Factors Affecting Tooth Color
– Tooth color influenced by factors such as light reflection, absorption, and transmission
– Brightness of a tooth can change based on background color and brightness
– Intrinsic color and extrinsic stains affect overall appearance of teeth
– Scattering and absorption of light within enamel and dentine determine intrinsic color
Types and Causes of Tooth Discoloration
– Tooth discoloration categorized as intrinsic or extrinsic stains
– Intrinsic stains cannot be removed through regular dental cleaning
– Extrinsic staining caused by factors like smoking, pigments in food and beverages, antibiotics, and metals
– Dental plaque can become stained by chromogenic bacteria
– Prolonged plaque accumulation can lead to enamel demineralization and formation of white spot lesions
Extrinsic Staining
– Extrinsic staining mainly caused by environmental factors
– Pigments from smoking, beverages, and foods can be adsorbed into dental pellicle or directly onto tooth surface
– Dental plaque, a biofilm of bacteria, can become stained by chromogenic bacteria
– Neglected plaque can calcify and form calculus, a hard deposit on teeth
– Tar from tobacco products can form a yellow-brown-black stain on teeth
Intrinsic Staining
– Intrinsic staining caused by factors within tooth structure
– Age, decay, orthodontic white spot lesions, fluorosis, amalgam restorations, tetracycline stain, genetic conditions, and non-vital coloring can cause intrinsic staining
– Secondary dentin formation and enamel thinning contribute to tooth darkening with age
– Tooth shade not influenced by gender or race
– Intrinsic staining cannot be removed through regular dental cleaning
Whitening Treatments
– Hydrogen peroxide most commonly used active ingredient in whitening products
– Hydrogen peroxide acts as oxidizing agent, breaking down to produce unstable free radicals
– Free radicals attach to organic pigment molecules in tooth enamel, resulting in whitening effect
– Dental professionals should correctly diagnose type, intensity, and location of tooth discoloration for successful whitening treatment
– Time exposure and concentration of bleaching compound determine tooth whitening endpoint
Tooth whitening or tooth bleaching is the process of lightening the color of human teeth. Whitening is often desirable when teeth become yellowed over time for a number of reasons, and can be achieved by changing the intrinsic or extrinsic color of the tooth enamel. The chemical degradation of the chromogens within or on the tooth is termed as bleaching.
Hydrogen peroxide (H
2O
2) is the active ingredient most commonly used in whitening products and is delivered as either hydrogen peroxide or carbamide peroxide. Hydrogen peroxide is analogous to carbamide peroxide as it is released when the stable complex is in contact with water. When it diffuses into the tooth, hydrogen peroxide acts as an oxidising agent that breaks down to produce unstable free radicals. In the spaces between the inorganic salts in tooth enamel, these unstable free radicals attach to organic pigment molecules resulting in small, less heavily pigmented components. Reflecting less light, these smaller molecules create a "whitening effect". There are different products available on the market to remove stains. For whitening treatment to be successful, dental professionals (dental hygienist or dentist) should correctly diagnose the type, intensity and location of the tooth discolouration. Time exposure and the concentration of the bleaching compound, determines the tooth whitening endpoint.
