Percolated non-Newtonian flow for silicone obtained from exfoliated bioinorganic layered double hydroxide intercalated with amino acid

A simple and scalable procedure was used to obtain thin, stable, homogeneous, and easy-to-handle films composed of silicone derived from dimethicones containing dispersed hydrotalcite-type materials previously organo-modified with amino acids. The absence of the typical X-ray pattern of the bioinorganic LDH filler suggested an exfoliation process that was further indirectly evidenced by a drastic change in the rheological behavior, which turned from a quasi-Newtonian behavior for the silicone free of LDH filler to an extensive developed gel-like structure for the nanocomposite derivatives. Visualized by the shear-thinning exponent of the complex viscosity in the low-frequency range, the percolation threshold was evident for filler loading as low as <5 w/W%, suggesting the presence of a largely developed interface between the filler and the polymer. The increase of more than one order of magnitude in viscosity was explained by the rather strong attrition phenomenon between the tethered amino acid anions and the silicone chains. UVB radiation absorption profiles make such bioinorganic polymer nanocomposites potentially applicable in skin protection. Thermo-gravimetric analysis revealed significant improvement in the thermal stability, especially in the final step of the polymer combustion, thus underlining the role of the hybrid material as a thermal retardant agent. (C) 2011 Elsevier B.V. All rights reserved.

Correction of Severe Ptosis with a Silicone Implant Suspensor: 22 Years of Experience

Background: Patients with severe ptosis caused by poor or absent function of the levator muscle but with good frontalis muscle excursion usually benefit from a frontalis sling procedure. This is currently carried out using organic or inorganic material to connect the upper eyelid to the frontalis muscle. Methods: The aim of this study was to evaluate retrospectively 112 patients who underwent frontalis sling procedures between 1989 and 2011 using a preformed silicone implant suspensor to correct severe ptosis. Results: The results obtained using this technique were good or fair in 95.54 percent of the cases and poor in 4.46 percent of the cases. The authors discuss the results of the study and the cases in which the procedure should be indicated and highlight the advantages of the method. Conclusion: The availability of this low-cost sterile device, together with the fact that it is ready to use, requires less invasive surgery, saves time, and is sufficiently versatile to allow adjustments to be made at any time, makes the silicone eyelid sling an attractive choice for correcting ptosis. (Plast. Reconstr. Surg. 129: 453e, 2012.)

Oral health related quality of life of edentulous patients after denture relining with a silicone-based soft liner

Background: Knowledge of benefits caused by a treatment on quality of life is very relevant. Despite the wide use and acceptance of soft denture liners, it is necessary to evaluate the patient's response about the use of these materials with regard to improvement in oral health related quality of life (OHRQoL). Objectives: The aim of this study was to evaluate the influence of denture relining in the OHRQoL of edentulous patients. Materials and methods: Thirty-two complete denture wearers had their lower dentures relined with a silicone-based material (Mucopren soft, Kettenbach, Germany) according to chairside procedures. OHRQoL was assessed before and after 3 months of relining by means of OHIP-EDENT, and the median scores were compared by Wilcoxon test (p <= 0.05). Results: After 3 months of relining, participants reported significant improvement of their OHRQoL (p <= 0.01). Conclusion: Denture relining with a soft liner may have a positive impact on the perceived oral health of edentulous patients.

EVALUATION OF THE POTENTIALITIES OF A CARBON NANOTUBES/SILICONE RUBBER COMPOSITE ELECTRODE IN THE DETERMINATION OF HYDROCHLOROTHIAZIDE

A multiwall carbon nanotube/silicone rubber (MWCNT/SR) composite electrode has been used for the determination of hydrochlorothiazide (HCTZ) in pharmaceutical formulations by differential pulse voltammetry (DPV). The electro-oxidation process was evaluated by cyclic voltammetry, from which it was observed that HCTZ presents an irreversible oxidation peak at 0.82 V vs. saturated calomel electrode (SCE) in the potential range from 0.5 to 1.1 V, in Britton-Robinson buffer pH 7.0 at MWCNT/SR. HCTZ was determined by DPV using a MWCNT/SR 70% (MWCNT, m/m) composite electrode after the optimization of the experimental parameters. The linear range was from 5.0 to 70.0 mu mol L-1, with a limit of detection (LOD) of 2.6 mu mol L-1. The HCTZ was determined in pharmaceutical formulations using the proposed composite electrode and the results agreed with those from the official high performance liquid chromatography (HPLC) method within 95% confidence level, according to the t-Student test.

Alternativa protética para correção da angulação com componentes não indexados sobre implantes Cone Morse indexados: sistema tubo parafuso

From a recent perspective the morse-taper dental implants connections are increasingly being used as an alternative for replacement of a missing teeth. Nevertheless, there are a large variety of prosthetic components available on the market with some limitations regarding the final prothesis. This article demonstrated the difficulties and limitations of prosthesis implant-retained connections when using morse-taper implants (with a prosthetic index) case in which the surgical placement of the implant wasn’t successfully performed. The alternative to overcome this scenario was the technique using the tube screw over the top of a mini abutment component. It was possible to manufacture and to have satisfactory adaptation, achieving the satisfaction of the patient, restoring function and esthetics.