Tooth eruption: first permanent tooth: 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 eruption: first permanent tooth

Sample item

A 6-year-old child has a new tooth behind the last deciduous molar, with no deciduous tooth having been shed there. Which tooth is this?

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

The answer and the reasoning

C. Mandibular first permanent molar

The first permanent molar, usually the mandibular one, erupts at about 6 years behind the second deciduous molar. It is an accessional tooth with no deciduous predecessor, which is why it is often mistaken for a deciduous tooth and neglected.

Option by option

  • A. Mandibular second permanent molar

    The second permanent molar erupts at about 11 to 13 years.

  • B. Maxillary first premolar

    Premolars erupt at about 10 to 11 years and replace deciduous molars.

  • C. Mandibular first permanent molar (correct)

    Correct. The six-year molar erupts distal to the deciduous molars and replaces none.

  • D. Maxillary canine

    The maxillary canine erupts at about 11 to 12 years.

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.

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Questions about this Dentistry question

What is the answer to this Dentistry question?

The best answer is C, Mandibular first permanent molar. The first permanent molar, usually the mandibular one, erupts at about 6 years behind the second deciduous molar.

Why is "Mandibular second permanent molar" not the answer?

The second permanent molar erupts at about 11 to 13 years.

Why is "Maxillary first premolar" not the answer?

Premolars erupt at about 10 to 11 years and replace deciduous molars.

Why is "Maxillary canine" not the answer?

The maxillary canine erupts at about 11 to 12 years.

What concept does this question test?

It tests Tooth eruption: first permanent tooth in Dentistry. It is an accessional tooth with no deciduous predecessor, which is why it is often mistaken for a deciduous tooth and neglected.

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 eruption: first permanent tooth?

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.