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Hydrogen-rich water (HRW) shows excellent antibacterial, anti-inflammatory, antioxidant, and wound-healing properties and plays a positive role in the treatment of various diseases, such as brain injury, kidney injury, and periodontitis. Current studies found that HRW can inhibit periodontopathogenic biofilm formation, inhibit oral connective tissue and bone tissue destruction, and show anti-inflammatory and antioxidant properties in periodontitis. Additionally, HRW can alleviate periodontal tissue damage by inhibiting oxidative stress and up-regulating the expression of antioxidant enzymes, such as glutathione peroxidase and superoxide dismutase. HRW exerts anti-inflammatory effects by regulating the nuclear factor erythroid 2-related factor 2 and mitogen-activated protein kinase pathways, which are closely associated with inflammation. Additionally, HRW inhibits the expression of inflammatory cytokines, such as interleukins, inhibits the growth and proliferation of bacterial plaque biofilms, and down-regulates glycosyltransferases and glucan-binding proteins to prevent bacterial adhesion and subsequent development of periodontitis. Furthermore, HRW has a positive effect on the expression of various cell growth factors, α-smooth muscle actin, and type I collagen, which promotes wound healing. Current clinical studies have demonstrated the biological safety of HRW (to a certain extent) and reported no adverse reactions. However, most studies on HRW in oral diseases are preclinical in vivo and in vitro studies. Therefore, further clinical studies are required to validate the therapeutic significance and optimal therapeutic regimen of HRW in human periodontitis. This article aims to review the therapeutic role and the underlying mechanisms of HRW in periodontitis.

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.

This review focuses on the current disparities and gaps in research on the characteristics of the oral ecosystem of denture wearers, making a unique contribution to the literature on this topic. We aimed to synthesize the literature on the state of current knowledge concerning the biological behavior of the different polymers used in prosthetics. Whichever polymer is used in the composition of the prosthetic base (poly methyl methacrylate acrylic (PMMA), polyamide (PA), or polyether ether ketone (PEEK)), the simple presence of a removable prosthesis in the oral cavity can disturb the balance of the oral microbiota. This phenomenon is aggravated by poor oral hygiene, resulting in an increased microbial load coupled with the reduced salivation that is associated with older patients. In 15–70% of patients, this imbalance leads to the appearance of inflammation under the prosthesis (denture stomatitis, DS). DS is dependent on the equilibrium—as well as on the reciprocal, fragile, and constantly dynamic conditions—between the host and the microbiome in the oral cavity. Several local and general parameters contribute to this balance. Locally, the formation of microbial plaque on dentures (DMP) depends on the phenomena of adhesion, aggregation, and accumulation of microorganisms. To limit DMP, apart from oral and lifestyle hygiene, the prosthesis must be polished and regularly immersed in a disinfectant bath. It can also be covered with an insulating coating. In the long term, relining and maintenance of the prosthesis must also be established to control microbial proliferation. On the other hand, several general conditions specific to the host (aging; heredity; allergies; diseases such as diabetes mellitus or cardiovascular, respiratory, or digestive diseases; and immunodeficiencies) can make the management of DS difficult. Thus, the second part of this review addresses the complexity of the management of DMP depending on the polymer used. The methodology followed in this review comprised the formulation of a search strategy, definition of the inclusion and exclusion criteria, and selection of studies for analysis. The PubMed database was searched independently for pertinent studies. A total of 213 titles were retrieved from the electronic databases, and after applying the exclusion criteria, we selected 84 articles on the possible microbial interactions between the prosthesis and the oral environment, with a particular emphasis on Candida albicans. [ABSTRACT FROM AUTHOR]

Dental caries is an oral disease caused by acid production by microbial metabolism and gradual demineralization of tooth enamel, followed by the destruction of tooth structure protein, whose occurrence and development are closely related to the daily diet and nutritional intake. Cow's milk is rich in lactose, protein, minerals, and other nutrients, which is a low caries diet. Many epidemiological surveys, in vivo and in vitro experiments, and clinical studies have supported the positive role of milk and dairy products in caries prevention and treatment. Based on the characteristics that caries are bacterial-mediated and diet-driven, this paper describes the mechanisms involved in the management of dental caries by functional and active components in milk and analyzes different anti-caries dairy products, especially those containing probiotics. Hopefully, it provides some theoretical reference for the prevention and treatment of dental caries through scientific milk consumption in the future.

The oral microecological balance is closely associated with the development of dental caries. Oxidative stress is one of the important factors regulating the composition and structure of the oral microbial community. Streptococcus mutans is closely related to the occurrence and development of dental caries. The ability of S. mutans to withstand oxidative stress affects its survival competitiveness in biofilms. The oxidative stress regulatory mechanisms of S. mutans include the synthesis of reductase, the regulation of iron and manganese uptake by metalloregulatory proteins, transcription regulator Spx, extracellular uptake of glutathione and other related signal transduction systems. The current research focuses on how S. mutans adapts to a complex external environment through an oxidative stress response and its influence on oral microecology. We can design targeted small molecular compounds for key signaling pathways to inhibit oxidative stress and weaken the virulence of S. mutans, which is important for oral microecological modulation and dental caries prevention and treatment.

Denture-related Candida stomatitis, which has been described clinically in the literature, is either localized or generalized inflammation of the oral mucosa in connection with a removable prosthesis. During this inflammatory process, the mycobacterial biofilm and the host's immune response play an essential role. Among microorganisms of this mixed biofilm, the Candida species proliferates easily and changes from a commensal to an opportunistic pathogen. In this situation, the relationship between the Candida spp. and the host is influenced by the presence of the denture and conditioned both by the immune response and the oral microbiota. Specifically, this fungus is able to hijack the innate immune system of its host to cause infection. Additionally, older edentulous wearers of dentures may experience an imbalanced and decreased oral microbiome diversity. Under these conditions, the immune deficiency of these aging patients often promotes the spread of commensals and pathogens. The present narrative review aimed to analyze the innate and adaptive immune responses of patients with denture stomatitis and more particularly the involvement of Candida albicans sp. associated with this pathology. [ABSTRACT FROM AUTHOR]

Among many factors affecting dental caries, bacteria are its initiating factor. From the perspective of ecological plaque hypothesis, the application of modern molecular biology methods enable scholars to deeply explore the relationship between the microbial population distribution, biodiversity, microbial community changes of dental plaque biofilm and the occurrence of dental caries in children. The decrease in microflora diversity is closely related to the occurrence of dental caries, which can be detected as early as 6 months before the occurrence of dental caries, providing an important basis for caries monitoring and caries risk assessment. Differential bacteria such as Lactobacillus and Veillonella may be used as biomarkers of caries in children to judge the risk of caries in children. However, current studies have shown that the dominant bacteria in the microbial community structure vary in different processes of caries occurrence and development, that the interaction between different flora is still not clear, and that the specific cariogenic mechanism of the oral plaque microbial community in the process of caries occurrence and development has not been clarified. Further research is still needed to explore the changes in plaque microbial diversity and composition during the development of dental caries and to screen specific dental caries biomarkers. This paper also summarizes the related research findings.

Oral microbial dysbiosis is the major causative factor for common oral infectious diseases including dental caries and periodontal diseases. Interventions that can lessen the microbial virulence and reconstitute microbial ecology have drawn increasing attention in the development of novel therapeutics for oral diseases. Antimicrobial small molecules are a series of natural or synthetic bioactive compounds that have shown inhibitory effect on oral microbiota associated with oral infectious diseases. Novel small molecules, which can either selectively inhibit keystone microbes that drive dysbiosis of oral microbiota or inhibit the key virulence of the microbial community without necessarily killing the microbes, are promising for the ecological management of oral diseases. Here we discussed the research progress in the development of antimicrobial small molecules and delivery systems, with a particular focus on their antimicrobial activity against typical species associated with oral infectious diseases and the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Oral microbial dysbiosis is the major causative factor for common oral infectious diseases including dental caries and periodontal diseases. Interventions that can lessen the microbial virulence and reconstitute microbial ecology have drawn increasing attention in the development of novel therapeutics for oral diseases. Antimicrobial small molecules are a series of natural or synthetic bioactive compounds that have shown inhibitory effect on oral microbiota associated with oral infectious diseases. Novel small molecules, which can either selectively inhibit keystone microbes that drive dysbiosis of oral microbiota or inhibit the key virulence of the microbial community without necessarily killing the microbes, are promising for the ecological management of oral diseases. Here we discussed the research progress in the development of antimicrobial small molecules and delivery systems, with a particular focus on their antimicrobial activity against typical species associated with oral infectious diseases and the underlying mechanisms.

Denture-related Candida stomatitis, which has been described clinically in the literature, is either localized or generalized inflammation of the oral mucosa in connection with a removable prosthesis. During this inflammatory process, the mycobacterial biofilm and the host’s immune response play an essential role. Among microorganisms of this mixed biofilm, the Candida species proliferates easily and changes from a commensal to an opportunistic pathogen. In this situation, the relationship between the Candida spp. and the host is influenced by the presence of the denture and conditioned both by the immune response and the oral microbiota. Specifically, this fungus is able to hijack the innate immune system of its host to cause infection. Additionally, older edentulous wearers of dentures may experience an imbalanced and decreased oral microbiome diversity. Under these conditions, the immune deficiency of these aging patients often promotes the spread of commensals and pathogens. The present narrative review aimed to analyze the innate and adaptive immune responses of patients with denture stomatitis and more particularly the involvement of Candida albicans sp. associated with this pathology.

Periodontal disease is a common and frequently occurring oral disease, with numerous investigations on periodontitis etiology and treatment. The development of periodontal disease is affected by many factors, including local stimulation and systemic risk factors, and dental plaque biofilm is regarded as an initial factor. The molecular mecha⁃ nisms of how dental plaque biofilm and other risk factors regulate the development of periodontal disease remain un⁃ clear. Autophagy is a ubiquitous self⁃regulating mechanism of eukaryotes and a process of cell self⁃phagocytosis and di⁃ gestion. Autophagy is a complex process, involving a variety of cellular and tissue activities, including cellular stress, clearance of endogenous and exogenous cellular components, development, aging and cancer. Recent studies have shown that autophagy is closely related to inflammation. This paper addresses recent research advances in understand⁃ ing the correlations between periodontal disease and autophagy to provide a reference in the study of new methods to treat periodontal disease from the perspective of autophagy in the future.

[Display omitted] • Brief overview of the etiology of caries, and the relationship between diet and caries. • To further systematize the mechanism of functional active ingredients in milk in the prevention f dental caries. • A systematic summary of the role of all caries-preventive dairy products in caries management, including flavored milk, fluoridated milk, fortified milk, cheese, yogurt, and probiotic-containing dairy products. Dental caries is an oral disease caused by acid production by microbial metabolism and gradual demineralization of tooth enamel, followed by the destruction of tooth structure protein, whose occurrence and development are closely related to the daily diet and nutritional intake. Cow's milk is rich in lactose, protein, minerals, and other nutrients, which is a low caries diet. Many epidemiological surveys, in vivo and in vitro experiments, and clinical studies have supported the positive role of milk and dairy products in caries prevention and treatment. Based on the characteristics that caries are bacterial-mediated and diet-driven, this paper describes the mechanisms involved in the management of dental caries by functional and active components in milk and analyzes different anti-caries dairy products, especially those containing probiotics. Hopefully, it provides some theoretical reference for the prevention and treatment of dental caries through scientific milk consumption in the future. [ABSTRACT FROM AUTHOR]

Dental plaque biofilms cause various dental diseases; therefore, inhibiting the growths of the dental plaque bacteria which produce biofilms can be a strategy for preventing dental disease. Certain sulfated polysaccharides from marine algae exert antimicrobial activities against human bacterial pathogens in addition to their physiological benefits. On the basis of these observations, the antimicrobial and antibiofilm activities of sulfated polysaccharides from different marine algae were evaluated against dental plaque bacteria. Among the sulfated polysaccharides, a fucoidan from Fucus vesiculosus showed notable antimicrobial activities against the selected dental plaque bacteria, including some foodborne pathogenic bacteria. The minimum inhibitory concentrations were of 125 to 1000 µg mL−1. Regarding the antibiofilm activity, the fucoidan at the concentrations of above 250 µg mL−1 completely suppressed the biofilm formations and planktonic cell growths of Streptococcus mutans and S. sobrinus. However, no eliminative effect on the completed biofilm was observed. The fucoidan consisted of almost fucose base polysaccharide containing approximately 14.0% sulfate content. The average molecular weight of the fucoidan was changed by heat treatment (121 °C for 15 min) and it affected the antimicrobial activity.

Bacterial taxa belonging to the phylum Synergistetes are commonly detected within diseased periodontal niches, but are rarely found within healthy oral sites. However, as they typically constitute a minor fraction of the oral microbiota, their precise distributions and disease-associations remain to be fully established. Here, we surveyed the Synergistetes taxa present within individual periodontal/subgingival and peri-implant/submucosal sites, within Chinese subjects (n = 18) affected by both peri-implantitis and periodontitis. Four individual, clinically-distinct sites were analyzed in each patient: healthy sulcus; periodontitis lesion; healthy peri-implant space; peri-implantitis lesion. We employed a clone library-based approach, using PCR-primers that specifically amplified ca . 650bp regions of the 16S rRNA gene from oral cluster A and B Synergistetes taxa. Twenty-one of the 72 sites (from 12/18 subjects) yielded Synergistetes 16S rRNA PCR products. Sequencing of cloned amplicon libraries yielded 1338 quality-filtered 16S rRNA sequences, which were assigned to 26 Synergistetes operational taxonomic units (OTUs; oral taxon SH01-SH26) using a 98.5% identity cut-off. We identified 25 Synergistetes oral cluster A OTUs (genus Fretibacterium ; corresponding to Human Oral Taxon (HOT) numbers 358, 359, 360, 361, 362, 363, 452, and 453), and one oral cluster B OTU ( Pyramidobacter piscolens oral taxon SH04, HOT-357). Three OTUs predominated: Fretibacterium oral taxon SH01 (HOT-360), Fretibacterium oral taxon SH02 (HOT-452), and Fretibacterium fastidiosum oral taxon SH03 (HOT-363). The Synergistetes community compositions within the respective periodontal and peri-implant sites were variable and complex, and no statistically-significant correlations could be established. However, the detection frequency of F. fastidiosum SH03 and Fretibacterium oral taxon SH01 were both positively associated with plaque index at healthy subgingival sites. Taken together, our results show that diverse Synergistetes populations inhabit both diseased and healthy periodontal and peri-implant niches, with considerable site-to-site variations in composition occurring within the same oral cavity. [ABSTRACT FROM AUTHOR]

We investigate tooth wear in the context of removing dental plaque biofilms from tooth surfaces using high velocity water droplets. A laboratory model system was designed using a dextran gel as a biofilm surrogate and a typodont model was used to reproduce the geometry of the mouth. Using uni-axial compression, the elastic modulus of Streptococcus mutans biofilms was 0.280kPa (±0.350; n=30), and the relaxation time was 11s (±12; n=10). The type of surface, concentration of sugar, chelation and osmotic pressure all had significant effects on biofilm stiffness. However, there was no direct relationship between biofilm stiffness and surface hydrophobicity or roughness. The elastic modulus of the gel was 17kPa (±12; n=3), and the relaxation time was 15s (±12; n=3) which was in the reported viscoelastic range of real bacterial biofilms. High velocity 115μL water drops travelling with an exit velocity of 60m/s were generated using a prototype interdental cleaning device (Sonicare AirFloss). High-speed imaging showed that the gel was removed within approximately 6ms of impact by adhesive failure from the tooth surface and within approximately 26ms of impact by cohesive failure. [ABSTRACT FROM AUTHOR]

Streptococcus gordonii and Streptococcus mutans avidly colonize teeth. S. gordonii glucosyltransferase (GtfG) and amylase-binding proteins (AbpA/AbpB), and S. mutans glucosyltransferase (GtfB), affect their respective oral colonization abilities. We investigated their interrelationships and caries association in a rat model of human caries, examining the sequence of colonization and non- vs. high-sucrose diets, the latter being associated with aggressive decay in humans and rats. Virulence-characterized wild-types of both species and well-defined mutants of S. gordonii with interrupted abpA and gtfG genes were studied. While both S. gordonii and S. mutans were abundant colonizers of rat’s teeth in the presence of either diet, if inoculated singly, S. mutans always out-competed S. gordonii on the teeth, independent of diet, strain of S. mutans, simultaneous or sequential inoculation, or presence/absence of mutations of S. gordonii’s abpA and gtfG genes known to negatively or positively affect its colonization and to interact in vitro with S. mutans GtfB. S. mutans out-competed S. gordonii in in vivo plaque biofilm. Caries induction reflected S. mutans or S. gordonii colonization abundance: the former highly cariogenic, the latter not. S. gordonii does not appear to be a good candidate for replacement therapy. These results are consistent with human data. [ABSTRACT FROM PUBLISHER]

Abstract: An HPLC–ELSD method was first developed for the quantitative analysis of principle triterpenoids in Ilex hainanensis, Ilex stewardii and Ilex pubescens. The established method, with excellent precision, repeatability and recovery, was successfully applied to determine four triterpenoids in 24 samples from different species and medicinal parts of Ilex, and the changing trend was discussed. HPLC–ESI–MSn was used for the identification of constituents in samples. The proposed method was simple, effective and suitable for investigations of these plants. Furthermore, the ethanol extracts from leaves of Ilex species, as well as their main components, were assessed for their antibacterial activities. The results indicated that the extracts of I. hainanensis, I. stewardii and I. pubescens could inhibit the growth of the tested oral pathogens, Streptococcus mutans and Actinomyces viscosu. Particularly, ilexgenin A was the most effective with MIC values of 7.8 and ⩽3.9μg/ml, respectively. [ABSTRACT FROM AUTHOR]

PURPOSE: Human denial plaque is implicated in a number of oral diseases. Collection of its undisturbed intact structure facilitates observing the formation and the effect of treatment. This study established a model in viva to collect intact natural dental plaque biofilm, and observed the features and evaluated the immediate penetration and bactericidal effect of an essential oil (EO) mouthrinse on ii at different periods. METHODS: Three 500μm wide grooves were cut into hydroxyapatite (HA) discs. The discs were worn by six volunteers for 6.24 and 48 hours, then broken into halves, uric served as control, while the other received a one-minute extra-oral EO mouthrinse treatment. 5.15 and 30 minutes later, the plaque was visualized with a vitality staining technique to observe the sustained changes of biofilm structure in situ arid the effect of EO on intact biofilm. The biofilm thickness and fluorescent density of vital and total bacteria were obtained through diagram analysis, assessing the percentage of thickness and fluorescent density of vital to total bacteria. All data analysis was performed using SPSS 13.0 software package. One-way ANOVA and Student-Neuman-Keuls tests were used. RESULTS: The thickness of 6h, 24h amid 48h biofilm was (11.92±4.63)μm. (18.63±4.66)μm. (27.55±6.35)μm. respectively, which increase significantly within 48 hours (P<0.05). especially those within 6 hours. The percentages of thickness and fluorescent density of vital to total bacteria at different periods showed no significant changes (P>0.05). For 6-hour samples, plaque vilality for thickness and fluorescent density decreased significantly within 5 minutes after exposure 10 the (P<0.05). Meanwhile, for 24, 48-hour samples, plaque vitality decreased significantly within 15 minutes (P<0.05). CONCLUSIONS: This study successfully establishes a model for collecting natural undisturbed plaque biofilm in situ, showing the changes constantly within 48 hours. EO mouthrinse has an immediate penetration and antimicrobial effect on the sustained dental plaque biofilm, especially 15 minutes later. [ABSTRACT FROM AUTHOR]

Nagayoshi M, Fukuizumi T, Kitamura C, Yano J, Terashita M, Nishihara T. Efficacy of ozone on survival and permeability of oral microorganisms. Oral Microbiol Immunol 2004: 19: 240–246.© Blackwell Munksgaard, 2004. In the present study, we examined the effect of ozonated water on oral microorganisms and dental plaque. Almost no microorganisms were detected after being treated with ozonated water (4 mg/l) for 10 s. To estimate the ozonated water-treated Streptococcus mutans, bacterial cells were stained with LIVE/DEAD® BacLightTM Bacterial Viability Kit. Fluorescence microscopic analysis revealed that S. mutans cells were killed instantaneously in ozonated water. Some breakage of ozonated water-treated S. mutans was found by electron microscopy. When the experimental dental plaque was exposed to ozonated water, the number of viable S. mutans remarkably decreased. Ozonated water strongly inhibited the accumulation of experimental dental plaque in vitro. After the dental plaque samples from human subjects were exposed to ozonated water in vitro, almost no viable bacterial cells were detected. These results suggest that ozonated water should be useful in reducing the infections caused by oral microorganisms in dental plaque. [ABSTRACT FROM AUTHOR]

Direct or in situ methods (e.g., confocal microscopy, microsensors) are used to study non-oral biofilms for almost two decades, and they have recently been introduced in the research of dental plaque. We combined a pH microsensor technique and transversal microradiography (TMR) in a pilot study where the effects of nutrient availability on plaque acidogenicity and on the development of caries-like lesions were assessed. One volunteer accumulated dental plaque for 7 days in 0.2-mm-wide and 0.8-mm-deep dentin grooves at four conditions: (1) saliva only, (2) 8 x 5 min/day dipping in 10% sucrose solution, (3) 7 x 5 min/day consumption of sweet cookies plus one meal/day, and (4) subject's regular diet. Plaque pH versus time and depth profiles in the grooves were recorded ex vivo before and after sugar challenge. 'Saliva' plaque responded to sugar with slow pH decrease -- minimum pH 5.6-5.8 was reached after 30 min, while sugar dipping resulted in metabolically active plaque (minimum pH 5.3-5.5 within 4-8 min). TMR analysis revealed no demineralization after these two periods. Metabolically active plaque leading to distinct lesions resulted from frequent plaque exposure to diets rich in starch and carbohydrates (groups 3 and 4). These findings strengthen the view that the plaque acidogenicity does not necessarily reflect cariogenicity, and that retention of food components may account for increased cariogenicity at plaque retention sites in the mouth. [ABSTRACT FROM AUTHOR]