To Evaluate The Clinical Patterns Of Complicated Cataracts: A Hospital Based Study

Background: Complicated cataracts or secondary cataracts are those cataracts that occurs secondary to other intraocular diseases. There are many causes of complicated cataracts but the most common cause is intraocular inflammation. Aim: To evaluate the clinical patterns of complicated cataracts in patients presenting to the Out–Patient Department of B. P. Koirala Lions Centre for Ophthalmic Studies (BPKLCOS). Material and Methods: All patients fulfilling the diagnostic criteria for complicated cataracts were enrolled from 1st January 2015 to 30th June 2016 (18 months). Detailed history and systematic examination along with necessary investigations were done. Results: Ninety two eyes of 69 patients had complicated cataracts. The mean age of presentation was 45.19 years (SD ± 18.1). Twenty four cases (34.8%) were male. The female to male ratio was 1.875:1. Forty six (66.7%) cases had unilateral involvement. The most common clinical pattern of complicated cataract was posterior subcapsular cataract (63, 68.5%). Conclusion: Posterior subcapsular cataract was the most common clinical pattern of complicated cataracts

Evaluation of the marginal fit of metal copings fabricated on three different marginal designs using conventional and accelerated casting techniques: An in vitro study.

Introduction: Abundant resources and techniques have been used for complete coverage crown fabrication. Conventional investing and casting procedures for phosphate-bonded investments require a 2- to 4-h procedure before completion. Accelerated casting techniques have been used, but may not result in castings with matching marginal accuracy. Aims and Objectives: The study measured the marginal gap and determined the clinical acceptability of single cast copings invested in a phosphate-bonded investment with the use of conventional and accelerated methods. Materials and Methods: One hundred and twenty cast coping samples were fabricated using conventional and accelerated methods, with three finish lines: Chamfer, shoulder and shoulder with bevel. Sixty copings were prepared with each technique. Each coping was examined with a stereomicroscope at four predetermined sites and measurements of marginal gaps were documented for each. Statistical Analysis: A master chart was prepared for all the data and was analyzed using Statistical Package for the Social Sciences version. Evidence of marginal gap was then evaluated by t-test. Analysis of variance and Post-hoc analysis were used to compare two groups as well as to make comparisons between three subgroups . Results: Measurements recorded showed no statistically significant difference between conventional and accelerated groups. Conclusion: Among the three marginal designs studied, shoulder with bevel showed the best marginal fit with conventional as well as accelerated casting techniques. Accelerated casting technique could be a vital alternative to the time-consuming conventional casting technique. The marginal fit between the two casting techniques showed no statistical difference.

The effect of remelting various combinations of new and used cobalt-chromium alloy on the mechanical properties and microstructure of the alloy.

Context: Remelting previously cast base metal alloy can adversely affect the mechanical properties of the alloy and necessitates addition of new alloy. Aims: To study the effect of remelting different combinations of new and used cobalt-chromium (Co-Cr) alloy on its mechanical properties and microstructure. Materials and Methods: Using induction casting, 24 tensile test specimens were prepared for eight different combinations of new and used Co-Cr alloy. The test specimens were assessed for yield strength and percentage elongation. Microhardness was evaluated using Vickers's hardness tester. The tensile testing was carried out on a 50 kN servo-hydraulic universal testing machine. Microstructure analysis was done using an optical photomicroscope on the fractured samples after acid etching. Statistical Analysis: The mean values (±standard deviation) and coefficient of variation were calculated. Student's 't' test was used for statistical analysis. Statistical significance was assumed at P=.05. Results: The mean yield strength of eight different combination groups were as follows: group A: 849 MPa, group B 1 : 834 MPa, group B 2 : 915 MPa, group B 3 : 897 MPa, group C 1 : 874 MPa, group C 2 : 859 MPa, group D 1 : 845 MPa, and group D 2 : 834 MPa. The mean percentage elongation for the different groups were as follows: group A: 7%, group B 1 : 7%, group B 2 : 8%, group B 3 : 7%, group C 1 : 8%, group C 2 : 7%, group D 1 : 7%, and group D 2 : 8%. The mean hardness values were as follows: group A: 373 VHN, group B 1 : 373 VHN, group B 2 : 346 VHN, group B 3 : 346 VHN, group C 1 : 364 VHN, group C 2 : 343 VHN, group D 1 : 376 VHN, and group D 2 : 373 VHN. Conclusion: Repeated remelting of base metal alloy for dental casting without addition of new alloy can affect the mechanical properties of the alloy. Microstructure analysis shows deterioration upon remelting. However, the addition of 25% and 50% (by weight) of new alloy to the remelted alloy can bring about improvement both in mechanical properties and in microstructure.