Effect of Manufacturing Conditions on Structural and Handling Properties of Braided Polyamide Suture
Suture performances include handling characteristics and knot mechanical properties. These performances depend mainly on frictional, flexural, and compressive forces. The interaction between these forces developed inside the suture knot governs the displacement mode and the deformability of the suture yarn inside the knot. In the present work, we studied the effect of manufacturing conditions on structural properties and handling characteristics. Obtained results show that manufacturing parameters have significant impact on slipperiness, flexibility, and compressibility. Consequently, suture performances widely depend on manufacturing parameters. We show that after a hot stretch step, suture structure becomes more uniform and compact. Furthermore, after this treatment, lateral deformation, friction force, and bending rigidity are reduced and knot performances are improved.
Exploitation of essential oil extracted from Tunisian Laurus nobilis for the development of PET antibacterial sutures
Abstract The main purpose of this study is the use of a Tunisian bio resource for the improvement of mechanical and physical properties of braided polyethylene terephthalate (PET) sutures. In this study, antibacterial PET sutures were developed using Tunisian essential oil of Laurus nobilis. A new lubrication process was proposed for this fact. The essential oil of L. nobilis was selected because of its antibacterial properties as well as analgesic, antiseptic, antiviral, and anti-infectious proprieties. Optimized extraction process of essential oil was also determined. Characteristics and cytotoxicity of extracted essential oil were also investigated. In order to study the impact of lubrication conditions on PET suture performances, mechanical properties and antibacterial effects of braided sutures were studied. The obtained results prove that sutures lubrication improves suture knot efficiency and leads to smoother surface. Developed sutures show also obvious antibacterial effect against Staphylococcus aureus ATCC 6538 G (+) colonies.
Microstructure of the solder-casting zone in bridges of dental gold alloys.
The composition and structure were studied in the cast and in the solder of bridges which had failed clinically. Both materials were gold alloys but with different contents of Pt, Ag and Zn. The metallographic investigation revealed defects mostly in the solder, situated in the subsurface layer. SEM studied of the fracture surface revealed large porosites and a structure of dense parallel lines--striations--, indicating that the material had failed from fatigue. The materials in the fractured bridges were identified by micro-probe measurements. It was stated that cast material and solder material used together, were of different composition.