Effects of Coffee Intake on Oxidative Stress During Aging-related Alterations in Periodontal Tissue

Background/aim: The purpose of this study was to determine the anti-aging effects of coffee intake on oxidative stress in rat periodontal tissue and alveolar bone loss. Materials and methods: Male Fischer 344 rats (8 weeks old) were randomized to four groups; the baseline group immediately sacrificed, the control group fed with normal powdered food for 8 weeks, and the experimental groups fed with powdered food containing 0.62% or 1.36% coffee components for 8 weeks. Results: Alveolar bone loss and gingival level of 8-hydroxydeoxyguanosine were significantly lower in the 1.36% coffee group than in the control group. Nuclear factor erythroid 2-related factor 2 translocation to the nucleus was significantly higher in the 1.36% coffee group than in the control group. Conclusion: Continuous intake of 1.36% coffee could prevent age-related oxidative stress in the periodontal tissue and alveolar bone loss, possibly by up-regulating the Nrf2 signaling pathway

Detection of Salivary miRNAs That Predict Chronic Periodontitis Progression: A Cohort Study

The aim of this two-year cohort study was to investigate salivary microRNAs (miRNAs) that predict periodontitis progression. A total of 120 patients who underwent supportive periodontal therapy were recruited. Unstimulated whole saliva was collected at baseline. Two years later, 44 patients were followed up (median age, 67.1 years) and divided into two groups: progression group (n = 22), with one or more sites with clinical attachment level (CAL) progression (>3 mm compared with baseline) or tooth extraction due to periodontitis progression; and the control group (n = 22), which did not exhibit CAL progression. In the microarray analysis of salivary miRNAs, hsa-miR-5571-5p, hsa-miR-17-3p, hsa-let-7f-5p, hsa-miR-4724-3p, hsa-miR-99a-5p, hsa-miR-200a-3p, hsa-miR-28-5p, hsa-miR-320d, and hsa-miR-31-5p showed fold change values = 2.0 in the progression group compared with the control group (p 0.7, indicating fair discrimination power. The expressions of salivary hsa-miR-5571-5p, hsa-let-7f-5p, hsa-miR-99a-5p, hsa-miR-28-5p, and hsa-miR-320d were associated with periodontitis progression in patients with chronic periodontitis. These salivary miRNAs may be new biomarkers for progression of periodontitis, and monitoring them may contribute to new diagnostics and precision medicine for periodontitis

Effects of hydrogen-rich water on aging periodontal tissues in rats

Oxidative damage is involved in age-related inflammatory reactions. The anti-oxidative effects of hydrogen-rich water suppress oxidative damage, which may aid in inhibiting age-related inflammatory reactions. We investigated the effects of drinking hydrogen-rich water on aging periodontal tissues in healthy rats. Four-month-old male Fischer 344 rats (n = 12) were divided into two groups: the experimental group (hydrogen-rich water treatment) and the control group (distilled water treatment). The rats consumed hydrogen-rich water or distilled water until 16 months of age. The experimental group exhibited lower periodontal oxidative damage at 16 months of age than the control group. Although protein expression of interleukin-1 beta did not differ, gene expression of Nod-like receptor protein 3 inflammasomes was activated in periodontal tissues from the experimental group as compared with the control group. Drinking hydrogen-rich water is proposed to have anti-aging effects on periodontal oxidative damage, but not on inflammatory reactions in healthy rats

Effects of self-efficacy on oral health behaviours and gingival health in university students aged 18- or 19-years-old

Aim Although self-efficacy is known to affect various health-related practises, few studies have clearly examined how self-efficacy correlates with oral health behaviors or the oral health condition. We examined the relationship between gingivitis, oral health behaviors and self-efficacy in university students. Material & Methods A total of 2,111 students (1,197 males, 914 females) aged 18 and 19 years were examined. The degree of gingivitis was expressed as the percentage of bleeding on probing (%BOP). Additional information was collected via a questionnaire regarding oral health behaviors (daily frequency of tooth-brushing, use of dental floss and regular check-up). Self-efficacy was assessed using the Self-Efficacy Scale for Self-care (SESS). Path analysis was used to test pathways from self-efficacy to oral health behaviors and %BOP. Results In the final structural model, self-efficacies were related to each other, and they affected oral health behaviors. Good oral health behaviors reduced dental plaque and calculus, and lower levels of dental plaque and calculus resulted in lower %BOP. Conclusion Higher self-efficacy correlated with better oral health behaviours and gingival health in university students. Improving self-efficacy may be beneficial for maintaining good gingival health in university students. To prevent gingivitis, the approach of enhancing self-efficacy in university students would be useful

Preventive effects of trehalose on osteoclast differentiation in rat periodontitis model

Aim Trehalose, which is a disaccharide formed by a 1,1 linkage of two glucose molecules, was suggested to have a suppressive effect on bone resorption. In this study, we examined the effects of topical application of trehalose on osteoclast differentiation in a rat periodontitis model. Material and Methods Rats were divided into four groups. One group received no treatment. In the other groups, experimental periodontitis was induced by ligature placement. These rats with experimental periodontitis received topical application of pure water (vehicle group), 30 mg/ml trehalose solution (30 mg/ml trehalose group) or 60 mg/ml trehalose solution (60 mg/ml trehalose group) to the gingival sulcus respectively. Results The vehicle group showed higher numbers of polymorphonuclear leucocytes, receptor activator of nuclear factor kappa B ligand (RANKL)-positive cells and osteoclasts compared with the no treatment group respectively. Trehalose-applied groups exhibited lower numbers of these cells compared with the vehicle group. Gene expressions of tumour necrosis factor-a, RANKL and toll-like receptor 4 were suppressed by trehalose. In addition, protein expressions of RANKL inducing pathway were less activated by trehalose. Conclusion Topical application of trehalose could suppress osteoclast differentiation by inactivation of RANKL inducing pathway in the rat periodontitis model

Awareness of Clenching and Underweight are Risk Factors for Onset of Crowding in Young Adults: A Prospective 3-Year Cohort Study

Bruxism is a parafunctional activity that can seriously affect quality of life. Although bruxism induces many problems in the oral and maxillofacial area, whether it contributes to the onset of malocclusion remains unclear. The purpose of this prospective cohort study was to investigate the association between the onset of malocclusion and awareness of clenching during the daytime in young adults. Among 1,092 Okayama University students who underwent normal occlusion at baseline, we analysed 238 who had undergone a dental examination and had complete data after 3 years (2013⁻2016). We also performed subgroup analysis to focus on the association between awake bruxism and the onset of crowding (n = 216). Odds ratios (ORs) were calculated using multivariate logistic regression analyses. The incidences of malocclusion and crowding were 53.8% and 44.5%, respectively. In multivariate logistic regression, awareness of clenching was a risk factor for crowding (OR: 3.63; 95% confidence interval [CI]: 1.08⁻12.17). Moreover, underweight (body mass index < 18.5 kg/m²) was related to the onset of malocclusion (OR: 2.34; 95%CI: 1.11⁻4.92) and crowding (OR: 2.52, 95%CI: 1.25⁻5.76). These results suggest that awareness of clenching during the daytime and underweight are risk factors for the onset of crowding in young adults

Particle simulation approach for subcellular dynamics and interactions of biological molecules

BACKGROUND: Spatio-temporal dynamics within cells can now be visualized at appropriate resolution, due to the advances in molecular imaging technologies. Even single-particle tracking (SPT) and single fluorophore video imaging (SFVI) are now being applied to observation of molecular-level dynamics. However, little is known concerning how molecular-level dynamics affect properties at the cellular level. RESULTS: We propose an algorithm designed for three-dimensional simulation of the reaction-diffusion dynamics of molecules, based on a particle model. Chemical reactions proceed through the interactions of particles in space, with activation energies determining the rates of these chemical reactions at each interaction. This energy-based model can include the cellular membrane, membranes of other organelles, and cytoskeleton. The simulation algorithm was tested for a reversible enzyme reaction model and its validity was confirmed. Snapshot images taken from simulated molecular interactions on the cell-surface revealed clustering domains (size ~0.2 μm) associated with rafts. Sample trajectories of raft constructs exhibited "hop diffusion". These domains corralled the diffusive motion of membrane proteins. CONCLUSION: These findings demonstrate that our approach is promising for modelling the localization properties of biological phenomena

Occlusal disharmony induces BDNF level in rat submandibular gland

Objectives: Brain-derived neurotrophic factor (BDNF), which is produced in rat submandibular gland, is one of the most abundant neurotrophins in the central nervous system. It is generally accepted that occlusal disharmony causes stress. The purpose of the present study was to investigate whether occlusal disharmony-induced chronic stress affects BDNF levels and morphology in rat submandibular gland. Design: Eight wks old male Wistar rats (n = 21) were randomly divided into three groups of 7 rats. In a control (C) group, the rats received no treatment for 8 wks. In a molar cusp-less (OD) group, maxillary molar cusps were cut off with a dental turbine at baseline and kept for 8 wks. In a molar cusp-less + recovered cusp (OR) group, maxillary molar cusps were cut off and then were recovered after 4 wks using resin material. After the experimental period, expression of BDNF mRNA and protein as well as histological findings were evaluated in the submandibular glands. The comparisons between the groups were made using the Mann-Whitney U test with Bonferroni correction. Results: The OD group showed a significant increase in submandibular gland BDNF mRNA and protein expression after 8 wks, and plasma adrenocorticotropic hormone and corticosterone levels increased in a time-dependent manner. There were no significant differences in BDNF expression in the submandibular glands and in levels of plasma adrenocorticotropic hormone and corticosterone between the OR and C groups. Conclusions: These results indicate that psychological stress induced by occlusal disharmony reversibly induces BDNF expression in the rat submandibular gland

Effects of exercise training on gingival oxidative stress in obese rats

Objective: The purpose of the present study was to investigate the effects of exercise training on serum reactive oxygen species (ROS) level and gingival oxidative stress in obese rats fed a high-fat diet. Design: Rats were divided into three groups (n = 14/group): one control group (fed a regular diet) and two experimental groups (fed a high-fat diet with and without exercise training [treadmill: 5 days/week]). The rats were sacrificed at 4 or 8 weeks. The level of serum reactive oxidative metabolites (ROM) was measured as an indicator of circulating ROS. The level of 8-hydroxydeoxyguanosine (8-OHdG) and reduced-form glutathione (GSH)/oxidised-form glutathione (GSSG) ratio were determined to evaluate gingival oxidative stress. Results: The obese rats fed a high-fat diet without exercise training showed higher serum ROM levels [Carratelli Units (CARR U)] (mean +/- SD; 413 +/- 64) than the control (333 +/- 12) at 4 weeks (p = 0.023). Such a condition resulted in higher 8-OHdG levels (ng/mg mtDNA) (0.97 +/- 0.18) (p < 0.05) and a lower GSH/GSSG ratio (17.0 +/- 3.1) (p < 0.05) in gingival tissues, compared to the control (0.55 +/- 0.13 for 8-OHdG and 23.6 +/- 5.8 for GSH/GSSG ratio) at 8 weeks. In addition, the obese rats fed a high-fat diet with exercise training showed lower serum ROM (623 +/- 103) (p<0.001) and gingival 8-OHdG levels (0.69 +/- 0.17) (p = 0.012) than those without exercise training (1105 95 for ROM and 0.55 +/- 0.13 for 8-OHdG) at 8 weeks. Conclusions: Obesity prevention by exercise training may effectively suppress gingival oxidative stress by decreasing serum ROS in rats