Presence of methanogenic archaea in necrotic root canals of patients with or without type 2 diabetes mellitus.

Theoretically, a necrotic root canal fulfils all requirements as a niche for methanogens to inhabit. However, their presence in it and its implication in apical periodontitis (AP) is controversial. Therefore, to contribute to ending the controversy, this study aimed to detect and compare methanogens' presence in two distinct niches with supposedly different microenvironments; both were necrotic root canals associated with AP but one from patients with type 2 diabetes mellitus (T2DM) while the other from non-diabetic patients. A clinical examination was performed on 65 T2DM patients and 73 non-diabetic controls. Samples from necrotic root canals were obtained, and methanogens were identified. The presence of methanogens was three times higher (27.6%) in the T2DM group than in non-diabetic patients (8.2%). In addition, methanogens' presence was associated with a higher prevalence of periapical symptoms.

Arsenopyrite weathering under conditions of simulated calcareous soil.

Mining activities release arsenopyrite into calcareous soils where it undergoes weathering generating toxic compounds. The research evaluates the environmental impacts of these processes under semi-alkaline carbonated conditions. Electrochemical (cyclic voltammetry, chronoamperometry, EIS), spectroscopic (Raman, XPS), and microscopic (SEM, AFM, TEM) techniques are combined along with chemical analyses of leachates collected from simulated arsenopyrite weathering to comprehensively examine the interfacial mechanisms. Early oxidation stages enhance mineral reactivity through the formation of surface sulfur phases (e.g., S n (2-)/S(0)) with semiconductor properties, leading to oscillatory mineral reactivity. Subsequent steps entail the generation of intermediate siderite (FeCO3)-like, followed by the formation of low-compact mass sub-micro ferric oxyhydroxides (α, γ-FeOOH) with adsorbed arsenic (mainly As(III), and lower amounts of As(V)). In addition, weathering reactions can be influenced by accessible arsenic resulting in the formation of a symplesite (Fe3(AsO4)3)-like compound which is dependent on the amount of accessible arsenic in the system. It is proposed that arsenic release occurs via diffusion across secondary α, γ-FeOOH structures during arsenopyrite weathering. We suggest weathering mechanisms of arsenopyrite in calcareous soil and environmental implications based on experimental data.

Hermangioma intraóseo: reto diagnóstico. Presentación de un caso y revisión de la literatura / Intraosseous hemangioma: a diagnostic challenge. Report of a case and review of the literature

Los hemangiomas son neoplasias benignas de origen endotelial, formadoras de vasos. Los hemangiomas intraóseos son condiciones raras que comprenden del 0.5 a 1% de todos los tumores intraóseos. Su localización más común es la columna vertebral y los huesos del cráneo. Aquéllos que se presentan en los maxilares son tumores muy raros. Dos tercios de éstos se localizan en la mandíbula, con una proporción de mujer a hombre de 2:1. El objetivo de este artículo es reportar un caso signifi cativo de un hemangioma central de grandes dimensiones de la rama de la mandíbula del lado derecho, el cual fuetratado exitosamente con resección quirúrgica y ligadura de vasos nutricionales. Caso clínico: Paciente de 14 años que presenta un área radiolúcida unilocular en la rama mandibular del lado derecho. Clínicamente se observa aumento de la cara difuso, que causa asimetría facialasintomática de tres años de evolución. Conclusiones: La importancia del hemangioma intraóseo de los maxilares radica en su proximidad con los dientes, lo que representa un alto riesgo de sangrado debido a cualquier traumatismo por intento de extracción. El diagnóstico de hemangioma intraóseo, debido a su baja incidencia e inusual manera de presentación, es un reto diagnóstico...