Evaluation of the polished surface characteristic of cobalt-chrome castings subsequent to various finishing and polishing techniques.

Finishing and Polishing constitutes an essential requisite after the fabrication of removable partial dentures. Improper finishing and polishing of cast framework will adversely affect the quality of functional units of partial dentures due to reduced dimensions. In this study the polished surface characteristic and loss of weight of the casting were evaluated and compared following different finishing and polishing techniques. A total number of thirty test specimens were cast and each surface finishing and polishing technique was carried out with a high speed polishing motor and an electropolishing unit under standardised conditions. Surface roughness was evaluated by means of a surface roughness analyzing instrument, Perthometer. The loss of weight due to the metal lost was observed on a sensitive electronic balance. The results of polishing technique employed with G3 group revealed better surface characteristic. It may be understood that sandblasting causes initial roughness and the sequence of coarse cylindrical abrasive, Black hard rubber polisher (coarse grit-Dentauram), Grey hard rubber polisher (Med-grit-Dentauram), Green hard rubber polisher (Fine-grit-Dentauram), Grey flexible rubber polisher (Fine grit-Renfert), felt buff with pumice slurry and felt buff with green polishing compound (Degussa) produced improved surface in this case. The loss of weight due to metal lost show concern with technique groups G4, G5, G6. It can be avoided by judicious sandblasting and application of proper grit of abrasive agents.

Experience with brain abscesses.

Brain abscesses were studied in 47 patients. Thirty-four (72%) of them were between 5-15 years and 9 were infants. Otogenic source (34%) was the commonest predisposing factor, followed by scalp and face infection (21.3%) and congenital cyanotic heart disease (12.8%). Twenty (42%) patients had multiple abscesses. Supratentorial abscesses were commonest (75.9%). Predominant clinical features were fever (87.2%), raised intracranial tension (78.7%) and altered sensorium (53.2%). A total of 38.3% presented with focal neurological deficit and 34% were admitted in Grade III or IV coma. Diagnosis of abscess and monitoring of its evolution was done principally by CT scanning. Causative organisms were isolated in 54.8% of cases and Staphylococci, Proteus and Pseudomonas were the common pathogens. Therapy was most often a combination of surgical aspiration with or without excision in addition to antimicrobial therapy. The overall mortality in our series was 44.7%. Bad prognostic factors were Grade III/IV of coma at admission, age below 2 years and multiple abscesses.