International Journal of Clinical Dentistry ISSN: 1939-5833
Volume 7, Number 1 © Nova Science Publishers, Inc.
COLORS IN TOOTH DISCOLORATION:
A NEW CLASSIFICATION AND LITERATURE REVIEW
Hamed Mortazavi1, Maryam Baharvand1
and Amin Khodadoustan2
1Associate Professor, Department of Oral Medicine,
Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2Periodontologist, DDS, MS, private practice, Tehran, Iran
Purpose: There has been a recent increasing interest in the management of dental
staining as shown by the large number of tooth whitening materials appearing in the
market. The aim of this review is to search the literature regarding tooth discoloration in
order to introduce a new classification in terms of different clinical colors.
Methods: The PubMed database was searched for articles pertaining to the topic
between the year 1932 and 2012. The search strategy for PubMed based on MeSH terms
was: “tooth discoloration”, OR “tooth discolorations”, OR “tooth diseases”, OR “tooth
Results: Based on the relevant evidence, it was shown that tooth discoloration can be
found in nine different color spectrums: black, brown, blue, green, grey, orange, pink,
red, and yellow. Each color may represent various origins, which needs further
investigations to be revealed.
Clinical significance: Our new classification based on clinical features of discolored
teeth helps clinicians achieve timely diagnosis and avoid inappropriate therapeutic
The aesthetic appearance of teeth has an important role in physical attractiveness of each
person. Discoloration of teeth is a more critical factor for many individuals to achieve an
aesthetic smile than restoring normal alignment of teeth within their arch [1-3]. According to
a recent study by Samorodnizky-Naveh, 37.3% of subjects were dissatisfied with their dental
appearance, and tooth color was the main reason for about 90% of them . Therefore, it is
crucial for dental practitioners to have an understanding of the etiology and clinical
Tel: +98-21-29902311, Fax: +98-21-22403194, Email: email@example.com
Hamed Mortazavi, Maryam Baharvand, and Amin Khodadoustan 18
presentation of tooth discoloration in order to make a diagnosis and select the most
appropriate treatment for each case .
Normally, teeth composed of many colors and a gradation of colors occurs in a single
tooth from gingival to the incisal edge. Because of the close contact of the dentin below the
enamel and thinning of the enamel the gingival third of teeth is darker than incisal third.
These differences in color may also be related to the thickness and translucency of enamel
and dentine. In most cases canine teeth are usually darker than central and lateral incisors.
Meanwhile, teeth become darker with age, so younger people have lighter teeth especially in
the primary dentition. This discoloration may be caused by the deposition of secondary and
tertiary dentine and pulp stones as a physiological senile change. Historically, tooth
discoloration has been classified as intrinsic or extrinsic in nature. Furthermore, a third
category of "Internalized discoloration" has recently been described (Box 1).
Intrinsic discoloration (ID) occurs following a change to the structural composition or
thickness of the dental hard tissues during tooth development (Box2). On the other hand, ID
occurs when the chromogen agents are deposited within the bulk of the tooth, especially in
the dentine, and are often of systemic or pulpal origin. This classification is divided into six
subgroups: 1) metabolic, 2) hereditary 3) iatrogenic 4) traumatic 5) idiopathic and 6) ageing
Extrinsic discoloration (ED) occurs when chromogen agents are deposited on tooth
surface or in the acquired pellicle. This classification can be divided into two subtypes: 1) non
metallic (direct staining), and 2) metallic (indirect staining).
Internalized discoloration describes the changes in normal tooth color because of dental
caries, tooth wearing and gingival recession, cracks and restorative materials. [2,5,6].
In contrast to all previous papers, in this review article we listed tooth discoloration based
on their color, which may help understand tooth discoloration and their causes more
The aim of this review was to search the literature regarding tooth discoloration in order
to introduce a new classification in terms of different clinical colors. The PubMed data base
was searched for relevant articles between the year 1932 and 2012.The following inclusion
criteria were used: extrinsic and intrinsic factors in tooth discoloration, chromogenic bacteria
and tooth staining, foods and tooth staining, medications and tooth discoloration, salivary
parameters and tooth staining, various dental materials and tooth discoloration, systemic
disease and tooth discoloration, habits and tooth staining. Exclusion criteria were articles
published in languages other than English and those without full texts.
The search concept based on MeSH terms was: “tooth discoloration, OR “tooth
discolorations”, OR “tooth diseases”, OR “tooth bleaching”. Totally 4371 articles were
initially found in PubMed, which their title and abstract were read to find the evidence met
our inclusion criteria mostly. Out of the relevant papers, 253 were review articles, 528 were
case reports, and the remainders 784 were clinical studies. Different color changes may be
found in discolored teeth as follows:
Colors in Tooth Discoloration 19
Box 1. Different types of tooth discoloration [5-9]
Type of discoloration Color produced
Intrinsic Metabolic causes
Congenital erythropoietic porphyria Red/brown or purple/brown
Amelogenesis imperfecta Yellow-brown or dark yellow
Dentinogenesis imperfect Blue-brown [opalescent]
Dentin dysplasia Brown
Tetracycline staining Yellow, brown, blue, black or grey
Minocycline staining Brown
Ciprofloxacin staining Green
Fluorosis White, yellow, grey, or black
Enamel hypoplasia Yellow-brown or white subsurface
Dentin hypercalcification Yellow, yellow-brown
Pulpal hemorrhage products Grey-brown, black-pink
Internal resorption Pink
Molar incisor hypomineralization White- yellow, brown
Non metallic [direct staining]
Tea, coffee, and other foods Brown to black
Cigars Brown to black
Plaques/ poor oral hygiene/ chromogenic bacteria Yellow, brown, green
Metallic [indirect staining]
Iron salts[polyvalent metal salts] Black
Copper salts Green
Silver nitrate Grey
Potassium permanganate Violet to black
Cadmium Yellow to brown
Tooth wear and gingival recession Yellow
Dental caries White spots, orange, brown to black
Restorations Brown, grey, black
Hamed Mortazavi, Maryam Baharvand, and Amin Khodadoustan 20
Box 2. Environmental and hereditary causes of generalized intrinsic discoloration
of teeth [5,6,8,9,16,21,26,27,37,39]
Prenatal Post natal Only teeth involved Accompanied by
Sickle cell anemia,
Measles, Chicken pox,
Box 3. Drugs related to tooth discoloration [5-9, 11, 13, 16, 21, 23, 26]
Essential oil Ramipril
Colors in Tooth Discoloration
Primary and permanent teeth with black-stains are frequently encountered in
schoolchildren with good oral hygiene and low caries rate. As this type of staining
contains an insoluble iron salt, ferric sulphide, and high levels of calcium and
inorganic phosphor, it has been considered to be a special form of dental plaque.
Actinomyces, porphyromonas gingivalis, and prevotella melaninogenicus have been
found as the predominant microorganisms involved in black staining [10,11].
However, Saba according to a PCR microbiological study, established the leading
role of actinomyces in formation of black staining compared to other microorganisms
. The underlying mechanism of bacterial chromogenicity has to be elucidated.
Colors in Tooth Discoloration 21
Black discoloration has also been found in people using iron supplements, containing
high amounts of iodine, and in iron foundry workers as well. Furthermore, the same
clinical manifestations were reported after use of 8% stannous fluoride that was
secondary to the combination of stannous (tin) ion with bacterial sulfides. This
pigmentation usually occurs in people with poor oral hygiene. The labial surface of
anterior teeth and the occlusal surface of the posterior teeth are the most common
affected sites [6,9].
A large number of medications may result in dental surface staining (Box 3). Like
other tetracycline derivatives, minocycline hydrochloride causes discoloration of
dental crowns and roots. Although the real mechanism is unknown, minocycline has
been shown to be incorporated into mineralizing dental tissues during tooth
formation . In addition to teeth, it induces pigmentation in other tissues such as
oral mucosa, nails, skin, and bone. However, only 3% to 8% of long-term users
become affected. Several patterns of staining have been noted in the dentition. For
example, the root of developing teeth is stained dark black . Other patterns will be
described in next parts of this paper .
Various materials used for root canal therapy may induce tooth discoloration,
because of un-reacted agents, or corrosion of some components owing to moisture
and/or chemical interaction with dentine. As an example, AH26, epoxy resin cement
containing bismuth trioxide as a filler and radiopaque material, can lead to black
discoloration in teeth after years .The same results were also reported by Davis
Blue, Blue- Brown, Blue-Grey, Dark Blue
This rare type of pigmentation is usually caused by chromogenic bacteria. Bussell
reported blue teeth discoloration in a 4- year -old boy with Wast syndrome. Further
investigations, revealed a moderate growth of pseudomonas aeruginousa, known as a
blue stain-producing bacterium usually implicated in chronic respiratory diseases, in
swab samples .
A blue-brown (opalescent) discoloration of teeth was also seen in patients with
dentinogenesis imperfecta (DI). It is a hereditary disorder of dentine in the absence of
any systemic problems characterized by abnormal dentinogenesis in primary and
permanent dentition. Severity of dental involvement depends on the stage of tooth
development, so that Primary teeth are affected more severely, followed by
permanent incisors and first molars. The second and third molars are less affected.
Three types of DI have been described: type I, is associated with osteogenesis
imperfecta (mixed connective tissue disorder of type I collagen), which may cause
opalescent primary teeth. Type II or hereditary opalescent dentine affects primary
dentition more severely than permanent teeth. A third type of disease is associated
with the radiographic feature of shell teeth having enamel of normal thickness,
extremely thin dentine, and an enlarged pulp. This type of disease is more common
in deciduous teeth [5, 9, 16].
A blue discoloration of dentition, on rare occasions, may be seen in patients with
Parkinson's disease .
Hamed Mortazavi, Maryam Baharvand, and Amin Khodadoustan 22
Another pattern of mynocycline staining is presented as a blue-grey discoloration of
the incisal three-fourths of crowns in fully erupted teeth. Dark blue dental
pigmentation has been reported in tetracycline users as well.
Intra-canal medicaments are used in management of traumatized teeth, inflammatory
root resorption, large periapical radiolucencies, and apexification . Despite their
therapeutic advantages, some of these agents can discolor teeth if not completely
removed from the access cavity. In agreement with this point, Kim reported a blue
greyish tooth discoloration associated with triple antibiotic paste containing
ciprofloxacine, metronidazole and minocycline 
Brown, Dark Brown, Brown to Black, Brown-Grey, Golden Brown
Brown stain as a thin, bacteria-free pigmented pellicle usually is observed on the
buccal surface of maxillary molars and lingual surface of mandibular incisors in
people who use a dentifrice with inadequate clinging and polishing action .
Extensive use of tea, coffee and tobacco products often results in significant brown
pigmentation of the enamel. The main mechanism of extrinsic staining of teeth from
foods is not fully understood. Some researchers have demonstrated that anionic
polyphenols, found in pigmented foods and beverages (e.g. red wine and black tea),
interact with cationic salivary pellicles to form thick layers of stained materials on
tooth surface [19,20]. On the other hand, it was noted that physical and chemical
forces allow pigments to come in contact with and adhere to the tooth surface .
The tobacco staining results from penetration of coal tar products on the tooth
surface. Smokers usually exhibit involvement of the lingual surface of the
mandibular incisors. The degree of staining is not necessarily related to the amount
of tobacco consumed, but rather depends on enamel defects the tobacco products
adhere to . Staining is also common in smokeless tobacco users.
Brown, brown –black and golden brown pigmentation has been reported, as an
extrinsic metallic stain, in individuals who use products containing iron, iodine and
stannous fluoride, respectively [6,16,23].
Chromogenic bacteria have also been reported in brown and black tooth
discoloration, especially in pediatric patients with good oral hygiene [5,6,24].
Chlorhexidine, one of the most current antiseptic mouthwashes, is associated with
brown or brown to black staining of teeth. The side effects of chlorhexidine were
first described by Flora in 1971 . The pigmentation may be seen only one week
to ten days after using and most frequently involves the interproximal surfaces near
the gingival margin. An intensive discoloration has been associated with the use of
tea and wine simultaneously . Chlorhexidine is adsorbed on the tooth via binding
of its positively charged molecules to negatively charged dental surface. Then some
cations such as calcium in plaque and saliva promote its slowly release in an active
Tetracycline can cause brown or brown –grey tooth pigmentation. Tetracycline
staining was first described in the mid-1950s. After a decade in 1963, United States
Food and Drug Administration issued a warning about the use of this antibiotic for
pregnant women and young children [16,26]. Urist and Ibsen demonstrated the
ability of tetracycline to form complexes with calcium ions on the surface of
Colors in Tooth Discoloration 23
hydroxyapatite crystals . Since it can cross the placental barrier, it must be
avoided from 29 weeks of pregnancy till delivery to prevent incorporation into the
dental tissue. The most critical time to avoid tetracycline for the prevention of tooth
discoloration in primary dentition is 4 months of uterus to 5 months post-partum. In
the permanent dentition, this period is from 4 months of infancy to approximately 7
years of age . It is noteworthy that there is no association between tetracycline
staining and dental caries .
Dental fluorosis is the most common cause of intrinsic tooth pigmentation. The
negative effects of fluoride on the enamel were first described by Dean in 1932 .
Dental fluorosis may arise endemically from natural water supplies, or fluoride
containing products. Fluorosis occurs when concentrations of fluoride exceeds 1ppm
in drinking water. The severity of pigmentation is age and dose dependent. Both
primary and permanent dentitions can be affected [6,16].
Alkaptonuria is an autosomal recessive metabolic disorder. Incomplete metabolism
of phenylalanine and tyrosine promotes aggregation of homogentisic acid with a
brown discoloration of permanent teeth has been reported in patients with
Dentine dysplasia type II is an autosomal dominant hereditary disorder that exhibits
some features of dentinigenesis imperfecta. Clinically, the teeth have a brown
discoloration similar to DI .
Molar incisor hypomineralization (MIH) is associated with a brown enamel
discoloration. Enamel in incisors and first permanent molars are severely
hypomineralized. Hypomineralization is not symmetrical and the appearance of
enamel is porous and brittle. The possible causes are: infections during early
childhood, dioxin in breast milk and genetic factors .
Sodium hypochloride is a bleaching agent without potential for dental discoloration.
However, Souza observed a brown pigmentation when NaOCl was combined with
Green, Green to Blue-Green
Chromogenic bacteria have been implicated in green staining, especially on the labial
surface of the maxillary anterior teeth at the gingival third. It is common in children
with poor oral hygiene and is more frequent in boys than girls [6,32].
Green staining of the maxillary anterior teeth has also been induced by penicilllium
and aspergillus. These microorganisms grow only in alight areas; therefore, anterior
teeth are usually affected .
Green discoloration of exposed roots of erupted teeth is another pattern of
mynocycline staining . Furthermore, a green to blue-green pigmentation has been
found in patients using products containing copper and nickel .
Green pigmentation in teeth (chlorodontia) may be associated with
hyperbilirubinemia. In this condition, bilirubin is deposited in mineralized tissues
such as bone and dentine. The primary teeth affected more frequently than permanent
dentition. The most common causes of hyperbilirubinemia leading to this type of
discoloration are as follows: 1) erythroblastosis fetalis, 2) biliary atresia, 3) biliary
hypoplasia, 4) premature birth, 5) ABO incompatibility, 6) neonatal respiratory
Hamed Mortazavi, Maryam Baharvand, and Amin Khodadoustan 24
distress, 7) significant internal hemorrhage, 8) congenital hypothyroidism, 9)
tyrosinemia, 10) α1-antitrypsin deficiency, 11) hemolytic anemia, 12) viral infection,
and neonatal hepatitis [9,33-35]. In addition, Swann and Guimaraes reported two
cases of green teeth associated with cholestasis caused by sepsis [36,37]. The
presence of green discoloration in teeth is an indicator of hyperbilirubinemia, and
determine when in life it was occurred . Clinically, the teeth demonstrate a sharp
dividing line, separating discolored (formed during hyperbilirubinemia) and normal
colored portions (formed after normal concentrations of bilirubin were restored) .
Grey, Dark Grey, Grey to Black
Grey pigmentation is common in teeth with amalgam restorations. Corrosive
amalgam discolors the dentine by formation of silver sulfide. This type of
discoloration is difficult to remove by bleaching, and tends to recur during the time
Mercury, lead, and silver nitrate salts used in dentistry can cause a grey staining in
Dental discoloration can occur as a result of materials used for endodontic
treatments. For example, Day showed that Ledermix, an intra-canal medicament
containing demeclocycline-HCl, can induce grey pigmentation if not removed
completely from access cavity at coronal level to gingival margin . Davis and
Parsons have reported the same discoloration after use of sealer and sealapex,
Dental traumatic injuries may create a dark grey discoloration when the blood
degradation products are diffused into the dental tubules. In such cases endodontic
treatment before or shortly after total pulp necrosis often prevents progression of
The orange discoloration is less common than brown or green and was reported in
3% of the population. It usually occurs on the labial surface of mandibular and
maxillary anterior teeth at the gingival third .
Chromogenic bacteria such as serratia marcescens and flavobacterium have
important roles in this type of staining, especially in children with poor oral hygiene
Some root canal cements may also have potential to cause tooth discoloration. van
der Bungt reported orange-red tooth discoloration after use of Grossman's, zinc
oxide/eugenol, and endometasone cements .
Trauma-related stains may create a pink to grey discoloration in the teeth. The real
mechanism of color change is not fully understood. Apparently, different colors
represent different entities, some of which are related to pulpal damage with
subsequent healing, whereas others result from pulpal necrosis . Pink
discoloration is usually seen one to three weeks after traumatic injuries because of
localized vascular damage .
Colors in Tooth Discoloration 25
Pink discoloration is a common clinical finding in teeth with internal resorption. This
condition is asymptomatic and usually detected through routine radiographic
examinations. The pink staining results from accumulation of granulation tissue in
the coronal dentine, undermining the crown. Infection and traumatic injuries to the
pulp tissue are the main causes of internal resorption as well as orthodontic
treatment. Radiographically, there is a punched out radiolucency, which disturb the
pulp chamber or root canal space [44,45]. In these cases endodontic treatments
should be done promptly, because extension of the defect can lead to a periodontal
Color change in the teeth can also occur as a result of materials used for endodontic
treatments. van der Burgt and davis demonstrated a pink discoloration after use of
some root canal cements such as Tubli-seal, Diaket anf Roth’801 in the teeth [14,42].
A similar pink or red discoloration has been reported in the maxillary incisors of
lepromatous leprosy patients. Since the causative microorganism prefers low
temperatures, teeth are involved in selected areas [9,46].
Red, Red-Purple, Red-Brown
This type of discoloration has been reported in congenital erythropoietic porphyria
(CEP). CEP is a rare autosomal recessive metabolic disease, with mutation in the
gene that codifies uroporphyrinogen-III synthtetase, leading to porphyrin
accumulation in urine, skin, bone and dentine [5,47]. CEP is also known as Günther's
disease and was first described in 1911 by Günther . In these cases, intraoral
examination revealed a red-purple or red-brown discoloration (Erythrodontia) in the
primary and permanent teeth. Furthermore, under Wood's lamp there was a bright red
fluorescence in the teeth .
Reddening of the upper central incisors in patients with lepromatous leprosy has been
reported by Rundall. This type of discoloration seems to be secondary to infection-
related necrosis and the rupture of small blood vessels within the pulp, with
deposition of hemoglobin into adjacent dental tubules .
A red-purple staining was also found by Tay when root canals were rinsed with 1.3%
NaOCl as an initial rinse followed by MTAD as the final rinse .
Yellow, Yellow- Green, Yellow-Brown
Yellow to yellow-brown discoloration has been observed in amelogenesis imperfecta
(AI), a hereditary condition characterized by various enamel defects such as
inadequate deposition of enamel matrix, insufficient mineralization of the matrix and
incomplete maturation of the enamel. The estimated frequency of this entity in
population varied between 1:718 and 1:14000. There are at least 14 different
subgroups, with numerous patterns of inheritance and a wide variety of clinical
Traumatic injuries to teeth can induce either a resorptive or calcific response. In
calcific phase, after an excessive irregular dentine deposition in the pulp chamber,
the clinical crown becomes yellow or yellow-brown whereas, the tooth is still vital
. This process is called dentin hypercalcification or calcific metamorphosis [6,9].
Several medications can lead to a yellow discoloration in teeth. For example, teeth
affected by tetracycline have a yellowish or yellow-brown discoloration, which is
Hamed Mortazavi, Maryam Baharvand, and Amin Khodadoustan 26
darker in eruption period, but the color diminishes with time . The same
appearances were also reported after use of oxytetracycline and ciprofloxacine [8,9].
Yellow-green discoloration was found in patients with erythroblastosis fetalis
(because of incorporation of bilirubin in the developing dentitions), sickle cell
anemia and thalassemia [due to deposition of blood pigments within the dentinal
Remaining of intra-canal medicaments such as Iodine-potassium iodide( Iodoform-
based medicaments) and UltraCal XS during the endodontic treatments can result to
a yellow to yellowish brown staining in the teeth [18,40].
Some habits such as smoking [cigars or cigarettes] or chewing of Khat (Catha edulis)
leaves for its stimulant properties may produce yellow-brown dental staining .
Many color changes can be encountered when dealing with tooth discoloration. Approach
to the patient with discolored teeth might be more efficiently accomplished using our new
classification based on clinical findings rather than previously etiology- oriented
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