Dental materials and radiology basics: total-etch bonding: 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: total-etch bonding

Sample item

After acid-etching dentine with phosphoric acid, the dentist dries the cavity until it looks chalky white and then applies a total-etch adhesive. The patient has postoperative sensitivity. What went wrong?

AOver-drying collapsed the collagen network and prevented resin infiltrationBExcessive light curingCToo short an etch time on enamelDContamination with eugenol

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

The answer and the reasoning

A. Over-drying collapsed the collagen network and prevented resin infiltration

Dentine must remain moist after etching so the collagen stays expanded for resin penetration. Over-drying collapses it and leaves unsealed tubules, causing sensitivity.

Option by option

A. Over-drying collapsed the collagen network and prevented resin infiltration (correct)
Correct. Collapsed collagen blocks hybrid layer formation.
B. Excessive light curing
More light does not make a tubule-sealing failure.
C. Too short an etch time on enamel
Enamel etch time does not cause dentinal sensitivity.
D. Contamination with eugenol
Eugenol contamination is a problem for resin polymerisation, not the cause here.

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 A, Over-drying collapsed the collagen network and prevented resin infiltration. Dentine must remain moist after etching so the collagen stays expanded for resin penetration.

Why is "Excessive light curing" not the answer?

More light does not make a tubule-sealing failure.

Why is "Too short an etch time on enamel" not the answer?

Enamel etch time does not cause dentinal sensitivity.

Why is "Contamination with eugenol" not the answer?

Eugenol contamination is a problem for resin polymerisation, not the cause here.

What concept does this question test?

It tests Dental materials and radiology basics: total-etch bonding in Dentistry. Over-drying collapses it and leaves unsealed tubules, causing sensitivity.

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 Dental materials and radiology basics: total-etch bonding?

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.