Thermal expansion and corrosion resistance of cobalt-chromium alloys fabricated by contemporary manufacturing processes: an in vitro study / Expansión térmica y resistencia a la corrosión de aleaciones de cobalto-cromo fabricadas mediante procesos de abricación contemporáneos: un estudio in vitro

In Purpose: The fabrication technique can influence the mechanical properties of Cobalt-Chromium (Co-Cr) dental alloys. Hence, the present study aims to determine the corrosion resistance and thermal expansion of alloys manufactured using three contemporary techniques. Material and Methods: A total of nine specimens of Co-Cr alloy were prepared according to ISO 22674 by each one of the three manufacturing processes (three in each process); conventional casting, direct metal laser sintering (DMLS) and milling (MIL). All these specimens were tested for coefficient of thermal expansion and corrosion resistance. The data was tabulated and analyzed statistically. Results: The difference in the thermal expansion of alloys fabricated using three techniques was non-significant at almost all the temperatures from 50 ºC to 950 ºC (p>0.05), except 450 ºC and 600 °C. The polarization resistance of specimens manufactured using the conventional method was more compared to DMLS and MIL at pH 5 (Conventional>MIL>DMLS) (p<0.001). Conclusion: The thermal expansion behavior of alloys manufactured using the three selected techniques were similar, whereas, at acidic pH, the corrosion resistance of conventional and MIL were better than the DMLS.

Antecedentes: La técnica de fabricación puede influir en las propiedades mecánicas de las aleaciones dentales de cobalto-cromo (Co-Cr). Por lo tanto, el presente estudio tiene como objetivo determinar la resistencia a la corrosión y la expansión térmica de aleaciones fabricadas con tres técnicas contemporáneas. Material y Métodos: Se prepararon un total de nueve probetas de aleación de Co-Cr según ISO 22674 por cada uno de los tres procesos de fabricación (tres en cada proceso); fundición convencional, sinterización directa de metal por láser (DMLS) y fresado (MIL). Todos estos especímenes fueron probados para determinar el coeficiente de expansión térmica y la resistencia a la corrosión. Los datos fueron tabulados y analizados estadísticamente. Resultados: La diferencia en la dilatación térmica de las aleaciones fabricadas con las tres técnicas no fue significativa en casi todas las temperaturas desde 50ºC hasta 950ºC (p>0,05), excepto 450ºC y 600ºC. La resistencia a la polarización de las muestras fabricadas con el método convencional fue mayor en comparación con DMLS y MIL a pH 5 (Convencional>MIL>DMLS) (p<0, 0 01). Conclusión: El comportamiento de expansión térmica de las aleaciones fabricadas con las tres técnicas seleccionadas fue similar, mientras que, a pH ácido, la resistencia a la corrosión de la convencional y la MIL fue mejor que la de la DMLS.

Role of posteromedial plating in condylar fractures of Tibia in adults

Background: The purpose of this study was to evaluate role of Posteromedial Plating in condylar fractures of Tibia, especially patients with posterior tibial shear fractures. Materials and methods: This prospective study included 12 patients with mean age 40 years (range 30 to 50 years) who sustained high velocity posterior tibial plateau fracture-subluxations with/ without associated Bicondylar fractures (Moore I & II Types, Schatzker’s Groups – IV, V and VI). Surgical management included stabilisation plating through a posteromedial/ posterior approach and additional postero lateral or antero lateral approach as needed. The patients were followed up at six week, three month, six month and one year postoperatively and assessed using Oxford Knee Score and Lyshom Score. Results: The mean OKS score was 40 (range 36 to 44) at the end of one year. The main clinical measures were early post-operative non weight bearing ROM, post-operative complication and functional outcome. The time to full weight bearing, the rate of post-operative complications and functional outcome was significantly better as evident by over 94 % showing good to excellent OKS and Lyshom scores. Conclusion: A posterior/ postero medial approach for posterior tibial plateau shear fractures (which are otherwise irreducible by conventional approaches) and buttress/ antiglide plate are usually needed to reduce the fractures anatomically, achieving absolute stability and mobilize early NWB, ROM of the knee joint to optimize the functional outcomes and minimize the complications, without the need for revision surgery.

Comparative study of functional outcome of dynamic compression plating with interlocking nailing for fracture shaft humerus in adults

A prospective observational study was conducted in Government Victoria Hospital, Visakhapatnam from 2013 to 2018 to evaluate Arogyasri scheme. Arogyasri scheme provides end to end cashless services for identified diseases in Andhra Pradesh. During this period, 891 gynecological surgeries were conducted under this scheme. Out of them, 44 were not approved for claim. A total of 10,880,238 rupees were claimed.

Effect of Mobile Phone Radiofrequency On Hippocampal Ca3 Neurons.

Objective: The purpose of the study is to investigate the effects of mobile phone [MP] radiofrequency electromagnetic fields (RF-EMF) exposure for different durations on dendritic morphology and nerve cell damage in CA3 sub region of Hippocampus in Swiss albino mice. Materials &Methods: Total 70 Swiss albino mice of both sexes were used in the study. Animals were divided into 10 groups randomly. Five groups (n=6) were used for assessment of neuronal damage by cresyl violet staining. Another five groups (n=8) were used for assessment of dendritic morphology by Golgi- Cox staining. Groups were divided by exposure duration (15, 30, 45 and 60 minutes/ per day for 30 days); age matched unexposed groups served as controls. Results: Results of the study have shown that there was decrease in the number of viable neurons and dendritic arborization in CA3 sub region of hippocampus in 30, 45 and 60 min exposed groups. Conclusions: Increased neuronal damage and decreased dendritic arborization of hippocampal CA3 neurons was found with increase in exposure duration of MPRF-EMF.

Flexible resins in the rehabilitation of maxillectomy patient.

Surgical resection is an established and common method for treatment of maxillofacial tumors. Such intervening surgery in this region may involve the destruction of antral, nasal, or orbital contents and jaws. Normally, the end result is a defect which may affect speech, swallowing, mastication and facial appearance. Prosthodontic restoration of functions and facial form is an excellent method in the replacement of missing parts and restoration of contour. Pertinent research in materials, designs and methods have resulted in whole array of possible prosthess that can be provided to meet specific patient needs. This case report describes the fabrication of definitive obturator prosthesis made of flexible acrylic resin on a chrome cobalt base.

Dengue fever presenting with acute colitis.

Gastrointestinal manifestations of dengue fever are mainly in the form of bleeding or liver function abnormalities. Dengue fever presenting as acute colitis-like picture is not reported to date. We report a 50-year-old man with dengue fever presenting with lower gastrointestinal bleeding and colonoscopic features of acute inflammatory colitis.

Segmental Jejunal Lipomatosis: A Rare Cause of Intestinal Obstruction

A rare case of a segmental small intestinal (jejunal) lipomatosis is described. A 33-year-old male was admitted with a clinical diagnosis of an acute intestinal obstruction. A plain erect abdominal x-ray showed multiple air-fluid levels. On an exploratory laparotomy, a jejunojejunal intussusception was found secondary to a segmental submucosal lipomatosis. This was treated by a segmental resection and anastomosis, which resulted in a complete cure. Here we present this case with a review of the relevant literature.