An overview of orthodontic material degradation in oral cavity

Abstract

Various types of metallic orthodontic appliances are used in the management of malocclusion. These appliances are placed in oral environment under many stresses and variations such as masticatory forces, appliance loading, temperature fluctuations, varieties of ingested food and saliva. These metals undergo electrochemical reactions with the oral environment resulting in dissolution or formation of chemical compounds. Various microorganisms and many aggressive ions containing oral environment can cause material degradation (corrosion) and its associated problems during long time exposure. Orthodontic alloys must have excellent corrosion resistance to the oral environment, which is highly important for biocompatibility as well as for orthodontic appliance durability. This article reviews various aspects of corrosion (surface degradation) of orthodontic alloys. It explores the emerging research strategies for probing the biocompatibility of materials. During orthodontic treatment, use of nickel free, better corrosion resistance alloys and less use of fluoride containing toothpaste or gel is expected.

Assessment of Ions released from Three Types of Orthodontic Brackets immersed in Different Mouthwashes: An in vitro Study

“…The physiochemical corrosion may be divided into seven categories: (i) Galvanic corrosion, (ii) intergranular corrosion, (iii) pitting corrosion, (iv) concentration cell corrosion, (v) stress corrosion, (vi) dezincification, and (vii) erosive-impingement corrosion. 22,23 The factors found to be influencing on corrosion can be divided into 24 internal corrosive factors (determined by metal composition, manufacturing method, and bracket surface characteristics) and external factors (which depend on media composition, pH, temperature, strain, illumination, impurities, dissolved salts, and oxidizing agents). Even when the same alloys were used, different results were obtained; this may be due to variation in analytical techniques, such as different sensitivities, interferences, and detection limits.…”

Stainless Steel: Material Facts for the Orthodontic Practitioner

“…If the continuity of this film is broken by different processes, such as welding or mechanical working, it will reform naturally within a very short period of time [2]. This phenomenon is fundamental because it provides stainless steel with its extraordinary corrosion resistance property [2][3][4][5], which is of paramount importance in orthodontics.…”

“…This property comes from the addition of chromium to the iron-carbon alloy. This base metal is highly reactive and forms a passive film [3]. This film of chromic oxide resists further attacks from the environment, thus preventing corrosion [4].…”

El níquel y su vínculo con el agrandamiento gingival: revisión de la literatura

“…Este último, presenta un aspecto blanco plateado, el cual es duradero, maleable y dúctil, con alta resistencia a la corrosión y oxidación (20). Gracias a la gran facilidad de permitir excelentes aleaciones con otros metales como el cromo y titanio, el níquel es de gran utilidad en la fabricación de la aparatología ortodón-cica, en donde se combina con el acero inoxidable en un 8% (22).…”