18­α­glycyrrhetinic acid induces apoptosis in gingival fibroblasts exposed to phenytoin.

Phenytoin (PHT)-induced gingival overgrowth is caused by the increased proliferation and reduced apoptosis of gingival fibroblasts in inflammatory gingiva. Licorice has long been used as a component of therapeutic preparations. It inhibits cell proliferation, induces cell apoptosis and has anti-inflammatory effects. 18-α-glycyrrhetinic acid (18α-GA), the active compound in licorice, promotes apoptosis in various types of cells. The present study determined whether 18α-GA affects apoptosis in gingival fibroblasts exposed to PHT. The present study aimed to establish a basis for the therapeutic application of 18α-GA to treat the gingival overgrowth induced by PHT. Human gingival fibroblasts from healthy donors were cultured to semi-confluence and then stimulated in serum-free DMEM containing PHT with or without 18α-GA for subsequent experiments. Apoptotic cells were detected by ELISA. Analysis of the distribution of cell cycle phases and the apoptotic cell population was performed by flow cytometry. The expression levels of mRNAs and proteins of apoptotic regulators were measured using reverse transcription-quantitative PCR and western blotting, respectively. Caspase (CASP) activities were assessed by an ELISA. Treatment with 18α-GA markedly increased the number of apoptotic cells, reduced BCL2 mRNA expression, increased CASP2 and receptor (TNFRSF)-interacting serine-threonine kinase 1 (RIPK1) domain containing adaptor with death domain, Fas (TNFRSF6)-associated via death domain, RIPK1, tumor necrosis factor receptor superfamily; member 1A, TNF receptor-associated factor 2, CASP2, CASP3 and CASP9 mRNA expression, and also upregulated the protein expression levels and activities of caspase-2, caspase-3 and caspase-9. These results demonstrated that 18α-GA induced apoptosis through the activation of the Fas and TNF pathways in the death receptor signaling pathway in gingival fibroblasts treated with PHT. 18α-GA exhibited therapeutic potential for the treatment of PHT-induced gingival overgrowth.

Effects of Extraoral Suction on Droplets and Aerosols for Infection Control Practices.

Dental professionals are at increased risk of being infected with airborne pathogens such as SARS-CoV-2 because they are often exposed to droplets/aerosols production during dental treatment. To scientifically clear the effects of extraoral and oral suctions on the droplets and aerosols produced by dental treatments using an ultrasonic scaler was analyzed. The adenosine triphosphate and bacteria in droplets and aerosols produced during simulated scaling were quantitatively observed by reactions with luciferin/luciferase and incubation in culture plates to grow bacteria, respectively. The protection against spreading droplets and aerosols by oral and extraoral suctions was recognized, and the areas were limited to the left and posterior sides of the dental chair head when a right-handed dentist and dental hygienist performed scaling. Extraoral suction is a very useful tool for reducing the infection risk of COVID-19 in dental care, but the effective area is limited depending on physical characteristics of dentist and dental hygienist.

Mortality-and Health-Related Factors in a Community-Dwelling of Oldest-Older Adults at the Age of 90: A 10-Year Follow-Up Study.

Mortality is obviously intended for epidemiological studies of community-dwelling older adults. There are several health-related factors associated with nutritional status and mortality. The aim of this study was to elucidate the risk factor for mortality in community-dwelling oldest-older adults at the age of 90 and clarify the structure of health-related factors associated with mortality. A 10-year follow-up study was performed for 93 subjects at the age of 90. The mean and median of their survival days were 2373 and 2581 days for women, and 1694 and 1793 days for men. By Cox's proportional hazards model, health-related factors associated with mortality were self-assessed for chewing ability, activities of daily living (ADLs), serum albumin, total cholesterol, serum creatinine, and gripping power for women but not for men. These factors interacted with each other, and the association of these factors was different in women and men. Self-assessed chewing ability was a powerful risk factor for mortality in women at the age of 90. It acted independently from nutritional status. For older adults, addressing healthy food choices together with improved oral functions is useful. However, risk factors for mortality may depend on the life stage of subjects. To investigate the risk factor for the mortality, the life course approach is necessary.

Impact of the Serum Level of Albumin and Self-Assessed Chewing Ability on Mortality, QOL, and ADLs for Community-Dwelling Older Adults at the Age of 85: A 15 Year Follow up Study.

Quality of life (QOL) and mortality are true endpoints of epidemiological or medical research, especially for community-dwelling older adults. Nutritional status and activities of daily living (ADLs) are associated with QOL and mortality. Good oral health status supports a good nutritional status. The aim of this study was to elucidate the complex structure of these important health-related factors. We surveyed 354 healthy older adults at the age of 85. Nutritional status was evaluated by the serum level of albumin. QOL, ADLs, self-assessed chewing ability, serum albumin level, and mortality during the 15 year follow up period were analyzed. Self-assessed chewing ability was associated with QOL and ADLs. Self-assessed chewing ability for slight-hard foods was associated with mortality in men. However, it was not associated with the serum albumin level. The serum albumin level was associated with mortality in women. These results indicate that maintaining good oral function is not enough. Nutritional instruction in accordance with oral function is indispensable for health promotion in older adults. When planning health promotion strategies for older adults, different strategies are needed for men and women.

Effects of self-assessed chewing ability, tooth loss and serum albumin on mortality in 80-year-old individuals: a 20-year follow-up study.

BACKGROUND: The association between dental status and mortality in community-dwelling older adults has been documented by several studies. The aim of this study was to analyze the contribution of self-assessed chewing ability, number of remaining teeth and serum albumin levels to mortality and the interactions between the three factors. METHODS: A 20-year follow-up study was conducted with 666 subjects aged 80 years (from 1996 to 2017) who resided in the 8 areas served by one health center in Iwate Prefecture. Health check-ups including physical fitness measurements were conducted at a meeting place or gymnasium. Medical interview and blood sampling were conducted by physician. Oral examination was examined by dentist. The number of remaining teeth, serum albumin levels, and self-assessed chewing ability were used as predictors of mortality. RESULTS: Among the 608 subjects (233 men and 375 women) included in this study, only 12 subjects (1.97%) survived after 20 years of follow-up. For men, dental status and serum levels of albumin were significantly associated with mortality. The hazard ratios of self-assessed chewing ability calculated by item response theory analysis and the inability to chew at least one food adjusted for serum albumin and tooth conditions were statistically significant in men. When adjusted by health status evaluated by blood tests, self-assessed chewing ability was statistically significant in men. According to path analysis, self-assessed chewing ability and serum albumin independently affected mortality in men. CONCLUSION: Masticatory dysfunction may be an important risk factor for mortality in men, even though it was self-assessed. Retaining chewing ability might be a useful predictor of longevity in older male adults.

Treatment with low-level sodium fluoride on wound healing and the osteogenic differentiation of bone marrow mesenchymal stem cells.

BACKGROUND/AIMS: Lacerations of the oral mucosa and fractures of alveolar processes commonly occur in traumatic dental injuries (TDIs). Impaired wound healing and tissue regeneration have severe consequences on the quality of life. Bone marrow mesenchymal stem cells (BMMSCs) possess the ability of self-renewal and multipotential differentiation. Treatment with low-level sodium fluoride (NaF) has emerged as a promising approach to enhance wound repair. The aim of this study was to assess the effects of low-level NaF on soft tissue healing and on the proliferation, migration and extracellular matrix synthesis of BMMSCs. MATERIAL AND METHODS: BMMSCs derived from mice were treated with 50 µM, 500 µM, or 5 mM NaF for 12, 24, and 48 hours, and cell proliferation was assessed by the MTS assay. Cell motility was detected at 12 and 24 hours by a wound healing assay, and osteoblastic differentiation for 21 days by 1% Alizarin Red S staining in 50 µM NaF-treated BMMSCs. Gene expression of Runx2 and Osteocalcin was evaluated by quantitative real-time PCR. An experimental rat skin wound model was employed, and levels of c-Myc, Ki67, fibronectin, and vimentin were assessed by immunohistochemistry. RESULTS: There was a significant induction in the proliferation and migration of BMMSCs treated with 50 µM NaF. The expression of Ki67 and c-Myc protein was increased in tissues treated with 50 µM NaF, and the expression of fibronectin and vimentin in the 50 µM NaF-treated tissues was stimulated. Alizarin Red staining revealed enhanced mineralization in 50 µM NaF-treated BMMSCs with increased expression of Runx2 and Osteocalcin, indicating their upregulated osteogenic differentiation. CONCLUSION: Low-level NaF could promote soft tissue healing and hard tissue regeneration.

The epigenetic regulation of CXCL14 plays a role in the pathobiology of oral cancers.

Background: Chemokines selectively attract and activate leukocytes and play roles in a variety of homeostatic and disease processes. Explore the biological properties of CXCL14 seems complicated due to unknown functional characteristics of CXCL14 in cancer. Methods: To study the multistep process of oral cancer development, we analyzed oral samples spanning normalcy, dysplasia and cancer from multiple perspectives, revealing a cascade of progressive changes. Results: CXCL14 protein was expressed in the cytoplasm adjacent to tumors. T classification (P<0.001), clinical stage (P=0.0013) and nodal metastasis (P=0.0035) were significantly associated with CXCL14 in relationships between CXCL14 expression levels and tumor and patient characteristics. Compared with non-tumor tissue, expression of the epidermal growth factor receptor (EGFR) gene was increased in dysplasia and was further sustained in cancer. Our data show an inverse relationship between CXCL14 and EGFR expression levels in tumor cells indicating that CXCL14 expression is beneficial for tumor suppression. To explore epigenetic regulation and the impact of CXCL14 on oral cancer, analysis of CpG islands methylation in the CXCL14 promoter region indicated that the abnormal hypermethylation of that promoter region in tumor cells and tissues is one of the mechanisms causing the reduced expression. Restoration of CXCL14 expression was induced by treatment with 5-aza-2'-deoxycytidine. Using in vivo mouse models, we demonstrate that the restoration of CXCL14 expression in irradiation-induced oral carcinoma cells induces the expression of Late Cornified Envelope (LCE) genes. Conclusions: Our data suggest that LCE genes are a novel target of CXCL14 and are likely to have a tumor suppressor function through the modulation of CXCL14 expression. In conclusion, CXCL14 might play a pivotal role in the pathobiology of oral cancer, probably by regulating DNA methylation and leukocyte migration. The level of CXCL14 expression may be a valuable adjuvant parameter to predict the prognosis of patients with oral carcinoma and may be a potential therapeutic target.

Micromolar Levels of Sodium Fluoride Promote Osteoblast Differentiation Through Runx2 Signaling.

Bone remodeling is a vital physiological process of healthy bone tissue in humans. Imbalances in this vital process lead to pathological conditions, including periodontal diseases. In this study, we characterized the effects of micromolar levels of NaF on the proliferation and osteogenic differentiation of MC3T3-E1 osteoblastic cells. NaF significantly enhanced the proliferation, alkaline phosphatase (ALP) activity, and mineralization of MC3T3-E1 cells. Quantitative real-time PCR analysis revealed that the expression of mRNAs encoding runt-related transcription factor 2 (Runx2), Osterix, Osteopontin and Osteocalcin was up-regulated in NaF-treated MC3T3-E1 cells compared with untreated controls. Western blot analysis demonstrated that Runx2 and Osterix were inhibited by Runx2 siRNA but were re-activated by treatment with NaF. Furthermore, in vivo evidence indicated that NaF protects against Porphyromonas gingivalis-induced periodontal inflammation and alveolar bone loss in a P. gingivalis-challenged experimental periodontitis animal model. These data suggest that NaF promotes the osteoblastic differentiation of MC3T3-E1 cells through the Runx2/Osterix pathway and may be effective for the treatment of bone-related disorders.

Micromolar sodium fluoride mediates anti-osteoclastogenesis in Porphyromonas gingivalis-induced alveolar bone loss.

Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride (NaF) on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin (IL)-1ß, matrix metalloproteinase 9 (MMP9), and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL (receptor activator of nuclear factor κB ligand) and macrophage colony-stimulating factor (M-CSF). The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells (NFAT) c1 was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATc1, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.

Effects of coenzyme Q10 on salivary secretion.

OBJECTIVES: Dry mouth is a condition associated with reduced salivary secretion and is thought to be related to aging. This study was conducted to test whether reduced (ubiquinol) or oxidized (ubiquinone) forms of CoQ10 affect salivary secretion and salivary CoQ10 content before and after treatment. DESIGN AND METHODS: Sixty-six patients were given either ubiquinol or ubiquinone orally at a dosage of 100 mg/day, or a placebo for 1 month, and salivary secretion and salivary CoQ10 content were analyzed before and after treatment. RESULTS: Both parameters were significantly improved following treatment with either form of CoQ10, suggesting the effectiveness of CoQ10 in attenuating dry mouth symptoms. CONCLUSION: CoQ10 was locally detected in salivary glands, suggesting that orally administered CoQ10 was transported to the salivary glands via the blood stream and exerted its activity, improving salivary secretion.