Speak freely about what the dentist said? (4,2)
I believe the answer is:
open up
'speak freely' is the definition.
(I've seen this in another clue)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for open up that I've seen before include "Talk more freely" , "Unlock building or reveal inner thoughts" , "reveal emotions?" , "Begin firing; disclose" , "Begin shooting; become more confiding" .)