Staining Types and Causes

A thorough understanding of the etiology of different tooth stains will enable dental professionals to guide patients to the proper whitening techniques for their needs. Obtaining information on diet, lifestyle, behaviors, oral health habits, and occupation will help practitioners identify the cause of the stain, which is critical to the discussion of the best options for that specific individual.6

Stains can be classified based on their etiology as either intrinsic or extrinsic. Intrinsic stains are located within the tooth structure, while extrinsic stains usually result from accumulation of chromatogenic substances which build up on the external tooth surfaces, mainly in the pellicle.1,7 While intrinsic stains can only be lightened by chemical means in a bleaching agent, the appearance of extrinsic stains can be lightened by mechanical removal (from abrasive agents or scaling procedures) and/or chemical bleaching.

Extrinsic Stain

Extrinsic staining is less likely to occur with effective oral hygiene habits. The staining agents (i.e., chromogenic bacteria, food/drink such as coffee, tea, red wine, blueberries, some drug and tobacco use, metallic compound exposure) will not adhere to a smooth enamel surface. Rather, the acquired pellicle and plaque/calculus accumulation incorporates the stain.6

Extrinsic stains can present as green, orange, brown, yellow, or black. Green and orange stains are typically found in patients with poor hygiene when certain chromogenic bacteria are present.6 Brown stains are common and could be due to a number of causes, such as tobacco and foods/beverages. Yellow extrinsic stain is often the result of poor hygiene and heavy plaque buildup, whereas black stain is less common and associated with iron in the saliva. This type of stain does not correlate with poor hygiene yet is commonly found as a line around the gingival margins.6

Intrinsic Stain

Intrinsic staining typically presents as yellow, brown, gray or orange. It also includes white or brown spots on teeth that can be caused by dental fluorosis, demineralisation, and hypocalcification. Tetracycline staining that is incorporated in tooth structure has a grayish brown hue.6 For a complete list of types of stain and how to approach removal (Table 1).

Table 1. Types of Tooth Stains.6
Type Source Clinical Approach
Extrinsic Stains
Green Chromogenic bacteria and fungi (Penicillum and Aspergillus species) from poor oral hygiene most often seen in children with enamel irregularities Should not be scaled because of underlying demineralised enamel. Have client remove during toothbrush instruction or lightly polish; may use HP to help with bleaching and removal.
Black stain Iron in saliva; iron-containing oral solutions; Actinomyces species; industrial exposure to iron; manganese, and silver Firmly scale because of calculus-like nature and selectively polish for complete removal.
Orange Chromogenic bacteria (Serratia marcescens and Flavobacterium lutescens) from poor oral hygiene Lightly scale and then polish selectively.
Brown stains
Tars from smoking, chewing, and dipping spit tobacco
Food and beverage pigment and tannins
Lightly scale and then polish selectively.
Lightly scale and then polish selectively.
Topical medications Stannous fluoride, chlorhexidine, or cetylpyridinium chloride mouth rinses Lightly scale and then polish selectively.
Yellow Oral biofilm Have client remove during toothbrush instruction.
Blue-green stain Mercury and lead dust Lightly scale and then polish selectively.
Red-black stain Chewing betel nut, betel leaf, and lime (pan); found in Western pacific and South Asian cultures Firmly scale and then polish selectively.
Intrinsic Stains
Dental fluorosis (white-spotted to brown-pitted enamel) Excessive fluoride ingestion during enamel development Cannot be removed by scaling or selective polishing.
Hypocalcification High fever during enamel formation Cannot be removed by scaling or selective polishing.
Demineralization (white or brown spots on enamel, may be smooth or rough) Acid erosion of enamel caused by oral biofilm Cannot be removed by scaling or polishing. Recommend daily 0.5% sodium fluoride rinses for remineralisation.
Tetracycline (grayish brown discolouration) Ingestion of tetracycline during tooth development Cannot be removed by scaling or selective polishing.

Genetics also can play a role in intrinsic staining and the natural colour of one’s teeth. Intrinsic staining can start during the stages of tooth developmental or can be associated with aging. In addition to the causes previously mentioned, extrinsic stains over time can contribute to intrinsic staining.8

Depending on the individual makeup of the patient and the type of stain, varied results from bleaching agents may be seen. For example, brown and yellow stains typically respond better to bleaching than blue/gray stains.7,8 Some stains, i.e., those caused by metallic compounds, are more difficult to bleach, therefore, discussing other treatment options with patients may be necessary. If the more conservative route of bleaching does not produce the desired degree of whitening, placing crowns, veneers or bonding, may be necessary to achieve the desired result.8