The glass-infiltrated oxide ceramic framework consists of a porous pre-sin¬tered ceramic core that is subsequently infiltrated with a low-viscosity glass. The ceramic core can be fabricated in the dental lab either by slip casting ceramic powder slurry on a porous refractory die, or by milling out from a pre-fabricated CAD/ CAM ceramic block made by powder dry pressing9, 19, 21, 25. The oxide ceramic framework can be fabricated from different oxide materials and infiltrated by different glass materials. The available used oxide ceramics are aluminum oxide (Al2O3), magnesium aluminum oxide (MgAl2O4), and zirconium oxide (ZrO2). Glass-infiltrated Oxide Ceramics were first introduced in dentistry as In Ceram ® Alumina in 1989. It consists of 75
Bagis Y, Baltacioglu I, Kahyaogullari S. Comparing Microleakage and the Layering Methods of Silorane-based Resin Composite in Wide Class II MOD Cavities. Operative Dentistry 2009; 34(5):578-85.
American businesswoman Carly Fiorina once concluded, “If a decision-making process is flawed and dysfunctional, decisions will go awry.” In the critically acclaimed memoir The Glass Castle, Jeannette Walls pilots a turbulent excursion through the bottleneck of her childhood and dysfunctionality and flawed decision-making is all too common. Throughout this memoir the reader learns of the the appearances and disappearances of stability and functionality, discovers the theme of fantasy vs. reality, and determines how and why the familial dynamics of the Walls alter through the duration of the memoir. The reasons for the instability of the family are evident.
...at more tentatively, with fluoride gels and varnishes or a chlorhexidine varnish. Some dentists may restore root caries with amalgam restorations. Another treatment option used by some dentists to restore root caries is Glass Ionomer Cements. Glass ionomer cements were first introduced in the early 1970s. They have good adherence to mineralized tooth tissue, which keeps the removal of tooth structure to a minimum. Glass ionomer cements also have the ability to leak and absorb fluoride into the tooth, which decreases the rate of secondary caries. These factors have increased the potential for glass ionomer cements to replace amalgam as a restorative material. (Hammel)
Have you ever wondered why the plastic bag that you left on the porch during winter cracks or breaks more easily than when you left it during summer time but a piece of wood which was left just like the plastic bag has no effect whatsoever? This is because of a phenomenon, which only happens to polymers, known as the glass transition. For each polymer, there is a certain temperature at which the amorphous polymers undergo a second order phase transition from a rubbery and viscous amorphous solid to a brittle and glassy amorphous solid called the glass transition temperature, Tg.1 When the polymer, or in this case, the plastic bag, is cooled below their glass transition temperature, it becomes hard and brittle like a glass but when it is used above their glass transition temperatures, it might have a different effect than when used at room temperature or below the glass transition temperature as normally, different types of polymers like clothes, food packaging, insulations for wires, etc. are either used above their glass transition temperatures or
GLASS written by ellen hopkins intermenes the real life struggles that teenagers face everyday, from love to drugs to destructive relationships. Ellen really hits home showing the life of a once 4.0 honors student Kristina; whose life easily got turned upside down from one toxic summer at her fathers that will show the darkest side possible of life. An estimated 12 percent of children in the United States live with a parent who is dependent on or abuses alcohol or other drugs. Based on data from 2002 through 2007, it was to be reported that 8.3 million children under the age of 18 lived with at least one substance-dependent or substance-abusing parent according to Substance Abuse and Mental Health Services Administration (Paragraph 4). The bond between a child and their parents is so pure yet
Ceramics are most commonly used in dental applications as restorative materials for crowns, cements and dentures.
In today’s society not many people realize that they are thankful to wake up and live another day. Just imagine being lost at night in an area you are completely unfamiliar with. Imagine it being cold, and you having no clothing. You don’t have any money and you are starving. Now, all your ears hear are the screams of the one’s around you being killed. To add to the torture, you are unable to control your next move, nor the next. There is constant death, starvation, and suffering happening all around you, but you cannot do anything to help the situation besides fending for yourself to survive. This is the devastating and cruel world that Chanrithy Him’s When Broken Glass Floats introduces to its readers.
One of the most interesting properties of glass is that of it being able to bend and reflect light. Through the bending and reflecting of light rays, an image is created. What happens though when the image formed is not the focal point but rather is the source of the image, the glass itself? In the commencement of Dave Eggers’s novel ‘The Circle,’ there is recurring images of glass. The lustrous, pristine, and progressive visage that glass supplies encapsulated the Company’s essence of high quality and rapid advancement, and as such comprised most of the physical structure of the building. However, the high-end aesthetic that glass provides is not the only idea that Eggers is attempting to promulgate through the glass images. The less obvious
Denture teeth can be made of acrylic poly(methyl methacrylate) (PMMA) or composite resins. PMMA is a polymer - a material made the from joining of methyl methacrylate monomers. Properties of PMMA include resistance to abrasion, chemical stability and a high boiling point. (Jun Shen et al. 2011). However, weak flexure and impact strength of PMMA are of concern as they account for denture failure. (Bolayir G, Boztug A and Soygun K. 2013). Composite denture teeth are made of a three distinct phases - filler, matrix and coupling agents. Out of the types of composite teeth available, nano-filled composite teeth are preferred. Composite teeth have a PMMA coating around the tooth and a high content of filler particles. This gives them strength, higher resistance to forces than acrylic teeth and provides compete polymerization due to the PMMA coating. (Anusavice, K. J., Phillips, R. W., Shen, C., & Rawls, H. R, 2012). If the interface between the PMMA denture base and PMMA or composite teeth was weak, the denture will not be able to sustain occlusal forces, making the base-teeth interface, an entity of significance.
In order to gain strong insight into the surface chemistry of silica we have perform a thorough literature search. Our goal is to identify the pioneer research performed on silica and silica supported catalyst. Particular interest lies in silica-water-cobalt and silica-alcohol-cobalt systems. This study is both on macro and micro level so that a complete theoretical base can be established. From this theoretical knowledge, key areas to look upon will be identified and a design of experiments will be established. The goal is to develop a both efficient and effective product (catalyst) using a novel methodology developed from past research.
The movie Shattered Glass is a 2003 American Drama film written and directed by Billy Ray. The screen play is based on the 1998 Vanity Fair article by H.G Bissinger. It is a true life drama centered on Steven Glass, who was a journalist at The New Republic and his steep fall when his 27 out of 41 of his articles were proven to be false. The movie highlights the political aspects of journalism and encompasses the processes that lead to the publishing of articles in magazines. At the end of the movie I must say I was taken aback on how the events revolved and took a whole different twist; I certainly didn’t see that coming. I had two major opinions when I was through with the movie and they would be discussed in detail below.
BACKGROUND Types of Silica Crystalline silica may be of several distinct types. Quartz, a form of silica and the most common mineral in the earth's crust, is associated with many types of rock. Other types of silica include cristobalite and tridymite. Potential for Exposure During Construction Concrete and masonry products contain silica, sand and rock containing silica. Since these products are primary materials for construction, construction workers may be easily exposed to respirable crystalline silica during activities such as the following: Chipping, hammering, and drilling of rock Crushing, loading, hauling, and dumping of rock   high dust concentrations.
For example, when placing composite materials or sealants an etchant has to be placed before the actual restorative material. An etchant is used to partially demineralize enamel rods. This is critical for micromechanical retention of material to adhere to the tooth surface. If these microscopic cavities were to be filled by saliva and debris from contact with the tongue, the material bonding process would fail. The oral cavity is a very hostile environment. In order to achieve maximum function of dental materials, the environment has to be stabilized. In some cases stabilization of the oral cavity involves temporary elimination of those conditions by tooth
Cosmetic dentistry is a specialized field that deals with improving the aesthetics of teeth and the human face. The teeth are an important part of human beauty. Even minor damage to the teeth, such as breakage or loss can drastically alter the overall appearance of the face. This is where cosmetic dentistry comes in to restore beauty. Cosmetic dentistry has become a highly specialized branch due to various advancements in surgical procedures and diagnostic techniques. Several new materials have also been discovered. These materials are very close to the natural enamel and bone from which teeth are made and are virtually indistinguishable. Cosmetic dentistry is an option in conditions such as teeth loss, gaps between teeth, cracked or chipped teeth, cavities and dental
In conclusion, the process of fabricating a removable partial denture from scratch is a long, complicated and detailed process. There must be complete harmony between the dentist and the technician to produce a perfect partial denture. Talbot (7) stated “The laboratory authorization requires detailed instructions. Framework evaluation and subsequent placement necessities adherence to basic prosthodontic principles”