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Biomedical subjects

N S Salem

Publications and source records attributed to N S Salem.

7 recordsLinked to original sources
PubMed1991

An in vivo study on the release of fluoride from glass-ionomer cement.

Fluoride release from a glass-ionomer cement was measured in vivo during an 8-day period. Maxillary acrylic resin appliances, each carrying four glass-ionomer cement specimens, were worn by four subjects at night. Unstimulated whole saliva samples were collected before the subjects retired to bed (pretreatment samples) and in the morning (posttreatment samples). The average fluoride concentration and saliva flow of pretreatment samples were 31 +/- 4 ng/mL and 0.5 +/- 0.1 mL/min, respectively. In all subjects there was a statistically significant posttreatment increase (.005 less than P less than .025) in salivary fluoride concentration. The release of fluoride was nearly constant during the test period.

Adult↗
PubMed1990

Glass ionomers for direct bonding: an in vitro assessment.

An in vitro study was carried out testing the shear/peel bonding strength of brackets cemented with a glass-ionomer cement. It was found that the adhesive achieves its optimal bond strength at 24 hours. It is suggested that there is still scope for improvement of the material's mechanical properties and the use of prolonged clinical trials.

Acids↗
PubMed1989

The effects of sterilization on the accuracy of silicone ear impression materials.

The dimensional stability of a range of elastomeric impression materials has been assessed to study the effect of storage in sterilizing solutions. Experiments were carried out on audiological silicones of condensation and addition types. Further, a number of dental-based materials comprising a polysulphide, a polyether, a condensation and an addition silicone, were also investigated for comparison. The results indicate that the addition silicones had the greatest dimensional stability over a range of storage conditions, which included aqueous glutaraldehyde and hypochlorite solutions.

Ear, External↗
PubMed1988

Mechanical properties of elastomeric impression materials.

Dental elastomeric impression materials of different consistencies, representing addition and condensation silicones, polysulphides and a polyether, were studied to determine their mechanical properties in terms of tearing energy, tensile properties and modulus determined at high strain rates. Whilst the polysulphides had the greatest resistance to tearing, they were more extensible, had lower moduli of elasticity and lower tensile strengths than the silicones. The polyether resembled the silicones in many respects.

Chemical Phenomena↗