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BACKGROUND: The prevalence of oral diseases is subject to change over time. In 2021, Guangdong Province conducted its fourth survey assessing the oral health status of individuals aged 65-74. MATERIALS AND METHODS: Evaluation criteria and potential influencing factors were identified. A sample of residents aged 65-74 from 13 designated monitoring sites in Guangdong Province was randomly selected for the study. Spearman correlation analysis was employed to investigate the clinical correlation between influencing factors and evaluation criteria. Negative binomial and zero-inflated negative binomial regression models were utilized to examine the factors influencing caries prevalence. In contrast, logistic regression was employed to identify the risk factors for caries occurrence. A p-value of ≤0.05 was considered statistically significant. RESULTS: The prevalence of caries rate of crowns, roots, and teeth were 76.36%, 52.25%, and 79.2%, respectively. Individuals with periodontal pockets exhibited a significantly higher risk of root caries. The presence of dental calculus significantly exacerbated the occurrence of crown, root, and dental caries, and increased the risk of crown and dental caries. Consuming sweet foods once or more a week notably increased the average root decayed score (D of roots), the prevalence rate of root caries, and the D score of the Decayed, Missing, and Filled teeth [DMFT] index in individuals already afflicted with this condition. Similarly, the consumption of sweetened drinks significantly elevated the risk of crown and root caries, exacerbating overall caries progression. Frequencies of manual toothbrush and toothpick cleaning showed a negative correlation with average tooth missing score (MT). In contrast, the frequency of manual/electric toothbrush and toothpick cleaning was negatively correlated with the DMFT index. Engaging in dental diagnosis and treatment behaviors significantly increased the number of filled crowns (F), MT, and DMFT scores while reducing the prevalence of dental caries. CONCLUSIONS: In Guangdong Province, caries prevalence among older individuals aged 65-74 remains substantial. Relevant professionals and institutions must provide comprehensive guidance and assistance to the older population, emphasizing the importance of reducing the consumption of sweets and sweetened beverages, adopting correct tooth brushing techniques and frequency (at least twice daily), timely treatment of periodontal diseases, conducting regular epidemiological caries surveys, and addressing economic barriers to accessing caries diagnosis and treatment services.

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The combined application of manure and mineral fertilizer represents an effective strategy for enhancing crop yield. However, the relationship between soil fertility and crop yield remains unclear in saline-alkaline soil. Here, a 9-year field experiment (2015-2023) was conducted to investigate the effects of manure application and crop rotations on crop yield and economic efficiency as well as potential associated mechanisms in the Hetao Irrigation District. The results showed that in the third cropping rotation cycle, combined application of manure and mineral fertilizers (NPKO) caused a 6.2%, 38.9%, 65.3%, and 132.2% increase in wheat, sunflower, wheat equivalent yield, and the economic income of sunflower, respectively. The average grain yield had a positive correlation with soil organic matter and nutrient supply. This suggested that the soil organic matter had a positive effect on the crop yield due to its impact on nutrient supply. Simultaneously, the sunflower seed setting rate increased by 65.2% under NPKO. The linear regression model revealed that each additional input of 20 Mg ha-1 of manure resulted in an increase of 3.56 kg ha-1 in crop phosphorus harvest and a 0.05 Kg ha-1 increase in wheat equivalent yield compared to NPK. In conclusion, our results highlighted that manure application promotes soil properties and improves crop yield.

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Ionic conductive hydrogel has recently garnered significant research attention due to its potential applications in the field of wearable and flexible electronics. Nonetheless, the integration of multifunctional and synergistic advantages, including reliable electronic properties, high swelling capacity, exceptional mechanical characteristics, and self-adhesive properties, presents an ongoing challenge. In this study, we have developed an ionic conductive hydrogel through the co-polymerization of 4-Acryloylmorpholine (ACMO) and sodium acrylate using UV curing technology. The hydrogel exhibits excellent mechanical properties, high conductivity, superior swelling capacity, and remarkable self-adhesive attributes. The hydrogel serves as a highly sensitive strain sensor, enabling precise monitoring of both substantial and subtle human motions. Furthermore, the hydrogel demonstrates the capability to adhere to human skin, functioning as a human-machine interface for the detection of physiological signals, including electromyogram (EMG) signals, with low interfacial impedance. This work is anticipated to yield a new class of stretchable and conductive materials with diverse potential applications, ranging from flexible sensors and wearable bio-electronics to contributions in the field of artificial intelligence.

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Alzheimer's disease (AD) is a progressive neurodegenerative disease with the hallmark of aggregation of beta-amyloid (Aß) into extracellular fibrillar deposition. Accumulating evidence suggests that soluble toxic Aß oligomers exert diverse roles in neuronal cell death, oxidative stress, neuroinflammation, and the eventual pathogenesis of AD. Aß is derived from the sequential cleavage of amyloid-ß precursor protein (APP) by ß-secretase (BACE1) and γ-secretase. The current effect of single targeting is not ideal for the treatment of AD. Therefore, developing multipotent agents with multiple properties, including anti-Aß generation and anti-Aß aggregation, is attracting more attention for AD treatment. Previous studies indicated that Quercetin was able to attenuate the effects of several pathogenetic factors in AD. Here, we showed that naturally synthesized Quercetin-3-O-glc-1-3-rham-1-6-glucoside (YCC31) could inhibit Aß production by reducing ß-secretase activity. Further investigations indicated that YCC31 could suppress toxic Aß oligomer formation by directly binding to Aß. Moreover, YCC31 could attenuate Aß-mediated neuronal death, ROS and NO production, and pro-inflammatory cytokines release. Taken together, YCC31 targeting multiple pathogenetic factors deserves further investigation for drug development of AD.

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Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.

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BACKGROUND: Apical periodontitis directly affects the stress state of the affected tooth owing to the destruction of the periapical bone. Understanding the mechanical of periapical bone defects/tooth is clinically meaningful. In this study, we evaluate the effect of periapical bone defects on the stress distribution in teeth with periapical periodontitis using finite element analysis. METHODS: Finite element models of normal mandibular second premolars and those with periapical bone defects (spherical defects with diameters of 5, 10, 15, and 20 mm) were created using a digital model design software. The edges of the mandible were fixed and the masticatory cycle was simplified as oblique loading (a 400 N force loaded obliquely at 45° to the long axis of the tooth body) to simulate the tooth stress state in occlusion and analyze the von Mises stress distribution and tooth displacement distribution in each model. RESULTS: Overall analysis of the models: Compared to that in the normal model, the maximum von Mises stresses in all the different periapical bone defect size models were slightly lower. In contrast, the maximum tooth displacement in the periapical bone defect model increased as the size of the periapical bone defect increased (2.11-120.1% of increase). Internal analysis of tooth: As the size of the periapical bone defect increased, the maximum von Mises stress in the coronal cervix of the tooth gradually increased (2.23-37.22% of increase). while the von Mises stress in the root apical region of the tooth showed a decreasing trend (41.48-99.70% of decrease). The maximum tooth displacement in all parts of the tooth showed an increasing trend as the size of the periapical bone defect increased. CONCLUSIONS: The presence of periapical bone defects was found to significantly affect the biomechanical response of the tooth, the effects of which became more pronounced as the size of the bone defect increased.

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AIM: To evaluate the effects of root canal treatment (RCT) and post-crown restoration on stress distribution in teeth with periapical bone defects using finite element analysis. METHODOLOGY: Finite element models of mandibular second premolars and those with periapical bone defects (spherical defects with diameters of 5, 10, 15, and 20 mm) were created using digital model design software. The corresponding RCT and post-crown restoration models were constructed based on the different sizes of periapical bone defect models. The von Mises stress and tooth displacement distributions were comprehensively analyzed in each model. RESULTS: Overall analysis of the models: RCT significantly increased the maximum von Mises stresses in teeth with periapical bone defects, while post-crown restoration greatly reduced the maximum von Mises stresses. RCT and post-crown restoration slightly reduced tooth displacement in the affected tooth. Internal analysis of tooth: RCT dramatically increased the maximum von Mises stress in all regions of the tooth, with the most pronounced increase in the coronal surface region. The post-crown restoration balances the internal stresses of the tooth and is most effective in periapical bone defect - 20-mm model. RCT and post-crown restoration slightly reduced the tooth displacement in all regions of the affected tooth. CONCLUSIONS: Root canal treatment seemed not to improve the biomechanical state of teeth with periapical bone defects. In contrast, post-crown restoration might effectively balance the stress concentrations caused by periapical bone defects, particularly extensive ones.

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Objectives: This study aimed to evaluate the potential clinical application of an infiltrant with different etchants as pit and fissure sealants and to compare them with a conventional resin-based sealant. Materials and methods: Seventy-five molars were randomly divided into three groups (n = 25): phosphoric acid etchant + conventional resin-based sealant (Group A); 15% hydrochloric acid etchant + infiltrant (Group B); phosphoric acid etchant + infiltrant (Group C). Fifteen teeth in each group were subjected to pit and fissure sealing procedures. After 500 thermocycling and methylene blue dye penetration, ten specimens were sectioned and the pencentages of dye penetration were measured under a stereomicroscope. Another five teeth in each group were sectioned and the microgaps between materials and enamel surface were measured using electron microscope scanning. Ten teeth in each group were used to measure shear bond strength and the failure mode was analyzed. Results: The results showed that infiltrant exhibited significantly less microleakage and microgap than resin-based sealant, no matter which echant was used. Although there was no significant difference betweern the three groups, infiltrant applied with 15% hydrochloric acid etching showed higher shear bond strength than resin-based sealant etching with 35% phosphoric acid. Conclusions: The infiltrant has significant advantages in reducing the degree of microleakage and microgap. Moreover, the infiltrant could achieve the same bonding strength as conventional resin-based sealant. Although, manufacturers do not currently recommend the infiltrant for fissure sealing, the potential clinical application would be an off-label use.Clinical relevance This report provides a theoretical basis for the potential clinical application of the infiltrant as a pit and fissure sealant, and provides a new perspective for selecting pit and fissure sealants.

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BACKGROUND: Tooth loss is a known marker of oral and systemic health, but large-scale population-based and cross-sectional multi-year comparative studies on tooth loss have yet to be much studied in China. This study explores the changing trends in tooth loss status and the associated factors influencing the prevalence of tooth loss over the past two decades in Guangdong, Southern China. METHODS: Data from three cross-sectional, representative oral epidemiological surveys in Guangdong Province were analyzed, including 400 in 1995, 720 in 2005, and 288 in 2015, for a total of 1408 participants. Sample selection is based on the National Census of China published by the National Bureau of Statistics. In this study, each year, the number of missing teeth (MT) and the prevalence of tooth loss (MT > 0) were calculated. Basic demographic information, socioeconomic status, caries and periodontal status, personal lifestyle factors, and dental health care behaviors were analyzed by multivariate logistic regression to estimate their associations with tooth loss. Statistical significance was evaluated with 2-sided tests with a significance level of P < 0.05. RESULTS: This study found that the mean number of missing teeth and the prevalence of tooth loss among adults aged 35-44 years in Guangdong Province did not change significantly in the first decade (1995-2005) but decreased significantly in the second decade (2005-2015) (0.94 and 40.8% in 1995, 0.99 and 42.9% in 2005, and 0.63 and 33.3% in 2015, respectively). The mean number of MT by tooth position was highest for the first and second molars, and both were larger in the mandible than in the maxilla. In 1995, populations with low educational attainment and the presence of caries or periodontal pocket (periodontal probing depth ≥ 4 mm) were associated with a higher chance of MT > 0. In 2005, those with low educational attainment, the presence of caries, and 40-44 years old were associated with a higher chance of MT > 0. Moreover, in 2015, females, rural residents, and those with caries or periodontal pocket were associated with a higher chance of MT > 0. CONCLUSIONS: Although tooth retention has improved recently (2005-2015) and the preventive effect of education level on tooth loss has increased over time, efforts to prevent tooth loss in adults need to be strengthened. Particular attention should be given to preventive interventions for women, rural residents, and those suffering from caries or periodontal pocket.

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BACKGROUND: Dental caries of deciduous teeth (Early Childhood Caries, ECC) has become a crucial oral health problem over the decades in China. The aim of this study was to examine the prevalence and severity of ECC among preschool children from Guangdong Province, Southern China. In addition, to assess the association of ECC with reported oral health-related behaviors. METHODS: A cross-sectional survey of 2592 participants was carried out in Guangdong Province by means of an equal-sized, stratified, multistage random sampling method during December 2015 and April 2016. The participants were divided into three groups according to their ages (3-, 4-, and 5-year-olds). Half of the participants were derived from urban areas, while the other from rural areas. According to the standard for clinical dentition examination of the WHO 2013 criteria, the presence of ECC was determined by the dmft (decayed-missing-filled tooth) index using a CPI (Community Periodontal Index) probe. A questionnaire about caries-related factors was completed by each of the participants' parents or grandparents through a face-to-face and one-on-one interview. Then, t-test, Chi2 tests, One-Way ANOVA served for statistical analysis, and logistic regression analysis as well as covariance analysis were executed to identify potential associated factors for ECC. RESULTS: The prevalence (% dmft > 0) of ECC was 68.3 (95% CI: 66.5-70.1), the mean dmft was 4.36 (95% CI: 4.17-4.55), and the filled rate was 1.2%. In multivariable modeling, associated factors for both prevalence and mean dmft were older age, rural areas, consumption of sweets before sleep, dental visit history, low household income, and low parental education level. Initiating toothbrushing after 3 years of age and being exclusively/ predominantly breastfed indicated only the prevalence; being female and frequently consuming sweetened milk/powdered milk indicated only the mean dmft. CONCLUSIONS: Preschool children in Guangdong Province, especially children from rural areas, experienced a significant amount of ECC. Associated factors for ECC included demographics, oral health measures, dietary factors, and socioeconomic factors. More attention should be given to prevention of ECC from early life. The construction of social support for oral health should be strengthened. Oral health education and promotion, especially of rural areas, should be intensified to reduce the inequality between urban and rural areas.

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PURPOSE: To assess the current prevalence of caries, gingival bleeding, calculus, and fluorosis and to determine the risk factors for caries in permanent teeth of 12-year-old students in Guangdong Province, China. MATERIALS AND METHODS: A cross-sectional survey was carried out among 1920 12-year-old students in Guangdong Province. All participants were required to undergo an oral health examination. Information concerning the subjects' family background, dietary habits, and relevant oral health behaviour were collected in a structured questionnaire. Chi-squared tests, Wilcoxon rank-sum tests, and the logistic regression model were used in the statistical analysis. RESULTS: The prevalence rates of caries in permanent teeth, gingival bleeding, calculus, and fluorosis were 43.07%, 40.57%, 43.75%, and 5.05%, respectively; the average decayed, missing, and filled teeth (DMFT) index was 1.06±1.721. Residence (odds ratios [OR] rural=1.798, 95% CI: 1.485-2.177), sex (OR female=1.352, 95% CI: 1.121-1.631), paternal education level (OR >9 years=0.755, 95% CI: 0.608-0.936), presence of calculus (OR yes=1.279, 95% CI: 1.057-1.548), and frequency of consumption of sugary snacks (OR frequently=1.418, 95% CI: 1.064-1.890) were statistically significantly associated with the risk of permanent teeth caries. CONCLUSION: Oral health in 12-year-olds in Guangdong Province remains to be improved. Rural residence, female sex, the presence of calculus, and frequent consumption of sugary snacks could increase the risk of caries. The paternal educational level was negatively associated with the risk of caries, whereas we found no association between the maternal educational level and the risk of caries in this population.

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@#As one of the most common chronic diseases of the oral cavity, caries gradually accumulate over the lifetime and affect approximately 80% of the world population. The epidemiological characteristics of the disease are specific in terms of regional distribution, temporal distribution and population distribution. Caries prevalence and mean decayed, missing and filled permanent teeth (mean DMFT) scores are the most commonly used indexes in oral epidemiology. Caries prevalence is used to describe the frequency of caries over a certain period of time. In addition, DMFT scores reflect the severity of caries in the population. The caries prevalence and the severity of caries are assessed as part of a dynamic process. In developing countries, caries prevalence is higher among urban populations than among rural populations. Currently, the epidemic characteristics of caries in urban and rural areas are changing, and the caries prevalence of urban residents is lower than that of rural residents. This article is a chronological review of the Oral Health Epidemiological Surveys of China from 1983 to 2015, the Preventive Dentistry study and other related studies. It is concluded that the epidemic characteristics of caries in urban and rural areas in China have changed from a higher caries prevalence in urban areas compared to that in rural areas to a lower caries prevalence in urban areas compared to that in rural areas. Several factors, such as the dynamic development of differences in dietary habits, economic levels and access to oral medical resources of urban and rural residents might have led to changes in caries prevalence in urban and rural areas. The caries prevalence of rural residents has increased greatly, which indicates that the caries prevention efforts of the relevant departments should be focused more on rural areas in the future.