Dental materials and radiology basics: inlay wax distortion: 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 · Dental materials and radiology basics: inlay wax distortion

Sample item

An inlay wax pattern is left on the bench for several hours before investing, and the final casting fits poorly. What property of wax explains this?

AHygroscopic expansion of the dieBPolymerisation shrinkage of the waxCRelease of internal stresses introduced during manipulation, causing distortionDWater sorption and swelling of the wax

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

The answer and the reasoning

C. Release of internal stresses introduced during manipulation, causing distortion

Wax is compressed during carving and cooling and then relaxes, so the pattern distorts with time. Investing promptly reduces this error.

Option by option

A. Hygroscopic expansion of the die
A hygroscopic expansion of the die is not a feature of a stone die.
B. Polymerisation shrinkage of the wax
Wax does not polymerise, so there is no polymerisation shrinkage.
C. Release of internal stresses introduced during manipulation, causing distortion (correct)
Correct. Stored stresses relax and distort the pattern.
D. Water sorption and swelling of the wax
Wax does not absorb water to a significant extent.

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, Release of internal stresses introduced during manipulation, causing distortion. Wax is compressed during carving and cooling and then relaxes, so the pattern distorts with time.

Why is "Hygroscopic expansion of the die" not the answer?

A hygroscopic expansion of the die is not a feature of a stone die.

Why is "Polymerisation shrinkage of the wax" not the answer?

Wax does not polymerise, so there is no polymerisation shrinkage.

Why is "Water sorption and swelling of the wax" not the answer?

Wax does not absorb water to a significant extent.

What concept does this question test?

It tests Dental materials and radiology basics: inlay wax distortion in Dentistry. Investing promptly reduces this error.

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 Dental materials and radiology basics: inlay wax distortion?

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.