Drug Induced Tooth Discolouration

摘要

It is essential that every health care professional who is Involved with the prescription or recommendation of drugs be fully aware of any resultant disorders that may arise as a side-effect. A range of drugs can affect the teeth. In this Review article, drugs that have the potential to induce tooth discoloration (intrinsic and extrinsic), Pathophysiology Mechanism and Treatment. Introduction Bright white teeth are highly regarded and sought after in today’s society. Consumers invest a lot of money on cosmetic dentistry and in commercial products that promise an aesthetically pleasing smile. It follows that consumers should want to avoid or limit exposure to materials that contribute to the discolouration of teeth. There has been a recent increase in interest in the treatment of tooth staining and discolouration as shown by the large number of tooth whitening agents appearing on the market. Some of these agents are sold as 'over-the-counter' products and have no professional involvement in their application [1] .Colour and colour perceptionA basic understanding of the elements of tooth colour is important for many aspects of restorative dentistry. Teeth are typically composed of a number of colours and a gradation of colour occurs in an individual tooth from the gingival margin to the incisal edge of the tooth. The gingival margin often has a darker appearance because of the close approximation of the dentine below the enamel. In most people canine teeth are darker than central and lateral incisors and younger people characteristically have lighter teeth, particularly in the primary dentition. Teeth become darker as a physiological age change; this may be partly caused by the laying down of secondary dentine, incorporation of extrinsic stains and gradual wear of enamel allowing a greater influence on colour of the underlying dentine. Also, and to be discussed further, tooth wear and gingival recession can directly or indirectly affect tooth colour [1] . The viewing conditions are extremely important and variables such as the light source, time of day, surrounding conditions and the angle the tooth is viewed from affect the apparent tooth colour. Light is composed of different wavelengths and the same tooth viewed under different conditions will exhibit a different colour, a phenomenon known as metamerism [1] .Tooth discolouration is usually described as extrinsic or intrinsic, based on the location of the stain [123] .Intrinsic discolourationGeneralized intrinsic or permanent discolouration is indicative of a disruption of normal tooth development, whereas localized intrinsic staining of 1 or 2 teeth can occur before or after teeth have erupted [23] .Intrinsic discolourations occurs following a change to the structural composition or thickness of the dental hard tissues. The normal colour of teeth is determined by the blue, green and pink tints of the enamel and is reinforced by the yellow through to brown shades of dentine beneath. A number of metabolic diseases and systemic factors are known to affect the developing dentition and cause discolouration as a consequence. Local factors such as injury are also recognized. Alkaptonuria Congenital erythropoietic porphyria Congenital hyperbilirubinaemia Amelogenesis imperfecta Dentinogenesis imperfecta Tetracycline staining Fluorosis Enamel hypoplasia Pulpal haemorrhagic products Root resorption Ageing