TGF-ß1 induces amoeboid-to-mesenchymal transition of CD44high oral squamous cell carcinoma cells via miR-422a downregulation through ERK activation and Cofilin-1 phosphorylation.

BACKGROUND: The objective of this study was to clarify the molecular mechanism of amoeboid-to-mesenchymal transition (AMT) of CD44high oral squamous cell carcinoma (OSCC) cells. METHODS: Morphology and expression of mesenchymal genes were investigated in CD44high OSCC cells (CD44high OM-1 cells) cultured on laminin-coated soft silicone gel. Additionally, microarray analysis was performed to investigate microRNA (miRNA) expression inhibited by transforming growth factor-ß1 (TGF-ß1) in CD44high OM-1 cells. RESULTS: When CD44high OM-1 cells were cultured on 2.0-kPa laminin-coated silicone gel, the cells exhibited an amoeboid-like round morphology. Cofilin-1 expression was found in the nucleus and cytoplasm of amoeboid-like CD44high OM-1 cells. The invasive capacity was significantly reduced after Cofilin-1 knockdown. Additionally, Cofilin-1 knockdown cells had an irregularly extended shape. Phosphorylated Cofilin-1 was significantly upregulated by TGF-ß1. Additionally, TGF-ß1 enhanced N-cadherin and Snail mRNA expression and induced a spindle-shaped morphology. ERK1/2 phosphorylation was induced by TGF-ß1. Microarray analysis revealed that miR-422a exhibited the greatest downregulation (fold change: 0.22) in the presence of TGF-ß1. Importantly, TGF-ß1-inhibited miR-422a expression was recovered by the ERK inhibitor or ERK1/2 knockdown. Additionally, miR-422a inhibitor-transfected CD44high OM-1 cells exhibited high N-cadherin and Snail mRNA expression. Furthermore, Cofilin-1 knockdown and miR-422a inhibition induced a spindle cell morphology. CONCLUSION: Cofilin-1 is involved in the invasive ability of CD44high OSCC cells. TGF-ß1 contributes to AMT by downregulation of miR-422a via ERK activation and Cofilin-1 phosphorylation. Our findings suggest that miR-422a and Cofilin-1 play major roles in the maintenance of amoeboid-like CD44high cells.

Age-related changes in oral tactile and thermal sensation throughout adulthood.

Although the life expectancy of women is over 80 years in many countries, oral sensation has scarcely been compared between adults ≥ 80 years and younger age groups. The purpose of this study was to clarify age-related changes in oral sensation throughout adulthood. After exclusion of individuals with factors that might have confounded somatosensory performance, 123 female participants were divided into four age groups: 20-39 years, 40-59 years, 60-79 years, and 80-96 years. Perceptions of tactile and thermal sensations were examined at points on the anterior and posterior palate, anterior and posterior tongue, lower labial-attached gingiva, lower lip, and buccal mucosa; two-point discrimination was examined only on the tongue. The tactile and two-point discrimination thresholds for the anterior and posterior tongue were significantly higher in the 80-96-year-old group than in any other age group (p < 0.05). The tactile threshold for the buccal mucosa was significantly higher in the 80-96-year-old group than in the 60-79-year-old group (p < 0.05). The percentage of participants able to perceive a warm stimulus (50 °C) in the buccal mucosa was significantly lower in the 80-96-year-old group than in the 20-39-year-old group (p < 0.05). Only the topography of the warm sensation perception changed with age. This cross-sectional study suggests that oral tactile and thermal sensation for warm stimuli deteriorates with age in a site-specific manner, especially after the age of 80 years, but the same does not occur with cool stimuli.

Rational extended thermodynamics of dense polyatomic gases incorporating molecular rotation and vibration.

The paper aims to construct a rational extended thermodynamics (RET) theory of dense polyatomic gases by taking into account the experimental evidence that the relaxation time of molecular rotation and that of molecular vibration are quite different from each other. For simplicity, we focus on gases with only one dissipative process due to bulk viscosity. In fact, in some polyatomic gases, the effect of bulk viscosity is much larger than that of shear viscosity and heat conductivity. The present theory includes the previous RET theory of dense gases with six fields as a particular case, and it also includes the RET theory of rarefied polyatomic gases with seven fields in the rarefied-gas limit. The closure is carried out by using the universal principles, that is, Galilean invariance and objectivity, entropy principle, and thermodynamic stability (convexity of entropy), where the duality principle connecting rarefied gases to dense gases also plays an important role. A detailed discussion is devoted to the expression of the production terms in the system of balance equations. As typical examples, we study a gas with virial equations of state and a van der Waals gas. Lastly the dispersion relation of a linear wave is derived, and its comparison with experimental data is made. This article is part of the theme issue 'Fundamental aspects of nonequilibrium thermodynamics'.

Bone Regeneration in a Canine Model of Artificial Jaw Cleft Using Bone Marrow-Derived Mesenchymal Stem Cells and Carbonate Hydroxyapatite Carrier.

OBJECTIVE: Cleft lip and palate (CLP) is a common anomaly of the orofacial region. Mesenchymal stem cell (MSC) transplantation has been a focus of regenerative medicine, and its application to the repair of bone defects in patients with CLP is highly anticipated. This study investigated the potential for using MSCs to regenerate bone in a jaw cleft as well as the survival of transplanted MSCs using a canine model of CLP. DESIGN: Mesenchymal stem cells collected from the bone marrow of beagle dogs were transplanted along with carbonate hydroxyapatite into jaw clefts in beagle dogs. Mesenchymal stem cells labeled with fluorescent silica nanoparticles were also transplanted, and a histological analysis was performed 3 months later to evaluate MSC survival. RESULTS: Carbonate hydroxyapatite regeneration into bone was enhanced by cotransplantation of MSCs. The survival rate of MSCs transplanted after 3 months was 5.7%. CONCLUSIONS: Transplanted MSCs promote bone regeneration, although their survival rate is low.

Measurement of bristle splaying of toothbrushes using digital imaging and evaluation of plaque removal efficacy over 3 months: A randomized controlled trial (RCT).

OBJECTIVE: The aim of this study was to develop an objective method to assess the degree of bristle splaying of used manual toothbrushes and to investigate their plaque removal efficacy. METHODS: A randomized controlled trial targeting Hiroshima University students was performed to assess the plaque removal efficacy of polybutylene terephthalate (PBT) manual toothbrushes. Participants were randomly assigned to the soft toothbrush group (n = 40) or the medium toothbrush group (n = 40). A small number of participants discontinued the intervention for personal reasons in both the medium (n = 6) and soft (n = 2) toothbrush groups. Toothbrushes were collected immediately after first use (T0: baseline), after 1 month of use (T1: month 1), after 2 months of use (T2: month 3) and after 3 months of use (T3: month 6), following the allocation of a new toothbrush. The bristle surface area was measured using digital software. RESULTS: The surface area of the bristles was significantly greater at T1, T2 and T3 than at T0 in the medium toothbrush group (n = 34) and soft toothbrush group (n = 38) (P < .001). Importantly, plaque removal efficacy, calculated from a modified plaque control record score and modified patient hygiene performance score, was significantly lower at T2 than at T0 in both groups. CONCLUSIONS: Our method for evaluation of bristle splaying is considered to be reliable and reproducible. PBT toothbrushes may become less effective after two months of use.

Extended Thermodynamics of Rarefied Polyatomic Gases: 15-Field Theory Incorporating Relaxation Processes of Molecular Rotation and Vibration.

After summarizing the present status of Rational Extended Thermodynamics (RET) of gases, which is an endeavor to generalize the Navier-Stokes and Fourier (NSF) theory of viscous heat-conducting fluids, we develop the molecular RET theory of rarefied polyatomic gases with 15 independent fields. The theory is justified, at mesoscopic level, by a generalized Boltzmann equation in which the distribution function depends on two internal variables that take into account the energy exchange among the different molecular modes of a gas, that is, translational, rotational, and vibrational modes. By adopting the generalized Bhatnagar, Gross and Krook (BGK)-type collision term, we derive explicitly the closed system of field equations with the use of the Maximum Entropy Principle (MEP). The NSF theory is derived from the RET theory as a limiting case of small relaxation times via the Maxwellian iteration. The relaxation times introduced in the theory are shown to be related to the shear and bulk viscosities and heat conductivity.

CD44(high) /ALDH1(high) head and neck squamous cell carcinoma cells exhibit mesenchymal characteristics and GSK3ß-dependent cancer stem cell properties.

BACKGROUND: CD44 and aldehyde dehydrogenase 1 (ALDH1) have been shown to be useful markers for identification of cancer stem cells (CSCs). We previously reported that glycogen synthase kinase 3ß (GSK3ß) is involved in regulation of the self-renewal ability of head and neck squamous cell carcinoma (HNSCC) CSCs. The purpose of the present study was to clarify the role of GSK3ß in CD44(high) /ALDH1(high) HNSCC cells. METHODS: Cells with greater expression of CD44 and higher ALDH1 enzymatic activity were FACS sorted from the OM-1 HNSCC cell line. The self-renewal ability of CD44(high) /ALDH1(high) cells was then examined using a tumor sphere formation assay. mRNA expressions of the stem cell markers Sox2, Oct4, and Nanog, as well as GSK3ß were evaluated by real-time RT-PCR. RESULTS: CD44(high) /ALDH1(high) cells exhibited higher tumor sphere forming ability and increased expression of stem cell markers as compared with CD44(high) /ALDH1(low) cells. Interestingly, spindle-shaped cells positive for vimentin were found in the CD44(high) /ALDH1(high) but not the CD44(high) /ALDH1(low) cell population. In addition, the ALDH1 activity and sphere forming ability of CD44(high) /ALDH1(high) cells was significantly inhibited by GSK3ß knockdown. On the other hand, CD44(high) /ALDH1(low) cells exhibited high epidermal growth factor receptor (EGFR) expression and increased cell growth. CONCLUSIONS: Our results show that GSK3ß plays a major role in maintenance of stemness of CD44(high) /ALDH1(high) HNSCC cells. Additionally, they indicate a close relationship between CSC and mesenchymal characteristics in HNSCC.

Elevation in 5-FU-induced apoptosis in head and neck cancer stem cells by a combination of CDHP and GSK3ß inhibitors.

BACKGROUND: Cancer stem cells (CSCs) are involved in both tumourigenesis and in tumour recurrence after therapy. In head and neck squamous cell carcinoma (HNSCC), there are two biologically different CSC phenotypes both of which express high levels of CD44 but differ in their expression levels of epithelial-specific antigen (ESA). One phenotype is CD44(high)/ESA(high) and has epithelial features (Epi-CSCs), while the other is CD44(high) /ESA(low), has undergone epithelial to mesenchymal transition (EMT-CSCs), has mesenchymal features and is migratory (Biddle et al., 2011). CSCs are resistant to therapeutically induced apoptosis but the molecular mechanisms by which they develop apoptotic resistance remains unclear. However, glycogen synthase kinase 3ß (GSK3ß) contributes to regulation of both the self-renewal and switching of these two CSC phenotypes (Shigeishi et al., 2013). METHODS: CD44(high) /ESA(low), CD44(high) /ESA(high) and CD44(low) cells were FACS sorted from the HNSCC cell line LUC4, and 5-FU-induced apoptosis was analysed by Annexin V staining followed by flow cytometry analysis. RESULTS: CD44(high) /ESA(low) cells exhibited marked resistance to 5-FU-induced apoptosis and had high expression of dihydropyrimidine dehydrogenase (DPD). The DPD inhibitor, 5-chloro-2, 4-dihydroxypyridine (CDHP) significantly enhanced 5-FU-induced apoptosis of CD44(high)/ESA(low) cells. Inhibition of GSK3ß induced CD44(high) /ESA(low) cells to undergo mesenchymal-to-epithelial transition (MET) to CD44(high)/ESA(high) cells and pre-existing CD44(high) /ESA(high) cells to differentiate. Apoptosis induced by 5-FU was thus facilitated. Combination of both CDHP and GSK3ß inhibitors markedly enhanced 5-FU-induced apoptosis of CD44(high) /ESA(low) cells. CONCLUSIONS: Our results suggest potentially new approaches for the elimination of the therapy resistant HNSCC CSC population.

Experimental Tooth Movement Into New Bone Area Regenerated by Use of Bone Marrow-Derived Mesenchymal Stem Cells.

OBJECTIVE: The aim of this study was to examine experimental tooth movement into regenerated bone in alveolar cleft with mesenchymal stem cells and a granulated carbonated hydroxyapatite scaffold. DESIGN: An artificial bone defect was created bilaterally in upper incisor regions of beagle dogs to simulate alveolar clefts in patients with cleft palate. The mesenchymal stem cells derived from the iliac bone marrow were cultured and transplanted with carbonated hydroxyapatite into the bone defect area. Carbonated hydroxyapatite alone was transplanted on the control side. Six months after the transplantation, multi-bracket appliances were attached to the lateral incisors and canines on both sides of the maxilla to exert an orthodontic force of 100 × g using an elastic chain. The distance between lateral incisor and canine was measured, and standardized x-ray images were taken every month. The tissue after tooth movement was evaluated by histological observation. RESULTS: The experimental tooth movement, accompanied by resorption of regenerated bone and new bone formation, was achieved on the experimental and control sides. Although there was no difference in the amount of tooth movement obtained on the experimental and control sides during the 6-month experimental period, the rate of tooth movement varied on the control side; whereas, the rate was consistent on the experimental side. Root resorption of the tooth was observed on the control side in one dog. CONCLUSION: It is suggested that mesenchymal/carbonated hydroxyapatite transplantation therapy has great potential as a new treatment modality for bone regeneration in patients with cleft palate.

Maintenance of stem cell self-renewal in head and neck cancers requires actions of GSK3ß influenced by CD44 and RHAMM.

Cells sorted from head and neck cancers on the basis of their high expression of CD44 have high potency for tumor initiation. These cells are also involved in epithelial to mesenchymal transition (EMT) and we have previously reported that cancer stem cells (CSCs) exist as two biologically distinct phenotypes. Both phenotypes are CD44(high) but one is also ESA(high) and maintains epithelial characteristics, the other is ESA(low) , has mesenchymal characteristics and is migratory. Examining CD44-regulated signal pathways in these cells we show that CD44, and also RHAMM, act to inhibit phosphorylation of glycogen synthase kinase 3ß (GSK3ß). We show that inhibitory phosphorylation reduces the formation of both "tumor spheres" and "holoclone" colonies, functional indicators of stemness. GSK3ß inhibition also reduces the expression of stem cell markers such as Oct4, Sox2, and Nanog and upregulates expression of the differentiation markers Calgranulin B and Involucrin in the CD44(high) /ESA(high) cell fraction. Transition of CSCs out of EMT and back to the epithelial CSC phenotype is induced by GSK3ß knockdown. These results indicate that GSK3ß plays a central role in determining and maintaining the phenotypes and behavior of CSCs in vitro and are likely to be involved in controlling the growth and spread of tumors in vivo.

Manual toothbrushes, self-toothbrushing, and replacement duration to remove dental plaque and improve gingival health: A scoping review from recent research.

OBJECTIVE: To investigate characteristics of manual toothbrushes, self-toothbrushing methods, and replacement duration of manual toothbrushes that effectively remove dental plaque, reduce gingivitis, and promote gingival health. STUDY DATA AND SOURCES: PubMed-MEDLINE, Scopus and Central Register Cochrane of Controlled trials (CENTRAL) were searched for randomized control trials (RCTs) from 01 January 2018 to 12 December 2023. Articles were subjected for including participants aged six years and older with a study duration of at least four weeks to investigate the efficacy of manual toothbrushes used self-toothbrushing. To investigate the appropriate time to replace manual toothbrushes, this study was focused on the physical properties of the bristles and changes in the microorganisms present in the bristles over time. STUDY SELECTION: Of 1520 retrieved articles, 26 studies were included after screening. The total number of manual toothbrushes was 40 and 5 kinds of self-toothbrushing techniques were selected in the review. 4 studies investigated the changes the physical properties bristles of manual toothbrushes. CONCLUSIONS: Among manual toothbrushes, the cross-angle and indicator bristles were found to significantly improve dental plaque index and gingival condition. Most toothbrushes with soft bristles had a trend of superior dental plaque removal and gingivitis improvement efficacy. Toothbrush with end-round shape bristles tip has tended to reduce the dental plaque and gingival index scores. Studies reported that brushing twice a day for at least two minutes using the Bass method had a positive effect on the dental plaque and gingival index. Further research is required to investigate the relationships between property physical bristle and clinical intraoral indices to clarify the replacement duration of manual toothbrushes. CLINICAL SIGNIFICANCE: The findings of this study could guide people's daily self-brushing habits, thereby aiding the prevention of periodontal disease. Moreover, our findings suggest the need for strategic clinical trial designs to verify the ideal timing to replace manual toothbrushes.

Age-dependent decrease in the chondrogenic potential of human bone marrow mesenchymal stromal cells expanded with fibroblast growth factor-2.

BACKGROUND AIMS: Human bone marrow mesenchymal stromal cells are useful in regenerative medicine for various diseases, but it remains unclear whether the aging of donors alters the multipotency of these cells. In this study, we examined age-related changes in the chondrogenic, osteogenic and adipogenic potential of mesenchymal stromal cells from 17 donors (25-81 years old), including patients with or without systemic vascular diseases. METHODS: All stem cell lines were expanded with fibroblast growth factor-2 and then exposed to differentiation induction media. The chondrogenic potential was determined from the glycosaminoglycan content and the SOX9, collagen type 2 alpha 1 (COL2A1) and aggrecan (AGG) messenger RNA levels. The osteogenic potential was determined by monitoring the alkaline phosphatase activity and calcium content, and the adipogenic potential was determined from the glycerol-3-phosphate dehydrogenase activity and oil red O staining. RESULTS: Systemic vascular diseases, including arteriosclerosis obliterans and Buerger disease, did not significantly affect the trilineage differentiation potential of the cells. Under these conditions, all chondrocyte markers examined, including the SOX9 messenger RNA level, showed age-related decline, whereas none of the osteoblast or adipocyte markers showed age-dependent changes. CONCLUSIONS: The aging of donors from young adult to elderly selectively decreased the chondrogenic potential of mesenchymal stromal cells. This information will be useful in stromal cell-based therapy for cartilage-related diseases.

Development and evaluation of the "Toothbrushing Timer with Information on Toothbrushes" application: A prospective cohort pilot study.

OBJECTIVES: For people, it is challenging to be conscious of the appropriate toothbrushing time to maintain good oral health in daily life. The aim of this study was to preliminarily examine the utility of an application (app) that combines a toothbrushing timer and information on toothbrushes. MATERIALS AND METHODS: We developed the "Toothbrushing Timer with Information on Toothbrushes" app to help users ensure appropriate toothbrushing time and learn about the beneficial characteristics of toothbrushes. A total of 18 participants were registered for the study. At baseline (T0) and after 1 month (T1) of app usage, study participants answered a digital questionnaire that comprised three questions on oral health practice, self-efficacy in oral hygiene, and quality of life related to oral health (Oral Health Impact Profile-14 [OHIP-14]). RESULTS: Five participants were excluded from the analysis as they did not answer the digital questionnaire. Finally, 13 participants completed the survey with a follow-up of 1 month. The 13 participants were grouped into health professionals (n = 8) and non-health professionals (n = 5). The total scores for oral health practice and self-efficacy related to oral hygiene increased after a month of app usage in health professional and non-health professional groups. However, there were no significant differences between T0 and T1 in either group. The total score of OHIP-14 was lower at T1 than at T0 in both groups. Therefore, participants showed better oral health practice, self-efficacy in oral hygiene, and quality of life related to oral health at T1 compared with that at T0. CONCLUSIONS: Our app showed positive results for the users and is useful in maintaining and promoting oral health awareness and practice. However, our pilot study lacks sufficient power and did not yield significant differences. Therefore, high-quality clinical trials with larger sample sizes are warranted for further improvement and evaluation.

Effectiveness of e-learning to promote oral health education: A systematic review and meta-analysis.

BACKGROUND: In recent times during and after the COVID-19 pandemic, e-learning is increasingly being used to give oral health education. However, the efficacy of e-learning in improving and promoting the oral hygiene and oral health knowledge, attitude and practice is unclear. Therefore, this systematic review and meta-analysis aim to clarify the effectiveness of e-learning compared to other conventional education methods for providing oral health. METHODS: An electronic database search was performed on PubMed-Medline, Scopus, and CENTRAL (Central Register Cochrane of Controlled trials). Randomized controlled trials (RCTs), including cluster or group RCTs, were collected in this study. The risk of bias was assessed with the Cochrane Handbook for Systematic Reviews of Interventions. Five different meta-analyses were conducted for plaque index, gingival index, oral health knowledge, oral health attitude, and oral health practice using a random effects model. RESULTS: A total of 282 articles were found through the database search; 19 articles were included in the qualitative synthesis and 9 articles in the quantitative synthesis. The meta-analysis found that compared with conventional education, e-learning exhibited no positive effect. However, the use of e-learning was superior to conventional education methods for oral health practice for adults in subgroup analysis. CONCLUSIONS: This paper could not indicate the effectiveness of e-learning in comparison with conventional education for oral health in total. However, for adults, it may be effective to get the oral health practice compared to the conventional education. Our study limitation is that there are only few studies that have assessed the effectiveness of e-learning. Therefore, numerous further high-quality studies should be conducted regarding the efficacy of e-learning compared with conventional education methods for oral health promotion.

Associations between Oral Human Herpesvirus-6 and -7 and Periodontal Conditions in Older Adults.

BACKGROUND: The associations between oral human herpesvirus-6 (HHV-6) and HHV-7, periodontal conditions, and lifestyle-related diseases, such as hypertension, diabetes, and dyslipidemia, have not been fully investigated in older adults. METHODS: Seventy-four older patients who visited Hiroshima University Hospital were enrolled. Tongue swab samples were employed, and a real-time polymerase chain reaction was performed to detect HHV-6 and HHV-7 DNA. Dental plaque accumulation, probing pocket depth, and bleeding on probing (BOP) (i.e., a sign of periodontal inflammation) were examined. The periodontal inflamed surface area (PISA) value (i.e., an indicator of the severity of periodontitis) was also examined. RESULTS: Of the 74 participants, one participant (1.4%) was HHV-6 DNA-positive and 36 participants (48.6%) were HHV-7 DNA-positive. A significant association between HHV-7 DNA and probing depth was found (p = 0.04). The HHV-7 DNA-positive participants had a higher positive rate of a ≥6-mm periodontal pocket with BOP (25.0%) than the HHV-7 DNA-negative participants (7.9%). Additionally, the HHV-7 DNA-positive participants had a higher PISA value than the HHV-7 DNA-negative participants. However, there was no significant association between HHV-7 and the PISA value (p = 0.82). No significant association was found between HHV-7 and lifestyle-related diseases (p > 0.05). CONCLUSIONS: Oral HHV-7 infection is associated with a deep periodontal pocket.

The green tea polyphenol (-)-epigallocatechin gallate precipitates salivary proteins including alpha-amylase: biochemical implications for oral health.

Green tea is a popular drink throughout the world, and it contains various components, including the green tea polyphenol (-)-epigallocatechin gallate (EGCG). Tea interacts with saliva upon entering the mouth, so the interaction between saliva and EGCG interested us, especially with respect to EGCG-protein binding. SDS-PAGE revealed that several salivary proteins were precipitated after adding EGCG to saliva. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) peptide mass fingerprinting indicated that the major proteins precipitated by EGCG were alpha-amylase, S100, and cystatins. Surface plasmon resonance revealed that EGCG bound to alpha-amylase at dissociation constant (K(d)) = 2.74 × 10(-6) M, suggesting that EGCG interacts with salivary proteins with a relatively strong affinity. In addition, EGCG inhibited the activity of alpha-amylase by non-competitive inhibition, indicating that EGCG is effective at inhibiting the formation of fermentable carbohydrates involved in caries formation. Interestingly, alpha-amylase reduced the antimicrobial activity of EGCG against the periodontal bacterium Aggregatibacter actinomycetemcomitans. Therefore, we considered that EGCG-salivary protein interactions might have both protective and detrimental effects with respect to oral health.

Analysis of the Deflection, Bristle Splaying, and Abrasion of a Single Tuft of a Polybutylene Terephthalate Toothbrush after Use: A Randomized Controlled Trial.

The aim of this study is to clarify the deflection, splaying, and abrasion of single tufts of polybutylene terephthalate (PBT) toothbrushes after use. A single-center randomized controlled trial is performed. The changes in deflection, bristle splaying, and abrasion are investigated for the middle single tuft of the top line (top-middle tuft) and the middle single tuft of the bottom line (bottom-middle tuft) of PBT toothbrushes with medium stiffness after 1 month, 2 months, and 3 months of use by 34 participants. A soft-material bending-resistance tester is used to assess the deflection of the single tufts. The deflection value of the top-middle tuft significantly increased after 1 month of use compared with the baseline. In contrast, the deflection of the bottom-middle tuft significantly increased after 3 months of use compared with the baseline and after 1 month and 2 months of use. Importantly, the change in deflection was distinctly different between the top- and bottom-middle tufts. The bristle splaying of both tufts significantly increased after use, but a significant change in bristle abrasion was not found. The bending stiffness of the top tuft of a PBT toothbrush may decrease more rapidly than that of the bottom tuft with use.

Prevalence of oral Epstein-Barr virus and Porphyromonas gingivalis and their association with periodontal inflamed surface area: A cross-sectional study.

We previously reported that oral herpesviruses, such as Epstein-Barr virus (EBV), are associated with periodontitis. However, the relationship between oral EBV or dual oral EBV and Porphyromonas gingivalis infections and periodontal inflammation severity remains unclear. We conducted this study to determine the relationship between oral EBV and P gingivalis prevalence and the periodontal inflamed surface area (PISA) in middle-aged and older adults. We analyzed 205 patients (median age, 70 years) who visited Hiroshima University Hospital. Tongue swab samples were used to investigate the presence of EBV and P gingivalis DNA using real-time PCR. Probing pocket depth and bleeding on probing were measured at 6 sites per tooth. PISA scores were calculated based on the results of probing pocket depth and bleeding on probing. Propensity scores were calculated via logistic regression analysis of 8 clinical factors: age, sex, smoking status, remaining teeth, denture use, hypertension, diabetes, and hyperlipidemia. EBV DNA was present in 41 of the 205 participants (20.0%). Thirty-seven EBV-positive or -negative participants in 74 matched pairs after propensity-score matching were examined via univariate analysis. EBV-positive participants exhibited higher plaque control record scores and PISAs than did EBV-negative participants. EBV DNA was significantly associated with plaque control record scores and PISA (both P = .04). Of the 205 participants, 111 were positive for P gingivalis (54.1%). Nineteen participants (9.3%) were infected with both oral EBV and P gingivalis. Logistic regression analysis revealed that dual infection with EBV and P gingivalis was significantly associated with diabetes (odds ratio = 3.37, 95% confidence interval: 1.13-10.1; P = .03). Oral EBV prevalence is associated with oral hygiene and the spread of inflamed periodontal tissue. Diabetes may be a risk factor for dual infection with oral EBV and P gingivalis.

Relationship between the prevalence of oral human papillomavirus DNA and periodontal disease (Review).

Human papillomavirus (HPV) is a small DNA virus that infects the basal keratinocytes of squamous epithelium in the skin, and in the oral and genital mucosa. Smoking and sexual behavior have been recognized as significant risk factors for oral HPV infection. In the present review, the findings of recent studies of oral HPV infection in relation to periodontitis are discussed, as well as periodontopathic bacteria and periodontal herpes virus. Previous research suggests that HPV localizes to the inflammatory periodontal tissue. Inflammatory periodontal pockets may thus act as a reservoir for HPV. The interactions between HPV and periodontopathic bacteria remain unclear, but it is hypothesized that oral HPV infection may be related to a characteristic oral microbiome. Smoking is associated with HPV and periodontitis, as smoking induces destruction of periodontal tissue and suppresses the host defense, allowing HPV to infect periodontal tissue. Carcinogenic HPV and periodontitis may lead to the development of oral cavity cancer. However, oral HPV E6/E7 expression (transcriptionally active HPV) has not yet been fully investigated in patients with periodontitis. Collectively, the evidence suggests that oral HPV prevalence may be associated with periodontitis. The effect of clinical factors (age, sex, smoking, immunosuppressive condition and vaccination) on oral HPV DNA prevalence should be considered when clarifying the relationship between oral HPV and periodontitis. Additionally, the sampling method should be carefully chosen to directly detect HPV DNA in periodontal tissues.

Relationship between oral and physical function and length of participation in long-term care prevention programs in community-dwelling older Japanese women.

PURPOSE: The present study aimed to clarify the relationship between community-dwelling older women's participation period in community-based exercise programs and their oral and physical functioning. METHODS: From May to September 2019, we recruited 205 older women (mean age: 77.6 ± 5.5 years) who had joined weekly long-term care prevention programs such as community-based exercise programs that included oral and physical exercises, in Hiroshima Prefecture, Japan. Physical function was evaluated using a handgrip strength test, a Timed Up & Go test, a one-leg standing test, and a 30-s chair stand test. Tongue pressure, oral diadochokinesis, and Dysphagia Risk Assessment for the Community-dwelling Elderly were measured to evaluate oral functioning. After adjusting for clinical factors (i.e., age, BMI, hypertension, diabetes, stroke, heart disease, joint disease, osteoporosis, remaining teeth, denture use, oral wetness, history of dental examinations in the last year, use of interdental brush and/or dental floss), we compared the oral and physical function parameters of participants from varying program engagement periods using propensity score matching. RESULTS: A significant increase in mean handgrip strength was found in people who had been participating for ≥ 5 years compared with those who had been participating for < 5 years (p = 0.01). Furthermore, repetition of the monosyllable/ka/was significantly greater for people in the ≥ 5 years group compared with those in the < 5 years group (p = 0.03). CONCLUSION: Long-term participation in an exercise program is positively associated with handgrip strength and tongue motor function in independent older women.