10-MDP-钙盐形成对牙本质粘接成绩影响的评价

目的　分析10-MDP-钙盐形成对牙本质粘接成绩的影响。方法　采用酸蚀冲洗粘接模式，根据牙本质表面的处理方式和选择粘接剂的不同将牙齿随机分为以下4组（n=5）进行处理，制作牙本质/树脂粘接试件：①对照组，直接使用全酸蚀粘接剂Single bond 2(SB2)处理后粘接；②10-MDP组，使用SB2处理进行粘接前，牙本质表面以含有磷酸酯单体10-MDP的自配底涂剂预处理；③CHX组，使用SB2处理进行粘接前，先以氯己定（CHX）预处理牙本质表面;④SBU组，使用包含10-MDP的通用型粘接剂Single bond universal(SBU)处理后进行粘接。通过微拉伸测试（μTBS）测试粘接强度，以X射线衍射(XRD)、原位酶谱测试表征自配10-MDP底涂剂和两种牙本质粘接剂处理的牙本质表面，分析10-MDP-钙盐形成对牙本质粘接成绩的影响。结果　微拉伸结果显示，不同处理方式的粘接试件在24 h水储后没有表现出明显的统计学差异(P>0.1)；经过6个月的水储后，与10-MDP组和SBU组相比，对照组的微拉伸强度显著降低(P<0.05)，而CHX组的微拉伸强度没有明显变化(P>0.05)。XRD结果显示,在10-MDP组和SBU组均检测到10-MDP-钙盐形成的特征性峰，表明有10-MDP-钙盐的形成。原位酶谱结果显示，10-MDP组与SBU组之间混合层荧光强度没有明显区别，但均明显高于对照组，CHX组荧光强度低于10-MDP组与SBU组。结论　10-MDP-钙盐的形成能够保护暴露的胶原纤维不接触到MMPs而免于水解，从而增强牙本质/树脂的粘接成绩。     

Indirect caries‐preventive effect of silver diamine fluoride on adjacent dental substrate: A single‐section demineralization study

This study assessed the indirect effect of 38% silver diamine fluoride (SDF) on demineralization of adjacent untreated sound and pre‐demineralized enamel and dentine using a single‐section model for digital transverse microradiography (TMR‐D). Forty‐eight bovine dentine single sections were demineralized, stratified (n = 12) according to integrated mineral loss (ΔZ), and treated with SDF or deionized water (DIW). Each “treated dentine” section was attached between untreated sound and pre‐demineralized enamel or dentine and then subjected to demineralization. ΔZ and lesion depths (LD) of all specimens at baseline, 24 and 48 h demineralization, and after treatment of “treated dentine” were quantified using TMR‐D. Fluoride in the demineralization solution of SDF clusters was determined using an ion‐selective electrode. ΔZ and LD of sound and ΔZ of pre‐demineralized enamel adjacent to SDF‐treated dentine did not increase over time. All untreated dentine demineralized significantly; however, ΔZ of sound dentine adjacent to SDF‐treated specimen was still significantly lower than control. SDF‐treated dentine remineralized and released fluoride even after 48 h. Consistent with clinical findings, when applied only to demineralized teeth in this chemical model, 38% SDF completely inhibited demineralization in adjacent untreated sound enamel. Demineralization prevention was observed to a lesser extent in adjacent pre‐demineralized enamel but not in dentine.     

Er:YAG激光桩道预处理的研究进展

本文回顾了Er:YAG激光活化根管冲洗技术的最新研究进展,包括光子诱导光声流(photon initiated photoacoustic streaming,PIPS)技术和冲击波增强发射光声流(shock wave enhanced emission photoacoustic streaming,SWEEPS)技术,探讨Er:YAG激光预处理桩道的原理、优点以及对纤维桩粘接强度的影响,以期为临床选择适宜的桩道处理方法提供新思路。     

Evaluation of the Amount of Root Canal Dentin Removed and Apical Transportation Occurrence after Instrumentation with ProTaper Next,OneShape, and EdgeFile Rotary Systems

IntroductionThe aim of this study was to evaluate the amount of root canal dentin removed and apical transportation occurrence after instrumentation of mesiobuccal canals of maxillary molars with ProTaper Next (PTN [Dentsply Maillefer, Ballaigues, Switzerland]), OneShape (OS [MicroMega, Besançon, France]), and EdgeFile (EF [Edge Endo, Albuquerque, NM]) rotary systems.MethodsTwenty-seven mesiobuccal canals of maxillary molars were used. Canals were randomly divided into 3 groups for canal preparation: PTN, EF X3, or OS (n = 9 for each group). Micro–computed tomographic imaging was used to measure apical transportation (mm) and the volume of dentin removed (mm³). The amount of dentin removed was measured for the coronal portion and for the whole canal length. Superposition of pre- and postoperative cross-sectional apical slices were used to measure apical transportation at 1 mm from the apex; the differences were evaluated using the Kruskal-Wallis test and Wilcoxon analysis. The Spearman correlation coefficient was used to display the relationship between variables for each group. The significance level was set at P < .05.ResultsThe percentages of the amount of dentin removed on the coronal portion and the amount removed for the whole canal length were statistically similar between groups (P > .05). The average amount of apical transportation for the PTN, OS, and EF X3 were 0.197, 0.263, and 0.218 mm, respectively. Statistically, there were no significant differences between the 3 rotary instruments for apical transportation.ConclusionsThe amount of dentin removed for the coronal third portion and the whole canal length was similar for the PTN, OS, and EF X3 rotary instruments. Although there were differences in the sizes of apical enlargement, no apical transportation was observed in any of the instrumentation systems.     

Droit à mourir et suicide assisté : état des lieux et analyse critique

ObjectivesIn the context of the present re-examination of the French bioethical laws by the National Advisory Ethics Committee (“Comité consultatif national d’éthique”: CCNE), a recent survey indicated a request of the public opinion to obtain a medical aid in end of life and a so-called “assisted suicide”. This led psychiatrists to re-consider their role and deontological position which usually led them to consider a request for an assistance in suicide as – a priori – a pathological demand, occurring within a suicidal crisis. The present article intends to: 1) describe the laws and practices of countries which allow medically assisted end of life help procedures; 2) clarify the definitions of “assisted suicide”, “assistance to suicide” and “euthanasia”; 3) consider available epidemiological data and the roles given to doctors and, more specifically psychiatrists, in these procedures; 4) analyse the rationale behind these demands. These considerations should enable French psychiatrists to clarify their position when facing requests for a medical aid in dying.MethodsFour European countries (Switzerland, the Netherlands, Belgium, Luxemburg) and Oregon (the first US state to introduce legislation) were considered, since they accumulated and published a large amount of experiences and data about “assisted suicide” and medical help in dying. In total, 127 articles were selected, mainly from PubMed and Cairn databases, published between 1997 and 2020. These articles deal with legal considerations, epidemiological data, ethical and sociological considerations.ResultsLaws and practices differ notably according to the state/country. In Belgium, the Netherlands and Luxemburg, as in Oregon, the medical help in dying has been de-criminalized, as long as certain legal criteria are met. In Switzerland, where no specific law exists in the penal code, non-governmental associations have benefited from the legal vacuum and organized the practice of “assisted suicide” for “altruistic motives”. In the scientific and legal literature, the terms used to describe and define the medical help in dying upon request differ greatly. In France, the National Advisory Ethics Committee defines euthanasia (“euthanasie”), assisted suicide (“suicide assisté”) and suicide assistance (“assistance au suicide”). Available epidemiological data, whatever the country considered, indicate that requests for a medical aid in dying are expressed mainly by patients aged over 60 years and suffering from cancer. Psychiatric diseases account for only 1% to 3%. Most often, systematic assessment by a psychiatrist is neither requested nor made, when the demand does not occur during a primary psychiatric illness. In the case of an existing primary psychiatric pathology, a psychiatrist assesses the case against formal legal predefined criteria. This latter practice was only recently introduced, after some feedback and after legal actions had been brought to Court. When the underlying motivations of the request are considered, it appears that, even in the absence of an evolving psychiatric condition, several psychological or psychopathological reasons prevail such as spirituality, attachment style, social isolation, despair, depression… which should greatly benefit psychiatric exploration, investigation and expertise.ConclusionIn some countries, the request for medically assisted help in dying has become a legal and social reality. In France, where the public debate is still open, it should be emphasized that a psychiatric assessment and interview should be systematically provided to any person requesting medical assistance to die or commit suicide. It is the commitment of psychiatrists to understand the implicit demands and unexpressed motives underlying this request which have strong links with the unique life-events and emotional experiences of the person. The psychiatrist has a unique role in the contextualization of such a request.     

Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.     

Constructing an In Silico Three-Class Predictor of Human Intestinal Absorption With Caco-2 Permeability and Dried-DMSO Solubility

Absorption of drugs is the first step after dosing, and it largely affects drug bioavailability. Hence, estimating the fraction of absorption (Fa) in humans is important in the early stages of drug discovery. To achieve correct exclusion of low Fa compounds and retention of potential compounds, we developed a freely available model to classify compounds into 3 levels of Fa capacity using only the chemical structure. To improve Fa prediction, we added predicted binary classification results of membrane permeability measured using Caco-2 cell line (Papp) and dried–dimethyl sulfoxide solubility (accuracy, 0.836; kappa, 0.560). The constructed models can be accessed via a web application.     

Impact of Dentin Substrate Modification with Chitosan-Hydroxyapatite Precursor Nanocomplexes on Sealer Penetration and Tensile Strength

IntroductionThe purpose of this study was to evaluate the effect of dentin conditioning with chitosan-hydroxyapatite precursor (C-HA) nanocomplexes on the depth of tricalcium silicate sealer penetration into dentinal tubules and ultimate tensile strength (UTS).Methodssurface charge and size distribution for C-HA nanocomplex formulation was evaluated followed by bioactivity assessment of standardized films of C-HA nanocomplexes (n = 15) incubated in simulated body fluid. Mineralization potential was assessed with X-ray diffraction and Fourier-transform infrared spectroscopy, whereas scanning electron microscopy was used for ultrastructural evaluation. Static water contact angles and UTS were measured on dentin discs (n = 2/group) and dentin beams (n = 10/group) treated with/without sodium hypochlorite/EDTA and C-HA nanocomplex conditioning. In phase 2, the depth of sealer penetration after C-HA nanocomplex conditioning was evaluated using fluorescent imaging (n = 12/group). The percent area penetration and mean/maximum penetration depth were calculated at 4- and 6-mm levels from the root apex. Data from contact angle measurements, mechanical testing, and penetration assessment parameters were subjected to the independent samples t test with a significance level set at P < .05.ResultsA formulation of C-HA nanocomplexes (2 mg/mL) was chosen as a polyanionic, hydrophilic, nonaggregating concentration having bioactivity potential established through the formation of phosphate/carbonate bonds and the crystalline nature of the formed minerals. A significantly lower contact angle and higher UTS were registered for the C-HA nanocomplex–conditioned group (P < .05). Statistically significant (P < .05) greater sealer penetration was recorded at the 4-mm level for all assessment parameters and percent area penetration at 6 mm for the C-HA nanocomplex group.ConclusionsC-HA nanocomplex conditioning enhances dentin surface wettability to facilitate greater tricalcium silicate sealer penetration and UTS of dentin.