Yes, salt water is the best and safest irrigant to use after oral surgery. The best would be physiological saline solution at 0.9% available at pharmacies.
This should be syringed (with a blunt tipped needle) into the healing socket to dislodge debris. Rinsing the whole mouth tends to be less effective when the wound is new and deep. Your dentist should be able to demonstrate how this can be done safely.
If you do not have access to commercially-available saline, then warm salt water that you make yourself can also be used.
However, if the salt concentration is too high, it can be a little unpleasant. If you do not have a syringe to irrigate the socket, or if you find it difficult to see into the mouth for irrigation, then holding the salt solution in the mouth for 5 minutes before gargling and then spitting out can be done.
I would avoid using mouthrinse on a fresh wound because there have been case reports of severe allergic reactions (anaphylaxis) to certain mouthrinse ingredients, notably chlorhexidine.
