RETRIEVING BROKEN INSTRUMENT IN HALF OF THE APIKAL ON CANINES TEETH WITH H-FILE BRAIDING TECHNIQUE

ABSTRACTBackground: Broken instruments affect the outcome and prognosis. A broken instrument will prevent the procedure of cleaning and shaping, irrigation and obturation of the root canal on the obstructed root section causing failure in endodontic treatment. There are some treatments for broken instrument including retrieving a broken fragment file and bypassing it on the root canal. the aim of the case report aims to provide an alternative for retrieving broken instruments using the H-file braiding technique. Method: A 38-year-old female patient came to the Dental Conservation Clinic RSGM Prof. Soedomo FKG UGM. A patient got a history of initial root canal treatment in a clinic, which ended with a separated file on canine teeth left upper. No complain pain, from the investigation radiographic there is an instrument broken in half apical. The teeth 23 seen temporary restoration cavity class I is still in good. Retrieving broken instruments using the H-file braiding technique, preparation with step back techniques, obturation with warm vertical condensation technique and class I composite resin restorations with fiber-reinforced retention. Result: No complain pain after 2 weeks retrieving broken instrument.Conclusion: The technique of the H-file braiding technique is one technique to retrieve a broken instrument, this procedure is simple, cost-effective, harmless to the teeth and gives root canal sealing.

The Contralateral Approach to intra- and Extraforaminal Lumbar Disk Herniations: Surgical Technique and Review of Surgical Procedures

Background Surgery for intra-/extraforaminal disk herniations (IEDH) is technically demanding due to the hidden location of the compressed nerve root section. Ipsilateral approaches (medial and lateral) are accompanied by extended resection of the facet joint and inadequate visualization of the pathology, especially at the L5–S1 level. Methods We describe a microsurgical interlaminar contralateral approach (MICA) suitable for IEDH at the lumbosacral junction that can also be used at L4–L5 and L3–L4. Conclusion The MICA provides access and sufficient intraforaminal visualization for IEDH in the lumbosacral region without resection of stability-relevant structures or manipulation of the nerve root ganglion.

Evaluation of the sealer/gutta-percha ratio on sets of root section surfaces of some extracted teeth sealed using the cold lateral condensation technique

Canal filling must be well adapted to the walls of the root canal to prevent bacterial infiltration. Endodontic seals play an essential role in ensuring tightness, without which the canal filling would suffer infiltrations. This study aimed to evaluate the areas occupied by the two components of the canal filling, as well as the sealer/gutta-percha ratio in the root canals of the maxillary central incisors after their filling using the cold lateral condensation technique with gutta-percha. Thirty extracted upper central incisors were rotatably prepared with ProTaper Universal up to F3 and sealed using the cold lateral condensation technique with gutta-percha. After setting the sealer, the roots of the teeth were sectioned perpendicularly to 1 (L1), 3 (L3), 6 (L6), and 8 (L8) mm from the apex. The surface of the sections was analyzed with a Leica EZ4D stereomicroscope and photographed at two magnification orders: 10x and 25x. The areas corresponding to the gutta-percha, sealer, gaps, and root canal were expressed in pixels using the ImageJ software, version 1.50i. The difference in the representation of sealer areas, gutta-percha and voids was statistically significantly different for all four sections analyzed. The best adaptation of the canal obturation was observed in L1 and L3. The gutta-percha area was statistically significantly higher than that of the sealer for the L1, L3, and L6 levels, while the sealer/gutta-percha ratio recorded the lowest value at the L3 level (0, 30) and the highest at its L8 (0.70) level, without registering statistically significant differences regarding the area at the four analyzed levels. The voids were mostly absent or recorded a minimal percentage area (<1%). Cold lateral condensation of gutta-percha has led to a good adaptation of gutta-percha to the root canal wall, with a small amount of sealer, especially to the sections made at 3 mm from the apex. Given the limitations of this study, we noted that the voids were few – observed in the 6 and 8 mm sections – and were negligible in many cases.

Multi-axial large-scale testing of a 34 m wind turbine blade section to evaluate out-of-plane deformations of double-curved trailing edge sandwich panels within the transition zone

Transverse cracks in the double curved trailing edge panels within the transition zone are among one of the increasingly encountered in-field damages found on wind turbine blades today. Believed to be root cause of these transverse cracks, are the out-of-plane deformation of the double curved trailing edge pressure side panels. These deformations are evaluated on the inner 15 m section of a 34 m wind turbine blade – referred to here as the root section. Through a parametrical study the free end of the root section is loaded in the quasi-static regime comprising edgewise loading (Fy) and torsional moment (Mz) around the longitudinal axis of the blade. The root section is through a multi-scale numerical analysis found to exhibit representative structural behavior in terms of out-of-plane deformations within the area of interest. A combination between Fy and Mz are found to generate the highest peak-to-peak out-of-plane deformation of 15.9 mm.

Evaluación de los efectos sinérgicos de cromo y plomo durante el proceso de fitorremediación con berro (Nasturtium officinale) en un humedal artificial//Evaluation of the synergistic effects of chromium and lead during the process of phytoremediation with watercress (Nasturtium officinale) in an artificial wetland

La contaminación por metales pesados ha aumentado con los años debido a sus diferentes aplicaciones. Se han evaluado distintas especies vegetales para bioacumular metales pesados, el berro es una especie con capacidad de fitorremediación. Sin embargo, falta información sobre la sinergia que ocurre cuando dos metales en el medio están presentes y condicionan su acumulación en las plantas. El objetivo de esta investigación fue evaluar el efecto sinérgico en la acumulación simultánea de Pb y Cr (VI) en berro. Se utilizó un sistema cerrado y un humedal artificial para evaluar el comportamiento de los metales en presencia de berro, cuantificando al final de cada experimento la concentración acumulada en tallos, hoja y raíz. La mayor concentración de ambos metales fue en raíz (Pb > Cr). Al incrementarse la presencia de Cr (VI) en solución, la planta absorbe más metal, y en combinación con Pb el índice de tolerancia se aumenta y el factor de translocación disminuye. Dentro del humedal construido el porcentaje de remoción de Pb y Cr total fue del >99.9% (100 mg L-1) y 95% (28.5 mg L-1), respectivamente. Los resultados obtenidos indican que existen interacciones ambientales, físicas y químicas que determinan la capacidad de bioacumulación en el berro, de los metales evaluados.ABSTRACTHeavy metal pollution has increased over the years due to its different applications. Different plant species have been evaluated to bioaccumulate heavy metals; watercress is a species with phytoremediation capacity. However, there is little information on the synergy that occurs when two metals in the medium are present and condition their accumulation in plants. The objective of this research was to evaluate the synergistic effect on the simultaneous accumulation of Pb and Cr (VI) in watercress. We used a batch system and an artificial wetland to evaluate the behavior of metals in the presence of watercress, quantifying at the end of each experiment the cumulative concentration in stems, leaf, and root. The highest concentration of both metals occurred in the root section (Pb> Cr). As the presence of Cr (VI) in solution increases, the plant absorbs more metal, and combination with Pb the tolerance index is increased and the translocation factor decreases. Within the constructed wetland the percentage of total Pb and Cr removal was >99.9 % (100 mg L-1) and 95% (28.5 mg L-1) respectively. The results show the presence of effects of environmental, physical and chemical interactions that determine the capacity of bioaccumulation of the metals evaluated in watercress.

Root Uptake and Distribution of Radionuclides 134Cs and 60Co in Sunflower Plants (Helianthus annuus. L)

Phytoremediation is the most common method to recover polluted environment caused by radionuclides. This study aims to determine the distribution of 134Cs and 60Co radionuclides in sunflower plants (Helianthus annuus. L). The sunflower plants were cultivated in soil media for 50 days, then transferred into a tube containing hydroponic solution contaminated by 134Cs and 60Co with variation of concentration of 134Cs (0.85 Bq/ml, 1.31 Bq/ml, 1.74 Bq/ml, 2.24 Bq/ml, 2.67 Bq/ml) and 60Co (4,213 Bq/ml, 8,537 Bq/ml, 12,187 Bq/ml). The distribution of radionuclides in roots, stems, leaves were observed using a gamma spectrometer to determine the accumulation of contaminants in plants. Samples were taken at varying intervals (0-720 hours) to determine the increased accumulation of contaminants in plants. The results showed that 134Cs and 60Co accumulated mostly in the leaf section. and the highest accumulation of 60Co was observed in the root section.

Stress Corrosion Cracking in Steam Turbine: Two Case Studies

Stress corrosion cracking in steam turbines had been an old problem though some modern steam turbines have almost eliminated this problem by several methods. The methods include design modification to reduce the stress levels below the threshold stress level for stress corrosion cracking, inducing compressive stress by different means and using pure steam [1, 2]. Some of the older steam turbine discs are prone to stress corrosion cracking. Two cases where such machines experienced stress corrosion cracking in their discs are discussed here. The row 6 disc of an integral steam turbine rotor developed cracks in the root sections. Some of the cracks were mechanically opened for the evaluation. Evaluation of the fracture surfaces with a scanning electron microscope showed evidence of intergranular mode of cracking. Optical microscopy of a cracked root confirmed intergranular mode of cracking. In addition, it showed branching of cracks. Based on these findings, it was concluded that stress corrosion cracking was the reason for the cracks. In addition, finite element analysis was used to calculate the stress distribution in the blade root of the disc. The location of the maximum equivalent stress coincided perfectly with that of the actual crack location in the disc root section. Unfortunately, redesign of the root geometry to minimize the local stress concentration is very difficult due to the size limitation of the blade roots. Small amount of chlorine was identified on the fracture surface and the chlorine could have come from the steam used. The customer was advised to analyze their steam quality and to improve the quality of the steam if needed. The cracked portion was removed from the disc and weld-build up to machine new root sections with the same type of roots. Root section of the row 6 disc of another steam turbine developed failure. This disc had radial entry type blades. Portion of the disc root and some blades were liberated from the disc due to the cracking. The fracture surface had heavy oxide layer on it. Evaluation of the fracture surface with a scanning electron microscope revealed intergranular mode of failure. Energy dispersive spectroscopy analysis of the fracture surface found oxides on the fracture surface. Optical microscopy showed secondary cracking and branched cracking. All these evidences confirmed that the failure occurred due to stress corrosion cracking. In addition, it was suspected that forging was not heat treated properly due to measured lower toughness and different microstructure. The lower toughness was believed to be a result of improper heat treatment rather than that of embrittlement. Methods to mitigate the risk of stress corrosion cracking were proposed.