1. Introduction:
Titanium alloys are very reactive materials and reacts instaneusely with oxygen, forming an oxide film, which give them excellent anti corrosive properties [??]. Thus, titanium alloys have proven to be the most tissue compatible inorganic materials, especially for dentistry [???].
Nickel-titanium wires, which have a near equiatomic composition, were introduced to orthodontic clinical use by Andersen and colleagues in the early 1970’s [???]. They have been highly popular in dentistry because have a much lower elastic modulus and wider elastic range than other orthodontic wires such as those composed of beta-titanium, stainless steel, and cobalt-chromium-nickel [???]. NiTi alloys have excellent biocompatibility with living tissue and corrosion resistance in various simulated body fluids [???]. These properties originating from the spontaneously formed thin oxide passivation layer mainly consist of TiO2 [???].
For patients with orthodontic fixed appliance, mouth rinsing with fluoride-containing products is an effective method for the prevention of caries because such appliances have complicated morphologies [???]. However, reduced corrosion resistance of pure titanium and titanium alloys in fluoride containing environments that attack the protective surface oxide layer and cause allergic reactions to NiTi wires after insertion had been reported [????]. The corrosion resistance of pure titanium and titanium alloys largely depends on the fluoride concentrations [???]. Some studies concerning the corrosion behavior of titanium alloys in fluoride containing environments have been reported [????]. It is claimed that the fluoride containing solution with fluoride ions more than 20 ppm may destroy the protective oxide la...
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...tive layer increases.
5. Conclusions
The corrosion resistance of NiTi was studied in ringer’s solution for different chloride ion concentrations. Our results show that the increasing of the chloride ion concentration can accelerate the corrosion of NiTi alloy. The OCP values in KCl and NaCl contained solutions are less negative at lower concentrations than in higher ones and the resistance to corrosion decreases as the chloride concentration increases. According to the EIS analysis, NiTi presents a good corrosion resistance even at higher concentration of chloride ions but the polarization resistance and capacitance value of protective oxide layer decreases as the concentration of ions increases.
Acknowledgements
The author acknowledges the Shiraz University, school of materials science and engineering for the financial supports. (Grant No. 89-GR-Eng-58)
Afshar H, Jafari A, Khami M, et al. Evaluation of Microleakage in Composite-Composite and Amalgam-Composite Interfaces in Tooth with Preventive Resin Restoration. Journal of Dentistry 2012; 9(2):128-34.
Metal alloys and precious metals are also used to make certain aspects of a cochlear implant. The electrode arrays that provide electrical stimulation in order to excite neurons are made out of platinum because they have very high corrosion resistance, good biocompatibility, easier to work with than iridium and have low chemical reactivity. On the other hand, metallic alloys like titanium are used to make the casing for the receiver/stimulator. Titanium is suitable for such an application because it is a light material with high corrosion resistance and rigidity and these properties are essential for the material that is going to be used to make the casing (Stöverl and Lenarz, 2009).
Normally, teeth stimulate the surrounding bone by compressive and tensile forces, these forces have a piezoelectric effect (which is the ability of a material to give an electric charge in response to mechanical stress) on the crystals and durapatite that synthesize the inorganic
Iqbal, M. K. (2013, March 27). NED University of Engineering and Technology. Retrieved from Department of Metallurgy Engineering: http://www.neduet.edu.pk/myd/TE/MY%20302.pdf
These kinds of polymers have both some advantages and disadvantages. Although they are bioactive and biodegradable and provide high comppressive strength, Degradation of such polymers leads to undesired tissue response due to producing acid formation in degradation process. Metallic scaffolds are another method for bone repair and regenaration. They provide high compressive strength and enormous permanent strength. Metallic scaffolds are mainly made of titanium and talium metals. The main disadvantages of metallic scaffolds are not biodegradable and also discharge metal ions. Recent studies in metallic scaffolds mainly focus on biodegradable materials which can be used improve bioactivity of metals such as titanium.
All-porcelain - Zirconia or aluminous materials are the most popular material choices for all-ceramic dental crowns. These materials provide a metal-free dental crown with a number of benefits. An aesthetic all-ceramic dental crown can be created with a thinner material because the accommodating metal core has been reduced or eliminated. The thinner option makes all-ceramic, or porcelain, dental crowns a treatment choice that is favored for areas with a limited amount of space. These crowns are more beautiful, but they do require care. These crowns are getting stronger all the time, and researchers are discovering new ways to use these crowns in high-impact areas of your
Throughout the history of dental medicine dentist have searched for the perfect material to aid in the treatment of the most common problem in people’s mouths, cavities. The material would also be useful in fixing chipped and broken teeth. Dentist needed a material that was strong, relatively low costing, easy to apply, durable, and able to limit the growth of bacteria. In the early 19th century in France dentist found their wonder material and that material was amalgam. The dental amalgam is constructed of a mixture of mercury and at least one other metal such as zinc, copper, tin, or silver. The combinations of these metals are the foundation of what gives silver amalgams their strong make up and shiny metallic appearance.
With the development of modern technologies, people enjoy their lives with higher level of quality. This results in the extension of average humane life time and the rapid changes of age structure of the population in the world. There are increasing demands for replacing the failed tissues on aged people. For example, if injury occurs on knees, the ability to flex the knee will be restricted due to pain. Deterioration of the knee joint would make it difficult to perform everyday activities. Even when you lie and sit, it still feels painful. Knee replacement surgery is a common solution to relief for the pains. These rapid increasing demands of implant demonstrate the new generation of implant materials with better mechanical properties and higher biological performance for the expectation of longer life.
Titanium metal (Ti) is the ninth most abundant element found in the Earth’s crust, being strong as steel but much less dense. Because of this, it is a very important alloying agent with many other metals including aluminium, iron and molybdenum. These alloys are used in aircraft as they are materials with low density that can resist to high temperatures. Titanium is also used to cover the hulls of ships and other structures exposed to water, as well as in desalinisation plants which convert sea water into fresh water [1].
Positive results have been seen on periodic checkups and most of the patients didn’t complain. One patient suffered from plaque deposition on abutment teeth due to insufficient oral hygiene. Gold copings protect root surface but are expensive which makes the treatment overall expensive. Most of the time canines are used as abutments because they are frequently the last teeth to be lost in the jaw because of their large root surface
...mpositional control needed and also the reactivity of the titanium. Fatigue failure has been known to occur with nitinol because of the extreme amounts of fatigue strain that it is necessarily exposed to. This is because it is still not completely defined how durable nitinol is, so it cannot be known what to use it for as it is the best of all metals known in this case. So it is used for the highest demanding applications but in some cases it can’t handle the pressure sustained. Another use for nitinol is a temperature control system, which would work by changing shape can activate a variable resistor or switch which would control the temperature, this is a situation where it is very significant for nitinol to be a smart material otherwise this system would simply just not work. There are many others but they are not really relevant to the engineering industry.
Fluoride is the 13th most abundant element in the earth’s crust and is naturally found in soil, water, foods, and several minerals, such as fluorapatite and fluorite (Nordqvist 1). Dentists use higher levels of fluoride in the forms of gel, foam, or varnish that can be applied to the teeth for cleaning (Dental 1). Then the fluoride is directly apply to teeth through fluoridated toothpaste and mouth rinses is at a lower level for those who use it for personal use (Dental 1).
Our analysis revealed that Affinis® had more dimensional stability in comparison to Panasil® and in the Panasil® impression material, the percentage of dimensional change was significant after 168 h. However, dimensional changes in all of the evaluation times were in the American Dental Association (ADA) standard range. Therefore, these materials had acceptable clinical dimensional stability for approximately 168 h. In the current study, impressions were made from stainless steel dies following the ADA specification for impression materials. This provides a protocol that can be easily replicated by others and it is the same as making a clinical
Gold is also precious for dentistry. Many dental product are made out of this unique metal. Gold has an ...
S. Thamizhmnaii , B. Bin Omar, S. Saparudin, S. Hasan, ‘Surface roughness investigation and hardness by burnishing on titanium alloy’,AMME journal, Volume 28 Issue 2 June 2008