Hard Tissue Pathology


Tooth stains are the result of various pigments deposited within the inner layers of the enamel, dentin and pulp (intrinsic stains) or on the outer enamel surface (extrinsic stains). They may be due to systemic factors and involve all the teeth or local factors that involve selected teeth (trauma).

Intrinsic Stains

A single discolored tooth is usually a result of previous trauma to the tooth. Internal bleeding from pulpal hyperemia stains the inner layer of the dentin. The discoloration appears 3 to 4 weeks after the accident. In patients under three years the tooth may lighten spontaneously after two months. No treatment is required unless pain, mobility, infection is present or if the patient or parent has aesthetic concerns. Lightening of the tooth is accomplished through endodontic treatment followed by internal bleaching (permanent teeth only) and composite. If radiographic examination of a discolored primary tooth reveals root resorption, endodontic therapy is contraindicated and extraction is recommended.

Image: Intrinsic Stains
Image: Intrinsic Stains - radiograph
Besides trauma intrinsic stains can be a result of systemic conditions. Usually multiple teeth are involved. The following more common conditions cause intrinsic staining:

Erythroblastosis fetalis

Bilirubin is incorporated into the developing dentition resulting in a yellow-green and blue-green discoloration of the teeth.

Image: Erythroblastosis fetalis

Cystic fibrosis

The disease alone or medication (tetracycline) results in dark teeth ranging from yellowish-gray to dark brown discoloration.

Image: Cystic fibrosis

Dentinogenesis imperfecta

A genetic abnormality of dentin collagen during the histo-differentiation phase results in brownish, semitransparent opalescent teeth.

Image: Dentinogenesis imperfecta


Is due to the defective mineralization of the enamel organic matrix from high levels of ingested fluoride resulting in chalky and opaque white or gray stain and patches. Fluoride is an effective caries preventive agent with no deleterious effects at proper daily dosage. Excess fluoride intake leads to fluorosis, thus fluoride intake for children and especially infants must be monitored. Excess fluoride intake leads to fluorosis, thus fluoride intake for children and especially infants must be monitored. The preventive effects of fluoride are predominately topical. Fluoride that is swallowed, such as fluoridated water and dietary supplements, have a topical effect on erupted teeth before swallowed, as well as a topical effect due to increased salivary and gingival crevicular levels. Similarly, topical fluoride that is swallowed may have a systemic effect. Parents should control the amount of fluoride ingested by children by following these guidelines:

  • Supervise tooth brushing of children under three.

  • Use only a smear of fluoridated toothpaste on children less than three years of age and a pea size on children aged three to six years,

  • Encourage the child to spit out excess toothpaste.

  • Do not let the child eat toothpaste.

Image: Fluorosis

For those children that are fed formula the intake of fluoride by infants is influenced more by the water used to reconstitute formulas than by the formulas themselves. Fluoride concentrations in ready-to-feed formulas are relatively low and do not contribute significantly to development of fluorosis. Powdered and liquid concentrates reconstituted with water with 0.7 to 1.2 ppm fluoride contribute to moderate fluorosis. Therefore in areas with these fluoride concentrations, infants may be ingesting fluoride in amounts that may cause fluorosis. To illustrate:

  • One cup (8 ounces) of 1ppm fluoridated water = approximately 0.25mg of fluoride.
  • Most babies drink 28-32 ounces of formula per day (4 bottles).
  • 4 bottles X 0.25mg fluoride = 1 mg fluoride/day.
  • The CDC, ADA and AAPD guidelines for ages 0-3 years is to receive 0.25mg fluoride.

Thus the infant receives four times the recommended dose of fluoride. Parents should be counseled to mix 1 bottle of fluoridated water with powdered formula per day. For the remaining bottles use non-fluoridated water.

Table 1. Dietary Fluoride Supplementation Schedule
Age<0.3 ppm0.3-0.6 ppm>0.6 ppm
Birth – 6 monthsNoneNoneNone
6 mos – 3 years0.25 mg/dayNoneNone
3 – 6 years0.50 mg/day0.25 mg/dayNone
6 – 16 years1.0 mg/day0.50 mg/dayNone

Treatment of intrinsic stains consists of vital and non-vital bleaching techniques and aesthetic restorations. Microabrasion may be considered for treatment of fluorosis.

Extrinsic Stains

Extrinsic stains may involve all or some of the teeth and result from an excess of various chemicals or minerals in the saliva. Stain location is around the mandibular incisors in the vicinity of the sublingual glands and the maxillary molars in the vicinity of the parotid glands.

  • Iron, magnesium, silver – black pigmentation
  • Mercury – gray or green pigmentation
  • Lead – gray pigmentation
  • Copper – brown or green pigmentation
  • Bromides – brown pigmentation
  • Nickel – green pigmentation
  • Cadmium – yellow pigmentation
  • Potassium – violet pigmentation
  • Chromogenic bacteria – green and orange stain accumulating on the gingival third of the labial surfaces of teeth usually due to poor oral hygiene. Chromogenic stain is easier to remove than chemical or mineral stain.

Removal of the stains ranges from simple rubber cup prophylaxis to aggressive ultrasonic scaling to composite polishing stones.

Image: Extrinsic Stains
Image: Extrinsic Stains

Enamel Defects

Enamel defects are due etiological factors occurring during the apposition and mineralization stages of dental development. Enamel defects include a group of clinical factors recognized as enamel hypoplasia, hypocalcification and hypomaturation. The etiology of enamel defects may be attributed to local, systemic and genetic factors.

In defects of local etiology a single tooth is involved such as a traumatic intrusion of a primary tooth into a permanent tooth.

Image: Enamel Defects 
Image: Enamel Defects 
Defects of systemic etiology involve multiple teeth developing during the time of action of the etiological factor (medications, fever, malnutrition, illnesses, etc.). Etiological factors occurring during pregnancy affect the primary teeth. Etiological factors occurring after birth will affect the permanent teeth.
Image: Defects of systemic etiology
Image: Defects of systemic etiology
Image: Defects of systemic etiology
Image: Defects of systemic etiology
Defects of genetic etiology usually affect all the primary and permanent teeth.
Image: Defects of genetic etiology