Drink lots and lots of fluids,
Muesli, soaked for an hour in fruit-juice, and then with added yoghurt or more fruit-juice can help too.
If you want to eat more fibre, to loosen things, make sure the fibre is soaked, and make sure you chew your food well.
Adding fibre to your diet without drinking lots extra will get you more clogged up. Fibre and lots and lots of fluids may help your system to get going again.
I don't recognise this problem btw. But then, I never got an ordinary local sedation at my dentist. I reacted badly on those sedations at other places in my body, and regular local sedation scares the shit out of me.