Impact of Cd and Pb on the photosynthetic and antioxidant systems of Hemerocallis citrina Baroni as revealed by physiological and transcriptomic analyses.

KEY MESSAGE: Cd induces photosynthetic inhibition and oxidative stress damage in H. citrina, which mobilizes the antioxidant system and regulates the expression of corresponding genes to adapt to Cd and Pb stress. Cd and Pb are heavy metals that cause severe pollution and are highly hazardous to organisms. Physiological measurements and transcriptomic analysis were combined to investigate the effect of 5 mM Cd or Pb on Hemerocallis citrina Baroni. Cd significantly inhibited H. citrina growth, while Pb had a minimal impact. Both Cd and Pb suppressed the expression levels of key chlorophyll synthesis genes, resulting in decreased chlorophyll content. At the same time, Cd accelerated chlorophyll degradation. It reduced the maximum photochemical efficiency of photosystem (PS) II, damaging the oxygen-evolving complex and leading to thylakoid dissociation. In contrast, no such phenomena were observed under Pb stress. Cd also inhibited the Calvin cycle by down-regulating the expression of Rubisco and SBPase genes, ultimately disrupting the photosynthetic process. Cd impacted the light reaction processes by damaging the antenna proteins, PS II and PS I activities, and electron transfer rate, while the impact of Pb was weaker. Cd significantly increased reactive oxygen species and malondialdehyde accumulation, and inhibited the activities of antioxidant enzymes and the expression levels of the corresponding genes. However, H. citrina adapted to Pb stress by the recruitment of antioxidant enzymes and the up-regulation of their corresponding genes. In summary, Cd and Pb inhibited chlorophyll synthesis and hindered the light capture and electron transfer processes, with Cd exerting great toxicity than Pb. These results elucidate the physiological and molecular mechanisms by which H. citrina responds to Cd and Pb stress and provide a solid basis for the potential utilization of H. citrina in the greening of heavy metal-polluted lands.

Stabilizing Perovskite Precursor by Synergy of Functional Groups for NiOx -Based Inverted Solar Cells with 23.5 % Efficiency.

Perovskite solar cells suffer from poor reproducibility due to the degradation of perovskite precursor solution. Herein, we report an effective precursor stabilization strategy via incorporating 3-hydrazinobenzoic acid (3-HBA) containing carboxyl (-COOH) and hydrazine (-NHNH2 ) functional groups as stabilizer. The oxidation of I- , deprotonation of organic cations and amine-cation reaction are the main causes of the degradation of mixed organic cation perovskite precursor solution. The -NHNH2 can reduce I2 defects back to I- and thus suppress the oxidation of I- , while the H+ generated by -COOH can inhibit the deprotonation of organic cations and subsequent amine-cation reaction. The above degradation reactions are simultaneously inhibited by the synergy of functional groups. The inverted device achieves an efficiency of 23.5 % (certified efficiency of 23.3 %) with an excellent operational stability, retaining 94 % of the initial efficiency after maximum power point tracking for 601 hours.

[Effects of dental health awareness and behaviours on the glycemic metabolic characteristics and periodontal disease of patients with type 2 diabetic].

OBJECTIVE: To analyze the effects of dental health awareness and behaviours on the relationship between glycemic metabolic characteristics and periodontal disease of type 2 diabetic patients. METHODS: In the study, 83 subjects with type 2 diabetes mellitus were recruited. The clinical periodontal indexes, such as pocket probing depth (PPD), attachment loss (AL), modified bleeding index (mBI), plaque index (PLI) were obtained with a Williams type periodontal probe; Laboratory examinations including glycosylated haemoglobin A1(HbA1C) were made, glucose assay tested, and the structured questionnaire interview conducted evaluationg the knowledge, attitude and practice (KAP) about periodontal health. RESULTS: The prevalence of moderate and severe periodontitis was 67.5%, compared with mild periodontitis, whose severities were affected by the higher level of HbA1C (≥8.0%) (OR 54.1-143.1), followed by using glycemic drug (OR=12.9-44.6), stress (OR=16.9-29.6), and the dissatisfaction with diabetic therapy (OR=16.9-18.0) et al. Meanwhile the attachment loss conditions were also correlated with the poor periodontal knowledge level(OR=3.4),older age(OR=1.1),and misjudgement of gingival inflammation (OR=13.3) et al. On the other hand, individuals with moderate and severe periodontitis, having bad teeth brushing effects and knowing about dental plaque inadequately, had a significantly higher risk for the poorly controlled glycemic results (HbA1C≥8.0%), and the OR was 8.61, 8.07, and 7.49 respectively. CONCLUSION: In patients with type 2 diabetes the severity of periodontal disease and the glycemic metabolic level (HbA1C) have a definite bidirectional adverse interrelationship, which is affected by the dental health awareness and behaviours.

Managing Interfacial Defects and Carriers by Synergistic Modulation of Functional Groups and Spatial Conformation for High-Performance Perovskite Photovoltaics Based on Vacuum Flash Method.

Interfacial nonradiative recombination loss is a huge barrier to advance the photovoltaic performance. Here, one effective interfacial defect and carrier dynamics management strategy by synergistic modulation of functional groups and spatial conformation of ammonium salt molecules is proposed. The surface treatment with 3-ammonium propionic acid iodide (3-APAI) does not form 2D perovskite passivation layer while the propylammonium ions and 5-aminopentanoic acid hydroiodide post-treatment lead to the formation of 2D perovskite passivation layers. Due to appropriate alkyl chain length, theoretical and experimental results manifest that COOH and NH3 + groups in 3-APAI molecules can form coordination bonding with undercoordinated Pb2+ and ionic bonding and hydrogen bonding with octahedron PbI6 4- , respectively, which makes both groups be simultaneously firmly anchored on the surface of perovskite films. This will strengthen defect passivation effect and improve interfacial carrier transport and transfer. The synergistic effect of functional groups and spatial conformation confers 3-APAI better defect passivation effect than 2D perovskite layers. The 3-APAI-modified device based on vacuum flash technology achieves an alluring peak efficiency of 24.72% (certified 23.68%), which is among highly efficient devices fabricated without antisolvents. Furthermore, the encapsulated 3-APAI-modified device degrades by less than 4% after 1400 h of continuous one sun illumination.

[Periodontal health status assessed by community periodontal index and related factors in adult population of Beijing urban community].

OBJECTIVE: To investigate the periodontal health conditions by using community periodontal index (CPI) and analyze the effects of related risk factors. METHODS: By stratified random sampling procedure, a total of 1 183 subjects aged 35-74 were recruited from 13 neighbour community and accepted structured interview and periodontal examination. RESULTS: The percentage of edentulous jaws was 2.3% (27/1 183). For the remaining 1 156 people, the percentage of subject with a highest CPI scores of 0,1,2,3,4 were 0.3%, 0.2%, 46.3%, 31.9%, 21.3%, respectively. At the sextant and tooth level, the numbers of healthy, bleeding, calculus, shallow pocket, deep pocket and missing pocket were 0.26, 0.25, 3.56, 1.06, 0.39, 0.48, and 3.32, 2.02, 15.43, 2.60, 0.70, 3.93, respectively. By multivariable logistic regression models, many risk indicators such as age, gender, smoking, the knowledge, attitudes and practices (KAP) status, etc. were demonstrated to be related to the distribution of deeper and missing pockets. CONCLUSION: The adult periodontal conditions of urban community were serious and affected by some demographic and behavior risk factors. More than half (53.2%) of the examined subjects require complex periodontal treatments.

Heterojunction In Situ Constructed by a Novel Amino Acid-Based Organic Spacer for Efficient and Stable Perovskite Solar Cells.

The optical properties and stability of metal halide perovskites can be improved by reducing their dimensionality. Because defects at the perovskite film grain body and boundaries cause significant energetic losses by nonradiative recombination, perovskite films with manageable crystal size and macroscopic grains are essential to improve the photovoltaic properties. Through theoretical calculation models and experiments, we show that the carboxyl group of 4-ammonium butyric acid-based cation (4-ABA+) can interact with the three-dimensional (3D) perovskite to produce in situ a secondary grain growth by post-treatment. It passivates the trap defects and broadens the light absorption. 4-ABA+ could induce a 2D capping layer on top of 3D mixed cation-based perovskite to construct a 2D/3D heterojunction. The 4-ABA+-modified perovskite film consists of large-sized grains with extremely low trap state densities and possesses a longer charge carrier lifetime and good stability, resulting in efficient perovskite solar cells with a champion efficiency of 23.16% and a VOC of 1.20 V. We show that the 4-ABA+-treated devices outperform the 3-ammonium propionic acid (3-APA+)- and 5-ammonium valeric acid (5-AVA+)-treated ones. Moreover, the devices exhibit high stability under high humidity and continuous light soaking conditions. This work gives a hint that our approach based on 4-ABA+ treatment is key to achieving better electrical properties, a controlled crystal growth, and highly stable perovskite solar cells.

[Effect of community periodontal care intervention on periodontal health and glycemic control in type 2 diabetic patients with chronic periodontitis].

OBJECTIVE: To evaluate the effectiveness of community periodontal care intervention in type 2 diabetic patients with chronic periodontitis who participated in community non-communicable diseases management service. METHODS: The randomized controlled and blinded community trial with a duration of six months was designed to compare effects of "periodontal initial therapy" on group I(22 cases), of "professional mechanical tooth cleaning (PMTC), i.e. coronal scaling" on group II(19 cases)and of "non-clinical therapy" on the control group(25 cases). The clinical periodontal indexes, such as probing depth (PD), attachment loss (AL), modified bleeding index (mBI), plaque index (PLI) were obtained with a Williams type periodontal probe; Laboratory examinations including glycosylated haemoglobin A1(HbA1C), glucose assay, were conducted. RESULTS: The reductions of PD in groups I and II were 0.71 and 0.70 mm, respectively, which was more significant than in control group (0.20 mm); the reductions of AL in groups I, II, and control group were 0.86, 0.57, and 0.03 mm, respectively, which showed significance in all the three groups. The subjects of groups I and II had 0.56% and 1.01% reductions of HbA1C respectively, and the significance was observed in group II. In addition, the improvement of HbA1C values in group II was highly correlated with the decrease in gingivitis (r=0.51, P=0.03). CONCLUSION: The community periodontal care approaches implemented in the community health service centers have significantly improved periodontal health as well as reduced glycemic level, which could be regarded as basic health care strategies for the patients with diabetes.

Enhancing Photostability of Perovskite Solar Cells by Eu(TTA)2(Phen)MAA Interfacial Modification.

Organic-inorganic lead halide perovskite solar cells (PSCs) exhibit spectacular changes in the photovoltaic area, but they still face the challenges of full spectral utilization and photostability under continuous light irradiation. The ultraviolet (UV) part in sunlight could induce oxygen vacancy in the mesoporous TiO2 (m-TiO2) layer, resulting in the degradation of perovskite photoactive films and the rapidly decreased device performance. In this work, we demonstrate that an effective luminescent downconversion material, Eu(TTA)2(Phen)MAA (ETPM), can be used as an interfacial modifier between the m-TiO2 layer and the perovskite photoactive layer to improve the power conversion efficiency (PCE) from 17.00 to 19.07%. The improved device performance can be ascribed to the effective utilization of incident UV light and reduced carrier recombination. Meanwhile, the conversion of the UV light by ETPM could inhibit the stability loss of the device under irradiation. As a result, the modified PSCs can maintain 86% of their initial value under continuous light soaking for 100 h, higher than that of 40% for the control device. This work indicates that the introduction of the luminescent downconversion material ETPM can successfully improve the PCE and photostability of PSCs.

Efficient rare earth co-doped TiO2 electron transport layer for high-performance perovskite solar cells.

Perovskite solar cells (PSCs) had received great attention as a result of their recent rapid increasing efficiency. However, the stability of PSCs is still a challenge due to the degradation of the perovskite layer caused by the high-energy ultraviolet (UV) irradiation. Inspired by the luminescent down converting ability for UV blocking and conversion as well as energy transfer between suitable rare earth (RE) ions, a planar CH3NH3PbI3 perovskite solar cell using Sm3+ and Eu3+ co-doped TiO2 electron transfer layer was designed. By optimizing the Sm3+ and Eu3+ doping concentration, the REs co-doped TiO2 ETL combines the advantages of high electron extraction and lower interfacial recombination caused by REs introduction, a power conversion efficiency of 19.01% was obtained. In addition, benefit from the enhanced ability to convert UV light into visible light of the co-doped ETL, the PSCs can sustain higher than at least 80% of the original efficiency over 25 days of full sunlight irradiation or after 100 h of UV illumination. Moreover, since the low-temperature pulsed laser deposition was adopted in ETL fabrication process, the large area (225 mm2) and flexibility devices were further explored, with PCEs of 12.60% and 15.48%, respectively. This work indicates that Sm3+ and Eu3+ co-doped ETLs are effective and promising method to enhance the photovoltaic performance and UV stability of PSCs, which can be further applied in other PSCs with different ETLs and co-doping types.

High-Performance CsPbIBr2 Perovskite Solar Cells: Effectively Promoted Crystal Growth by Antisolvent and Organic Ion Strategies.

Growing attention has been paid to CsPbIBr2 perovskite solar cells (PSCs) after balancing the band gap and stability features of the interested full-inorganic perovskites. However, their power-conversion efficiency (PCE) still lags behind that of the PSCs using hybrid halide perovskite and how to increase the corresponding PCE is still a challenge. Herein, antisolvents and organic ion surface passivation strategies were systematically applied to precisely control the growth of CsPbIBr2 crystals for constructing a high-quality full-inorganic perovskite film. Through careful adjustments, a CsPbIBr2 film with a pure phase, full coverage, and high crystallinity with preferable (100) orientation was successfully obtained by introducing diethyl ether as the antisolvent followed by guanidinium surface passivation. The optimal CsPbIBr2 film was composed by a large grain with an average size of 950 nm, few grain boundaries, and higher hydrophobic property. Planer PSC using the optimal CsPbIBr2 film and electron-beam-deposited TiO2 compact layer exhibits a PCE of 9.17%, which ranks among the highest PCE range of the reported CsPbIBr2 PSCs. Besides, the designed CsPbIBr2 PSC exhibited good long-term stability, which could maintain 90% of the initial PCE in 40% humidity ambient, which remained constant after heat treatment at 100 °C for 100 h. Based on the optimal CsPbIBr2 film, the flexible and large-area (up to 225 mm2) PSCs were further fabricated. The adopted film improvement methods were further extended to other kinds of full-organic PSCs, which demonstrated the universality of this strategy.

Sn-doped 3D ATO inverse opal/hematite hierarchical structures: facile fabrication and efficient photoelectrochemical performance.

The coupling of hematite with a three-dimensional (3D) conductive inverse opal (IO) skeleton provides an efficient route to enhance the photoelectrochemical (PEC) properties of hematite without changing its chemical composition. In this work, novel 3D antimony-doped SnO2 (ATO) IO/hematite heterostructures were facilely fabricated, and their PEC properties were thoroughly studied. Analysis of the morphologies and photocurrent densities of the 3D ATO IO//Fe2O3 heterostructures reveals that the high conductivity of the ATO skeleton as well as the high specific area and good light harvesting properties of the 3D IO structures greatly enhance their PEC performance. In particular, further morphology tuning by changing the diameters of the ATO IO skeletons could optimize the optical and electrical properties of the as-prepared heterostructures, demonstrating the important influence of morphology engineering on PEC performance. Moreover, after a simple Sn-doping process, the PEC properties of the as-prepared structure could be further enhanced; a photocurrent density of 1.28 mA cm-2 at 1.23 V vs. RHE was obtained under AM 1.5G illumination.

Changing use and knowledge of fluoride toothpaste by schoolchildren, parents and schoolteachers in Beijing, China.

OBJECTIVE: To assess the oral hygiene practices, current use of and knowledge about fluoride toothpaste among schoolchildren, parents, and schoolteachers; to describe the attitudes of parents and schoolteachers in relation to improving schoolchildren's oral health. DESIGN: Cross-sectional study. PARTICIPANTS: 1,557 schoolchildren, 1,132 parents, and 352 schoolteachers were recruited by multistage stratified sampling procedure in a district of Beijing, China. METHODS: Self-completed questionnaire. RESULTS: The percentage of schoolchildren, parents, and schoolteachers who actually used fluoride toothpaste was 88%, 86%, and 87%, respectively, and 74-78% of the respondent groups brushed their teeth twice a day or more. 64% of schoolchildren, 73% of parents, and 74% of schoolteachers confirmed the caries preventive effect of fluoride toothpaste. Toothpaste recommended by oral health professional organisations was preferred by respondents - particularly by schoolchildren - when purchasing toothpaste (86%). 93% of parents and 56% of schoolteachers recognised their important role in promoting children's oral health; however, their lack of knowledge seemed to be a major obstacle in fulfilling this role. CONCLUSIONS: The use of fluoride toothpaste in Beijing appears to have increased during the past decade. In addition to mass communication comprehensive school-based oral health programmes are needed to continuously promote the use of fluoride toothpaste among schoolchildren.

Improved method of step length estimation based on inverted pendulum model.

Step length estimation is an important issue in areas such as gait analysis, sport training, or pedestrian localization. In this article, we estimate the step length of walking using a waist-worn wearable computer named eButton. Motion sensors within this device are used to record body movement from the trunk instead of extremities. Two signal-processing techniques are applied to our algorithm design. The direction cosine matrix transforms vertical acceleration from the device coordinates to the topocentric coordinates. The empirical mode decomposition is used to remove the zero- and first-order skew effects resulting from an integration process. Our experimental results show that our algorithm performs well in step length estimation. The effectiveness of the direction cosine matrix algorithm is improved from 1.69% to 3.56% while the walking speed increased.

Enhanced Performance of Perovskite Solar Cells with Zinc Chloride Additives.

Perovskite solar cells (PSCs) have attracted extensive attention due to their impressive photovoltaic performance. The quality of the perovskite layer is very critical to achieve high device performance. Here, we explore the partial substitution of PbI2 by ZnCl2 in the preparation of CH3NH3PbI3 and its effects on perovskite morphology, optical properties, and photovoltaic performance. Consequently, the device with 3% ZnCl2 shows great improvement in power conversion efficiency (PCE) from 16.4 to 18.2% compared to that of the control device. Moreover, the device is more stable than the control device, with only 7% degradation after aging for 30 days. These results are attributed to the increased grain size, improved film morphology, and reduced recombination loss after the partial substitution of PbI2 by ZnCl2 in the perovskite film. This work develops a new approach for morphology control through rational additives in the perovskite film, and paves the way toward further enhancing the device performances of PSCs including PCE and stability.

Oral health knowledge, attitudes and behaviour of adults in China.

OBJECTIVES: To describe oral health behaviour, illness behaviour, oral health knowledge and attitudes among 35-44 and 65-74-year-old Chinese; to analyse the oral health behaviour profile of the two age groups in relation to province and urbanisation, and to assess the relative effect of socio-behavioural risk factors on dental caries experience. METHODS: A total number of 4,398 35-44-year-olds and 4,399 65-74-year-olds were selected by multistage stratified cluster random sampling which involved 11 provinces in China. Data were collected by self-administered structured questionnaires and clinical examinations (WHO criteria). RESULTS: 32% of the 35-44-year-olds and 23% of the 65-74-year-olds brushed at least twice a day but only 5% used fluoridated toothpaste; 30% and 17% respectively performed 'Love-Teeth-Day' recommended methods of tooth brushing. A dental visit within the previous 12 months was reported by 25% of all participants and 6% had a dental check-up during the past two years. Nearly 15% of the subjects would visit a dentist if they experienced bleeding from gums; about 60% of the subjects paid no attention to signs of caries if there was no pain. Two thirds of the urban residents and one fifth of the rural participants had economic support for their dental treatment from a third party, either totally or partially. Significant variations in oral health practices were found according to urbanisation and province. At age 35-44 years 43% of participants had daily consumption of sweets against 28% at age 65-74 years. Dental caries experience was affected by urbanisation, gender, frequency, time spent on and method of tooth brushing. Knowledge of causes and prevention of dental diseases was low with somewhat negative attitudes to prevention observed. CONCLUSION: Systematic community-based oral health promotion should be strengthened and preventive-oriented oral health care systems are needed, including promotion of further self-care practices and the use of fluoridated toothpaste.

SIFT-Based Indoor Localization for Older Adults Using Wearable Camera.

This paper presents an image-based indoor localization system for tracking older individuals' movement at home. In this system, images are acquired at a low frame rate by a miniature camera worn conveniently at the chest position. The correspondence between adjacent frames is first established by matching the SIFT (scale-invariant feature transform) based key points in a pair of images. The location changes of these points are then used to estimate the position of the wearer based on use of the pinhole camera model. A preliminary study conducted in an indoor environment indicates that the location of the wearer can be estimated with an adequate accuracy.

The second national survey of oral health status of children and adults in China.

OBJECTIVES: To describe the oral health status of Chinese children and adults at national level in relation to location and province and to highlight changes in dental caries experience. DESIGN: Cross-sectional study, oral epidemiological survey based on WHO methodology, clinical examinations. SETTING: National survey by National Committee for Oral Health. SUBJECTS: Representative samples of provinces, districts, townships; cluster sampling including subjects aged 5,12,15,18, 35-44 and 65-74. Each age group consisted of 23,452 participants, i.e. total of 140,712 individuals. RESULTS: At age 5, 76.6% were affected by dental caries and mean dmft was 4.5. Mean DMFT varied from 1.0 in 12-year-olds, 1.4 in 15-year-olds, 1.6 in 18-year-olds, 2.1 in 35-44-year-olds to 12.4 in 65-74-year-olds. In adults, caries experience was higher in females than in males. The effect of urbanisation on caries prevalence in children varied by province and age. Among adolescents and young adults caries levels were high in urban areas while caries experience was high for old-age people of rural areas. At national level, changes in dental caries prevalence of 12- and 15-year-olds were small. However, some provinces with extensive oral health programmes (e.g. Love Teeth Day) showed declining caries experience whereas provinces with limited preventive activities had increasing levels of caries. For all age groups, gingival bleeding and calculus were most frequent. Severe periodontal conditions were relatively rare. CONCLUSION: The systematic implementation of preventive oral care and community-oriented health programmes are needed for the continuous promotion of oral health in China.

Oral health knowledge, attitudes and behaviour of children and adolescents in China.

OBJECTIVES: A national representative study to describe oral health behaviour, illness behaviour, oral health knowledge and attitudes among 12-year-old and 18-year-old Chinese, to analyse the oral health behaviour profile of the two age groups in relation to province and urbanisation, and to assess the relative effect of socio-behavioural risk factors on dental caries experience. METHODS: The total number of 4,400 of each age group were selected and data were collected by clinical examinations (WHO criteria) and self-administered structured questionnaires. RESULTS: 44.4% of the respondents brushed their teeth at least twice a day but only 17% used fluoridated toothpaste. Subjects who saw a dentist during the previous 12 months or two years were 31.3% and 35.3% for 12-year-olds and 22.5% and 20.2% for 18-year-olds, respectively. Nearly one third (29%) of 12 year-olds and 40.5% of 18-year-olds would visit a dentist in case of signs of caries but only when in pain. Nearly half of the participants (47.2%) had never received any oral health care instruction. Significant variations in oral health practices were found according to province and regular dental care habits were more frequent in urban than in rural areas. The risk of dental caries was high in the case of frequent consumption of sweets and dental caries risk was low for participants with use of fluoridated toothpaste. CONCLUSION: Systematic community-oriented oral health promotion programmes are needed to target lifestyles and the needs of children, particularly for those living in rural areas. A prevention-oriented oral health care policy would seem more advantageous than the present curative approach.

[Prevalence and related factors of periodontitis in community-dwelling Chinese with diabetes].

OBJECTIVE: To evaluate the periodontal conditions in community-dwelling Chinese with diabetes and analyze some related factors. METHODS: A total of 90 (45- to 84- year-old) patients with diabetes, participating in community-based non-communicable diseases management system, were recruited in this study. The examination items on these patients included periodontal measurements performed by pocket probing depth (PPD), attachment loss (AL), sulcus bleeding index (SBI), plaque index (PLI), and blood sugar metabolic level surveillance, as well as structured questionnaire interview. RESULTS: The prevalence of periodontitis was 100%, while 37.1% was diagnosed as having mild periodontitis, 24.4% with moderate, and 38.5% with advanced periodontitis. The AL level in male was significantly higher than that in female. The periodontal destruction was highly correlated with HbA1C value and affected by some socio-behavior factors based on multinomial logistic model. CONCLUSIONS: There is a positive correlation between AL and HbA1C level, and AL and HbA1C should be measured regularly. The patients' periodontal inflammation needs effective control. Priority should be given to the low income population and those with little periodontal knowledge for behavior interventions.

[A survey of cognition and utilization of fluoride toothpaste and associated factors].

OBJECTIVE: To survey the situation of cognition and utilization of fluoride toothpaste and associated factors amongst elementary and middle school students in Haidian district, Beijing. METHODS: Sample of students was recruited by a multistage, stratified, and probability proportional to size sampling procedure. Self-administered structured questionnaires were used to collect information concerning the knowledge of, attitudes to and utilization of fluoride toothpaste and associated factors. A total of 1 557 students completed the questionnaire effectively. RESULTS: The percent age of students who used fluoride toothpaste when brushing their teeth were 87.8%. More than 60% of students knew that fluoride toothpaste could prevent dental caries by strengthening the out layer of tooth surface. 41.6% of the students doubted about the harmless of fluoride toothpaste even to be used properly. Advertisement was the main source of information about the fluoride toothpaste. CONCLUSIONS: The percentage of students using fluoride toothpaste was high and the majority of them knew that fluoride toothpaste could prevent caries. The oral health education programme concerning the optimal use of fluoride in dental caries prevention is highly recommended.