Effect of Porcelain‐Firing Cycles and Surface Finishing on the Marginal Discrepancy of Titanium Copings

Purpose : The aim of the study was to evaluate the effect of simulated porcelain firing cycles and surface finishing on the marginal fit of commercially pure titanium (Cp Ti) copings. Materials and Methods: A machined stainless steel die system with standard 0.5‐mm copings was fabricated. Wax patterns were prepared by pouring the molten wax on a two‐part stainless steel die. Thirty specimens were cast in Cp Ti. These were divided into three groups with ten specimens in each group. Group 1 was treated with conventional cold working and later oxidized. Group 2 specimens were oxidized initially and then cold worked. Group 3 was heat treated in its original investment and later treated as in group 1. All specimens were later subjected to sequential simulated porcelain firing cycles, that is, oxidation, bonder, opaque, body, and glaze firing. Following the completion of each firing cycle, marginal discrepancy was measured in μm using a traveling microscope. The obtained data were subjected to one‐way analysis of variance (ANOVA) and Student's t‐test. The statistical level of significance was set at 1%. Results: The results showed that the mean and SD values (in μm) were 55 ± 2.6, 43 ± 3.0, and 68 ± 4.0 after oxidation for groups 1, 2, and 3, respectively. Mean and SD values (in μm) after glaze firing were 76 ± 3.9, 64 ± 4.1, and 89 ± 4.3 for groups 1, 2, and 3, respectively. The mean marginal opening was largest for group 3 specimens. One‐way ANOVA showed the difference within the three groups was highly significant after oxidation (F‐value 149.37 at p‐value 0.0000) and glaze firing (F‐value 82.43 at p‐value 0.0000). Conclusions: (1) The Student's t‐test values demonstrated that increased marginal openings of the specimens resulted after the sequential simulated porcelain firing cycles. (2) Marginal discrepancy values improved when the specimens were thermocycled prior to cold working.     

Decline in rotavirus hospitalisations following introduction of Australia's national rotavirus immunisation programme

Aim: To determine the impact of rotavirus immunisation on rotavirus hospitalisations in young children. Methods: Annual hospitalisations for rotavirus gastroenteritis to The Children's Hospital at Westmead, a tertiary care paediatric hospital in Sydney, were recorded from 2001 for 6 years prior to and 2.5 years following the introduction of rotavirus vaccines to the National Immunisation Program. Data on hospital‐acquired rotavirus gastroenteritis were collected prospectively. Results: Hospitalisations for rotavirus gastroenteritis declined in the two full rotavirus seasons (2008 and 2009) after vaccine introduction by 75% compared with mean annual hospitalisations from 2001 to 2006. The greatest decline was seen in those <12 months of age (93%), but the reduction occurred consistently across all age groups, even in children not eligible for immunisation, suggesting an effect on herd immunity. A substantial decline in nosocomial rotavirus gastroenteritis was seen from 2007 to 2009, suggesting a reduction in virus transmission in the hospital setting. Conclusion: This study demonstrates a substantial reduction in hospitalisations in children of all ages to a large paediatric hospital and reduced nosocomial infections since the introduction of a nationally funded rotavirus immunisation programme in Australia.     

Stem cell transplantation: brief review and current status

In recent years stem cell has come up as a great advance in therapy for a number of illnesses and has potential for revolutionising the medical field. Right from myelodysplastic syndrome to amyloidosis it has been tried. The present review is a modest endeavour to acquaintain in brief about current status of stem cells.     

Preparation and evaluation of sustained release microballoons of propranolol

Background and the purpose of the study

The purpose of the present investigation was to characterize, optimize and evaluate microballoons of Propranolol hydrochloride and to increase its boioavailability by increasing the retention time of the drug in the gastrointestinal tract.

Methods

Propranolol hydrochloride-loaded microballoons were prepared by the non-aqueous O/O emulsion solvent diffusion evaporation method using Eudragit RSPO as polymer. It was found that preparation temperature determined the formation of cavity inside the microballoon and this in turn determined the buoyancy. Microballoons were subjected to particle size determination, micromeritic properties, buoyancy, entrapment efficiency, drug loading, in vitro drug release and IR study. The correlation between the buoyancy, bulk density and porosity of microballoons were elucidated. The release rate was determined in simulated gastric fluid (SGF) of pH 1.2 at 37±0.5°C.

Results

The microballoons presented spherical and smooth morphologies (SEM) and were porous due to presence of hollow cavity. Microballoons remained buoyant for >12 hrs for the optimized formulation. The formulation demonstrated favorable in vitro floating and release characteristics. The encapsulation efficiency was high. In vitro dissolution kinetics followed the Higuchi model. The drug release from microballoons was mainly controlled by diffusion and showed a biphasic pattern with an initial burst release, followed by sustained release for 12 hrs. The amount of the drug which released up to 12 hrs was 82.05±0.64%. Statistical analysis (ANOVA) showed significant difference (p<0.05) in the cumulative amount of drug released after 30 min, and up to 12 hrs from optimized formulations.

Conclusion

The designed system for propanolol would possibly be advantageous in terms of increased bioavailability and patient compliance.     

Modified technique for retaining silicone auricular prosthesis: a case report

Prosthetic rehabilitation of auricular defects can be a demanding procedure due to a broad variety of clinical presentations and a wide array of treatment options. The retention of auricular prostheses is a major factor influencing the successful outcome of rehabilitative treatment following cancer surgery or trauma. Auricular prostheses have been retained by methods including implants, adhesives and spectacle frames but the choice of repair ultimately depends on patient factors, amount of soft tissue loss, and location of the auricular defect. This article describes a newer technique of using resin template for silicone auricular prosthesis, for better retention and orientation. Moreover it is cost effective and aesthetically acceptable for patients who decline or need to postpone implant retained prosthesis reconstruction.     

Biatrial drainage of Inferior Vena Cava through Fossa Ovalis Atrial Septal Defect via atrial septal gutter

A successful surgical correction of biatrial drainage of inferior vena cava through Fossa Ovalis Atrial Septal Defect via atrial septal gutter in a patient surviving to adulthood is reported. Relevant literature is briefly reviewed. The usefulness of contrast echocardiography in resolving the diagnostic dilemmas in such cases is highlighted.