Characteristics of Chinese patients with primary Sjögren's syndrome: preliminary report of a multi-centre registration study.

BACKGROUND: We established a multi-centre online registry for primary Sjögren's syndrome (pSS) in China, and compared Chinese patients with those from other countries. METHODS: Data were from 87 rheumatology centres in 27 provinces. All 2986 patients had pSS according to the 2002 American-European Consensus Group or the 2016 American College of Rheumatology/European League Against Rheumatism. All centres used the same methods. Data on demographics, clinical parameters, laboratory results, disease activity and treatments were examined. RESULTS: The female:male ratio was 22.9:1, and the mean age at onset was 46.31 years. A total of 332 (11.1%) patients had thyroid disease, including hyperthyroidism (1.2%), hypothyroidism (6.0%) and subacute thyroiditis (3.9%). Dry eye had a prevalence of 68.59% in Chinese patients, 93.7-96% in European patients and 97.3% in American patients. Dry mouth had a prevalence of 86.5% in Chinese patients, 93.2-96% in European patients and 97.9% in American patients. Fewer Chinese than European patients had arthritis (6.9% vs. 15-19.3%). ANA positivity was 90.7% in Chinese, 81.3% in European and 77.6% in American patients. Anti-SSA antibody positivity was 84.6% in Chinese, 71% in European and 68.2% in American patients. The most commonly used drugs in Chinese patients were hydroxychloroquine (n = 1818; 67.5%), glucocorticoids (n = 1720; 63.9%) and total glucosides of paeony (n = 1120; 41.7%). CONCLUSIONS: This study provided information on the phenotypes of Chinese patients with pSS, and identified several differences with patients from other geographical regions.

[Esthetic proportions of maxillary anterior teeth of 120 Chinese adults].

OBJECTIVE: To analyze the esthetic proportions of maxillary anterior teeth in term of the apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown in 120 Chinese adults. METHODS: Maxillary gypsum casts were obtained from the dental laboratories of stomatological hospitals in North China, Southeast China, and Southwest China, according to the inclusion criteria and exclusion criteria. Standardized digital photographs of each cast were recorded. The apparent widths and actual widths and heights of the central incisors, lateral incisors and canines were determined by ImageJ software for the calculation of apparent widths proportion of the adjacent teeth and width/height ratio of the clinical crown. The ideal apparent widths proportion (Golden proportion and Preston proportion) and width/height ratio (0.80) were tested. The gender, arch side, and regional differences were investigated. RESULTS: The apparent widths proportion of the lateral/central incisor was 0.724±0.047, of the canine/lateral incisor was 0.814±0.092. The width/height ratio of the central incisor was 0.848±0.072, of the lateral incisor was 0.834±0.094, of the canine was 0.883±0.098. The esthetic proportions were different from the predicted ideal ratio (P < 0.001). The apparent widths proportion of lateral/central incisor was significantly larger in the right side than that in the left side (0.730± 0.044 vs. 0.718±0.050), and was significantly smaller in North China than that in Southwest China (0.711±0.051 vs. 0.731±0.044). The width/height ratio of the central incisor was significantly larger in the female than that in the male (0.855±0.074 vs. 0.835±0.068), and in the right side than that in the left side (0.855±0.073 vs. 0.842±0.072). The width/height ratio of the lateral incisor was significantly larger in the female than that in the male (0.843±0.097 vs. 0.817±0.084). CONCLUSION: The apparent widths proportion of adjacent teeth and the width/height ratio of the clinical crown in Chinese adults are different from the foreigner's. The esthetic proportion parameters have significant population specificity, and the measurements cannot be generalized as well as it should be applied with caution.

Recycling agriculture wastes of ramie stalk as bioadsorbents for Cd(2+) removal: a kinetic and thermodynamic study.

In this study, we exhibit the recycling of agriculture wastes of ramie stalk as bioadsorbents for Cd(2+) removal. Based on our experimental results, it is realized that Cd(2+) adsorption to ramie stalk is highly pH sensitive, indicating the adsorption is driven by surface complexation reaction. The high adsorption capacity of ramie stalk toward Cd(2+) (qm = 10.33 mg g(-1), 0.09 mol-Cd g(-1)), which corresponds to around 21.95% of active adsorption sites available of ramie stalk, is believed to be closely related to its high cellulose and lignin content. The inhomogeneous surface of ramie stalk due to the high cellulose and lignin content also accounts for the observation that the adsorption kinetic is described well by the pseudo second order kinetic model. Results from thermodynamic studies suggest that the adsorption process is endothermic and spontaneous. All these properties demonstrate the potential of ramie stalk as a low cost bioadsorbent for the application of heavy metal removal.

Low-level laser therapy for orthodontic pain: a systematic review.

This review aimed to evaluate the clinical outcome of different lasers management on orthodontic pain. Cochrane Library (Issue 7, 2014) and MEDLINE (1966-2014.7) were searched to collect randomized controlled trials on lasers for orthodontic pain. Studies meeting the inclusion criteria were systematically evaluated. The Cochrane Collaboration tools RevMan5.1.7 and GRADEpro 3.6 were used in this systematic review and meta-analysis. As a result, 11 randomized controlled trials (RCTs) studying on low-level laser therapy (LLLT) for orthodontic pain control were included. Meta-analysis and risk of bias assessment were implemented using RevMan5.1.7, and level of evidence assessments was measured by GRADEpro 3.6. In the outcome of the score of the most painful day, the comparison of laser versus placebo (pain associated with tooth movement) demonstrated that LLLT reduced the pain score significantly compared with placebo groups (MD = -4.39, 95% CI range -5.9--2.88, P < 0.00001). In the same way, the most painful day was significantly brought forward in laser versus control group (MD = -0.42, 95% CI range -0.74--0.10, P = 0.009). Furthermore, the outcome of the end of pain day showed a trend of pain termination earlier in laser versus control and placebo groups, but without statistical significance (MD = -1.37, 95% CI range -3.37-0.64, P = 0.18 and MD = -1.04, 95% CI range -4.22-2.15, P = 0.52). However, for the reason of downgrade factors, all the GRADE level of evidences of eight comparisons for three outcomes showed a very low quality. Therefore, for the methodological shortcomings and risk of bias of RCTs included, insufficient evidence was submitted to judge whether LLLT was effective in relieving orthodontic pain. Further and more perfect researches should be done in order to recommend LLLT as a routine method for orthodontic pain.

Socioeconomic inequalities in dental caries among 5-year-olds in four Chinese provinces.

OBJECTIVE: To explore socioeconomic inequalities in dental caries among 5-year-olds in four Chinese provinces. METHODS: This study used data from 1,732 children living in Guangxi, Hubei, Jilin and Shanxi who participated in the Third National Oral Health Survey in 2005. Questionnaires were completed by parents to collect information on family socioeconomic position (parental education and household income) and children's dental behaviours (toothbrushing frequency, sugar intake frequency and last dental visit). Children were clinically examined for dental caries, which was reported using the dmft index. Socioeconomic inequalities in children's caries experience were assessed in negative binomial regression models. RESULTS: There were significant gradients in children's dmft by household income. Children's dmft increased from 2.63 in the highest income group to 4.70 in the lowest income group. However, parental education was not significantly related to childhood dental caries. CONCLUSION: Clear social gradients in caries experience of deciduous teeth were found by household income but not parental education.

Preparation and characterisation of andrographolide niosomes and its anti-hepatocellular carcinoma activity.

OBJECTIVE: In this study, a novel andrographolide (AG) preparation formulation, niosomes, was prepared to improve the bioavailability and tissue distribution of AG. METHODS: The niosomal formulation of AG was prepared by film hydration/sonication method and tissue distribution was measured by liquid chromatography-mass spectrometry (LC-MS) method in mice, and anti-hepatocellular carcinoma (anti-HCC) activity was examined by MTT method in HepG2. RESULTS: Entrapment efficiency, drug-loading ratio and average particle size of AG niosomes were 72.36%, 5.90% and 206 nm, respectively. The tissue distribution in mice demonstrated that the AG niosomes were absorbed in liver much more than the free AG. Furthermore, the anti-HCC activity in HepG2 cells showed that there was no significant difference between free AG and AG niosomes. CONCLUSION: The present results suggest that AG niosomes may have a significant potential of liver targeting, which is valuable in chemotherapy of HCC.

Tissue Distribution of mtDNA Copy Number And Expression Pattern of An mtDNA-Related Gene in Three Teleost Fish Species.

Teleosts are the most speciose vertebrates and have diverse swimming performance. Based on swimming duration and speed, teleosts are broadly divided into sustained, prolonged, and burst swimming fish. Teleosts with different swimming performance have different energy requirements. In addition, energy requirement also varies among different tissues. As mitochondrial DNA (mtDNA) copy number is correlated with ATP production, we speculated that mtDNA copy number varies among fish with different swimming performance, as well as among different tissues. In other species, mtDNA copy number is regulated by tfam (mitochondrial transcription factor A) through mtDNA compaction and mito-genome replication initiation. In order to clarify the tissue distribution of mtDNA copy number and expression pattern of tfam in teleosts with disparate swimming performance, we selected representative fish with sustained swimming (Pseudocaranx dentex), prolonged swimming (Takifugu rubripes), and burst swimming (Paralichthys olivaceus). We measured mtDNA copy number and tfam gene expression in 10 tissues of these three fish. The results showed the mtDNA content pattern of various tissues was broadly consistent among three fish, and high-energy demanding tissues contain higher mtDNA copy number. Slow-twitch muscles with higher oxidative metabolism possess a greater content of mtDNA than fast-twitch muscles. In addition, relatively higher mtDNA content in fast-twitch muscle of P. olivaceus compared to the other two fish could be an adaptation to their frequent burst swimming demands. And the higher mtDNA copy number in heart of P. dentex could meet their oxygen transport demands of long-distance swimming. However, tfam expression was not significantly correlated with mtDNA copy number in these teleosts, suggesting tfam may be not the only factor regulating mtDNA content among various tissues. This study can lay a foundation for studying the role of mtDNA in the adaptive evolution of various swimming ability in teleost fish.

[Identification model of tooth number abnormalities on pediatric panoramic radiographs based on deep learning].

Objective: To identify tooth number abnormalities on pediatric panoramic radiographs based on deep learning. Methods: Eight hundred panoramic radiographs of children aged 4 to 11 years meeting the inclusion and exclusion criteria were selected and randomly assigned by writing programs in Python (version 3.9) to the training set (480 images), verification set (160 images) and internal test set (160 images), taken in Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology between November 2012 to August 2020. And all panoramic radiographs of children aged 4 to 11 years taken in the First Outpatient Department of Peking University School and Hospital of Stomatology from June 2022 to December 2022 were collected as the external test set (907 images). All of the 1 707 images were obtained by operators to determine the outline and to label the tooth position of each deciduous tooth, permanent tooth, permanent tooth germ and additional tooth. The deep learning model with ResNet-50 as the backbone network was trained on the training set, validated on the verification set, tested on the internal test set and external test set. The images of test sets were divided into two categories according to whether there was abnormality of tooth number, to calculate sensitivity, specificity, positive predictive value and negative predictive value, and then divided into four types of extra teeth and missing permanent teeth both existed, extra teeth existed only, missing permanent teeth existed only, and normal teeth number, to calculate Kappa values. Results: The sensitivity, specificity, positive predictive value and negative predictive value were 98.0%, 98.3%, 99.0% and 96.7% in the internal test set, and 97.1%, 98.4%, 91.9% and 99.5% in the external test set respectively, according to whether there was abnormality of tooth number. While images were divided into four types, the Kappa value obtained in the internal test set was 0.886, and that in the external test set was 0.912. Conclusions: In this study, a deep learning-based model for identifying abnormal tooth number of children was developed, which could identify the position of additional teeth and output the position of missing permanent teeth on the basis of identifying normal deciduous and permanent teeth and permanent tooth germs on panoramic radiographs, so as to assist in diagnosing tooth number abnormalities.

[Contemporary dietary patterns and oral disease].

The achievements and breakthroughs in scientific field have provided scientific evidence for the relationship amongst diet, nutrition and chronic diseases, including oral diseases. Thus many international organizations and the governments of most countries were pushed to pay their attention to the prevention of chronic diseases by dietary patterns. From 1989 to 2018, the Food and Agriculture Organization of the United Nations and World Health Organization organized expert consultations for many times to issue a series of global strategies and action plans on diet and health. The governments of China, Japan and US had produced the Dietary Guidelines for Residents. The results showed that the morbidity and mortality of many chronic diseases had been decreased by following the dietary guidance. However, the scientific achievements did not seem to produce tremendous enhancement in public health for various reasons. In the present article, the authors analyses the relationship between contemporary dietary patterns and oral health, and make suggestions on preventing and controlling oral diseases via dietary patterns for policy makers and dental professionals.

[Development and improvement of Chinese oral public health system].

The pandemic of COVID-19 in early 2020 is a big challenge to the mechanism of major epidemic prevention and control, the national public health management system, as well as medical and health resources in China. Going through the COVID-19 crisis, we should fully understand the problems and vulnerabilities of the current public health system in China, and it is imperative to deepen and strengthen the public health system which should be throughout whole life cycle and whole process. Oral cavity is the first portal of human body, while illness finds its way in by the mouth. Oral health is highly related to general health and quality of life. The outbreak has drawn the public's attention to the public health system. The establishment and improvement of the oral public health system with the concept of "public health with Chinese characteristics" should also attract people's attentions and thoughts. Furthermore it is urgent to recognize the importance of oral public health.

[Effects of titania nanotubes with different diameters on human gingival fibroblast].

Objective: To study the effects of titania nanotubes with three different diameters on human gingival fibroblast (HGF). Methods: Three groups of specimens were prepared. Titania nanotubes with diameters of 30, 100, and 200 nm were synthesized on titanium surfaces through electrochemical anodization at 10, 30, and 60 V, respectively. Specimens were assigned into the three groups according to the diameter of the titania nanotubes. Pure smooth titanium without any treatment was set as the control group. HGF were seeded on the surface of the samples. The cell morphology on the specimens was observed with immunofluorescence staining after 2 h, the cell adhesion after 2 d and cell proliferation after 1, 3, and 7 d were detected using methyl thiazolyl tetrazolium assay, and the secretion of type Ⅰ collagen after 7 d was determined using enzyme-linked immunosorbent assay (each group has three samples for each experiment). Results: HGF on the control group exhibited an oval shape without noticeable extensions. HGF on titania nanotubes with a diameter of 30 nm and titania nanotubes with a diameter of 100 nm elongated further and were arranged orderly. HGF on titania nanotubes with a diameter of 200 nm were sparsely distributed without noticeable extensions. Titania nanotubes with a diameter of 30 nm and titania nanotubes with a diameter of 100 nm could enhance the cell attachment (0.603±0.021 and 0.773±0.045), and secretion of type Ⅰ collagen [(36.5±9.5) and (47.7±4.5) µg/ml, respectively] compared with the control group whose cell attactment was 0.427±0.057, and secretion of type Ⅰ collagen was (22.2±5.9) µg/ml (P<0.05). Furthermore, titania nanotubes with a diameter of 100 nm showed more cell attchment than titania nanotubes with a diameter of 30 nm did (P<0.05). Ttania nanotubes with a diameter of 200 nm clearly impaired the cell adhesion (0.250±0.046) and secretion of type Ⅰ collagen [(10.1±3.7) µg/ml] compared with the control group (P<0.05). At each time point, titania nanotubes with a diameter of 100 nm showed the highest cell proliferation, and the amount of cell proliferation was significantly higher than that on the titania nanotubes with a diameter of 200 nm and the control group at each time point (P<0.05), and was also significantly higher than that on the titania nanotubes with a diameter of 30 nm at day three (P<0.05). At each time point, titania nanotubes with a diameter of 200 nm showed the lowest cell proliferation, which was significantly lower than that on the control group at each time point (P<0.05), except that there was no significant difference in the amount of cell proliferation between titania nanotubes with a diameter of 200 nm and the control group at day one (P>0.05). Conclusions: Titania nanotubes with a diameter of 100 nm can improve the HGF attachment, proliferation, and secretion of type Ⅰ collagen.

microRNA-21 ameliorates the impairment of autophagy in palatal wound healing.

Fibroblast injury and autophagy dysfunction have been shown to contribute to the persistence of oral wounds. Recently, microRNAs have emerged as vital regulators and fine tuners of various pathophysiological cellular processes that influence the wound healing process. This study explored the biological function and regulatory mechanism of miRNA-21 (miR-21) in the healing of oral wounds by interfering with autophagy. Healthy gingival cells derived from wild-type (WT) and from miR-21KO mice were characterized by immunocytofluorescence, and changes in wound healing were subsequently assessed using an in vitro scratch wound healing assay. The roles of critical proteins required for autophagy, autophagy related 5 (ATG5) and Bcl-2 interacting coiled-coil protein 1 (Beclin1) were evaluated by immunohistochemistry. Human gingival fibroblasts (HGFs) were transfected with a miR-21 mimic and a miR-negative control, and the relative expression of miR-21, ATG5, Beclin1 and LC3-I/II was characterized by qRT-PCR and Western blot. Pathological changes were observed in a palatal wound healing model using WT and miR-21KO mice. Immunohistochemistry was used to examine extracellular matrix (ECM) proteins and autophagy markers. Cell migration was delayed in gingiva-derived mesenchymal stem cells (GMSCs) from miR-21KO mice compared with WT mice. The expression of ATG5 and Beclin1 was significantly up-regulated in miR-21KO gingiva. Transfection of a miR-21 mimic into HGFs inhibited autophagy and up-regulated miR-21 expression. Knockdown of miR-21 suppressed the expression of fibronectin and CTGF, enhanced the autophagy effect of fibroblasts, suggesting that autophagy is involved in miR-21 regulated palatal wound healing. Taken together, these results suggest that miR-21 promotes oral wound healing by increasing ECM production through the inhibition of autophagy and facilitates clinical management of wound healing.

Super-factors associated with transmission of occupational COVID-19 infection among healthcare staff in Wuhan, China.

BACKGROUND: Globally, there have been many cases of coronavirus disease 2019 (COVID-19) among medical staff; however, the main factors associated with the infection are not well understood. AIM: To identify the super-factors causing COVID-19 infection in medical staff in China. METHODS: A cross-sectional study was conducted between January 1st and February 30th, 2020, in which front-line members of medical staff who took part in the care and treatment of patients with COVID-19 were enrolled. Epidemiological and demographic data between infected and uninfected groups were collected and compared. Social network analysis (SNA) was used to establish socio-metric social links between influencing factors. FINDINGS: A total of 92 medical staff were enrolled. In all participant groups, the super-factor identified by the network was wearing a medical protective mask or surgical mask correctly (degree: 572; closeness: 25; betweenness centrality: 3.23). Touching the cheek, nose, and mouth while working was the super-factor in the infected group. This was the biggest node in the network and had the strongest influence (degree: 370; closeness: 29; betweenness centrality: 0.37). Self-protection score was the super-factor in the uninfected group but was the isolated factor in the infected group (degree: 201; closeness: 28; betweenness centrality: 5.64). For family members, the exposure history to Huanan Seafood Wholesale Market and the contact history to wild animals were two isolated nodes. CONCLUSION: High self-protection score was the main factor that prevented medical staff from contracting COVID-19 infection. The main factor contributing to COVID-19 infections among medical staff was touching the cheek, nose, and mouth while working.

[Prevention and control of oral diseases via "Common Risk Factor Approach"].

People are generally more aware of infectious diseases, cardiovascular diseases, trauma and other fatal diseases rather than oral diseases. In fact, the oral disease as a whole is ranked the third among the chronic diseases of human beings. There have been accumulating evidences that oral health plays a significant role in general health and quality of life. There is a wide recognition that oral health shares common risky/pathogenic factors with other Non-Communicable Diseases (NCD). Oral microorganisms may cause dental caries and periodontal diseases, and they may also cause atherosclerosis and heart diseases, thus these usually end up to chronic diseases. On the other hand, unhealthy diet, physical inactivity, tobacco and alcohol consumption, psychological stress, poor sanitation, accidents and a sedentary lifestyle contribute to both oral diseases and a number of general chronic diseases. Oral health cannot be dealt with in isolation from other health issues. That is why the WHO recommended the "Common Risk Factor Approach (CRFA)" for oral health promotion. In this article, the authors give essential interpretation of CRFA and make suggestions on preventing and controlling oral diseases via CRFA.

[Analyze the national directory of rare diseases, define the diagnostic role of the stomatologists].

A rare disease, also referred to as an orphan disease, is defined as the disease with a low prevalence or that affects a small percentage of the population. It is a well model of human disease, which can facilitate the in-depth study and understanding of related diseases. Therefore, five Chinese governmental authorities, including the National Health Commission of the People's Republic of China, jointly issued the "First National Directory of Rare Diseases" (the First List) on May 11, 2018. The First List covers 121 rare indications. In the analysis of the directory, we found that among the 121 diseases, there are 51 (42.2%) with oral characterization. Oral manifestations mainly include craniofacial abnormalities, dentition (dental) abnormalities, oral soft tissue lesions, jaw bone lesions, salivary gland related diseases, etc., even some of them are the first, earliest and inevitable clinical manifestations of some patients with rare diseases. In order to strengthen the understanding of stomatological counterparts on the importance of the national directory of rare diseases and deeply understand the important and irreplaceable role of stomatologists in the diagnosis and treatment of rare diseases, the present review article is specifically written to introduce the oral characterization of the rare diseases listed in the catalogue, aiming at improving the diagnosis and treatment capabilities of these diseases by peers and benefiting the public.

[Application and prospect of three-dimentional printing in stomatology].

Three dimentional printing is a new rapid prototyping technology based on digital model files, which developed through a combination of multi-disciplines such as information technology, precision machinery and materials science. With rapid development in recent years, three dimentional printing technology has been widely used in the medical fields, stomatology especially. It gradually penetrates into various parts of stomatology, such as education, practice and innovation, making stomatology clinical medicine more and more efficient, accurate and minimally invasive. Combined with basic research and clinical cases, this article describes the application and developent prospects of three dimentional printing technology in stomatology.

[Holistic integrative medicine: application in prevention and treatment of oral mucosal diseases].

Holistic integrative medicine (HIM), as one of the important ideas in the field of medicine, arouses great concern recently. HIM regards the human body as a whole, turns data and evidence in medical research back to facts, integrates technologies and experience developed in clinical research into medical skills. The repeated practices at the levels of fact, experience, and medical skills will generate true knowledge to solve the wide spread problems brought by linearized thinking and fragmented knowledge. With the development of highly divided medical disciplines, how to utilize and practice HIM has become a common concern of the medical community. Specialization of stomatology, which is a first level discipline like medicine, has also become a trend for years. However, holistic concept cannot be overlooked, especially in the development of oral medicine. This article aims at the communication and exchange of knowledge about HIM among dental professionals. In order to serve the patients better, the authors look forward to practicing the HIM concept in the field of oral medicine through the efforts of us all.

A tribo-mechanical analysis of PVA-based building-blocks for implementation in a 2-layered skin model.

Poly(vinyl) alcohol hydrogel (PVA) is a well-known polymer widely used in the medical field due to its biocompatibility properties and easy manufacturing. In this work, the tribo-mechanical properties of PVA-based blocks are studied to evaluate their suitability as a part of a structure simulating the length scale dependence of human skin. Thus, blocks of pure PVA and PVA mixed with Cellulose (PVA-Cel) were synthesised via freezing/thawing cycles and their mechanical properties were determined by Dynamic Mechanical Analysis (DMA) and creep tests. The dynamic tests addressed to elastic moduli between 38 and 50kPa for the PVA and PVA-Cel, respectively. The fitting of the creep compliance tests in the SLS model confirmed the viscoelastic behaviour of the samples with retardation times of 23 and 16 seconds for the PVA and PVA-Cel, respectively. Micro indentation tests were also achieved and the results indicated elastic moduli in the same range of the dynamic tests. Specifically, values between 45-55 and 56-81kPa were obtained for the PVA and PVA-Cel samples, respectively. The tribological results indicated values of 0.55 at low forces for the PVA decreasing to 0.13 at higher forces. The PVA-Cel blocks showed lower friction even at low forces with values between 0.2 and 0.07. The implementation of these building blocks in the design of a 2-layered skin model (2LSM) is also presented in this work. The 2LSM was stamped with four different textures and their surface properties were evaluated. The hydration of the 2LSM was also evaluated with a corneometer and the results indicated a gradient of hydration comparable to the human skin.

[Epidemiologic features of hand-foot-mouth disease in Haikou city from 2008 to 2015].

Objective: To analyze the epidemiologic features of hand-foot-mouth disease (HFMD) in Haikou city from 2008 to 2015. Methods: Descriptive methods on epidemiology and detection on pathogens were conducted in Haikou city from 2008 to 2015. Results: A total of 71 611 patients were diagnosed as HFMD in Haikou city from 2008 to 2015, including 728 severe cases, accounting for 1.02% among all the cases. The average annual incidence was 458.89/100 000. A total of 11 deaths were caused by the disease, with the average annual mortality rate as 0.07/100 000. Two peaks of incidence were seen, from April to July and from September to November. Age of the patients mainly fell in children aged 5 and below, taking up 95.78% of the total cases. Among all the patients, 1-year-olds presented the highest incidence as 12 881.24/100 000. The reported incidence for males was higher than that in females. There were 4 districts in Haikou city that reported the disease. Residential areas of the patients were scattered around, with a percentage of 79.89%. Spectrums of pathogens that causing the prevalence of HFMD were EV71 type, Cox A16 type and other enteroviruses, which prevailing in turns, since 2011. Conclusions: Haikou city had been an area with high incidence of HFMD. The incidence started to show a rising trend recently. It is suggested that programs as surveillance, case management, health education and comprehensive prevention and control of disease on HFMD targeting on key population should be intensively implemented to reduce the mortality of the disease.

The prevalence of dental erosion in preschool children in China.

OBJECTIVE: To describe the prevalence of dental erosion and associated factors in preschool children in Guangxi and Hubei provinces of China. METHODS: Dental examinations were carried out on 1949 children aged 3-5 years. Measurement of erosion was confined to primary maxillary incisors. The erosion index used was based upon the 1993 UK National Survey of Children's Dental Health. The children's general information as well as social background and dietary habits were collected based on a structured questionnaire. RESULTS: A total of 112 children (5.7%) showed erosion on their maxillary incisors. Ninety-five (4.9%) was scored as being confined to enamel and 17 (0.9%) as erosion extending into dentine or pulp. There was a positive association between erosion and social class in terms of parental education. A significantly higher prevalence of erosion was observed in children whose parents had post-secondary education than those whose parents had secondary or lower level of education. There was also a correlation between the presence of dental erosion and intake of fruit drink from a feeding bottle or consumption of fruit drinks at bedtime. CONCLUSION: Erosion is not a serious problem for dental heath in Chinese preschool children. The prevalence of erosion is associated with social and dietary factors in this sample of children.