Ameloblastoma plexiforme del maxilar: manejo quirúrgico y protético. A propósito de un caso

El ameloblastoma es un tumor odontógeno benigno de derivación epitelial, de elevada invasión local, crecimiento intermitente y con alta probabilidad de recidiva. Puede dividirse en los siguientes tipos histológicos: folicular, plexiforme, acantomatoso, a células basales y granulares. El ameloblastoma folicular es el subtipo histológico más común. Se manifiesta prevalentemente durante la tercera, cuarta y quinta década de vida, sin predilección para el sexo, aun así se puede encontrar en cualquier grupo de edad incluyendo niños. La mayoría de los ameloblastomas se encuentra sobretodo en mandíbula (al nivel del ángulo y rama). Las características clínicas, incluso si complementadas con radiografías y muestras histológicas, no son útiles a la hora de predeterminar el comportamiento biológico y por lo tanto el pronóstico de un ameloblastoma individual. Los autores presentan un caso localizado de ameloblastoma plexiforme localizado en la parte posterior del maxilar de un hombre de 30 años; el término "plexiforme" se refiere al aspecto de anastomosis de los islotes del epitelio odontógeno, en contraste con el tipo «folicular». En este artículo se discuten importantes aspectos de la patología, del tratamiento quirúrgico y protésico. En conclusión, es necesaria una cooperación estricta a largo plazo de un grupo de clínicos, patólogos, cirujanos y prostodoncistas, para ofrecer el mejor tratamiento individualizado en cada caso. The ameloblastoma is a clinically persistent benign tumor derived from odontogenic epithelium, locally invasive, intermittent in growth and with high a probability of recurrence. The following histologic patterns may be distinguished: follicular, plexiform, spindle cell, acanthomatous, basal cell type and granular cell. The follicular ameloblastoma is the most common histologic tipe. The majority of patients are in 3th, 4th and 5th decade, but can be found in any age group including children. The majority of ameloblastomas are observed in the mandible (mostly angle or ramus). Clinical features, even if combined with radiology or histology findings, are not useful when trying to determine the biological behaviour and therefore the prognosis of an individual ameloblastoma. The authors report a case of plexiform ameloblastoma in the posterior maxilla, in male 30 year old otherwise healthy; the term "plexiform" refers to the appearance of anastomosing islands of odontogenic epithelium in contrast to a follicular pattern. Important questions on pathology, surgical and prosthetic therapy are discussed in this paper. In conclusion, a close cooperation of clinicians, pathologists, surgeons and prosthesists is necessary and very important over a long period of time for the best management of each individual case

The management of atrophies classified as V class according to Cawood & Howell by piezo-electric surgery

Introducción: Los casos analizados presentaban atrofias severas (V clase según Cawood y Howell) (1), que se caracterizan por presentar una densidad de la cresta transversal inferior a 4 mm y vertical inferior a 6 mm; ello hace pensar en la posibilidad de una rehabilitación implanto-soportada. Objetivo: Evaluación de la rehabilitación de pacientes afectados por severa atrofia del maxilar superior clase V según Cawood y Howell) (1) rehabilitados con elevación del seno maxilar e injerto de hueso autólogo. Materiales y métodos: Estudio longitudinal a partir de una muestra de 32 pacientes, con atrofia maxilar severa y edentulismo parcial o total. En todos los pacientes se ha colocado un injerto con técnica de reconstrucción onlay mono o bicortical y se ha adoptado la cirugía piezoeléctrica para realizar el elevación del seno, el cual podía ser mono o bilateral, de hueso autólogo procedente de la cresta ilíaca anterior. Seguimiento realizado durante 2 años. Resultados: A los dos años del control final, el 94,05% de todos los implantes colocados tras la intervención de elevación se presentan osteointegrados y cargados protésicamente. La cresta ilíaca anterior resulta ser la zona idónea para la extracción medular, necesaria para la elevación del seno. Las posibilidades de supervivencia del implante son realmente elevadas si se espera el tiempo clínico necesario para la recuperación y la integración del injerto. El éxito de todas las intervenciones de elevación del seno maxilar se debe a la adopción de la cirugía piezoeléctrica, que permite efectuar la incisión de entrada y realizar el desprendimiento de los tejidos con un traumatismo mínimo para la membrana de Schneider. La integridad de la membrana y la utilización de bone-chips de origen autólogo no ha hecho necesario recurrir a la utilización de membranas reabsorbibles, simplificando así el procedimiento quirúrgico. La utilización de la cresta ilíaca anterior como zona donante, permite disponer de abundante tejido óseo cortical, necesario para colocar los onlay y para reconstruir el defecto óseo. Introduction: Valutation of rehabilitated patients by sinus lift in upper jaw and by autologous bone graft from iliac crest. Materials and methods: Rehabilitation of 32 patients with severe atrophies of upper jaw and partial or total edentulism by positioning of mono- or bicortical onlay with piezosurgery to obtain a sinus lift mono- or bilateral by autologous bone grafts from anterior iliac crest. Results: 94.05% of successes after a two years follow-up. Conclusions: Respecting of timing surgery, a correct use of the piezosurgery technique and of the autologous bone graft from anterior iliac crest let a successful implantological rehabilitation. Moreover the iliac crest is a very good donor site of bone tissue for the management of severe atrophies in the upper jaw. An accidental laceration of Schneider's membrane was observed in filling phase in the 5.26% of cases

Analysis of cadmium root retention for two contrasting rice accessions suggests an important role for oshma2

Two rice accessions, Capataz and Beirao, contrasting for cadmium (Cd) tolerance and root retention, were exposed to a broad range of Cd concentrations (0.01, 0.1, and 1 M) and analyzed for their potential capacity to chelate, compartmentalize, and translocate Cd to gain information about the relative contribution of these processes in determining the different pathways of Cd distribution along the plants. In Capataz, Cd root retention increased with the external Cd concentration, while in Beirao it resulted independent of Cd availability and significantly higher than in Capataz at the lowest Cd concentrations analyzed. Analysis of thiol accumulation in the roots revealed that the different amounts of these compounds in Capataz and Beirao, as well as the expression levels of genes involved in phytochelatin biosynthesis and direct Cd sequestration into the vacuoles of the root cells, were not related to the capacity of the accessions to trap the metal into the roots. Interestingly, the relative transcript abundance of OsHMA2, a gene controlling root-to-shoot Cd/Zn translocation, was not influenced by Cd exposure in Capataz and progressively increased in Beirao with the external Cd concentration, suggesting that activity of the OsHMA2 transporter may differentially limit root-to-shoot Cd/Zn translocation in Capataz and Beirao

Painful constipation: a neglected entity?

Functional chronic constipation is a common symptom in daily clinical practice. Although the definition of constipation may be variable, there is usually agreement that (at least for research purposes) the definition given by the Rome Committee are useful. However, some blind spots or hidden angles remain, even in the more thorough classifications; among these, there is painful constipation, a poorly defined yet clinically encountered entity. The present article reviews the current knowledge about painful constipation, trying to put together the scarce data available, and to frame it in the more general context of chronic constipation

Clar Sextet Analysis of Triangular, Rectangular and Honeycomb Graphene Antidot Lattices

Pristine graphene is a semimetal and thus does not have a band gap. By making a nanometer scale periodic array of holes in the graphene sheet a band gap may form; the size of the gap is controllable by adjusting the parameters of the lattice. The hole diameter, hole geometry, lattice geometry and the separation of the holes are parameters that all play an important role in determining the size of the band gap, which, for technological applications, should be at least of the order of tenths of an eV. We investigate four different hole configurations: the rectangular, the triangular, the rotated triangular and the honeycomb lattice. It is found that the lattice geometry plays a crucial role for size of the band gap: the triangular arrangement displays always a sizable gap, while for the other types only particular hole separations lead to a large gap. This observation is explained using Clar sextet theory, and we find that a sufficient condition for a large gap is that the number of sextets exceeds one third of the total number of hexagons in the unit cell. Furthermore, we investigate non-isosceles triangular structures to probe the sensitivity of the gap in triangular lattices to small changes in geometry

Programming JADE and Jason Agents Based on Social Relationships Using a Uniform Approach

Abstract. Interaction is an essential feature in multiagent systems. De-sign primitives are needed to explicitly model desired patterns. This work presents 2COMM as a framework for defining social relations among parties, represented by social commitments. Starting from the definition of interaction protocols, 2COMM allows to decouple interaction design from agent design. Currently, adapters were developed for allowing the use of 2COMM with the JADE and the JaCaMo platforms. We show how agents for the two platforms can be implemented by relying on a common programming schema

Reasoning about Communicating Agents in the Semantic Web

Abstract. In this article we interpret the Semantic Web and Web Service issues in the framework of multi-agent interoperating systems. We will advocate the application of results achieved in the research area of reasoning about actions and change by showing scenarios and techniques that could be applied.