Ultra-structure characterization of self-etching treated cementum surfaces

Objectives: to evaluate the effect of different conditioning treatments on surface roughness and topography ofdental cementum. Study Design: Extracted human canines were used for the present study. The mesial surfacefrom the cervical third of the roots were ground flat with wet 600-grit silicon carbide paper. They were polished(up to 1/4 μm diamond paste) and treated as follows: 1) No treatment, 2) 35% H3PO4 during 15 s, 3) Clearfil SEBond primer (SEB), 4) One-Up Bond F (OUB). The adhesive systems were applied following manufacturer’s instructions.SEB primer and OUB were removed from surfaces by washing and ultrasonic agitation with ascendingethanol solutions. Digital images of treated surfaces (5x5 and 15x15 μm) were obtained by means of an atomicforce microscope (AFM) analysis. The average surface roughness (Ra nanometers) of the scanned areas was assessed.Data were analyzed by ANOVA and SNK multiple comparisons tests (p<0.05). Results: phosphoric acidtreatment produced the highest mean roughness value, at all scan sizes. At 5x5 μm AFM images, for self-etchadhesive systems no differences in roughness were detected. At 15x15 μm, when One-Up Bond F was employedthe lowest value was obtained. Conclusions: When phosphoric acid treatment was applied, cementum surfaceroughness increased and a strong demineralization with exposed collagen fibers could be observed (AU)

Insuficiencia renal aguda y disfunción tubular proximal en paciente diagnosticado de infección VIH tratado con tenofovir / Acute renal failure and proximal renal tubular dysfunction in a patient with acquired immunodeficiency syndrome treated with tenofovir

Tenofovir es un nuevo inhibidor de la transcriptasa inversa con buena actividad frente a cepas resistentes del virus de inmunodeficiencia humana (HIV), de estructura similar a adefovir y cidofovir. Con éstos se ha descrito la aparición de un defecto en el transporte de sustancias en el túbulo proximal. Los estudios in vitro y las primeras referencias clínicas sobre tenofovir indicaban que presentaba poca toxicidad a nivel renal, y que su toxicidad a nivel mitocondrial era escasa. No obstante se han descrito recientemente casos de disfunción tubular proximal e insuficiencia renal relacionados con el uso de este fármaco. Además tenofovir puede aumentar las concentraciones plasmáticas de didanosina, aumentando la toxicidad mitocondrial de ésta, y los inhibidores de la proteasa pueden provocar una acumulación de tenofovir en las células tubulares renales, pudiendo desarrollarse una tubulopatía proximal. Presentamos una paciente HIV positiva que había presentado complicaciones con el tratamiento con didanosina, que desarrolla un cuadro de insuficiencia renal aguda y tubulopatía proximal (glucosuria normoglucémica, acidosis metabólica hiperclorémica) tras el tratamiento con tenofovir. Aunque la nefrotoxicidad de este fármaco parece ser menos frecuente que con otros análogos de nucleósidos, la utilización de tenofovir en pacientes con disfunción renal subyacente, durante largos períodos de tiempo, o asociados a didanosina y/o inhibidores de la proteasa, podría asociarse a ésta toxicidad. Si se utiliza tenofovir en estos pacientes deben monitorizarse la aparición de signos de tubulopatía, además de vigilar la función renal y la aparición de signos de toxicidad mitocondrial, suspendiendo su utilización para evitar la progresión a insuficiencia renal avanzada

Tenofovir, a new nucleotide reverse transcriptase inhibitor that has good antiviral activity against drug-resistant strains of HIV, is structurally similar to cidofovir and adefovir and seems to be less nephrotoxic. Nephrotoxicity of cidofovir and adefovir is well established and they have been associated with increase for acute renal insufficiency due to tubular toxicity, possibly induced via mitochondrial deplection. Tenofovir has little mithocondrial toxicity in in vitro assays and early clinical studies. However some cases of renal tubular dysfuntion and renal failure related to tenofovir treatment have been published recently. Increased plasma concentrations of didanosine were observed after the adition of tenofovir and protease inhibitors can interact with the renal transport of organic anions leading to proximal tubular intracellular accumulation of tenofovir, yield Fanconi syndrome-type tubulopathy. We present a case in wich acute renal failure and proximal tubular dysfunction developed after therapy with tenofovir in a patiente with HIV who had suffered from complications of didanosine treatment. Although nephrotoxicity certainly occurs much less frequently with tenofovir that it does with other nuclotide analogues, use of tenofovir by patients with underlying renal disfuntion, for longer durations and/or associated with didanosine or lopinavir-ritonavir, might be associated with renal toxicity. Patients receiving tenofovir must be monitored for sings of tubulopathy with simple tests such us glycosuria, phosphaturia, proteinuria, phosphoremia and renal function, as well as assessment for signs of mithocondrial toxicity when a nucleoside analogue is being administered, and therapy should be stopped to avoid the risk of definitive renal failu

Efectos del grabado ácido en la amelogénesis imperfecta hipomineralizada. Estudio microscópico y microanalítico / Acid-etching effects in hypomineralized amelogenesis imperfecta. A microscopic and microanalytical study

Objetivos: El objetivo del presente trabajo consistió en definir los patrones morfológicos y de calcificación en el esmalte de dientes afectados con amelogénesis imperfecta hipomineralizada, tras la aplicación del grabado ácido, mediante la utilización de la microscopía electrónica analítica cuantitativa.Diseño del estudio: Se estudian 5 fragmentos de caninos humanos permanentes de pacientes con amelogénesis imperfecta hipomineralizada y 5 caninos controles. Todas las muestras fueron tratadas con ácido fosfórico y posteriormente procesadas para su estudio morfológico y microanalítico. Resultados: Se observan dos tipos de patrones de grabados, I y II, así como áreas o islotes de patrón I insertados en extensas áreas homogéneas en las que predomina el patrón II. No se aprecian diferencias significativas en la concentración de calcio entre las muestras con amelogénesis imperfecta hipomineralizada y control después del grabado ácido tras el estudio microanalíticocuantitativo. El patrón tipo III no fue observado. Conclusiones: Se describen los cambios y distribución en la estructura del esmalte después del grabado ácido durante 30 segundosen dientes con amelogénesis imperfecta hipomineralizada. Aunque los datos obtenidos coinciden con alteraciones en el desarrollo de los prismas, no se detectan alteraciones en la concentración de calcio

Objectives: The purpose of this study was to use quantitative x-ray microprobe analysis with scanning electron microscopy to define the morphostructural and calcification patterns in the enamel of teeth with the hypomineralized variant of amelogenesis imperfecta. Study design: We compared 5 fragments of permanent human canines from patients with clinically diagnosed hypomineralized amelogenesis imperfecta and 5 normal permanent canines from subjects without amelogenesis imperfecta. All specimens were etched with phosphoric acid for morphological and microanalytical examination. Results: Two types of etching patterns were found; in addition, islets of pattern I were seen within areas of pattern II. Microanalysisdetected no significant differences in calcium concentration between specimens with amelogenesis imperfecta and normal control specimens after acid etching. Pattern III was not observed. Conclusions: The changes and their distribution in the enamel structure after 30 s of acid etching are described in teeth with this rare disorder. Although these data seem to coincide with alterations in prism development, no alterations in calcium concentrationwere found

Estudio sobre la fuerza de adhesión de un sellador de fisuras al esmalte comparando la técnica de grabado ácido con un sistema autodhesivo / No disponible

Objetivo: Evaluar las fuerzas de adhesión de un sellador de fisuras (..) (AU)

Objective: To evaliate the shear bond strength of a fissure (..) (AU)