An Unusual Case of Green Teeth Secondary to Neonatal Hyperbilirubinemia

Sir,

A 10-month-old boy was referred because of greenish pigmentation on his deciduous teeth from the time of eruption. Intra-oral examination revealed yellowish-green pigmentation in the crown of the incisors [Figures 1 and 2]. There was no evidence of caries, bad oral hygiene, or abnormal sequence of eruption of oro-dental morphology. Oral soft tissues were normal.

Figure 1.

Boy with yellowish-green discoloration of incisors

Figure 2.

Boy with yellowish-green discoloration of incisors

His medical records revealed that he was born in the 32^nd week, weighing 1500 g, with an Apgar score of 1 and 4 in the first and fifth minute, respectively. He was admitted to the neonatal intensive care unit, where he subsequently developed signs of respiratory distress and had to be put on the ventilator. On day 15, he was found to have conjugated hyperbilirubinaemia, which gradually progressed (maximum value: 59 mg/dL; conjugated fraction: 41 mg/dL on day 30). He was diagnosed with neonatal cholestatic jaundice and neonatal sepsis with Staphylococcus aureus. The baby was hospitalized for 1.5 months and received intravenous antibiotics along with high-intensity phototherapy to reduce the production of bilirubin. Gradually, the bilirubin level decreased to 8 mg/dl by 2 months of age and returned to normal by 4 months of age. The parents were explained about the cause of his green teeth, and counseling was done. The child was asked to come for regular follow-ups.

Green teeth are a rare finding in children with neonatal hyperbilirubinaemia, which may be secondary to neonatal cholestasis (e.g., biliary atresia, sepsis, pathological hyperbilirubinemias, and metabolic diseases), hemolytic anemia, congenital hypothyroidism, and drugs.[1] In concentrations exceeding 30 mg/100 ml, bilirubin is deposited into the enamel and/or dentine during the period of matrix formation, therefore changing its color permanently as these tissues lose their metabolic activity after maturation.[2,3]

The location and extension of pigmentation correspond to the dental formation period. The deciduous tooth calcification process begins in the fourth month of intrauterine life. The dental crown of the incisors is completely formed 1 month after birth. Thus, it is possible to project a condition of hyperbilirubinemia in the first 1 month of life.[4] Other causes can be poor oral hygiene, chromogenic bacteria, colored foods and beverages, metallic compounds, and topical medication.[5]

The pigmentation may vary from yellow to deep shades of green. Histologically, green circular stripes parallel to the incremental lines of the dentin are observed. We can also observe a change in the dentinal tubule direction and a larger amount of interglobular dentin next to that line.

Aesthetic treatment should be considered primarily to prevent peer teasing and build confidence of the child. Treatment options include composite resin restorations, bleaching techniques, transillumination with ultraviolet light, diet guidance, and oral hygiene instruction. Because of advancement in neonatal care, green teeth are considered a rarity and can result in anxiety to the family. The idea of reporting this case here has been to make our dermatologist, pediatrician, and dentist colleagues about this extremely rare consequence of congenital hyperbilirubinaemia.[2]

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Conflicts of interest

There are no conflicts of interest.