This study characterized the interactions of mineral trioxide aggregate with a synthetic tissue fluid composed of a neutral phosphate buffer saline solution and root canal dentin in extracted human teeth using inductively coupled plasma-atomic emission spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction. Mineral trioxide aggregate exposed to synthetic tissue fluid at 37°C released its metallic constituents and produced precipitates with a composition and structure similar to that of hydroxyapatite [Ca 10 (PO4) 6 (OH) 2 -HA]. Endodontically prepared teeth filled with mineral trioxide aggregate and stored in synthetic tissue fluid at 37°C for 2 months produced at the dentin wall an adherent interfacial layer that resembled hydroxyapatite in composition. The authors conclude that Ca, the dominant ion released from mineral trioxide aggregate, reacts with phosphates in synthetic tissue fluid, yielding hydroxyapatite. The dentin-mineral trioxide aggregate interfacial layer results from a similar reaction. The sealing ability, biocompatibility, and dentinogenic activity of mineral trioxide aggregate is attributed to these physicochemical reactions. (MTA) is a mechanical mixture of three powder ingredients: Portland cement (75%), bismuth oxide (20%), and gypsum (5%) (1). It also contains trace amounts of SiO 2 , CaO, MgO, K 2 SO 4 and Na 2 SO 4 . The major component, Portland cement, is a mixture of dicalcium silicate, tricalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. MTA is prepared as a mixture of powder and water and is used in a slurry form, which gradually hardens in the oral environment.Since its introduction as a root-end filling material in 1993, the use of MTA has expanded to many applications of root repair and bone healing (2-4). These applications include direct pulp capping, repair of root and furcation perforations, and apexification. A material for such applications should have the ability to seal the dental pulp from bacterial and chemical invasion, and the candidate material should be biocompatible to prevent toxicity and tissue irritability. Both in vitro and in vivo studies have shown that MTA fulfills these requirements quite satisfactorily. The superior sealing ability of MTA over conventional retrograde filling materials, such as amalgam, IRM, and Super EBA, has been demonstrated in numerous microleakage tests using dye, fluid, bacteria, and endotoxin infiltration techniques (5-10). Its excellent biocompatibility has been evidenced in several favorable biologic processes induced by MTA, namely, minimal toxicity and pulpal irritation, mild periapical inflammation, nonmutagenicity, cell adherence and growth, increased levels of alkaline phosphatase and osteocalcin, interleukin production (IL-6, IL-8), periodontal ligament attachment, cementum growth, and dentinal bridge formation (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26).Studies on MTA have mainly examined its various biologic properties, but lit...

Background: Primary teeth pulp exposures have traditionally been treated with formocresol or ferric sulphate pulpotomies or calcium hydroxide pulp capping. The aim of this study was to observe the tissue response when mineral trioxide aggregate (MTA) was used. Methods: Ten primary teeth had direct pulp caps and 11 had a pulpotomy with MTA. The teeth were restored and then clinically reviewed monthly for five months and before extraction. Radiographs were taken prior to treatment, after one month and prior to extraction. After extraction, the teeth were examined histologically and the responses to treatment were assessed. Results: One pulpotomy and two pulp capping cases had postoperative pain and signs of pulp degeneration. Radiographs showed no root resorption, no periodontal pockets and no furcation radiolucencies. No cases had draining sinuses or increased mobility. Most pulps responded favourably from a clinical perspective although a variety of responses were noted histologicallynormal odontoblasts, irregular odontoblasts, intrapulpal calcifications, dentinal bridges, cementum formation, internal resorption, inflammatory infiltrate and pulp necrosis. Conclusions: The responses of pulps in primary teeth to MTA pulpotomies and pulp caps were favourable from clinical and radiographic perspectives although a variety of histological responses were noted. MTA may be a favourable material for pulp capping and pulpotomies in primary teeth.Key words: Pulpotomy, pulp cap, primary teeth, mineral trioxide aggregate.Abbreviations and acronyms: Ca(OH) 2 = calcium hydroxide; HA = hydroxyapatite; MTA = mineral trioxide aggregate.

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Forty-nine per cent of patients returned for recall after a minimum of 6 months with patient age, patient gender and pulp status affecting the rate of recall significantly.

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Reservoir performance is dependent upon system interaction between the completion hardware, the wellbore reservoir section and its connection to surface. A-priori condition used to design a robust completion solution are housing units capable of draining and collecting fluids along the entire completion length and simultaneously produce oil while delaying more mobile fluids. Therefore the completion design should focus on: Those scenarios that are expected to have greater impact in the producer wells: These include for example PI increase, adjusting drawdown pressure, flux balancing, delaying early entry of high mobile water or gas along the entire completed interval, well clean-up through time and extending well production life.Wether it is expected to accelerate initial production or balanced management of the field. The goal in both cases is to achieve efficient area drainage and uniform sweep while not leaving by-passed oil in the ground.Whether the contingency plans are for, alternative re-completions or preparing the wellbore for future operations such as EOR related activities to stimulate production from much lower oil residual saturations.Having hardware ready that allows changes in operational modes from producer to injectors or viceversa, or permits installation of slim hole units, technologies to enhance porosity or permeabilty, reduce viscosity and mobility ratios, implement fine reservoir characterization models, avoid reaching ultra-high WCUT too soon or to implement intermediate EOR operations to slow down this tendency. In Ecuador, an operator has completed several wells equipped with ICDs, in both consolidated and non-consolidated reservoirs and with variable rock and fluid properties including viscosities varying between 4 to 47 cP. This paper describe the combination of ICD design, geo-steerirng, calibration with real-time log data, installation procedures and fluid historical production results through time.

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