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A high incidence of oral injuries during contact sports has been reported. The wearing of mouthguards in contact sports effectively prevents oral injuries and protects oral structures, but the rate of wearing mouthguards is thought to be rather low. To encourage the wearing of mouthguards, we considered that students should be educated on the safety of wearing mouthguards. We discuss the causes of oral injuries and awareness concerning the use of mouthguards among Japanese high-school students of a rugby football team. The problems of existing mouthguards were investigated, and then custom-made mouthguards were fabricated. Most of the problems disappeared when using the custom-made mouthguards. Although there were still some students who complained about the mouthguards, it was suggested that the higher rate of wearing mouthguards might have resulted from the safety education. From the results of this study, safety education for users should be supplied to raise motivation and prevent trauma by wearing a mouthguard. [ABSTRACT FROM AUTHOR]

The article introduces the "International Journal of Sports Dentistry." The journal from the Japanese Academy of Sports Dentistry has the aim to share scientific interests and developments on the field of sports dentistry among all the researchers and clinicians around the world. It hopes to be a medium for interchange of information of research fields of sports dentistry and for the people involved in the clinic as well.

Abstract: Interleukin-1 (IL-1) plays a crucial role in the immunopathological responses involved with tissue destruction in chronic inflammatory diseases, such as periodontal disease, as it stimulates host cells including fibroblasts to produce various inflammatory mediators and catabolic factors. We comprehensively investigated the involvement of mitogen-activated protein kinases (MAPKs)/activator protein-1 (AP-1) and IκB kinases (IKKs)/IκBs/nuclear factor-κB (NF-κB) in IL-1β-stimulated IL-6, IL-8, prostaglandin E2 (PGE2) and matrix metalloproteinase-1 (MMP-1) production by human gingival fibroblasts (HGF). Three MAPKs, extracellular signal-regulated kinase (ERK), p38 MAPK and c-Jun N-terminal kinase (JNK), which were simultaneously activated by IL-1β, mediated subsequent c-fos and c-jun mRNA expression and DNA binding of AP-1 at different magnitudes. IKKα/β/IκB-α/NF-κB was also involved in the IL-1 signaling cascade. Further, IL-1β stimulated HGF to produce IL-6, IL-8, PGE2 and MMP-1 via activation of the 3 MAPKs and NF-κB, as inhibitors of each MAPK and NF-κB significantly suppressed the production of IL-1β-stimulated factors, though these pathways might also play distinct roles in IL-1β activities. Our results strongly suggest that the MAPKs/AP-1 and IKK/IκB/NF-κB cascades cooperatively mediate the IL-1β-stimulated synthesis of IL-6, IL-8, PGE2 and MMP-1 in HGF. [Copyright &y& Elsevier]

Ethnopharmacological Relevance: Propolis is a resinous substance collected by honeybees from various plant sources and has been used in traditional folk medicine for centuries. Propolis has various biological properties, including antibacterial, antiviral, anti-inflammatory, and anti-tumor properties. The use of propolis in oral health care is attributable to its antimicrobial and anti-inflammatory effects. However, limited evidence exists on the in vivo efficacy of propolis against periodontal pathogens., Aim of the Study: We aimed to evaluate the efficacy of Brazilian green propolis (BGP)-containing toothpaste for improving the oral environment and define its antibacterial compounds., Materials and Methods: Overall, 48 student volunteers aged 18-40 years (24 females and 24 males) were randomly categorized into the BGP and placebo groups. The BGP and placebo groups received toothpaste with and without BGP, respectively. After a baseline assessment, the plaque index (PI) score, gingival index (GI) score, and proportion of periodontal pathogens on the tongue surface were analyzed at 0, 1, and 2 weeks. Antibacterial compounds were identified using liquid-liquid partitioning, high-performance liquid chromatography purification, and nuclear magnetic resonance methods., Results: The concentration of BGP in the toothpaste was set at 0.0347 w/v%. Compared with the placebo group, the BGP group demonstrated a reduction in the PI score (p < 0.05) but not in the GI score, as well as a reduction in Porphyromonas gingivalis (Pg)/Total bacteria (Tb), Fusobacterium nucleatum (Fn)/Tb, and Aggregatibacter actinomycetemcomitans (Aa)/Tb (p < 0.05) but not in Streptococcus salivalius/Tb. Effect sizes for Pg, Fn and Aa were 0.360, 0.556, and 0.164, respectively. The antibacterial compounds of the BGP-containing toothpaste included a mixture of kaempferide/betuletol., Conclusions: We confirmed the efficacy of propolis toothpaste with an optimal kaempferide/betuletol ratio for improving oral microbiota, thereby suggesting that BGP toothpaste is clinically useful in maintaining oral health and preventing periodontal disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background/aim: We have previously reported the protection of doxorubicin-induced keratinocyte toxicity by alkaline extract of the leaves of Sasa senanensis Rehder (SE). In order to extend the generality of the cell protective effect of SE, we investigated whether it also protects rat PC12 and human SH-SY5Y neuron model cells from amyloid β-peptide (Aβ)-induced injury., Materials and Methods: Viability of cells was determined by the MTT method. Cytotoxicity was evaluated by the concentration that reduces the cell viability by 50% (CC 50 ). Protection from Aβ-induced cytotoxicity was evaluated by the concentration that reversed the Aβ-induced reduction of viability by 50% (EC 50 ). The selectivity index (SI) of neuroprotective activity was defined as the ratio of EC 50 to CC 50 Aβ 1-42 aggregation was assayed using Aβ 1-42 ammonium hydroxide., Results: SE showed hormetic growth stimulation at lower concentrations in both neuron precursors and differentiated cells. SE reproducibly inhibited Aβ-induced cytotoxicity against both undifferentiated and differentiated neuron cells. Both the extent of differentiation induction and viability depended on the cell density, suggesting the release of growth and differentiation stimulation substances into culture supernatant. Higher concentrations of SE partially reduced the Aβ 1-42 aggregation., Conclusion: Hormetic growth stimulation and inhibition of aggregation may be involved in the neuroprotective activity of SE., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

This review article summarizes the recent progress of ultraviolet rays (UV) protective substances, including our original reports. We have established a simple assay method for the determination of anti-UV activity that can be applicable to any kind of adherent cells. This method provides information of both anti-UV activity and cytotoxicity of any kind of samples even though those samples contain unknown amounts of test compounds. We found that lignin-carbohydrate complex (LCC) showed one- or two-order higher anti-UV activity compared to well-known lower molecular weight polyphenols and hot-water extracts of Kampo medicines and tea leaves. Among synthetic compounds, water-soluble azulenes showed the highest anti-UV activity. LCC showed additive or synergistic anti-UV activity with vitamin C. Alkaline extract of Sasa senanensis Rehder leaves (SE), an LCC-rich over-the-counter (OTC) drug, also showed potent antiviral and vitamin C-synergized radical scavenging activity. SE has been utilized to manufacture tooth paste, soap and gel cosmetic to increase the level of quality of life (QOL)., (Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Previous studies have shown a much greater antiviral activity of alkaline extract of the leaves of Sasa senanensis Rehder (SE) against human immunodeficiency virus (HIV), compared to lignin precursors, tannins and flavonoids, suggesting its possible application to oral diseases. Systematic comparative study with herpes simplex virus (HSV) has been limited compared to that with HIV. In the present study, we investigated whether combination of SE with other popular antiviral agents further enhances their individual activity., Materials and Methods: Cell viability of mock-infected, HIV-infected and HSV-infected cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The antiviral activity was evaluated by the selectivity index, defined as the ratio of 50% cytotoxic concentration to 50% effective concentration. Synergy between SE and antiviral agents was evaluated by MacSynerg and CompuSyn software., Results: SE showed potent anti-HIV activity, although its activity was two-orders lower than that of azidothymidine, 2',3'-dideoxycytidine dextran sulfate and curdlan sulfate. Combination of SE with these antiviral agents produced synergistic effects. Using a newly established MTT assay system for anti-HSV activity, SE and acyclovir were found to have synergistic anti-HSV activity., Conclusion: The present study suggests the possible efficacy of the clinical application of SE combined with antiviral agents., (Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Previous studies have shown activity against viruses, bacteria, inflammation and oral lichenoid dysplasia of alkaline extract of the leaves of Sasa senanensis Rehder (SE), suggesting its possible application to oral diseases. In the present study, we performed a small-scale clinical test to investigate whether SE is effective against halitosis and in oral bacterial reduction., Materials and Methods: A total of 12 volunteers participated in this study. They brushed their teeth immediately after meals three times each day with SE-containing toothpaste (SETP) or placebo toothpaste. Halitosis in the breath and bacterial number on the tongue were measured by commercially available portable apparatuses at a specified time in the morning., Results: Some relationship was observed between halitosis and bacterial number from each individual, especially when those with severe halitosis were included. Repeated experiments demonstrated that SETP significantly reduced halitosis but not the bacterial number on the tongue., Conclusion: The present study provides for the first time the basis for anti-halitosis activity of SE., (Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Background: Previous studies have shown antiviral, antibacterial, and anti-inflammatory activity of alkaline extract of the leaves of Sasa senanensis Rehder (SE). In order to manufacture an SE-containing toothpaste for combating oral diseases, we investigated the possible interaction between the candidate ingredients of toothpaste: SE, isopropyl methylphenol (IPMP, antibacterial agent) and charcoal prepared from Sasa senanensis Rehder., Materials and Methods: Cell viability of mock-infected, HIV-infected and UV-irradiated cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Superoxide radical scavenging activity was determined by electron-spin resonance spectroscopy. Antibacterial activity against Porphyromonas gingivalis 381 and Streptococcus mutans ATCC25175 was determined by the turbidity assay., Results: Exposure to less than 50% SE or less than 0.31 mM IPMP for 10 min scarcely damaged human cultured gingival and periodontal ligament fibroblasts. Both SE and IPMP showed bi-modal action, stimulating the bacterial growth at lower concentrations, but synergistically inhibiting it at higher concentrations. Addition of extremely high concentrations of charcoal enhanced both anti-HIV and anti-UV activity of SE., Conclusion: Practically, addition of charcoal may not be recommendable, since one or two orders higher concentrations of charcoal as compared with SE, are required to achieve the synergistic effect for anti-HIV and anti-UV activity. Rather, addition of about one tenth of the amount of IPMP may be recommendable for enhancing the antibacterial activity.

Background: Previous studies have shown antiviral, antibacterial, and anti-inflammatory activity of alkaline extract of the leaves of Sasa senanensis Rehder (SE). Here, we investigated whether SE is effective on oral lichenoid dysplasia and osteoclastogenesis., Materials and Methods: A male patient with white lacy streaks in the oral mucosa was orally administered SE three times a day for 11 months. The area of white streaks was monitored by intraoral photography. Interleukin-6 and -8 in the saliva were determined by enzyme-linked immunosorbent assay. Osteoclastogenesis of mouse macrophage-like RAW264.7 cells, induced by receptor activator of nuclear factor-κB ligand (RANKL) was monitored by tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cell formation., Results: Long-term treatment with SE progressively reduced both the area of white steaks and the levels of salivary interleukin-6 and -8. SE significantly inhibited the macrophage differentiation towards osteoclasts., Conclusion: The present study suggests the therapeutic potential of SE towards oral diseases.

Phytophenols such as para-substituted 2-methoxyphenols exhibit antioxidant and anti-inflammatory activities, however, their biological activities are concentration-dependent, possibly due to their dual property of being both antioxidant and prooxidant. Eugenol (2-allyl-2-methoxyphenol) and isoeugenol (4-propenyl-2-methoxyphenol) did not reveal cyclooxygenase-2 (COX-2)-inhibiting activity in macrophages stimulated with lipopolysaccharide (LPS). In contrast, vanillin (2-hydroxy-3-methoxybenzaldehyde) and guaiacol (2-methoxyphenol), especially the former, inhibited LPS-stimulated nuclear factor kappa B (NF-kappaB) activation and cyclooxygenase (COX)-2 gene expression in cells of the RAW 264.7 murine macrophage cell line. Among the 2-methoxyphenols, vanillin demonstrated a potent anti-inflammatory activity. The phenolic O-H bond dissociation enthalpy (BDE) and molecular orbital energies (chemical hardness [eta], electronegativity [chi], and electrophilicity [omega]) were examined to clarify the mechanism responsible for inhibition of COX-2 expression. The BDE, chi, and omega values for vanillin were significantly higher than the corresponding values for the other 2-methoxyphenols. The anti-inflammatory activity of 2-methoxyphenols depended on the BDE and the phenol function was crucial for eliciting this activity. In addition, the anti-inflammatory activity depended on the chi and omega. These findings make vanillin attractive as a candidate therapeutic agent.

We have previously reported that sodium fluoride (NaF) showed slightly higher cytotoxicity against human oral tumor cell lines than normal human oral cells. Possible changes in the NaF sensitivity of three normal human oral cell types (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF) during in vitro ageing were investigated in the present study. When these cells were subcultured at 1:4 split ratio every week, their saturation density declined with increasing population doubling level (PDL), and they ceased to divide when they reached 20 PDL. Mitochondrial function, evaluated by MTT stainability per cell basis, was elevated at the terminal phase. NaF dose-dependently reduced the viable cell number, but did not show any beneficial (growth promoting) effect (so-called "hormesis") at lower concentrations. NaF produced large DNA fragments, without induction of internucleosomal DNA fragmentation, possibly due to weak activation of caspases -3, -8 and -9. Higher concentrations of NaF were required to reduce the number of viable senescent cells than younger cells, indicating that cells become resistant to cytotoxicity of NaF with in vitro ageing.

As an initial step to study the effect of sodium fluoride on the oral environment, we investigated how sodium fluoride (NaF) affects the branching morphogenesis of fetal mouse submandibular gland (SMG). When mouse SMG was prepared from the embryo at 13 days post prenatal stage and cultured, gradual development of branching morphogenesis was observed. Addition of NaF affected this morphological change in bimodal fashions. At a lower concentration of NaF (< 2 microM), the branching morphogenesis was slightly enhanced, whereas at a higher concentration of NaF (4 - 8 microM), it was almost completely inhibited. The inhibitory effect of NaF at the higher concentration was abrogated by stimultaneous addition of epidermal growth factor (EGF), but not by 5alpha-dihydrotestosterone (DHT) or insulin-like growth factor (IGF). These data demonstrate that EGF can effectively reduce the cytotoxic activity of NaF at micromolar concentration.

We investigated six endodontic agents for their ability to induce apoptosis and modify the cytotoxic activity of NaF against human squamous cell carcinoma (HSC-2) and human promyelocytic leukemia (HL-60) cell lines. Four Group I agents (Form Cresol, Cam Phenic, Eucaly Soft, GC Fuji Varnish), but not two Group II agents (Caviton, Canals-N), induced internucleosomal DNA fragmentation and activated caspases 3, 8 and 9 in HL-60 cells. Only Cam Phenic among these agents additively enhanced the cytotoxic activity of NaF in HSC-2 and HL-60 cells. Form Cresol and Cam Phenic reduced the glucose consumption at early stage, possibly due to their toxic effect. Amino acid analysis suggests that the higher cytotoxicity of Form Cresol may be derived, at least in part, from its oxidizing action.

We have recently found that sodium fluoride (NaF) induced apoptotic cell death in tumor cell lines. We investigated here whether 6 popular antitumor compounds modify the cytotoxic activity of NaF against human squamous cell carcinoma (HSC-2) and human promyelocytic leukemia (HL-60) cell lines. Cytotoxic concentrations of cisplatin, etoposide, doxorubicin or peplomycin (tentatively termed as Group I compounds), but not methotrexate and 5-FU (tentatively termed as Group II compounds), enhanced the cytotoxic activity of NaF. NaF and Group I compounds induced internucleosomal DNA fragmentation in HL-60 cells, whereas Group II compounds were inactive even in the presence of NaF. Most Group I compounds except doxorubicin (which induced DNA fragmentation less effectively than others) activated caspase 3 more efficiently than Group II compounds. Caspase 8 (involved in non-mitochondrial extrinsic pathway) and caspase 9 (involved in mitochondrial intrinsic pathway) were also activated, but to a much lesser extent. NaF reduced the glucose consumption at early stage, possibly by inhibition of glycolysis, whereas cisplatin and etoposide reduced the glucose consumption at later stage, suggesting that early decline of glucose consumption is rather specific to NaF.

We have recently found that millimolar concentrations of sodium fluoride (NaF) induced apoptotic cell death, characterized by caspase activation and DNA fragmentation, in tumor cell lines. This finding paved the way to investigating the interaction between NaF and the oral environment. As an initial step, we investigated redox compounds, metals and saliva, which may modify the cytotoxic activity of NaF against a human oral squamous cell carcinoma cell line (HSC-2). The minimum exposure time to NaF required for cytotoxicity induction was 8 hours. Noncytotoxic concentrations of antioxidants (sodium ascorbate, gallic acid, epigallocatechin gallate, chlorogenic acid, curcumin, superoxide dismutase, catalase), oxidants (hydrogen peroxide, sodium hypochlorite), metals (CuCl, CuCl2, FeCl2, FeCl3, CoCl2) or saliva neither protected against, nor enhanced the cytotoxic activity of NaF. Cytotoxic concentrations of these compounds produced somewhat additive, but not synergistic, effects on the cytotoxicity of NaF. ESR analysis demonstrated that NaF did not apparently change the radical intensity of sodium ascorbate and gallic acid, measured under alkaline conditions. During the cell death induction in human promyelocytic leukemia HL-60 cells by NaF, the consumption of glucose rapidly declined, followed by a decline in the consumption of major amino acids. The present study suggests that the cytotoxic activity of NaF is not regulated by the redox mechanism, but rather linked to the rapid decline in glucose consumption at early stage.