Classification of discoloration

  • Intrinsic discoloration
  • Extrinsic discoloration
  • Combination of both

1.Based on the Etiology of tooth discoloration

Intrinsic stains

  • Pre-eruptive causes– Disease
    i. Alkaptonuria
  • iiHematological disorders
    iii. Disease of enamel and dentin
  • iv. Liver diseases.– Medications
    i. Tetracycline stains and other antibiotic use
  • ii. Fluorosis stain.
  • Posteruptive causes of discoloration– Pulpal changes
    – Trauma
    – Dentin hypercalcification
    – Dental caries
    – Restorative materials and operative procedures – Aging
    – Functional and parafunctional changes.

Extrinsic stains
• Daily acquired stains

– Plaque
– Food and beverages – Tobacco use
– Poor oral hygiene
– Swimmer’s calculus
– Gingival hemorrhage.  

  • Chemicals
    – Chlorhexidine
  • – Metallic stains.

2.Classification of extrinsic stains (Nathoo in 1997)

  • •  N1 type dental stain (direct dental stain): Here colored materials bind to the tooth surface to cause discoloration. Tooth has same color, as that of chromogen.
  • •  N 2 type dental stain (direct dental stain): Here chromogen changes color after binding to the tooth.
  • •   N3 type dental stain (indirect dental stain): In this type prechromogen (colorless) binds to the tooth and undergoes a chemical reaction to cause a stain.

3.Different Types of Stains according to Color:


It usually results due to contact with certain metallic elements such as silver, iron and lead.It may appear as thin line running approximately 1 mm or so above the gingival margin, it may occur on both the facial and lingual surfaces of teeth.Stain is firmly attached to the surface but remains extrinsic, thus it may be removed by brush and abrasives. But, it recurs later on.

Green stain

It usually occurs as thick deposit involving the cervical one-third of facial surface of maxillary incisors of young children. It affects boys more frequently than girls.

It is associated with poor oral hygiene and decalcification is sometimes present in enamel, underlying the deposit. It occurs due to chromogenic bacteria or fungi or it may be caused by bacterial action on remnants of enamel cuticle. It is extrinsic and may be removed by simple brushing and abrasive.

Orange stain

It occurs infrequently and usually involve both facial and lingual surfaces of the incisors. It is easily removed than green stain and its cause is unknown but it is believed to be the result of chromogenic bacteria. It is associated with poor oral hygiene and removed with the help of brush and abrasives.

Brown stain

It can be seen in non-smokers and is usually lighter brown than that of tobacco and form a tenacious, but delicate film on surface of the teeth. It is usually seen more commonly on lingual surface of lower incisors and buccal surface of maxillary molar teeth. It is formed due to altered salivary mucins which have undergone change through the action of bacterial enzymes.


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