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Objective: Firearm injuries are the leading cause of death for children in the United States. Child access prevention (CAP) laws have been passed in some states. This study examines characteristics of children with firearm injuries in states with different types of CAP laws., Methods: The Pediatric Health Information System database was reviewed to identify all pediatric firearm injury patients between 2016 and 2021. Hospital data were categorized based on state laws as (1) no CAP laws (2) some CAP laws or (3) strict CAP laws. CAP laws that specifically outlined criminal liability for the negligent storage of firearms were considered a strict restriction, whereas any other form of CAP law was considered some restriction. χ-squared and independent-samples median testing were performed to compare restriction levels., Results: Between 2016 and 2021, 12 853 firearm injuries were recorded in the Pediatric Health Information System database. In states with strict CAP laws, patients were significantly older (P < .001) and had a significantly higher household income (P < .001) compared with patients in states with no CAP laws. Gender, race, and the number of firearm injuries differed between the 3 restriction levels. There were less firearm injuries observed than expected in cities with strict CAP laws., Conclusions: CAP laws are associated with a higher age and household income of pediatric firearm injury patients. Given the disparities seen between cities, a federal CAP law may best protect children nationwide., Competing Interests: CONFLICT OF INTEREST DISCLOSURES: The authors have indicated they have no conflicts of interest relevant to this article to disclose., (Copyright © 2024 by the American Academy of Pediatrics.)

The isolation of a compound from a natural source involves many organic and mostly toxic solvents for extraction and purification. Natural deep eutectic solvents have been shown to be efficient options for the extraction of natural products. They have the advantage of being composed of abundantly available common primary metabolites, being nontoxic and environmentally safe solvents. The aim of this study was to develop a natural deep eutectic solvent-based extraction method for galanthamine, an important therapeutic agent for the treatment of Alzheimer's disease. This alkaloid can be produced by synthesis or by extraction from Narcissus bulbs. To develop an efficient extraction method, a number of different natural deep eutectic solvents was first tested for their solubilization capacity of galanthamine bromide salt. Promising results were obtained for ionic liquids, as well as some amphoteric and acidic natural deep eutectic solvents. In a two-cycle extraction process, the best solvents were tested for the extraction of galanthamine from bulbs. The ionic liquids produced poor yields, and the best results were obtained with some acid and sugar mixtures, among which malic acid-sucrose-water (1 : 1 : 5) proved to be the best, showing similar yields to that of the exhaustive Soxhlet extraction with methanol. Furthermore, the natural deep eutectic solvent was more selective for galanthamine., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Issue Addressed: Comprehensive sexuality education (CSE) is important for the sexual and reproductive health of young people. To better understand young people's views and experiences of sexual health education in NSW, a student needs assessment survey was conducted in 2017., Methods: This paper presents the findings from 1603 NSW students in Years 8-12 following online recruitment. Descriptive analyses explored students' views and experiences in relation to sources of sexual health information, education providers, school-based topics covered and resources drawn on., Results: Findings indicate that school, parents, friends and social media are students' most common sources of information on sexual and reproductive health. Approximately one-third of students reported wanting more information on topics related to relationships, reproductive health, consent and sexual decision-making and sexual harassment, abuse and bullying, and two-thirds of transgender and gender diverse students wanted more information on gender identity. For the topics which students reported receiving the least information about at school, they were most likely to seek this out on social media and websites., Conclusion: Findings provide valuable insight for improving CSE in NSW. The influence of social media, parents and the internet should be taken into consideration when developing resources and programme content. Professional development for educators could contribute to improving the quality of CSE delivered. Accurate and up to date resources must be utilised to support student engagement and effective learning., (© 2021 Australian Health Promotion Association.)

Background Reproductive coercion (RC) occurs when a person's autonomous decision-making regarding reproductive health is compromised by another. RC screening, that is, the use of routine, non-invasive screening questions asked of service users/clients, is one strategy that can be used to assess for RC. Routine screening for RC was implemented within Family Planning NSW clinical consultations in December 2018. A cross-sectional study was undertaken to review the outcomes of screening to better understand the situation of RC among women accessing family planning services. Methods A retrospective review of clinical consultation data of eligible women attending Family Planning NSW clinics in 2019 was undertaken. Descriptive analysis was conducted and modified Poisson regression was used to estimate prevalence ratios and assess associations between binary outcomes and client characteristics. Results Of 7943 women eligible for RC screening, 5497 were screened (69%) and 127 women (2.3%) disclosed RC. RC was more likely to be disclosed among clients who were unemployed, had a disability or had more than one visit within 1 year. Conclusions Sexual and reproductive health clinicians, in particular, are well placed to conduct RC screening. However, they must have adequate training and access to resources to implement screening and respond to women who disclose RC.

Chlamydial infections in humans are widely distributed and are responsible for a variety of acute and chronic diseases. Both Chlamydia trachomatis and Chlamydia pneumoniae can lead to chronic conditions that have been linked to complications and sequelae. This study aimed to develop a culture method in order to detect in vitro antichlamydial activity of different extracts obtained from native Argentinian plants used as antimicrobials in local ethnomedicine and to evaluate their inhibitory activity over Chlamydia trachomatis and Chlamydia pneumoniae growth. The inhibitory activity over different stages of the chlamydial life cycle on cell culture was assessed: the entry, the inclusion developing after entry, and the exponential growth stage. Also, the capability of rendering the cell refractory to chlamydial infection by pre-incubation with the extracts was assayed. Inhibitory activity of water-based and organic-based extracts obtained from Hydrocotyle bonariensis Lam. (Araliaceae), Lithraea molleoides (Vell.) Engl. (Anacardiaceae) and Hybanthus parviflorus (Mutis ex L.f.) Baill. (Violaceae) were tested against five strains of Chlamydia trachomatis (L2/434/BU and four clinical isolates form both neonatal conjunctivitis and adult genital infections, genotypes D, E, and K) and against Chlamydia pneumoniae AR39. The Hydrocotyle bonariensis dichloromethane extract showed a broad inhibitory activity over the exponential growth stage of Chlamydia trachomatis and Chlamydia pneumoniae independently from the chlamydial strain and the cell line. These results suggest a high inhibitory potential on both Chlamydiae species. In order to characterize the Hydrocotyle bonariensis dichloromethane active extract, an 1 H-NMR was performed. The 1 H-NMR characterization showed a spectrum with characteristic signals of the fatty acid moiety of lipids or cerebrosides, volatile phenolics, phytosterols, methyl triterpenes signals, and glucose moiety of the cerebrosides., (© 2021 Published by Elsevier Ltd.)

Provided in this paper is a theory of long-range electron transfer with near sound (supersonic or subsonic) velocity along one-dimensional crystal lattices. The theory represents the development of an earlier work by introducing Marcus formulation. To illustrate its application to a realistic case, the theory is used to offer an explanation of two puzzling observations made by Donovan and Wilson in transient photoconduction experiments with non-dopable perfectly crystalline polydiacetylene crystals in the presence of an electric field: transport velocity value close to sound velocity being independent of field for four orders of magnitude of field (10 2 V/m-10 6 V/m) and, in the low field values, an ultra-high mobility greater than 20 m 2 /V s. We also study factors eventually leading to lowering of the transport velocity.

Banana passion fruit of the Passiflora genus, are commercially cultivated on a small to medium scale, mainly as edible fruits or as components of traditional herbal medicines. This subgenus comprises several species and hybrid specimens that grow readily in the wild. Due to their taxonomical complexity, many of these species have recently been reclassified (Ocampo Pérez and Coppens d'Eeckenbrugge, 2017), and their chemical profile has still to be determined. In this study, an 1 H NMR-based platform was applied to the chemical profiling of seven wild species of the Passiflora subgenus, and UHPLC-DAD-MS was additionally used for the identification of phenolic compounds. A total of 59 compounds were detected including 26 O- and C-glycosidated flavonoids and polyphenols, nine organic acids, seven amino acids, GABA, sucrose, glucose, myo-inositol, and five other non-identified compounds. Two of the identified compounds are the previously undescribed C-glycosyl flavonoids, apigenin-4'-O-β-glucopyranosyl, 8-C-β-(6″acetyl)-glucopyranoside and apigenin-4-O-β-glucopyranosyl-8-C-β-neohesperidoside. These C-glycosyl flavonoids were isolated to confirm their proposed structures by NMR and LCMS analysis. The PCA score plots obtained from the 1 H NMR data of the studied Passiflora samples showed P. cumbalensis and P. uribei as the species with the most distinguishable chemical profile. In addition, a correlation analysis using OPLS-DA was conducted between 1 H-NMR data and the quorum quenching activity (QQ) of Chromobacterium violaceum ATCC 31532. This analysis revealed P. lehmannii, and P. uribei extracts to be the most active, and apigenin-4'-O-β-glucopyranosyl, 8-C-β-(6″acetyl)-glucopyranoside and apigenin-4-O-β-glucopyranosyl-8-C-β-neohesperidoside were identified as possibly responsible for the QQ activity. To confirm this, QQ activity of both compounds was tested against C. violaceum ATCC 3153. An inhibition of violacein production of 0.135 mM (100 μg/mL) and 0.472 mM (300 μg/mL) was observed for apigenin-4'-O-β-glucopyranosyl,8-C-β-(6″acetyl)-glucopyranoside and apigenin-4-O-β-glucopyranosyl-8-C-β-neohesperidoside respectively, while bacterial growth was unaffected in both cases. Furthermore, both compounds showed the ability to inhibit the production of the toxoflavin of the phytopathogen Burkholderia glumae ATCC 33617., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Natural deep eutectic solvents (NADES) are a type of ionic liquid (IL) or deep eutectic solvent (DES), the ingredients of which are exclusively natural products (non-toxic and environmentally friendly). Here, we explore the potential of NADES as an alternative to conventional organic solvents (e.g., aqueous methanol or ethanol) for the extraction of flavonoids from Scutellaria baicalensis stem bark to investigate their extractability depending on structural variation. Four NADES, each containing citric acid in combination with β-alanine, glucose, xylitol, or proline (at a molar ratio of 1:1), and a variable amount of water, were used to extract the flavonoid aglycones: baicalein ( 1 ), scutellarein ( 3 ), wogonin ( 5 ), and oroxylin A ( 7 ), and their glycosides, baicalin ( 2 ), scutellarin ( 4 ), wogonoside ( 6 ) and oroxyloside ( 8 ) from the powdered bark of S. baicalensis . The chemical profile and yield of the extracts were determined using HPTLC and HPLC. The extractability of individual flavonoids was found to be influenced by the concentration of water (20-60%, w/w) in the NADES. Among the tested flavonoids, the extraction yield of baicalein ( 1 ), scutellarein ( 3 ), wogonin ( 5 ), oroxylin A ( 7 ) with NADES was 2 to 6 times that of aqueous methanol. However, the amount of their corresponding glycosides (baicalin ( 2 ), wogonoside ( 6 ) and oroxyloside ( 8 )) extracted with NADES was only 1.5-1.8 times higher than with aqueous methanol. Interestingly, the more hydrophilic glycosides were less extracted than their corresponding aglycones despite the high hydrophilicity of the NADES. These results prove that NADES may be used for extraction of compounds with a wide range of hydrophilicity., Competing Interests: The authors declare no conflict of interest.

Numerous aquatic invertebrates survive harsh environments by displaying dormancy as encysted embryos. This study aimed at determining whether metabolomics could provide molecular insight to explain the "dormancy syndrome" by highlighting functional pathways and metabolites, hence offering a novel comprehensive molecular view of dormancy. We compared the metabolome of morphologically distinct dormant encysted embryos (resting eggs) and non-dormant embryos (amictic eggs) of a rotifer (Brachionus plicatilis). Metabolome profiling revealed ~5,000 features, 1,079 of which were annotated. Most of the features were represented at significantly higher levels in non-dormant than dormant embryos. A large number of features was assigned to putative functional pathways indicating novel differences between dormant and non-dormant states. These include features associated with glycolysis, the TCA and urea cycles, amino acid, purine and pyrimidine metabolism. Interestingly, ATP, nucleobases, cyclic nucleotides, thymidine and uracil, were not detected in dormant resting eggs, suggesting an impairment of response to environmental and internal cues, cessation of DNA synthesis, transcription and plausibly translation in the dormant embryos. The levels of trehalose or its analogues, with a role in survival under desiccation conditions, were higher in resting eggs. In conclusion, the current study highlights metabolomics as a major analytical tool to functionally compare dormancy across species.

The actin cytoskeleton is modulated by regulatory actin-binding proteins which fine-tune the dynamic properties of the actin polymer to regulate function. One such actin-binding protein is tropomyosin (Tpm), a highly-conserved alpha-helical dimer which stabilises actin and regulates interactions with other proteins. Temperature sensitive mutants of Tpm are invaluable tools in the study of actin filament dependent processes, critical to the viability of a cell. Here we investigated the molecular basis of the temperature sensitivity of fission yeast Tpm mutants which fail to undergo cytokinesis at the restrictive temperatures. Comparison of Contractile Actomyosin Ring (CAR) constriction as well as cell shape and size revealed the cdc8.110 or cdc8.27 mutant alleles displayed significant differences in their temperature sensitivity and impact upon actin dependent functions during the cell cycle. In vitro analysis revealed the mutant proteins displayed a different reduction in thermostability, and unexpectedly yield two discrete unfolding domains when acetylated on their amino-termini. Our findings demonstrate how subtle changes in structure (point mutations or acetylation) alter the stability not simply of discrete regions of this conserved cytoskeletal protein but of the whole molecule. This differentially impacts the stability and cellular organisation of this essential cytoskeletal protein., (Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.)

Astragalus roots from Astragalus membranaceus Bunge or Astragalus membranaceus var. mongholicus (Bunge) Hsiao are among the most popular traditional medicinal plants due to their diverse therapeutic uses based on their tonic, antinephritic, immunostimulant, hepatoprotectant, diuretic, antidiabetic, analgesic, expectorant and sedative properties. Currently, the herb is produced or cultivated in various sites, including 10 different locations in China with very diverse environmental conditions. These differences affect their metabolic pools and consequently their medicinal properties. The comparative metabolic profiling of plants of different geographical origins or ages could contribute to detect biomarkers for their quality control and thus guarantee the efficacy of the herbal medicines produced with this drug. In this paper nuclear magnetic resonance spectroscopy (NMR)-based metabolomics was applied for to plants of different origins and age for this purpose. The results of this study show that in the set of samples evaluated, age is more discriminating than geographical location. The quantity of individual flavonoids and some primary metabolites contributed most to this age differentiation. On the other hand, based on the analysis of orthogonal partial least square (OPLS) modeling, the marker metabolites for the geographical origin were saponins and isoflavonoids.

Introduction: The value of information obtained from a metabolomic study depends on how much of the metabolome is present in analysed samples. Thus, only a comprehensive and reproducible extraction method will provide reliable data because the metabolites that will be measured are those that were extracted and all conclusions will be built around this information., Objective: To discuss the efficiency and reliability of available sample pre-treatment methods and their application in different fields of metabolomics., Methods: The review has three sections: the first deals with pre-extraction techniques, the second discusses the choice of extraction solvents and their main features and the third includes a brief description of the most used extraction techniques: microwave-assisted extraction, solid-phase extraction, supercritical fluid extraction, Soxhlet and a new method developed in our laboratory--the comprehensive extraction method., Results: Examination of over 200 studies showed that sample collection, homogenisation, grinding and storage could affect the yield and reproducibility of results. They also revealed that apart from the solvent used for extraction, the extraction techniques have a decisive role on the metabolites available for analysis., Conclusion: It is essential to evaluate efficacy and reproducibility of sample pre-treatment as a first step to ensure the reliability of a metabolomic study. Among the reviewed methods, the comprehensive extraction method appears to provide a promising approach for extracting diverse types of metabolites., (Copyright © 2014 John Wiley & Sons, Ltd.)

Natural products have been the source of many drugs used in modern therapeutics, and particularly in the case of anticancer drugs, more than 50 % originally came from natural products. Their importance as a source of leads for new drugs therefore cannot be underestimated. However, due to the painstaking way of conventional lead-finding, the attention towards natural products has been deviated in the last decades. A new strategy for the detection of active compounds is necessary to get natural product research out of its stalemate. Metabolomics, with its holistic approach and the possibility it provides for the simultaneous detection of all sorts of metabolites, has the potential to be instrumental for this new approach. Therefore, this review aims at providing examples that illustrate the possibilities of using metabolomics as a tool to find active compounds from natural products, specifically anticancer drugs. Two different methods, IN SILICO and IN SITU, have been introduced as possible approaches. Current methods to detect anticancer activity in natural products have been briefly reviewed and compared in the first section, and various applications of metabolomics in cancer research are mentioned as they can provide comprehensive information of cancer metabolites utilized in the IN SITU approach. Metabolomics will certainly improve the efficiency of lead-finding from natural products and thus reinstate this prolific source of potential anticancer drugs., (Georg Thieme Verlag KG Stuttgart-New York.)

The genus Ilex to which mate (Ilex paraguariensis) belongs, consists of more than 500 species. A wide range of metabolites including saponins and phenylpropanoids has been reported from Ilex species. However, despite the previous works on the Ilex metabolites, the metabolic similarities between species which can be used for chemotaxonomy of the species are not clear yet. In this study, nuclear magnetic resonance (NMR) spectroscopy-based metabolomics was applied to the classification of 11 South American Ilex species, namely, Ilex argentina, Ilex brasiliensis, Ilex brevicuspis, Ilex dumosa var. dumosa, I. dumosa var. guaranina, Ilex integerrima, Ilex microdonta, I. paraguariensis var. paraguariensis, Ilex pseudobuxus, Ilex taubertiana, and Ilex theezans. (1)H NMR combined with principal component analysis (PCA), partial least square-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) showed a clear separation between species and resulted in four groups based on metabolomic similarities. The signal congestion of (1)H NMR spectra was overcome by the implementation of two-dimensional (2D)-J-resolved and heteronuclear single quantum coherence (HSQC). From the results obtained by 1D- and 2D-NMR-based metabolomics it was concluded that species included in group A (I. paraguariensis) were metabolically characterized by a higher amount of xanthines, and phenolics including phenylpropanoids and flavonoids; group B (I. dumosa var. dumosa and I. dumosa var. guaranina) with oleanane type saponins; group C (I. brasiliensis, I. integerrima, I. pseudobuxus and I. theezans) with arbutin and dicaffeoylquinic acids, and group D (I. argentina, I. brevicuspis, I. microdonta and I. taubertiana) with the highest level of ursane-type saponins. Clear metabolomic discrimination of Ilex species and varieties in this study makes the chemotaxonomic classification of Ilex species possible., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Iso-alpha-acids are known to contribute to the characteristic bitter taste of beer. Six iso-alpha-acids were isolated from a carbon dioxide extract of the cones of Humulus lupulus L. by centrifugal partition chromatography followed by separation through beta-cyclodextrin binding. This method overcame the low yield issue of most isolation procedures that results from the low stability of these compounds to light and oxygen. Their full identification was performed using one- and two-dimensional NMR spectrometry, including (1)H- and (13)C-NMR, (1)H-(1)H COSY, HMQC and HMBC and electrospray ionisation mass spectrometry. The results confirmed the structures of the isolated compounds as trans-isocohumulone, cis-isocohumulone, trans-isohumulone, cis-isohumulone, trans-isoadhumulone and cis-isoadhumulone. Epimers can be easily distinguished by observing the chemical shift differences of the H-5, H-1''', H-2''' and C-5 signals and the different splitting pattern of H-5 and H-2''., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

The metabolomic analysis of 11 Ilex species, I. argentina, I. brasiliensis, I. brevicuspis, I. dumosavar. dumosa, I. dumosa var. guaranina, I. integerrima, I. microdonta, I. paraguariensis var. paraguariensis, I. pseudobuxus, I. taubertiana, and I. theezans, was carried out by NMR spectroscopy and multivariate data analysis. The analysis using principal component analysis and classification of the (1)H NMR spectra showed a clear discrimination of those samples based on the metabolites present in the organic and aqueous fractions. The major metabolites that contribute to the discrimination are arbutin, caffeine, phenylpropanoids, and theobromine. Among those metabolites, arbutin, which has not been reported yet as a constituent of Ilex species, was found to be a biomarker for I. argentina,I. brasiliensis, I. brevicuspis, I. integerrima, I. microdonta, I. pseudobuxus, I. taubertiana, and I. theezans. This reliable method based on the determination of a large number of metabolites makes the chemotaxonomical analysis of Ilex species possible.

The occurrence of antigenic variation among nine isolates of bovine respiratory syncytial virus (BRSV) was determined by examining their reaction patterns to human respiratory syncytial virus (HRSV) subgroup A and B monoclonal antibodies (MAbs) by enzyme immunoassay and radioimmunoprecipitation with fractionation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis by using MAbs and polyclonal antisera to HRSV and BRSV. Shared epitopes were demonstrated on four of five structural proteins between BRSV and both subgroups A and B of HRSV. The nine isolates of BRSV showed different patterns of reactivity in enzyme immunoassays with panels of MAbs to HRSV subgroups A and B. Major variations in the molecular weights of the P (phosphoprotein) and F (fusion protein) proteins were demonstrated among the BRSV isolates tested. These results suggest that BRSV belongs to a different antigenic grouping than HRSV and that BRSV is composed of two distinct subgroups.

The use of posterior composites is riddled with so many controversies that the puzzled practitioner must step warily among them. This modality is a minefield, where one careless movement can bring disaster. All composite restorations are subject to three big destructive forces--moisture, polymerization shrinkage, and clinical wear--forces that can eventually produce both microleakage and deterioration of the silane coupling agent linking filler particles to resin matrix. Despite the extreme technique sensitivity of posterior composite resins, knowledge of resin technology, sound operative dentistry principles and foresight in case selection can be effective in producing durable cosmetic restorations. Posterior composite resin restorations bonded to enamel and dentin reputedly strengthen teeth in both conventional and adhesive types of preparations provided polymerization shrinkage can be controlled. It is imperative that a knowledge of occlusal contacts be used to influence cavity outline, confining the trauma or occlusal forces away from the tooth-resin interface and helping to minimize occlusal wear. With the increased use of posterior resins, the trend in cavity preparations should break away from the traditional Black preparation toward the adhesive type preparation. If the Black Class II preparation is used, it is suggested that bevels be confined to the facial and lingual margins of the proximal box. Prewedging helps to maintain a conservative Class II preparation. Shade selection must be made prior to rubber dam isolation for greater accuracy and to help prevent postinsertion discoloration. The enamel should be pumiced to present a clean substrate for acid etching. The smear layer should be removed. The type of pulp protection applied before acid etching is dependent on the material used. After etching, the enamel should be washed with a 1 per cent potassium chloride solution. It is a more universally chemically stable solution than additive-laden local water supplies. The potassium chloride solution lowers the electrostatic forces on the enamel that would interfere with the flow of enamel bonding agents. Furthermore, tests have shown that the use of potassium chloride washes increase the strength of the enamel body by 40 per cent. Because of the depth of most posterior cavities, an incremental filling technique must be used to ensure a thorough polymerization of the resin and to forestall a massive polymerization shrinkage. When finished and contoured, the margins of the restoration should be re-etched, washed, and dried and then covered with an application of unfilled resin to discourage microleakage. Traditional operative dentistry technique must become flexible enough to meet the new demands of resin technology.(ABSTRACT TRUNCATED AT 400 WORDS)

With the cascade of new restorative products being unveiled almost monthly, dentists incorporating endodontics into their practices must be able to evaluate the potential of these products for successful integration into their procedures. This evaluation should be based on a knowledge of how the new products relate to the smear layer formed along the root canal walls. Rather than relying on information supplied by the dental manufacturers, the aware dentist should regularly resort to the most current research reports available in journal or abstract form. With the use of certain products in some clinical situations, other branches of restorative dentistry may suggest retention of the smear layer. Although pulpally infected teeth have been successfully treated for generations in the presence of the smear layer, it has become accepted practice now in endodontics to remove the smear layer. Different quantities and qualities of smear layer can be produced by various techniques of instrumentation. However, they all present a barrier to intimate contact between obturating materials and the canal wall. Various types of solvents will produce different results in smear layer removal. One ideal endodontic irrigant follows the use of the antimicrobial 5.25 per cent sodium hypochlorite solution with the equally antimicrobial 6 per cent citric acid solution or 17 per cent EDTA. Chelating agents are effective in that they remove the smear layer, open the dentinal tubules, and produce a clean surface for closer obturation. Removal of the smear layer encourages the creation of a good apical plug to prevent over filling, post-filling sensitivity, and possible microleakage. The use of glass ionomer cements and unfilled resin as a cementing medium following smear layer removal shows promising results in both strength of cementation and the possibility of reducing post lengths. Controversies will always arise in dentistry with the advent of new information and the discovery of new clinical techniques. But a total awareness of both sides of a controversy will enable the practitioner to find a way through the confusion.

A patient developed postendodontic pain 3 years after undergoing root canal therapy in a maxillary first premolar tooth. Radiographic examination revealed that a recently extracted impacted second premolar had originally obscured the x-ray view of a third root on the first premolar. Endodontic therapy in the unfilled root was rejected because the tooth had been restored with full coverage. Apicoectomies and retroseals were performed on all roots, and the tooth became asymptomatic.

The diplomates of the American Association of Endodontists were surveyed regarding difficulties in regionally anesthetizing acutely painful mandibular molar teeth. Frequently patients developed evidence of adequate regional block anesthesia but experienced pain when the dentist attempted access. A pilot projection was undertaken to determine if a scientific basis existed for this problem. With the animal under general anesthesia, the mandibular nerve of a cat was isolated and then regionally blocked. A stimulating electrode was implanted in a cuspid tooth and a receiving electrode in the cortex of the brain. When a state of inflammation was created in the tooth in the presence of a regional block, there was an increasing cortical response to this stimulation. It was concluded that the pilot project offered a realistic technique for the study of this clinical entity.

Use of a double arch, closed-mouth technique as described in this article enables dentists to obtain cast and die placement in centric occlusion in a single step. Complete closure of the teeth is mandatory for registering the interocclusal relationship correctly. The accuracy of the interocclusal relationship is more likely because of the decreased number of steps in the technique. Several different trays are available for the double arch impression technique. The more rigid trays buttress the impression material and reduce the possibilities of distortion in the final impression. Several variations in the double arch impression technique are possible, and tray selection is dependent on the demands of each patient.