Tooth development and dental anatomy: erythrodontia: practice question

A Dentistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dentistry · Tooth development and dental anatomy: erythrodontia

Sample item

A child's teeth are reddish-brown and fluoresce red under ultraviolet light. The urine is red and the skin is photosensitive with scarring. What is the underlying cause?

AExcess fluoride ingestionBNeonatal hyperbilirubinaemiaCCongenital erythropoietic porphyriaDTetracycline exposure during tooth formation

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Congenital erythropoietic porphyria

In congenital erythropoietic porphyria, porphyrins deposit in developing teeth, causing red-brown discolouration (erythrodontia) with red fluorescence under UV. Photosensitivity and red urine accompany it. Tetracycline gives yellow-grey stain with yellow fluorescence.

Option by option

A. Excess fluoride ingestion
Fluorosis gives chalky white to brown mottled enamel with no photosensitivity.
B. Neonatal hyperbilirubinaemia
Bilirubin causes a greenish or blue-green stain after severe neonatal jaundice.
C. Congenital erythropoietic porphyria (correct)
Correct. Porphyrin deposition explains the red teeth and fluorescence.
D. Tetracycline exposure during tooth formation
Tetracycline stain is yellow to grey-brown and fluoresces yellow.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Dentistry question

What is the answer to this Dentistry question?

The best answer is C, Congenital erythropoietic porphyria. In congenital erythropoietic porphyria, porphyrins deposit in developing teeth, causing red-brown discolouration (erythrodontia) with red fluorescence under UV.

Why is "Excess fluoride ingestion" not the answer?

Fluorosis gives chalky white to brown mottled enamel with no photosensitivity.

Why is "Neonatal hyperbilirubinaemia" not the answer?

Bilirubin causes a greenish or blue-green stain after severe neonatal jaundice.

Why is "Tetracycline exposure during tooth formation" not the answer?

Tetracycline stain is yellow to grey-brown and fluoresces yellow.

What concept does this question test?

It tests Tooth development and dental anatomy: erythrodontia in Dentistry. Photosensitivity and red urine accompany it. Tetracycline gives yellow-grey stain with yellow fluorescence.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Tooth development and dental anatomy: erythrodontia?

Learn the dental formula, eruption ages and tooth structure once, as tables. Then use the flashcards and the other Dentistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.