paracetamol only comes in 500mg per tab unless mixed with something else then it is 300mg/?? unless u have a script
You may take 1600mg of ibuprofen at once - however, it is usually taken as a slow release in that large a quanitity. So, the 400mg you may take with/at the same as the paracetamol but only 1 tablet not 2 - if they are 200mg then yes, take 2. Please make sure you eat before you take them
Generally you are told to take these every 4-6 hours. As your dentist didnt give you a script (I assume) then read the boxes