Restorative & Materials · single question
For total-etch bonding, how long is phosphoric acid typically left on enamel before rinsing?
Show answer and explanation
Correct answer: B. 15-20 seconds
- A. 3-5 seconds is too brief for adequate enamel etching.
- B. Correct. Enamel is etched for about 15-20 seconds (dentin etch time is shorter, ~10-15 s) and then thoroughly rinsed.
- C. 60 seconds over-etches and can weaken the surface.
- D. 2 minutes is far too long and harmful.
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