Polymerase Chain ReactionABSTRACT
Dental caries is the most common chronic infectious disease of the oral cavity. The bacterium Streptococcus mutans is the sole pathogen that causes this disease. However, substantial evidence suggests that prevention and treatment strategies developed from traditional "cariogenic pathogen theory" are inefficient in reducing the prevalence of dental caries. An increasing number of individuals adopt the ecological view of the microbiota in the pathogenesis of dental caries. Recent technological improvements have enabled the detection and analysis of oral microorganisms, and many studies have focused on this area. The core microbiota is defined as a cluster of microbes playing critical roles in the initial and development phases of dental caries and may provide future direction for microorganism-related etiological studies.
Subject(s)
Humans , Dental Caries , Metabolism , Microbiota , Mouth , Metabolism , Streptococcus mutans , VirulenceABSTRACT
The human microbiome project (HMP) promoted further understanding of human oral microbes. However, research on the human oral microbiota has not made as much progress as research on the gut microbiota. Currently, the causal relationship between the oral microbiota and oral diseases remains unclear, and little is known about the link between the oral microbiota and human systemic diseases. To further understand the contribution of the oral microbiota in oral diseases and systemic diseases, a Human Oral Microbiome Database (HOMD) was established in the US. The HOMD includes 619 taxa in 13 phyla, and most of the microorganisms are from American populations. Due to individual differences in the microbiome, the HOMD does not reflect the Chinese oral microbial status. Herein, we established a new oral microbiome database-the Oral Microbiome Bank of China (OMBC, http://www.sklod.org/ombc ). Currently, the OMBC includes information on 289 bacterial strains and 720 clinical samples from the Chinese population, along with lab and clinical information. The OMBC is the first curated description of a Chinese-associated microbiome; it provides tools for use in investigating the role of the oral microbiome in health and diseases, and will give the community abundant data and strain information for future oral microbial studies.