Abfraction is a theoretical concept explaining a loss of tooth structure not caused by tooth decay (non-carious cervical lesions). It is suggested that these lesions are caused by forces placed on the teeth during biting, eating, chewing and grinding; the enamel, especially at the cementoenamel junction (CEJ), undergoes large amounts of stress, causing micro fractures and tooth tissue loss. Abfraction appears to be a modern condition, with examples of non-carious cervical lesions in the archaeological record typically caused by other factors. Definition
Abfraction is a form of non-carious tooth tissue loss that occurs along the gingival margin. In other words, abfraction is a mechanical loss of tooth structure that is not caused by tooth decay, located along the gum line. There is theoretical evidence to support the concept of abfraction, but little experimental evidence exists.The term abfraction was first published in 1991 in a journal article dedicated to distinguishing the lesion. The article was titled "Abfractions: A New Classification of Hard Tissue Lesions of Teeth"  by John O. Grippo. This article introduced the definition of abfraction as a "pathologic loss of hard tissue tooth substance caused by bio mechanical loading forces". This article was the first to establish abfraction as a  new form of lesion, differing from abrasion, attrition, and erosion.Tooth tissue is gradually weakened causing tissue loss through fracture and chipping or successively worn away leaving a non-carious lesion on the tooth surface. These lesions occur in both the dentine and enamel of the tooth.
Control and Prevention
Characteristics of Tin for Industrial Uses
Tin oxide metals are used for their variable valence state and positive charge deficit from their oxygen vacancy. When heated to temperatures above 2602 °C or 2875 K, tin oxides start to boil and produce fumes. For example, tin forms Sn2when heated in oxygenated environments; also called feebly acid. Tin oxide is known for being a good catalyst in solid photochemical reactions (photocatalysis) and electric production from light (photoelectrocatalysis). The energy produced form splitting water in photoelectrocatalysis is used for the creation of dehydrated dyes.Tin is found in nature as an off-white or gray crystal mineral called cassiterite. The corrosion resistant metal is harvested primarily in Malaya, Bolivia, Indonesia, Zaire, thailand, and Nigeria. Traditionally, tin was used to create containers; however, since the increase use of plastics and aluminum its no longer common. There are two allotropic forms of tin, depending on the temperature. A variety of tin alloys morphologies exist including the following metals: soft solder, fusible, pewter, bronze, Babbit, White, and phosphor bronze metal. Tin oxide metals are corrosive resistant which is important in industrial uses. Industrial Applications of Tin oxides
Stannous oxide (SnO)
Stannous oxide (SnO) is used for manufacturing glass materials, like ceramics. The compound is insoluble in water and takes the form of a brow-black powder or blue-black crystalline solid. It is labeled as both an irritant and health hazard in the chemical safety sections of safety data sheets.