Effect of Morinda citrifolia juice on the bonding strength and nanoleakage of crowns dentin / 口腔疾病防治

Objective@#To explore the effect of Morinda citrifolia juice (MCJ) combined with ethylene diamine tetraacetic acid (EDTA) on premolar bonding strength and nanoleakage and compare the results with those of the most commonly used root canal irrigation solution, sodium hypochlorite (NaClO), to provide a reference for clinical application.@*Methods@#This study was approved by the ethics review committee. Sixty-three human premolars extracted for orthodontic treatment were randomly divided into a control group (distilled water group) and 6 experimental groups according to the different rinsing solutions used after the surface enamel was removed. The experimental groups included Group A (2.5% NaClO), Group B (5.25% NaClO), Group C (6% MCJ), Group D (2.5% NaClO-17% EDTA), Group E (5.25% NaClO-17% EDTA), and Group F (6% MCJ-17% EDTA) (n = 9). After soaking in the corresponding rinsing solution for 20 minutes, they were layered and stacked on their surfaces to form 4 mm × 4 mm × 3 mm Z350 resin blocks. Six samples from each group were cut into 1 mm × 1 mm × 8 mm specimen strips for microtensile bonding strength testing. The fracture type was determined under a stereomicroscope, and the remaining 3 samples from each group were aged and cut into 1 mm thick slices for interface nanoleakage testing and scanning electron microscopy observation of the resin dentin bonding interface.@*Results@#There were significant differences in the microtensile bonding strength among the groups (P<0.05), and the control group had the highest bonding strength. Among experimental groups, Group B had the lowest bonding strength, mainly bonding interface fracture, and Group F had the highest bonding strength, mainly mixed fracture. There were significant differences in nanoleakage among all groups (P<0.05), and the control group had the lowest nanoleakage value. Among experimental groups, Group B had the highest nanoleakage, with resin protrusions being unaltered, and Group F had the lowest nanoleakage value, with resin protrusions being thick and dense.@*Conclusion@#The higher the concentration of NaClO was, the worse the bonding strength and edge sealing of the crown dentin were. The effects of root canal irrigation with MCJ and EDTA on the adhesive strength and edge sealing of crown dentin were less pronounced than those of root canal irrigation with NaClO and EDTA.

Effects of graphene on the proliferation, migration and morphology of dental pulp stem cells / 口腔疾病防治

Objective@# To investigate the effects of graphene on the proliferation, migration and cell morphology of dental pulp stem cells (DPSCs).@*Methods@#Graphene powder was prepared by the oxidation-reduction method, and a 0.5 mg/mL graphene dispersion was prepared. Raman spectroscopy and atomic force microscopy were used to characterize the structure and surface morphology of graphene. DPSCs were isolated and cultured in vitro. MTT assay was used to detect the effects of different concentrations of graphene dispersions (0, 1, 5, 10, 20, 50, 100 μg/mL) on the proliferation and wound healing assay was used to detected the migration abilities of DPSCs. The effects of graphene on the morphology of DPSCs were observed by immunofluorescence staining. @*Results @# In the present study, compared with the control group (0 μg/mL), the proliferation of DPSCs in the 100 μg/mL group was inhibited at 72 h (P < 0.05), and the proliferation of DPSCs in the other groups was not significantly affected (P > 0.05). Graphene dispersions at 10 and 20 μg/mL promoted the migration of DPSCs (P < 0.05). After being cultured in 20 μg/mL graphene dispersions for 3 days, the DPSCs showed a large and orderly cytoskeletal structure, and the spread area of cells was not significantly different from that of the control group (0 μg/mL) (P > 0.05), while some cells had the morphological characteristics of nerve cells.@* Conclusion @# Graphene has good biocompatibility and is expected to be a suitable material for tissue engineering within fitting concentration.

Computational fluid dynamics analysis of the flow of ultrasonic irrigations in root canal / 口腔疾病防治

Objective@#To study the computational fluid dynamics (CFD) characteristics of ultrasonic root canal irrigation when the file was placed at a certain depth in the root canal, to provide a reference for clinical application.@*Methods @#First, scanning laser vibrometry (SLV) was utilized to analyze the characteristics of vibrational ultrasonic files under specific power. Then ICEM CFD 18.0 software was used to establish the root canal ultrasonic irrigation model. The insertion position of the ultrasonic working tip was set 1 mm away from the physiological apical foramen, and cloud images of the results were obtained by FLUENT 18.0 software. Volume fraction, flow velocity and pressure in the root canal were evaluated after setting the computing conditions.@*Results@#The vibration of the ultrasonic working tip was mainly transverse vibration with slight longitudinal vibration. The amplitude of transverse vibration of each part of the working tip was different. Maximum values were observed at the apical end area of the file, and the closer to the base of the file, the smaller the amplitude. The area where the cavitation volume fraction of the rinsing fluid was greater than 0 was concentrated around the working point. The flow rate of the irrigating fluid was up to 2 m/s, within the area 0.2 mm in front of the working tip, the velocity of the irrigating fluid was greater than 0.1 m/s, while within the area 0.8 mm from the root tip, the velocity of the irrigating fluid was small or even zero. The apical pressure value was non-positive when the tip of the file was 1 mm away from the apical foramen in this model.@*Conclusion@# Based on the experimental results, it appears that when the ultrasonic working tip was placed 1 mm short of the working length, the ultrasonic irrigating flow did not overflow the root apical foramen and the irrigation process was relatively safe; the irrigation fluid had a strong irrigation effect within approximately 0.2 mm in front of the working tip.

Understanding changes in doctor moral hazard behaviour in response to government healthcare reform / Entendiendo los cambios en el riesgo moral del comportamiento médico en respuesta a la reforma de atención de salud del gobierno / Compreendendo mudanças no comportamento de risco moral médico em resposta a reforma governamental de cuidados à saúde

Doctor moral hazard has a significant effect on the doctor-patient relationship, increases the cost of healthcare, and introduces medical risks. It is a global concern. Doctor moral hazard behaviour is evolving in response to China's healthcare reform program which was inaugurated in 2009.A scientific understanding of doctor behaviour would facilitate the prevention and control of doctor moral hazard behaviour. This study used the principles and methodology of Glaser and Strauss's grounded theory. Theoretical and snowball samplings were used to identify 60 subjects. Semi-structured in-depth interviews were conducted with each subject. Themes were identified through substantial (open) coding and theoretical coding. Six types of doctor moral hazard behaviour were extracted from the data. A behavioural model was described and diagrammed to provide a conceptual framework of current doctor moral hazard behaviour. The conceptual model of doctor moral hazard behaviour can be used in several ways to correct or prevent undesirable actions. Rules governing hospital procedures can be strengthened and enforced by supervision and punishment; the asymmetry of information between doctor and patient can be reduced; patient participation in treatment decisions can be increased; the effectiveness of medical ethics education can be improved.

Para un médico, el riesgo moral tiene un efecto significativo en la relación médico-paciente, incrementa el costo de la atención de salud e introduce riesgos en la salud. Se trata de una preocupación global. El riesgo moral del comportamiento médico ha evolucionado en respuesta al programa de reforma de atención de salud del gobierno de China, inaugurado en 2009. Un entendimiento científico del comportamiento de los médicos facilitaría la prevención y el control del riesgo moral. El presente estudio usa los principios y metodología de la teoría fundamentada de Glaser y Strauss. Se usaron muestras teóricas y multiplicativas para identificar 60 sujetos y realizar entrevistas semiestructuradas en profundidad. Los temas se identificaron mediante codificación sustancial abierta y teórica. De los datos se extrajeron seis tipos de riesgo moral del comportamiento médico. Se describió y diagramó un modelo de comportamiento para proporcionar una estructura conceptual del riesgo moral del comportamiento médico actual. El modelo conceptual de riesgo moral del comportamiento médico puede usarse de varias maneras para corregir o prevenir acciones no deseadas. Las normas procedimentales de los hospitales pueden fortalecerse y exigirse mediante supervisión y castigo; se puede reducir la asimetría de la información que se da entre el médico y el paciente, incrementar la participación del paciente en decisiones de tratamiento y mejorar la efectividad en la educación en ética médica.

Risco moral médico tem um efeito significativo na relação médico-paciente, aumenta o custo dos cuidados à saúde e introduz riscos médicos. É uma preocupação global. Comportamento de risco moral médico vem se desenvolvendo em resposta ao programa de reforma de cuidados à saúde da China, que se iniciou em 2009. Uma compreensão científica do comportamento médico facilitaria a prevenção e controle do comportamento de risco moral médico. Este estudo utilizou os princípios da metodologia da Teoria Fundamentada de Glaser e Strauss. Amostragem teóricas e por bola de neve foram utilizadas para identificar 60 participantes. Entrevistas detalhadas semi-estruturadas foram realizadas com cada participante. Temas foram identificados através de codificação (aberta) substancial e codificação teórica. Seis tipos de comportamento de risco moral médico foram obtidos dos dados. Um modelo comportamental foi descrito e diagramado de forma a fornecer um enquadre conceitual do comportamento de risco moral médico. O modelo conceitual de comportamento de risco moral médico pode ser utilizado de diversas formas para corrigir ou prevenir ações indesejáveis. Regras que governam procedimentos em hospitais podem ser fortalecidas e reforçadas por supervisão e punição; a assimetria de informações entre médicos e pacientes pode ser reduzida; a participação dos pacientes nas decisões sobre tratamento pode ser aumentada; e a efetividade da educação ética médica pode ser melhorada.

Association study of the oestrogen signalling pathway genes in relation to age at natural menopause.

Genetic factors play a significant role in influencing the variation of age at natural menopause (AANM). Estrogen receptor beta (ESR2), is an important factor in the mechanism of action of estrogen, while the aromatase gene (CYP19) and the 17-alpha-hydroxylase gene (CYP17) are involved in the biosynthesis of estrogen. We tested whether polymorphisms of ESR2, CYP19 and CYP17 genes are associated with AANM in Caucasian females. A total of 52 SNPs (17 for ESR2, 28 for CYP19, and 7 for CYP17) were successfully genotyped for 229 Caucasian women having experienced natural menopause. Comprehensive statistical analyses focusing on the association of these genes with AANM were conducted. The effects of age, height and age at menarche on AANM were adjusted when conducting association analyses. We found that six SNPs (2, 6-7, 9, 13 and 16) within ESR2 were not significantly associated with AANM after Bonferroni correction. However, two blocks of ESR2 were associated with AANM. For CYP19, two SNPs (24 and 27) were nominally associated with AANM. No significant association was observed between CYP17 and AANM. Our results suggest that genetic variation in the ESR2 and CYP19 genes may influence the variation in AANM in Caucasian women.