Mechanical Characteristics of (TiO2-ZnO)/PMMA Nanocomposites for Dentures

Mechanical properties (impact strength, compressive strength and flexural strength) have been studied for (Polymethyl-methacrylate (PMMA)) polymer reinforced with nano (TiO2+ZnO) (0 v%, 1 v%, 2 v%, 3 v%, 4 v% and 5 v%). Ultrasonic dispersion technique was used to prepare the nanocomposites samples, follow with cold casting technique using Teflon molds standard conditions. Charpy impact instrument was used to measure the impact strength, the compressive strength of each sample which was tested in newton units using digital compression tester (TinusOlsen: H50KT, England), while flexural strength can be found from mathematical formulas which depend on the impact strength, compressive strength and flexural strength. Results show that values increase in 1 v%, then decrease alternately by (2 v%, 3 v%, 4 v%, and 5 v%), while 0 v% is the less value of volume fraction of fillers. Young modules values increase alternately by the volume fraction of fillers until 2 v%, while if it is higher and lower than 2 v% it decreases the modulus of elasticity.

Restauración de molares endodonciados, con resina híbrida sobre muñón de amalgama: a propósito de un caso / Restoration of endodontic molars with hybrid resin over amalgam stump: about a case

Introducción: En la actualidad la restauración funcional y estética de dientes endodonciados con gran pérdida de tejido dentario, es efectuada a través del método indirecto; sin embargo, la construcción de muñones de amalgama como elemento de sustitución de metal es una opción terapéutica viable. Objetivo: Mostrar la viabilidad de la restauración estética y funcional de molares endodonciados y con gran pérdida de tejido dentario, por vía directa mediante resina híbrida sobre muñón de amalgama. Presentación del caso: Tratamiento impuesto a un paciente de 35 años con antecedentes de traumatismo dentario condicionantes de fracturas complicadas de corona en 36 y 37, tratados con endodoncias radicales de 2 años de evolución. Acudió a la consulta presentando pérdidas de más de dos tercios del tejido coronal en ambos casos. Luego de comprobar que ambos molares cumplían con los requerimientos, se realizó la preparación de las cavidades, seguida de la confección de muñones de amalgama, sobre los cuales pasadas las 48 horas, se realizó la restauración definitiva con resina híbrida nano composite. Conclusiones: El tratamiento cosmético con nano composite sobre muñón de amalgama, resulta una alternativa terapéutica viable en la restauración estética y funcional por vía directa, aun en molares con gran pérdida de tejido dentario y tratamiento pulporadicular radica(AU)

Introduction: Nowadays functional and aesthetic restoration of endodontic teeth with a great loss of dental tissue, is performed by means of an indirect method, however the construction of amalgams stumps as an element for the metal substitution is a viable therapeutic option. Objective: To show the viability of endodontic molars aesthetic and functional restoration with a great loss of dental tissue, through direct method with resin on amalgam stump. Case Presentation: Treatment applied to a 35-year-old patient with antecedents of traumatism conditioning complicated fractures of crown in 36 and 37, treated with radical endodontic therapy 2 years ago. Arrived to the consulting room presenting losses of more than two thirds of the coronal tissues in both cases. After verifying that both molars met the requirements, the cavities were prepared, followed by the conformation of amalgams stumps over which after 48h, was applied a nano hybrid resin for the definitive restoration. Conclusions: The cosmetic treatment with Nano composite resin over the amalgam stump is an alternative and viable therapy for the functional and aesthetic restoration by means of a direct procedure, even in molars with great loss of dental tissue and subjected to radical endodontic therapy(AU)

Bio-Nanotechnology for Active Food Packaging.

The most commonly used packaging material is associated with environmental issues as they are non-degradable in nature. The number of attempts are made for developing the eco-friendly degradable biopolymers as ideal food packaging. The biopolymers developed are not commercialized as they have poor mechanical strength and resistance properties. Thus to enhance the following faults in the reinforcing material are added which resulted in the composites formation. During various food processing operations the nanotechnology approach is employed such as encapsulation of the material in the nanoparticles, which can be delivered to the targeted site, enhancement of the flavor, integration of antibacterial agents with the nanoparticle in the food, enhancement of shelf-life for storage, and contamination sensing. Food packaging substances synthesized by nanotechnology may increase the shelf-life of the food as they provide resistive packaging, increase the level of food safety, liberate the preservatives for enhancing the life of the food and notify the consumer either the food is consumable or spoiled. Nano-supplements are integrated by the encapsulation method for efficient dietary as well as drug delivery systems. Nano-materials are not well evaluated for the health risk and environmental issues associated with it even the side-effects are unexploited. Various authorities are working prompt designing of guidelines and legislation policies for further acceptance of Nano-based materials in food packaging systems. Biologically synthesized nanoparticles will serve as a significant tool to conquer present contests that are linked with food packaging constituents.

OCT- An Emerging Diagnostic Tool in Sensing Marginal Integrity of Nano Composites.

Objectives: The purpose of the present research was to demonstrate images of failure into the structure of nano composites using optical coherence tomography. Methods: Ten human third mandibular molars were taken in the study. A class V cavity was prepared and restored with nano composite universal. 20 OCT images of each tooth were obtained and a total of 200 images were evaluated after restoration. Spectral domain (SD-OCT), at 840 nm and a measured spatial resolution of 10 µm was used for the study, which is based on the Michelson interferometer set-up and is controlled by the software OCT 800 – Complex Square/LabView, that collects data and generates the image. The restored surfaces were scanned in a bucco-lingual direction and tomographic images were obtained. Later, the crown of each tooth was sectioned in a occlusogingival direction (buccolingually) and images of each section were obtained by a Stereo microscope. Images of OCT and stereo microscope were compared and evaluated. Results: Images obtained by OCT helped in identifying failures at surface and in the internal structure of composites. Significance: Images obtained from OCT helps in detecting the failures, gaps, bubbles which adversely effect the longevity of restoration.

Preparation and Application of Fluorescein Isothiocynate Fluorophore Nano-composites / 分析化学

Nano-composite fluorescence with silica shell had been prepared by improving St(o)ber route. The precursor was obtained via chemical reaction of fluorescein isothiocyanate(FITC) and 3-aminopropyltrietho-)xysilane(APTEOS)). Then, the controlled hydrolysis and condensation of tetraethylorthosilicate(TEOS) leaded) to the formation of organic-inorganic nano-composites. The transmission electron microscope(TEM) showed that the nano-composites with a diameter of about 70 nm were uniform, spherical and mono-dipersed. The nano-composites fluorescence significantly reduced dye leaching and had strong fluorescence when they were by water for several times. Labeled bovine scrum albumin(BSA) with the nano-composites fluorescence showed green fluorescence measured by laser scanning confocal microscope.