Identification: cementum annulation: practice question

A Forensic Medicine 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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Forensic Medicine · Identification: cementum annulation

Sample item

In a sectioned single-rooted tooth of an adult, the annual incremental lines in the cementum are counted. How is the age at death then calculated?

ANumber of lines multiplied by the eruption ageBNumber of lines minus the usual eruption ageCNumber of lines alone, without correctionDNumber of lines plus the usual age at eruption

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

The answer and the reasoning

D. Number of lines plus the usual age at eruption

Cementum is laid down in yearly layers after the tooth erupts. Adding the count of annual lines to the average age at which that tooth erupts gives an estimate of the age at death. It is an alternative to Gustafson's method.

Option by option

A. Number of lines multiplied by the eruption age
Multiplying the lines by the eruption age has no biological basis.
B. Number of lines minus the usual eruption age
Subtracting the eruption age would give an age lower than the real one.
C. Number of lines alone, without correction
Lines count only the years after eruption, so the eruption age must be added.
D. Number of lines plus the usual age at eruption (correct)
Correct. Lines count the years since eruption, so the eruption age is added.

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 Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is D, Number of lines plus the usual age at eruption. Cementum is laid down in yearly layers after the tooth erupts.

Why is "Number of lines multiplied by the eruption age" not the answer?

Multiplying the lines by the eruption age has no biological basis.

Why is "Number of lines minus the usual eruption age" not the answer?

Subtracting the eruption age would give an age lower than the real one.

Why is "Number of lines alone, without correction" not the answer?

Lines count only the years after eruption, so the eruption age must be added.

What concept does this question test?

It tests Identification: cementum annulation in Forensic Medicine. Adding the count of annual lines to the average age at which that tooth erupts gives an estimate of the age at death. It is an alternative to Gustafson's method.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Identification: cementum annulation?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine 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.