Límite apical de la obturación endodóntica / Limit apical endodontic obturation

Sigue existiendo controversias al momento de determinar la correcta longitud de trabajo en endodoncia y el posterior límite apical de la obturación, por tal motivo se realiza esta revisión bibliográfica comparando distintos puntos de vista sobre el concepto y las consideraciones a tener en cuenta, también se clasifican los métodos para determinar la longitud de trabajo, así también se incluye los conceptos de permeabilidad apical y limpieza del foramen apical sus técnicas y sus indicaciones. Se conoce la importancia de la obturación del conducto por ser uno de los factores que determinan el éxito o fracaso del tratamiento en la mayoría de los estudios realizados, pero hasta hoy día no se tiene claro el límite apical donde deben terminar los proceso de preparación y obturación. Los objetivos de este trabajo son: conceptualizar la obturación endodóntica, establecer sus objetivos, conceptualizar la longitud de trabajo y límite apical de la obturación, clasificar las técnicas de determinación de la longitud de trabajo y obturación teniendo en cuenta el estado pulpar, establecer la diferencia entre permeabilidad apical y desbridamiento apical, valorar las reacciones de los tejidos periapicales a todos estos procedimientos y analizar el éxito y fracaso del tratamiento de conducto; y a la vez, exponer nuevos conceptos con el propósito de ayudar al clínico a obtener buenos resultados en la terapéutica endodóntica, se ha demostrado que un mejor resultado para el tratamiento del conducto radicular se observa cuando los procedimientos intraconductos terminan dentro del límite del sistema radicular. El pronóstico se redujo notablemente son la subobturación significativa y con la extravasación del material obturado.

Effect of immediate and delayed post space preparation on the apical seal of root canals obturated with different sealers and techniques

During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation technique and quality of filling. OBJECTIVE: The purpose of this study was to investigate the effect of immediate and delayed post space preparation on the integrity of the apical seal. MATERIAL AND METHODS: Sixty-four extracted human incisors were biomechanically prepared using the step-back technique. Sixty roots were randomly assigned to 6 experimental groups of 10 teeth each and the remaining 4 roots served as positive and negative controls (n=2). The root canals in the different groups were obturated with cold lateral and warm vertical condensation of gutta-percha and one of two sealers (Sealapex and Diaket). Post space was prepared either individually or simultaneously. An insulated copper wire was cut into 10-cm-long pieces. In each canal, one piece was inserted to maintain contact with gutta-percha and extended to the outside as one of two working electrodes. A stainless steel wire with the same dimensions of those of the copper wire, used as the other working electrode, was immersed into the background electrolyte from the center of the bottle. The electrical current between standard and experimental electrodes in canals was measured over a period of 10 days applying a conductivity meter. The Kruskal-Wallis test (p=0.05) determined whether there was a significant difference in microleakage among the groups and the Mann-Whitney U test (p=0.01) was used for multiple comparison grouping variables. RESULTS: The results suggest that only the differences between the root canal filling techniques were statistically significant (p<0.01). There were no statistically significant difference in the sealers and the times of filling removal for post space preparation (p>0.01). CONCLUSION: The quality of the root canal filling is important for the integrity of the apical seal.

Potentiometric and conductometric studies on some diphenyformazans and their metal chelates

The ACID dissociation constant pKa values of 1-aryl-5 -[o- hydroxybenzene]-3-benzoylformazan derivatives in ethanol- water mixtures have been determined pH-metrically at 25 +/- 0.2 degree. Increase in the concentration of ethanol results in the increase of pK for all formazan derivatives. The formation constant log kMML values of some lanthanide complexes were determined in 70% [v/v] ethanol. The potentiometric and conductometric studies revealed that 1: 1 and 1: 2 [metal: ligand] complexes were formed in solution. The correlation of the stability constants of complexes in relation to ionic radii, ionic potential and electronegativity of the lanthanides was discussed

Preliminary investigation of the use of charge transfer compounds as gas sensors

Some charge-transfer compounds namely tetrathiafulvaene Salt TTF [+] -tetracyariodiquinomethane TCNQ, tetrathiafulvaene chloride TTFCl, LiTCNQ, and TTF/oxanol dye have been investigated for use as gas sensors. Thin discs and films are tested for detecting some pollutant gases [SO[2], H[2]S, NO[2], CO, O[2], CH[4]], by considering changes in conductivity. It has been found that the conductance is decreased when SO[2], H[2]S, NO[2], Cl[2], CH[4] and O[2] gases pass over the surface of TTF/TCNQ. The same-trend has been noticed when little SO[2] and CO gases are adsorbed on the surface of LiTCNQ., TTFCl, TTF/TCNQ and TTF/DYE

Electrical conductance of co [III] complexes of acetylpyridine-Thiosemicarbazone halides in aqueous solutions at 25 C

The conductance of Co [III] complexes of acetylpyridine- thiosemicarbazone halides has been measured in water at 25C and the data are analyzed using the Fuoss-Onsager equation for 1: 1 associated electrolytes. The characteristic functions, lambda o, a 0 and KA were derived and the association constant KA was analyzed on the basis of the solvent separated-ion pair model

Determinación de la longitud de trabajo de los conductos radiculares a través de métodos electrónicos / Electronic determination of root canal length work

Se realiza una revisión bibliográfica, que permite comparar, a través de los resultados la efectividad de la conductometria electrónica con la obtenida por métodos convencionales dando a conocer resultados obtenidos, confiabilidad y establecer ventajas y desventajas de este método..