Influence of Biofilm Maturity on the Antibacterial Efficacy of Cold Atmospheric Plasma in Oral Microcosm Biofilms.

As biofilms mature, biomass and extracellular polysaccharide (EPS) content increases, enhancing pathogenicity. Therefore, this study aimed to evaluate the antibacterial efficacy of cold atmospheric plasma (CAP) against oral microcosm biofilms and the influence of biofilm maturity on treatment. Oral microcosm biofilms were cultured on hydroxyapatite disks for 2 and 6 days. Based on the treatment and biofilm maturity, these were subsequently allocated into six groups (N = 19 each): Groups 1 and 2 were incubated with distilled water for 1 min; Groups 3 and 4 were treated with CAP for 2 min, and Groups 5 and 6 were treated with 0.12% chlorhexidine gluconate for 1 min. Groups 1, 3, and 5 represent 2-day biofilms, and Groups 2, 4, and 6 represent 6-day biofilms. Treatments were repeated daily for 5 days. Antibacterial efficacy was analyzed by measuring oral biofilms' red fluorescence intensity (RatioR/G) and quantifying EPS content and bacterial viability. The RatioR/G was 1.089-fold and 1.104-fold higher in Groups 4 and 6 than in Groups 3 and 5 following antibacterial treatment, respectively (p < 0.001). EPS content increased by 1.71-fold in Group 6 than in Group 5 (p < 0.001). Bacterial survival rate was the lowest in Group 3 (p = 0.005). These findings underscore the relevance of CAP treatment in maintaining antibacterial efficacy regardless of the biofilm development stage, highlighting its potential utility in oral care.

In vitro evaluation of the tooth bleaching efficacy and safety of high-concentration hydrogen peroxide with cold atmospheric plasma.

BACKGROUND: Using hydrogen peroxide (HP) for tooth bleaching may induce various side effects. Cold atmospheric plasma (CAP) is a promising solution. We aimed to evaluate and compare the efficacy and safety of tooth bleaching using high-concentration HP with CAP with conventional in-office bleaching. METHODS: Fifty-one discolored extracted human teeth were assigned to three groups: Group 1 (light-emitting diode with 35 % HP), Group 2 (CAP with 35 % HP), and Group 3 (only CAP). Bleaching was conducted over three sessions for a total of 20 min. The bleaching effect was evaluated based on the changes in color (ΔE00 and WID) and lightness (ΔL⁎ and ΔG). Safety was assessed by examining the dark areas on the enamel and monitoring the pulp chamber temperature. The study analyzed how different bleaching methods and durations affected ΔE00 and ΔWID using repeated-measures analysis of variance (ANOVA). The Kruskal-Wallis and Mann-Whitney tests were used for ΔL⁎ and dark areas, and one-way ANOVA for ΔG after 20 min of bleaching. RESULTS: The ΔE00 and WID demonstrated an interaction based on the bleaching method and time, with Group 1 exhibiting the highest ΔE00 and WID at all treatment times (p < 0.001). ΔL⁎ and ΔG did not differ significantly between Groups 1 and 2 (p = 0.056 and 0.062, respectively) and were lowest in Group 3 (p < 0.001). Group 1 exhibited the darkest areas and highest pulp chamber temperatures (p < 0.001). Group 1 exhibited statistically significant color changes. Group 2 demonstrated similar effects, but with enhanced safety profiles. CONCLUSIONS: Group 2, although displaying a slightly less pronounced color change compared with Group 1, achieved a color alteration readily discernible to the naked eye. This suggests that CAP with 35 % HP could be an interesting area for further investigation as an alternative to traditional in-office bleaching methods.

Development of a novel in vitro model for non-cavitated carious lesion formation reflecting carious lesion activity.

BACKGROUND: Oral biofilms are a critical component in dental caries formation. However, current remineralization studies often overlook the impact of microbial factors. Therefore, a comprehensive clinically relevant assessment of caries is needed. This study aimed to develop a novel in vitro model capable of generating non-cavitated carious lesions that incorporates both mineral loss and microbial activity using quantitative light-induced fluorescence-digital (QLF-D) technology. METHODS: A total of 44 artificial early carious lesions were formed using bovine incisors. The extent of fluorescence loss (ΔF) was analyzed using a QLF-D camera. Oral microcosm biofilms were then employed to construct 22 active and 22 inactive carious lesions. The red fluorescence emission rate (ΔR) and bacterial viability (RatioG/G+R) was measured using QLF-D camera and a live-dead bacterial assay, respectively. Independent t-tests were performed to compare ΔF, ΔR, and bacterial viability of artificial carious lesions according to their activity status. RESULTS: No significant difference in ΔF between the lesions was found based on activity status (p = 0.361). However, the ΔR of active lesions was 1.82 times higher than that of inactive lesions, and the RatioG/G+R was 1.49 times higher in active lesions than in inactive lesions (both p < 0.001). CONCLUSIONS: The significant differences observed in ΔR and RatioG/G+R between active and inactive lesions emphasize the importance of considering lesion activity status when evaluating the potential efficacy of remineralization agents. This study presents a novel in vitro remineralization assessment model that reflects carious lesion activity while controlling baseline mineral distributions of lesions.

Oral Health-Related Factors Associated with Dysphagia Risk among Older, Healthy, Community-Dwelling Korean Adults: A Pilot Study.

Most previous studies addressing dysphagia examined individuals who already had diseases causing dysphagia and did not pay much attention to oral health conditions as a risk factor. This pilot study investigated 62 healthy adults aged 65 years or older who were living independently in the community, performed basic activities of daily living independently, and had no history of a causative disease of dysphagia to identify the factors associated with dysphagia risk, especially oral health. The Dysphagia Risk Assessment Scale was used to screen the patients for dysphagia. Hyposalivation was diagnosed by evaluating the unstimulated salivary flow rate, and orofacial muscle strength (anterior tongue elevation, buccinator muscle, and lip strength) was quantitatively measured using the Iowa Oral Performance Instrument. To analyze the factors associated with dysphagia risk, the Mann-Whitney test, Kruskal-Wallis test, and multiple logistic regression analyses were conducted. In the final regression model adjusted for sociodemographic characteristics, the oral health-related factors independently associated with dysphagia risk were buccinator muscle strength, hyposalivation, and subjective masticatory discomfort (p < 0.05). Therefore, our findings suggest that weak buccinator muscle strength, hyposalivation, and subjective masticatory discomfort are valuable indicators for the early detection of dysphagia in older, healthy, independent, community-dwelling adults.

Red fluorescence intensity as a criterion for assessing remineralization efficacy in early carious lesions.

OBJECTIVES: Evaluating early carious lesion activity with an objective and clinically valid approach is crucial for developing effective treatment plans. Therefore, we here assessed the activity of non-cavitated carious lesions using a quantitative light-induced fluorescence-digital (QLF-D) camera and compared the remineralization efficiency after fluoride treatment according to the lesion's activity level. METHODS: Red fluorescence emission rate (ΔR) and fluorescence loss (ΔF) were evaluated in 44 non-cavitated carious lesions by using a QLF-D camera. Based on the ΔR level, the lesions were classified into 22 active (ΔR ≥37.55) and 22 inactive carious lesions (ΔR <37.55). Each lesion was treated with 1.23 % fluoride gel for 60 s and then immersed into artificial saliva for 7 days. Subsequently, ΔR and ΔF changes in the lesions were measured. RESULTS: Significant interactions between lesion activity and time were found for both ΔR and ΔF (p < 0.001). ΔR of active lesions declined faster and ΔF increased more steeply than did inactive lesions. Specifically, on day 7 post-fluoride treatment, the ΔR reduction rate was 1.40-times higher in active lesions, and the ΔF recovery rate was 2.50-times higher, indicating that active lesions respond more markedly to fluoride application. CONCLUSIONS: This study highlighted the significance of ΔR in predicting remineralization efficiency in non-cavitated carious lesions after fluoride application. It underscored the importance of accurately assessing caries activity when formulating effective treatment plans. Lesion activity, as determined by ΔR, not only influences the outcome of remineralization treatments but also provides a more objective measure for tailoring caries management strategies.

Impact of channel nanostructures of porous carbon particles on their catalytic performance.

Mesoporous carbon particles have great potential due to their unique structural properties as support materials for catalytic applications. Particle shapes and channel nanostructures of mesoporous carbon particles can determine the reactant/product transport efficiency. However, the role of the channel nanostructure in the catalytic reaction has not been much explored. Herein, we introduce a facile method to fabricate a series of porous carbon particles (PCPs) with controlled channel exposure on the carbon surface and investigate the impact of the channel nanostructure of the PCPs on the catalytic activity. By employing a membrane emulsification method with a controlled solvent evaporation rate, we fabricate block copolymer (BCP) particles with uniform size and regulated degrees of cylindrical channel exposed to the particle surface. Followed by the carbonization of the BCP particles, a low amount (1.3 wt%) of Pt is incorporated into the PCP series to investigate the impact of channel nanostructures on the catalytic oxidation reaction of o-phenylenediamine (OPD). Specifically, PCP featuring highly open channel nanostructures shows a high reaction rate constant of 0.154 mM-1 s-1 for OPD oxidation, showing 5.5 times higher catalytic activity than those of closed channel nanostructures (0.028 mM-1 s-1). This study provides a deeper understanding of the impact of channel nanostructure within mesoporous carbon particles on catalytic activity.

SAM-Support-Based Electrochemical Sensor for Aß Biomarker Detection of Alzheimer's Disease.

Alzheimer's disease has taken the spotlight as a neurodegenerative disease which has caused crucial issues to both society and the economy. Specifically, aging populations in developed countries face an increasingly serious problem due to the increasing budget for patient care and an inadequate labor force, and therefore a solution is urgently needed. Recently, diverse techniques for the detection of Alzheimer's biomarkers have been researched and developed to support early diagnosis and treatment. Among them, electrochemical biosensors and electrode modification proved their effectiveness in the detection of the Aß biomarker at appropriately low concentrations for practice and point-of-care application. This review discusses the production and detection ability of amyloid beta, an Alzheimer's biomarker, by electrochemical biosensors with SAM support for antibody conjugation. In addition, future perspectives on SAM for the improvement of electrochemical biosensors are also proposed and discussed.

Antimicrobial Effects of Non-Thermal Atmospheric Pressure Plasma on Oral Microcosm Biofilms.

We comparatively evaluated the antibacterial effects of non-thermal atmospheric pressure plasma (NTAPP) on oral microcosm biofilms. Oral microcosm biofilms, which are derived from inoculation with human saliva, were cultured on 48 hydroxyapatite disks for 6 days. The prepared biofilms were divided into three different daily treatment groups: distilled water for 1 min, 0.12% chlorhexidine (CHX) for 1 min, and NTAPP for 5 min. Using a quantitative light-induced fluorescence-digital camera, the red fluorescence intensity of the biofilms was measured as red/green ratios (RatioR/G) before and after treatment. Total and aciduric bacteria were counted as colony-forming units. Using live/dead bacterial staining, bacterial viability was calculated as the RatioG/G+R. RatioR/G was approximately 0.91-fold lower in the NTAPP group than in the CHX group on day 1 of treatment (p = 0.001), and approximately 0.94-fold lower on both days 2 and 3 (p < 0.001). The number of total bacteria was higher in the NTAPP group than in the CHX group, but not significantly different. The number of aciduric bacteria was lowest in the CHX group (p < 0.001). However, bacterial viability was lowest in the NTAPP group. Restricted bacterial aggregation was observed in the NTAPP group. These findings suggest that NTAPP may more effectively reduce the pathogenicity of oral microcosm biofilms than 0.12% CHX.

Factors Affecting Masticatory Performance of Older Adults Are Sex-Dependent: A Cross-Sectional Study.

This cross-sectional study assessed the oral and physical factors contributing to improvement of the masticatory performance of community-dwelling older adults in South Korea. We enrolled 84 healthy older adults (38 men, 46 women; age, 71.40 ± 5.15 years) and assessed their skeletal muscle mass index (SMI), functional tooth units (FTUs), and mixing ability index (MAI). Associations between variables were analyzed using Spearman's correlation coefficient, and the effects of SMI and FTUs on the MAI were evaluated through linear multiple regression. FTUs were positively associated with the MAI in men and women (r = 0.339, p = 0.038 and r = 0.461, p = 0.001, respectively). SMI and FTUs were moderately associated in men (r = 0.459, p = 0.004). MAI showed an approximately 4.4 times increase for each FTU in men (B = 4.442, p = 0.037); however, after the SMI was added, this effect was no longer significant. In women, the MAI increased by about 6.7 times with each FTU (B = 6.685, p = 0.004). FTUs had a significant effect on the MAI only in women with low muscle mass. While there was no significant effect of the SMI on the MAI, its influence should not be overlooked.

Catalytic approaches towards highly durable proton exchange membrane fuel cells with minimized Pt use.

Proton exchange membrane fuel cells (PEMFCs) produce electricity from H2 without carbon emission, and they are considered as environmentally benign energy conversion devices. Although PEMFCs are mature enough to find themselves in a few commercial automobiles such as Hyundai Nexo and Toyota Mirai, their durability should be enhanced, especially under transient conditions, and Pt use should be reduced significantly to expand their market. Herein, we introduce examples of how catalysts can contribute to enhancing the durability of PEMFCs while minimizing Pt use. Numerous electrocatalysts have been reported claiming superior activity in a half-cell setup, but they often fail to show the same enhancement in a single cell setup due to various transfer problems, impurity poisoning, etc. This perspective focuses on catalysts tested in a membrane-electrode-assembly (MEA) setup. As examples to obtain durability under transient conditions, catalysts used in reversal-tolerant anodes (RTAs) and selective anodes are explained. RTAs can endure sudden H2 starvation, and selective anodes can operate properly when O2 is unexpectedly mixed with H2 in the anode. As examples with high durability in long-term operation, Pt-based nanoparticle catalysts encapsulated with carbon shells are explained. Interestingly, PtCo nanoparticles supported on Co-N-C or PtFe nanoparticles encapsulated with a carbon shell presented a superior cell performance in spite of <1/10 Pt use in an MEA setup. Non-Pt group metal (PGM) catalysts used in an MEA setup are also briefly explained. With these highly durable catalysts which can respond properly under transient conditions with minimum Pt use, PEMFC technology can bring about a more sustainable society.

Identification of Survival-Specific Genes in Clear Cell Renal Cell Carcinoma Using a Customized Next-Generation Sequencing Gene Panel.

PURPOSE: Although mutations are associated with carcinogenesis, little is known about survival-specific genes in clear cell renal cell carcinoma (ccRCC). We developed a customized next-generation sequencing (NGS) gene panel with 156 genes. The purpose of this study was to investigate whether the survival-specific genes we found were present in Korean ccRCC patients, and their association with clinicopathological findings. MATERIALS AND METHODS: DNA was extracted from the formalin-fixed, paraffin-embedded tissue of 22 ccRCC patients. NGS was performed using our survival-specific gene panel with an Illumina MiSeq. We analyzed NGS data and the correlations between mutations and clinicopathological findings and also compared them with data from the Cancer Genome Atlas-Kidney Renal Clear Cell Carcinoma (TCGA-KIRC) and Renal Cell Cancer-European Union (RECA-EU). RESULTS: We found a total of 100 mutations in 37 of the 156 genes (23.7%) in 22 ccRCC patients. Of the 37 mutated genes, 11 were identified as clinicopathologically significant. Six were novel survival-specific genes (ADAMTS10, CARD6, NLRP2, OBSCN, SECISBP2L, and USP40), and five were top-ranked mutated genes (AKAP9, ARID1A, BAP1, KDM5C, and SETD2). Only CARD6 was validated as an overall survival-specific gene in this Korean study (p = 0.04, r = -0.441), TCGA-KIRC cohort (p = 0.0003), RECA-EU (p = 0.0005). The 10 remaining gene mutations were associated with clinicopathological findings; disease-free survival, mortality, nuclear grade, sarcomatoid component, N-stage, sex, and tumor size. CONCLUSIONS: We discovered 11 survival-specific genes in ccRCC using data from TCGA-KIRC, RECA-EU, and Korean patients. We are the first to find a correlation between CARD6 and overall survival in ccRCC. The 11 genes, including CARD6, NLRP2, OBSCN, and USP40, could be useful diagnostic, prognostic, and therapeutic markers in ccRCC.

Lens-Shaped Carbon Particles with Perpendicularly-Oriented Channels for High-Performance Proton Exchange Membrane Fuel Cells.

Two-dimensional sheet-like mesoporous carbon particles are promising for maximizing the number of active sites and the mass transport efficiency of proton exchange membrane fuel cells (PEMFCs). Herein, we develop a series of lens-shaped mesoporous carbon (LMC) particles with perpendicularly oriented channels (diameter = 60 nm) and aspect ratios (ARs) varying from 2.1 to 6.2 and apply them for the fabrication of highly efficient PEMFCs. The membrane emulsification affords uniform-sized, lens-shaped block copolymer particles, which are successfully converted into the LMC particles with well-ordered vertical channels through hyper-cross-linking and carbonization steps. Then, an ultralow amount (1 wt %) of platinum (Pt) is loaded into the particles. The LMC particles with higher ARs are packed with a higher density in the cathode and are better aligned on the cathode surface compared to the LMC particles with lower ARs. Thus, the well-ordered channels in the particles facilitate the mass transport of the reactants and products, significantly increasing the PEMFC performance. For example, the LMC particles with the AR of 6.2 show the highest initial single cell performance of 1135 mW cm-2, and the cell exhibits high durability with 1039 mW cm-2 even after 30 000 cycles. This cell performance surpasses that of commercial Pt/C catalysts, even at 1/20 of the Pt loading.

Different outcomes of multiple sialadenitis involving the submandibular and zygomatic salivary glands in a Welsh Corgi dog.

A ten-year-old indoor, castrated male Cardigan Welsh Corgi (Canis familiaris) presented with the chief complaints of chronic vomiting, retching, hypersalivation, and bilateral submandibular masses for two months. The systemic examinations, including serum chemistry, radiography, ultrasonography, and fluoroscopy, were unremarkable. A fine-needle aspiration revealed bilateral submandibular sialadenitis. Broad-spectrum antibiotics with phenobarbital were prescribed to alleviate the ptyalism. Thereafter, the left submandibular glands were normalised, and the right submandibular glands decreased to half their size. Three weeks later, the animal had an emergency visit because of a sudden left exophthalmos. Computed tomography and magnetic resonance imaging revealed enlarged left zygomatic and right mandibular salivary glands. The affected glands were surgically removed; the histopathologic examination confirmed non-septic sialadenitis, and the patient was finally diagnosed with idiopathic sialadenitis. Vomiting continued after the gland removal and the dog required a gradual increase in the phenobarbital dosage and an additional antiepileptic drug (potassium bromide) to manage the symptoms. The patient died eight months later from an unknown cause. This case report of bilateral submandibular sialadenitis concurrent with unilateral zygomatic sialadenitis in a Welsh Corgi dog suggests that when multiple salivary glands are involved, the response to anti-epileptic drugs and the prognosis is poor compared to that involving a single salivary gland.

Successful management of feline CD4+ CD8+ T-cell mediastinal lymphoma with pericardial effusion.

A 2-year-old, castrated, male Russian blue cat presented with acute dyspnoea, cyanosis, and lethargy. A thoracic radiography revealed a large cranial mediastinal mass; the computed tomography revealed caudal lobe atelectasis of the right lung with pericardial and pleural effusions. The cytodiagnostic tests revealed high-grade CD4+ CD8+ T-cell mediastinal lymphoma as clinical stage Vb; l-asparaginase-cyclophosphamide-doxorubicin-vincristine-prednisolone (l-CHOP)-based chemotherapy was initiated, following which the mass shrunk rapidly; 1 week after the initiation of chemotherapy, the appetite-related and respiratory symptoms improved dramatically, and the pleural and pericardial effusion resolved. The patient remains in complete remission three years after the initiation of the l-CHOP chemotherapy. Therefore, the accurate diagnosis and instantaneous initiation of chemotherapy may resolve life-threatening pleural and pericardial effusions in cats with high-grade aberrant T-cell mediastinal lymphoma.

Remineralizing efficacy of fluoride in the presence of oral microcosm biofilms.

OBJECTIVES: The oral biofilm structure or composition can affect the penetration of remineralizing agents. Therefore, this study evaluated the remineralizing efficacy of fluoride using a pH-cycling model with oral microcosm biofilms. METHODS: Artificial carious lesions were formed in 80 bovine incisors. The pH-cycling conditions with or without oral microcosm biofilms were applied to 40 specimens each. The pH-cycling scheme was repeated for 12 days. Fluorescence loss (ΔF,%) of early carious lesions was measured for all specimens using a quantitative light-induced fluorescence-digital camera, before and after fluoride application. Biofilms on specimens were further analyzed for red fluorescence intensity (red/green ratios) and colony-forming unit counts. The effects of pH-cycling conditions and treatments on changes in ΔF (ΔΔF) and the effects of interactions between factors were analyzed using two-way analysis of variance. RESULTS: The fluoride-treated group with oral biofilms had an approximately 0.89-fold lower ΔΔF than the fluoride-treated group without oral biofilms (p < 0.0001). When oral biofilms were absent, the fluoride-treated group showed a 1.31-fold greater ΔΔF compared to that in the distilled water-treated group (p < 0.0001). When oral biofilms were present, the fluoride-treated group showed a 1.14-fold greater ΔΔF compared to that in the distilled water-treated group; however, this difference was not statistically significant. CONCLUSIONS: There was a significant difference in fluoride remineralizing efficacy based on the presence of biofilms on early carious lesions. Therefore, fluoride remineralization assessment in the absence of oral biofilms could lead to an overestimation of efficacy. CLINICAL SIGNIFICANCE: Fluoride application might not have a robust remineralization effect on early carious lesions in the presence of a mature biofilm on the tooth surface.

Factors affecting subjective and objective masticatory function in older adults: Importance of an integrated approach.

OBJECTIVES: This study aimed to subjectively and objectively assess masticatory function and identify related factors in older adults. METHODS: From July 2017 to September 2018, we enrolled 115 healthy participants aged between 65 and 86 years. They underwent oral examination, and their stimulated salivary secretion rate and masseter muscle tone and biomechanical properties were assessed. Masticatory performance with two-colored chewing wax was objectively evaluated using the mixing ability index (MAI). Key food intake ability (KFIA) was subjectively assessed using a questionnaire. RESULTS: The MAI score was significantly associated with the number of remaining teeth (r = 0.524, p < 0.001) and the tone (r = -0.222, p = 0.017), elasticity (r = -0.242, p = 0.009), and dynamic stiffness (r = -0.265, p = 0.004) of the masseter muscles. In contrast, the KFIA score was only significantly associated with the number of remaining teeth (r = 0.450, p < 0.001). A weak association between the MAI and KFIA scores was observed (r = 0.304, p = 0.001). CONCLUSIONS: A combination of objective and subjective methods should be used to accurately assess masticatory function in older adults. In addition to physical factors such as the number of remaining teeth, properties of the masticatory muscles should be evaluated to improve the masticatory function of older adults. CLINICAL SIGNIFICANCE: In addition to dental problems, various maxillofacial and oral factors must be considered when establishing management strategies for the improvement of masticatory function in older adults.

Influential Factors of Masticatory Performance in Older Adults: A Cross-Sectional Study.

While appropriate nutrient intake is important for older adults, various oral problems cause decreased masticatory function. This cross-sectional study aimed to identify the factors associated with decreased masticatory performance in older adults. Oral examinations were performed on 80 participants (mean age: 75.10 ± 5.64 years) to determine the number of functional tooth units (FTUs). Symptoms of periodontal and temporomandibular diseases were evaluated via a questionnaire. The tone, elasticity, and dynamic stiffness of the masseter muscle were measured using the Myoton® PRO device. The mixing ability test was used to assess the masticatory performance, and the mixing ability index (MAI) was calculated. The analysis of covariance test was performed to adjust for confounding factors, and multiple logistic regression analysis was performed to identify the risk factors affecting MAI. A lower MAI was significantly associated with higher tone (p = 0.006) and lower elasticity (p = 0.013). The number of FTUs (adjusted odds ratio (OR) = 0.724, p = 0.029), tone (adjusted OR = 1.215, p = 0.016), and elasticity (adjusted OR = 4.789, p = 0.038) were independently associated with the MAI. Muscle function training and prosthetic treatments may help increase masticatory performance in older adults, which would improve overall health.

Relationship between Vitamin D Deficiency and Periodontitis in Korean Adults Aged ≥60 Years: Analysis of Data from the Korea National Health and Nutrition Examination Survey (2013-2014).

There have been contradictory reports on the effects of vitamin D in the prevention of periodontitis. We analyzed the association between vitamin D status (levels of plasma 25(OH)D) and periodontitis using the Korea National Health and Nutrition Examination Survey (KNHANES) 2013-2014 database. Among the participants in the KNHANES (2013-2014), only those aged ≥60 years who completed a health interview survey, periodontal examination, and blood test were included in the study. Thus, data from 701 participants were used in the final analysis. Periodontal status was evaluated using the Community Periodontal Index (CPI), and periodontitis was defined as having a CPI score of 3 or 4. Plasma 25(OH)D levels were classified according to two criteria: 20 ng/mL and quartile value. The chi-square test and multivariate logistic regression analyses were performed to analyze the prevalence of periodontitis according to plasma 25(OH)D levels. Univariate analyses showed that periodontitis was not significantly associated with plasma 25(OH)D levels. In the multivariate logistic regression model adjusted for sociodemographic characteristics, the difference in the prevalence of periodontitis between those with a normal range of 25(OH)D and those with low plasma of 25(OH)D levels was not statistically significant. Vitamin D intake has been reported to have benefits in maintaining periodontal health; however, total plasma 25(OH)D levels showed no significant association with periodontitis based on CPI scores in this study. Additionally, these findings reaffirmed the importance of toothbrushing and smoking cessation to prevent periodontitis in people aged ≥60 years.

Antibacterial and antibiofilm activities of cinnamon essential oil nanoemulsion against multi-species oral biofilms.

Cinnamon essential oil (CEO) has antibacterial properties, but its ability to suppress the formation of multi-species oral biofilms has not been fully elucidated. This study evaluated the antibacterial and antibiofilm activities of cinnamon essential oil nanoemulsion (CEON) against oral biofilms formed using a microcosm biofilm model. The biofilms were formed on bovine enamel specimens over a 7-day period, during which all specimens were treated with one of three solutions: 5% CEON (n = 35), 0.5% cocamidopropyl betaine (n = 35), or 0.12% chlorhexidine gluconate (CHX; n = 35). Antibacterial and antibiofilm activities were determined by the red/green ratios (R/G values) of 7-day-old mature biofilms photographed with quantitative light-induced fluorescence-digital, the number of aciduric bacterial colony-forming units (CFUs) within each biofilm, and the absorbance of bacterial suspensions. One-way and repeated-measures analysis of variance were performed to compare differences among the three solutions. R/G values were lowest in the 0.12% CHX group, but not significantly differ from the 5% CEON group. The number of CFUs and absorbance were lowest in the 5% CEON group. This study showed that nanoemulsified CEO inhibited the maturation of multi-species oral biofilms and the growth of oral microorganisms in biofilms, including aciduric bacteria that cause dental caries.

Influence of a novel pH-cycling model using dental microcosm biofilm on the remineralizing efficacy of fluoride in early carious lesions.

OBJECTIVES: To evaluate the remineralizing efficacy of fluoride in early carious lesions using a novel microbial pH-cycling model that combines the chemical pH-cycling model with dental microcosm biofilms. MATERIALS AND METHODS: Artificial carious lesions were formed in 48 bovine incisors. The chemical and microbial pH-cycling models were applied to 24 specimens, respectively; the latter was applied after formation of dental microcosm biofilms for 6 days, based on the human saliva inoculation. The pH-cycling schedule was repeated for 12 days. All specimens were evaluated for fluorescence loss (ΔF) using quantitative light-induced fluorescence-digital before and after the pH-cycling. Specimen biofilms were further analyzed for red/green values (R/G ratios) and colony-forming units (CFUs). One-way analysis of variance and Tukey's post hoc analysis were used to analyze change in fluorescence loss (ΔΔF) according to the pH-cycling model and treatment. RESULTS: When the chemical pH-cycling and microbial pH-cycling models were used, ΔΔF was 1.36 (p = 0.008) and 1.17 (p > 0.05) times higher, respectively, in the fluoride-treated group than that in the distilled water-treated group. In the microbial pH-cycling model, R/G ratios and CFU counts of biofilms were not significantly different between treatments (p > 0.05). CONCLUSIONS: No significant difference was observed in the remineralizing efficacy of fluoride according to the presence of dental biofilms covering early carious lesions. CLINICAL RELEVANCE: The remineralizing efficacy of fluoride could be overestimated in the absence of dental biofilms. Therefore, for accurate evaluation of the clinical value of remineralizing agents, dental biofilms should be included in in vitro tests.