No abstract

Dental erosion is the chemical dissolution of the tooth structure. Factors like eating disorders and gastrointestinal diseases are recognized as intrinsic factors for dental erosion. To regulate the growth of teeth, people are implanted with orthodontic wires made of different materials. These are exposed to the influence of oral environment, food intake, toothpastes, and mouthwashes. During this process, the materials may undergo corrosion. Hence, various researchers have made a study on the influence of artificial saliva (AS) on the corrosion behavior of these alloys. The excellent corrosion resistance to the oral environment of dental alloys is important for biocompatibility as well as for orthodontic employment permanence. Various types of metal alloys are being used for the orthodontic treatment, which undergo chemical or electrochemical reaction with the oral environment. The oral environment is highly belligerent under several situations and leads to corrosion. This article reviews the effects of fluoride concentration, the pH value and protein content in AS and the composition of the metal alloys on the corrosion resistance of orthodontic appliances using electrochemical methods and surface characterization techniques such as scanning electron microscopy inductively coupled plasma-optical emission spectroscopy (ICP-OES) and X-ray photoelectron microscopy.

Most organic compounds contain heterocyclic atoms such as nitrogen, sulfur, oxygen and multiple bonds in the molecules. Heterocyclic compoundshave paying attention a significant curiosity for their highlyelectron-donating and strong coordination abilities, andstill receive much consideration because of their applications. One of the vital applications of heterocyclic compounds is corrosion inhibition against metals. The inhibitor forms a film onto the metal surface by either physisorption or chemisorption. The adsorption process, inhibition mechanism, and inhibition efficiency depend on the electronic and structural properties of the inhibitor, the temperature and pressure of the reaction, the nature of the metallic surface, and the flow velocity of corrosive medium. In this review the corrosion inhibition properties of heterocyclic compounds towards the metal surface in different media are focused.