The present study assessed the bacterial contamination and the efficacy of control infection protocol in clinica=l practices in Faculty of Dentistry in Tishreen university. An evaluation of surface bacterial contamination in 4 laboratory of clinical
dental practices was for undergraduate stage and 4 laboratory of clinical practices for postgraduate stage. The samples for the study were taken from various sites from and beside dental-chair. The bacterial contamination was studied by observing and recording the colony morphology on the culture plates, Gram's staining with light microscopic screening of the slides, and the biochemical characterization of the isolates using standard bacteriology protocols.The findings showed bacterial contamination in all the surfaces in the laboratory of dental practices. The level of bacterial accumulation on examined surfaces did not change over time. bacteriological analysis showed that 100% of dental chair had bacterial contamination. More the 77% of collected swabs showed Gram-positive cocci, making it the major bacterial group contaminating the surfaces of dental-chair in the dental operatory. The presented study highlights the fact that all sites of dental practice is a potential source of cross infection. The results of this study mandate a strict audit process and protocols to be set in place for preventing cross-contamination from the dental chair in a dental operatory.
The aim of this work is to study the flow behavior of white Vaseline "which
is used in pharmaceutical industry and Cosmetics" in statical state.
The study was carried out on the white vaseline in the molten state under
the effect of temperture, sh
ear stress (τ), and shear rate (γ) by using capillary
viscometer, then the corrections have been done to expermintal data. It was
found from the obtained results that, real viscosity decreased with increasing
real shear rate (γc). Also it was found that the vaseline is a pseudoplastic
material (n<1).
For determining viscous activation energy at constant shear rtae (Eγ) and
shear stress (Eτ), the relationship between real viscosity (ηc) and (1/T) was
studied. It was found that the viscous activation energy decreased with
increasing the shear rate and shear stress, where the value of viscous activation
energy reflectes the temperature–sensitivity of real viscosity.
Elastic properties for vaseline were studied by determining the die swell
ratio (B) (Barus effet), and it was found that (B) increased with increasing
shear stress, but it decreased with increasing L/R ratio, while the temperature
do not have any effect on (B). The time residence (tr) of vaseline in the die was
deterimined and studied the relationship between (B) and (tr).
Note: vaseline does not carry any kind of bacteria, because it is unsuitable
medium for their growth.
