Dental materials and radiology basics: titanium implant biocompatibility: 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: titanium implant biocompatibility

Sample item

Commercially pure titanium is widely used for dental implants because it resists corrosion in saliva and tissue fluids. What is the main reason?

AA permanent hydroxyapatite coating is always presentBA stable self-repairing titanium dioxide surface filmCIts elastic modulus is identical to that of cortical boneDA nickel-rich surface layer protects the metal from attack

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

The answer and the reasoning

B. A stable self-repairing titanium dioxide surface film

Titanium rapidly forms a thin, adherent, stable oxide layer (passivation) which re-forms if scratched, giving corrosion resistance and a surface compatible with osseointegration. Its modulus is still several times that of bone, and hydroxyapatite coatings are optional extras.

Option by option

A. A permanent hydroxyapatite coating is always present
Many fixtures are uncoated, and a coating is not the source of corrosion resistance.
B. A stable self-repairing titanium dioxide surface film (correct)
Correct. The self-healing oxide film passivates the surface.
C. Its elastic modulus is identical to that of cortical bone
Titanium is stiffer than cortical bone, so stress transfer remains a design issue.
D. A nickel-rich surface layer protects the metal from attack
Commercially pure titanium contains no nickel layer; nickel is more a concern in some wires.

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 B, A stable self-repairing titanium dioxide surface film. Titanium rapidly forms a thin, adherent, stable oxide layer (passivation) which re-forms if scratched, giving corrosion resistance and a surface compatible with osseointegration.

Why is "A permanent hydroxyapatite coating is always present" not the answer?

Many fixtures are uncoated, and a coating is not the source of corrosion resistance.

Why is "Its elastic modulus is identical to that of cortical bone" not the answer?

Titanium is stiffer than cortical bone, so stress transfer remains a design issue.

Why is "A nickel-rich surface layer protects the metal from attack" not the answer?

Commercially pure titanium contains no nickel layer; nickel is more a concern in some wires.

What concept does this question test?

It tests Dental materials and radiology basics: titanium implant biocompatibility in Dentistry. Its modulus is still several times that of bone, and hydroxyapatite coatings are optional extras.

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: titanium implant biocompatibility?

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.