There are basically two types of Stains:
- Extrinsic stains
- Intrinsic stains
Extrinsic stains are largely due to environmental factors including smoking, pigments in beverages and foods, antibiotics, and metals such as iron or copper. Colored compounds from these sources are absorbed into acquired dental pellicle or directly onto the surface of the tooth causing a stain to appear.
Extrinsic stains are largely due to environmental factors including smoking, pigments in beverages and foods, antibiotics, and metals such as iron or copper. Colored compounds from these sources are absorbed into acquired dental pellicle or directly onto the surface of the tooth causing a stain to appear.
- Dental plaque
Dental plaque is a clear biofilm of bacteria that naturally forms in the mouth, particularly along the gumline, and it occurs due to the normal development and defenses of the immune system. Although usually virtually invisible on the tooth surface, plaque may become stained by chromogenic bacteria such as Actinomyces species. Prolonged dental plaque accumulation on the tooth surface can lead to enamel demineralization and formation of white spot lesions which appear as an opaque milk-colored lesion.
- Calculus
Neglected plaque will eventually calcify, and lead to the formation of a hard deposit on the teeth, especially around the gum line. The organic matrix of dental plaque and calcified tissues undergo a series of chemical and morphological changes that lead to calcification of the dental plaque and therefore leading to the formation of calculus. The color of calculus varies, and may be grey, yellow, black, or brown.
- Tobacco
Tar in the smoke from tobacco products (and also smokeless tobacco products) tends to form a yellow-brown-black stain around the necks of the teeth above the gum line. The nicotine and tar in tobacco, combined with oxygen, turns yellow and over time will absorb into the pores of enamel and stain the teeth yellow.
- Tooth wear and aging
Tooth wear is a progressive loss of enamel and dentine due to tooth erosion, abrasion and attrition. As enamel wears down, dentine becomes more apparent and chromogenic agents are penetrated in the tooth more easily.
Dental caries (tooth decay)
The evidence regarding carious tooth discoloration is inconclusive; however the most reliable evidence suggests that carious lesion allows for exogenous agents to enter dentine and hence increased absorption of chromogenic agents causing discoloration to the tooth.
Restorative Materials
The materials used during root canal treatments, such as eugenol and phenolic compounds, contain pigment that stain dentine. Restorations using amalgam also penetrate dentine tubules with tin over time therefore causing dark stains to the tooth.
Enamel hypoplasia
Enamel hypoplasia causes enamel to be thin and weak. It produces a yellow-brown discoloration and can also cause the enamel’s smooth surface to be rough and pitted which causes the tooth to be susceptible to extrinsic staining, tooth sensitivity, malocclusion, and dental caries. The evidence regarding enamel hypoplasia is inconclusive; however the most likely cause is infection or trauma caused to the primary dentition. Disturbances to the developing tooth germ during neonatal and early childhood stages such as maternal vitamin D deficiency, infection, and medication intake can cause enamel hypoplasia.
Fluorosis
Dental fluorosis causes enamel to become opaque, chalky white, and porous. The enamel can break down and cause the exposed subsurface enamel to become mottled and produce extrinsic dark brown-black stains. Dental fluorosis occurs due to excessive ingestion of fluoride or overexposure to fluoride during the development of enamel which usually occurs between the ages of one to four. Fluoridated drinking water, fluoride supplements, topical fluoride (fluoride toothpastes), and formula prescribed for children can increase the risk of dental fluorosis. Fluoride is considered an important factor in the management and prevention of dental caries, the safe level for daily fluoride intake is 0.05 to 0.07 mg/kg/day.
Removal of extrinsic staining
Extrinsic staining may be removed through various treatment methods:
Prophylaxis
Dental prophylaxis includes the removal of extrinsic staining using a slow-speed rotary handpiece and a rubber cup with abrasive paste, mostly containing fluoride. The abrasive nature of the prophy paste, as it is known, acts to remove extrinsic staining using the action of the slow-speed handpiece and the paste against the tooth.
Micro-Abrasion
Allows a dental professional to make use of an instrument which emits a powder, water and compressed air to remove biofilm, and extrinsic staining.
These methods are sufficient to clear out and clean the extrinsic stains but are not sufficient to treat or clean the intrinsic stains for that another procedure is done which is commonly known as tooth bleaching or teeth whitening.
A 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 treatment done to restore the original shade of teeth within or on the tooth is termed as bleaching. Hydrogen peroxide is the active ingredient most commonly used in whitening products and is delivered as 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 oxidizing 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”. Dental professionals should correctly diagnose the type, intensity and location of the tooth discoloration. Time exposure and the concentration of the bleaching compound, determines the tooth whitening endpoint.
