Implants rings in a surgical procedure (8)

I believe the answer is:

ingrains

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'implants' is the definition.
The answer and definition can be both related to thinking as well as being verbs in their -s form.
Maybe there's an association between them I don't understand?

'rings in a surgical procedure' is the wordplay.
'rings in a' can be anagrammed to 'INGRAINS'.
Though, I'm unsure how the anagram is indicated.

Can you help me to learn more?

(Another definition for ingrains that I've seen is " Establishes".)

I've seen this clue in the Sydney Morning Herald.

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