Clinical report and fractographic analysis of a fractured partial laminate veneer.

Ceramic partial laminate veneers represent a conservative option for the correction of morphological abnormalities, diastemas, and fractured anterior teeth, with minimal or no tooth preparation. The present clinical report describes the use of a partial laminate veneer to correct the shape of a maxillary right central incisor to match the restoration of the more damaged adjacent tooth. The failure of the partial laminate veneer after only 18 months was analyzed using a systematic fractographic approach, identifying critical considerations that should be addressed when providing this type of restoration.

Metal-Free Dearomatization: Direct Access to Spiroindol(en)ines in Batch and Continuous-Flow.

A metal-free, phosphine-catalyzed intramolecular "umpolung Michael addition" on alkynes to form spiroindol(en)ines is reported. This nucleophilic catalysis enables the formation of a wide scope of five- and six-membered spiroindol(en)ines in moderate to excellent yields in batch as well as under continuous-flow conditions. Triphenylphosphine-catalyzed nucleophilic activation of alkynes allows the exclusive formation of exo-product under mild reaction conditions.

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids.

An efficient sequence based on the Ugi-azide reaction and rhodium(III)-catalyzed intermolecular annulation has been established for the preparation of tetrazole-isoquinolone/pyridone hybrids. Several N-acylaminomethyltetrazoles were reacted with arylacetylenes to form the hybrid products in moderate to very good yields. The method relies on the capacity of the rhodium catalyst to promote C(sp2)-H activation in the presence of a suitable directing group. The Ugi-azide reaction provides broad molecular diversity and enables the introduction of the tetrazole moiety, which may further assist the catalytic reaction by coordinating the metal center. The scope of the isoquinolones is very wide and may be extended to the preparation of complex compounds having heterocyclic moieties such as pyridone, furan, thiophene and pyrrole, as well as the corresponding benzo-fused derivatives. The developed procedure is simple, reproducible and does not require inert conditions.

Applications of Convertible Isonitriles in the Ligation and Macrocyclization of Multicomponent Reaction-Derived Peptides and Depsipeptides.

Peptide ligation and macrocyclization are among the most relevant approaches in the field of peptide chemistry. Whereas a variety of strategies relying on coupling reagents and native chemical ligation are available, there is a continuous need for efficient peptide ligation and cyclization methods. Herein we report on the utilization of convertible isonitriles as effective synthetic tools for the ligation and macrocyclization of peptides arising from isocyanide-based multicomponent reactions. The strategy relies on the use of convertible isonitriles-derived from Fukuyama amines-and peptide carboxylic acids in Ugi and Passerini reactions to afford N-alkylated peptides and depsipeptides, respectively, followed by conversion of the C-terminal amide onto either N-peptidoacyl indoles or pyrroles. Such activated peptides proved efficient in the ligation to peptidic, lipidic and fluorescently labeled amines and in macrocyclization protocols. As a result, a wide set of N-substituted peptides (with methyl, glycosyl and amino acids as N-substituents), cyclic N-methylated peptides and a depsipeptide were produced in good yields using conditions that involve either classical heating or microwave irradiation. This report improves the repertoire of peptide covalent modification methods by exploiting the synthetic potential of multicomponent reactions and convertible isonitriles.

Ceramic partial laminate veneers in anterior teeth: A literature review.

STUDY SELECTION: Partial laminate veneers, defined as small ceramic restorations adhesively luted onto unprepared anterior teeth, are an interesting and conservative alternative to conventional ceramic and composite resin veneers in the anterior region. This literature review aimed to summarize the available laboratory and clinical data on ceramic partial laminate veneers. An electronic search of the MEDLINE/PubMed, EBSCO, and Web of Science databases was conducted. The keywords used were "partial veneer," "partial laminate veneer," "ceramic fragment," and "sectional veneer." The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. The risk of bias in the included studies was assessed using the QUIN tool. RESULTS: Of the 266 identified articles, only 16 met the inclusion criteria (ten clinical reports, five laboratory studies, and one retrospective clinical study). To date, no randomized controlled clinical trials have been conducted. Most laboratory studies displayed a low risk of bias, with partial laminate veneers rendering adequate strength and color stability. Clinical reports have shown large variability in material selection, luting, and finishing/polishing protocols. CONCLUSIONS: Low-quality evidence is available for ceramic partial laminate veneers. Available data from laboratory studies suggest good mechanical and optical performances comparable to those of conventional ceramic and composite resin veneers. Further clinical studies with longer follow-up periods are warranted.

Contemporary flowable bulk-fill resin-based composites: a systematic review.

Flowable bulk-fill resin-based composites (BF-RBCs) represent a new and interesting alternative for the bulk-fill restorative techniques in the posterior region. However, they comprise a heterogeneous group of materials, with important differences in composition and design. Therefore, the aim of the present systematic review was to compare the main properties of flowable BF-RBCs, including their composition, degree of monomer conversion (DC), polymerization shrinkage and shrinkage stress, as well as flexural strength. The search was conducted following PRISMA guidelines in the Medline (PubMed), Scopus and Web of Science databases. In vitro articles reporting on the DC, polymerization shrinkage/shrinkage stress, and flexural strength of flowable BF-RBCs strength were included. The QUIN risk-of-bias (RoB) tool was used for assessing the study quality. From initially 684 found articles, 53 were included. Values for DC ranged between 19.41 and 93.71%, whereas polymerization shrinkage varied between 1.26 and 10.45%. Polymerization shrinkage stresses reported by most studies ranged between 2 and 3 MPa. Flexural strength was above 80 MPa for most materials. A moderate RoB was observed in most studies. Flowable BF-RBCs meet the requirements to be indicated for bulk fill restoration technique in the posterior region. However, important variations among composition and properties hinder extrapolation of the results to materials different from those reported here. Clinical studies are urgently required to assess their performance under a real working scenario.

Amendment of soils with metal-rich sludge: Potential water toxicity due to metal release via over-time slaking.

Industrial metal-rich sludge can improve soil properties, but it is potentially toxic to soils and adjacent aquatic systems. The soil-sludge-water interactions influence metals bioavailability over time, a phenomenon mostly regulated by the still debatable "sludge physical protection" or "sludge delayed release" hypotheses. The present study aimed to investigate: (1) whether sludge increases soil aggregate stability against slaking, (2) which hypothesis mostly regulates metal release from soils to water and (3) the ecotoxicity of the metals released during soil slaking for aquatic organisms. Under a realistic field scale, soils amended with an industrial sludge or spiked with equivalent metal solutions (of Cr, Cu, Ni, Zn) were collected over three months to test soil aggregate stability, the ecotoxicity of the slaking water and metal contents in soil and water. The "sludge physical protection" was verified for all metals, though for Cu the "sludge delayed release" hypothesis appears plausible after three months. Soil amendment with sludge did not lead to effects on the growth of the microalga Raphidocelis subcapitata, contrarily to the observed for the metal-spiked soil. Criteria regulating soils sludge-amendment management should thus include doses not hazardous to biota, and not only metal threshold levels.

Heavy metal availability assessment using portable X-ray fluorescence and single extraction procedures on former vineyard polluted soils.

The periodic application of copper-based fungicides (Bourdeaux mixture) to vineyards of the Mediterranean region has generated an important pollution source that in some cases requires a quick intervention due to the high bioavailable copper content measured. Despite some vineyards were abandoned 40 years ago, noticeable amounts of Cu and other man-related metals are still nowadays detected in soils. In the present work, the development of a mobility test for the available heavy metal (Cu, Pb, Zn and As) content in soil has been performed using portable X-ray fluorescence (FP-XRF) combined with single leaching test, and was applied to a calcareous soil of a former vineyard area in Catalonia (NE Spain). The combined methodology has provided useful information for fast and detailed risk assessment, in terms of mobility and bioavailability of metals. The anthropogenic contribution was evaluated by means of the Concentration Enrichment Ratios (CER) in soil. The results reflect a clear anthropogenic contribution for Cu, a partial anthropogenic contribution for Pb proceeding from an external pollution source, and a non-significant external contribution for As and Zn. The topsoil concentration ranges for Cu (70-128 mg kg-1) were found to be above the background level and several samples above the regional governmental limits (Generic Reference Levels or GRL values) for soil ecosystem protection and for human health (90 mg kg-1). The present study reveals that the use of FP-XRF equipment constitute a highly valid option for quick decision making during the field location, characterization and quantitative elemental analysis of soil samples for screening of potential pollutants such as heavy metals.

Synthesis of spiroindolenines by intramolecular ipso-iodocyclization of indol ynones.

A high-yielding fast spirocyclization of easily available indol ynones has been developed by applying N-iodosuccinimide. The formation of the desired product occurs in an atom-economical way, under mild conditions, instantly after the addition of the reagent. The expected 1,2-rearrangement was not observed. The procedure represents a metal free spirocyclization of indoles with an opportunity for further functionalizations.

Restauración clase II MOD mediante uso de resina bulk-fill fluida y resina de estratificación natural: combinando fortalezas en una preparación extensa / Class II MOD restoration using bulk-fill flowable and natural layering resin composites: combining strengths in an extensive preparation

RESUMEN La restauración de grandes preparaciones cavitarias clases II MOD es un escenario clínico de alta complejidad. Elegir correctamente una resina compuesta y planificar la secuencia de estratificación permitirá mejorar la adaptación de las masas de resina y controlar el estrés de contracción de polimerización. En el siguiente reporte de caso clínico, se expone el protocolo paso a paso para el uso combinado de una resina compuesta para estratificación de esmalte de alto índice de refracción para la restauración de los rebordes marginales perdidos y la superficie oclusal, junto a una resina compuesta bulk-fill de baja viscosidad para la reconstrucción dentinaria en un diente posterior con gran destrucción coronaria.

ABSTRACT The restoration of large class II MOD cavity preparations is a highly complex clinical scenario. Selecting correctly a composite resin and planning the stratification sequence will improve the adaptation of the composite resin masses and will control the polymerization shrinkage stress. In the following clinical case report, the step- by-step protocol of the combined use of an high-refractive-index enamel-like composite resin is shown for the restoration of lost marginal ridges and the occlusal surface, together with a low viscosity Bulk-Fill composite resin for dentine reconstruction in a highly damaged posterior tooth.

A Novel Technique for Bulk-Fill Resin-Based Restorations: Achieving Function and Esthetics in Posterior Teeth.

Advances in the mechanical properties of composite resins have allowed for their use in posterior teeth. Conventional resins have several problems associated with polymerization shrinkage stress. The development of "bulk-fill" resins has allowed for their use in single increments up to depths of 4 mm, with very low polymerization shrinkage stress. Nevertheless, differences in anatomy and the desire for optimal esthetics present unique difficulties. This article describes a step-by-step technique using flowable bulk-fill resin as a substitute for dentin in a single increment, together with a high-reflective-index resin to restore enamel and decrease clinical time, obtaining anatomically and esthetically acceptable results without detriment to the mechanical properties required to restore the functionality of the posterior teeth.

Does Post-etching Cleaning Influence Bond Strength of Lithium Disilicate Laminate Veneers?

This paper aims to present a clinical case of laminate veneers in lithium disilicate (LD) reinforced ceramic, complemented with scanning electron microscopy and energy dispersive x-ray spectroscopy analysis of this ceramic's surfaces submitted to some of the different post-etching cleaning protocols proposed by literature. Many dentists are applying all-ceramic restorations, especially veneers, with the most applied material being LD, due to its good mechanical properties, esthetics, and ability to adhere to tooth substrate. The cementation process is critical to clinical success of indirect restorations. Combination of hydrofluoric acid and silane application on the inner surface of ceramic has been the most recommended method to increase bond strength between ceramic and tooth substrate. As a result of surface corrosion, residual subproducts are formed and precipitate on the ceramic surface, affecting the bonding process to the resin cement. Elimination of residue is recommended in the literature and can be done via 3 common techniques: thorough washing with air/water spray for 30 seconds, 37% phosphoric acid for 60 seconds, or ultrasonic bath for 4 to 10 minutes. Little information on LD ceramics post-etching cleaning methods is available in the literature. For this ceramic, the thorough washing with air/water spray for 30 seconds appeared to remove most of the residue without damaging the material. Being also the most practical and easiest of the reviewed procedures, it was, therefore, the protocol of choice for the clinical cases presented in this paper with success after 18 months.

A Step-by-Step Conservative Approach for CAD-CAM Laminate Veneers.

The use of CAD/CAM technology has allowed the fabrication of ceramic restorations efficiently and with predictable results. Lithium disilicate is a type of glass ceramic material that can be used for the elaboration of laminate veneers, being monolithic restorations which require characterization through a covering ceramic in order to achieve acceptable esthetic results. The next case report shows a predictable clinical protocol for the rehabilitation of the anterior teeth through the preparation of CAD/CAM veneers (e.max CAD, Ivoclar Vivadent, Liechtenstein) which have been characterized by a nanofluorapatite ceramic (e.max Ceram, Ivoclar Vivadent, Liechtenstein) through the layering technique.

Alternativas clínicas para el uso de composites Bulk-Fill compactables y fluidos: Reporte de un caso paso a paso / Clinical Alternatives for the Use of Compactable and Flowable Bulk-Fill Composites: A Step-by-Step Case Report

Resumen: El uso de resinas compuestas Bulk-Fill para la restauración de dientes posteriores ha sido masificada en los últimos años en las diferentes disciplinas clínicas de la Odontología. Esto puede deberse principalmente a la simplicidad en la técnica de aplicación de este material ya que requiere de su inserción dentro de la preparación cavitaria en espesores de resina compuesta de hasta 4-5mm, lográndose una reducción considerable de tiempo de trabajo clínico. Ante la existencia de diferentes viscosidades de este tipo de resinas compuestas, ciertas dificultades han sido identificadas ante la selección de cada material Bulk-Fill en relación a las posibles combinaciones que se pueden realizar entre las diferentes marcas disponibles en el mercado, inclusive cuando se usan junto con resinas compuestas convencionales. El objetivo del siguiente reporte de caso, es mostrar dos posibilidades clínicas paso a paso utilizando inicialmente resinas Bulk-Fill compactable en un solo incremento para un segundo molar superior, y luego, a través de la combinación de resinas compuestas Bulk-Fill del tipo fluidas, junto a resinas compuestas Bulk-Fill compactables y resinas compuestas convencionales de estratificación para esmaltes de alto índice de refracción para un primer molar superior.

Abstract: The use of Bulk-Fill composite resins to perform posterior restorations has been massified in recent years in the different clinical disciplines of Dentistry. This may be due mainly to the simplicity in the application technique of this material as it requires its insertion into the cavity preparation in 4-5mm of composite resin thickness, achieving a considerable reduction of clinical working time. Given the existence of different viscosities of this type of composite resins, certain difficulties have been identified before the selection of each Bulk-Fill material related to the possible combinations that can be made between the different brands available in the market, even when they are used with conventional composite resins. The purpose of the following case report, is to present two step-by-step clinical possibilities using initially, compactable Bulk-Fill composite resin in a single increment for the restoration of a second upper molar, and later, through the combination of Bulk-Fill flowable composite resin together with compactable Bulk-Fill composite resin and a high- refractive-index enamel-like conventional composite resin, for a first upper molar.

The learning environment at a public university in northern Chile: how is dental education perceived by students? / El ambiente de aprendizaje en una universidad pública del norte de Chile: ¿cómo perciben los estudiantes la formación en odontología?

ABSTRACT. Introduction: the learning environment is considered essential in health sciences careers due to its significant influence on students overall learning achievements. The DREEM questionnaire was developed as a tool to obtain this environment's profile. In Chile, the learning environment has been studied in medical schools but no information is available on the field of public dentistry schools. The goal was to determine the students' perception of the learning environment in the dental career at Arturo Prat University in Iquique (Chile), based on the DREEM questionnaire. Methods: the Spanish version of DREEM was applied to 103 volunteers. Students were grouped in three levels: basic (first year), pre-clinical (second and third years) and clinical (fourth and fifth years). Data were processed and scores were determined for each level and for each DREEM domain (learning, teacher, academic perception, atmosphere, and social perception) which constitutes the learning environment. The Tukey test was used to determine statistical differences between groups. Results: no significant differences were found between the basic and the pre-clinical levels, but statistical differences were found at the clinical level. The overall score was 117.81/200, meaning a "more positive than negative" environment, despite a decrease in perception from the basic to the clinical level. Conclusion: the learning environment is perceived positively by students, despite a decreasing perception from the basic to the clinical level, mostly due to psychosocial factors.

RESUMEN. Introducción: el ambiente de aprendizaje se considera esencial en las carreras de ciencias de la salud debido a su significativa influencia en los logros académicos de los estudiantes. El cuestionario DREEM fue desarrollado como una herramienta para obtener el perfil de dicho ambiente. En Chile, se ha estudiado el ambiente de aprendizaje en las escuelas de medicina, pero no existe información en el campo de las escuelas públicas de odontología. El objetivo del presente estudio consistió en determinar la percepción de los estudiantes sobre el ambiente de aprendizaje en la carrera de Odontología de la Universidad Arturo Prat de Iquique (Chile), con base en el cuestionario DREEM. Métodos: se aplicó la versión española de DREEM a 103 voluntarios. Los estudiantes se agruparon en tres niveles: básico (primer año), preclínico (segundo y tercer años) y clínico (cuarto y quinto años). Se procesaron los datos y se determinaron los puntajes para cada nivel y para cada dominio del cuestionario DREEM (aprendizaje, profesor, percepción académica, ambiente y percepción social) que hace parte del ambiente de aprendizaje. Se utilizó la prueba de Tukey para determinar diferencias estadísticas entre los grupos. Resultados: no se encontraron diferencias significativas entre los niveles básico y preclínico, pero se hallaron diferencias estadísticas en el nivel clínico. La puntuación total fue de 117.81/200, lo que significa que hay un entorno "más positivo que negativo", a pesar de una disminución en la percepción del nivel básico al clínico. Conclusión: el ambiente de aprendizaje es percibido positivamente por los estudiantes, a pesar de una percepción decreciente desde el nivel básico hasta el clínico, sobre todo debido a factores psicosociales.

Neumoencéfalo postraumático tratado con oxígeno normobárico en una niña / Post-traumatic pneumocephalus treated with normobaric oxygen in a girl

Introducción: El neumoencéfalo es el atrapamiento de aire dentro de la cavidad craneal; puede comportarse como una lesión ocupativa, incrementar la presión intracraneana, provocar herniación cerebral e incluso la muerte. En ocasiones el tratamiento debe ser urgente. Si las manifestaciones son menos graves, pueden resolverse utilizando oxígeno (O2) normobárico. Caso clínico. Se presenta una niña de nueve años con traumatismo craneoencefálico grave y fístula transitoria de líquido cefalorraquídeo (LCR); desarrolló estado de estupor, síndrome de hipertensión intracraneana y meningitis secundaría a la fístula de LCR. La tomografía axial computada (TAC) mostró neumoencéfalo bifrontal de predominio izquierdo. Se trató antibióticos por 15 días y O2 nomobárico al 40 por ciento durante siete días. El control tomográfico mostró resolución del neumoencéfalo. Conclusión: El uso de O2 normobárico en concentraciones del 40 al 100 por ciento es útil en el tratamiento del neumoencéfalo de causa diversa. Es una modalidad de tratamiento de bajo costo, no invasiva y con excelentes resultados en pacientes seleccionados