First, you will begin to feel a sort of pins and needles type effect, that will gradually be taken over by a loss of feeling or numbness.
The classic signs that the tooth is numb are…
- The pain has gone
- The tooth doesn’t hurt to press on like before
- Your lip goes numb on the one side
- Your tongue goes numb on the one side
- Your cheek goes numb.
Not all injections will cause ' your lip to go numb' or 'your tongue to go numb on the one side', but most extractions on bottom teeth will. You may feel some numbness elsewhere such as your nose. It just depends on the site of the anaesthetic and your nerve supply.
A few minutes after the injections the dentist will start by asking you questions such as:
Do you feel any numbness? Does the tooth still hurt? Has your lip or half the side of your tongue gone numb?
This will give them a good idea of whether the injections have worked. Assuming they have, the next stage is for the dentist to have a good press around your tooth. I would say something like,“ I’m just going to have a press around your tooth, please tell me if you feel any sharpness or pain- the anaesthetic can take away all the pain, but you may still feel some pressure- a dull pushing- that is totally normal, but nothing sharp like a pin or prick.”
If you only feel pushing or feel nothing at all, then the dentist is good to begin removing the tooth. However, if it is still a bit sore or sharp in places, then some extra topping up with anaesthetic is needed.
This may be in the same position as before in which case you won’t feel much, or directly around the actual tooth. We call this an intra-ligamentary injection because we put anaesthetic directly into the ligament. It is a little sharp scratch and often a touch of anaesthetic escapes as we remove the needle, giving a bit of a bitter taste which you will want to rinse out.
Sometimes the tooth will need a few extra injections, or another type of anaesthetic to get it properly numb. In some cases when you start moving the tooth, it can occasionally become painful again. The anaesthetic may need topping up further, but it may just be the pressure of moving the tooth.
When the tooth is no-longer sharp the dentist can start the extraction.
It is not always that easy to tell the difference between pressure and pain (particularly for children). You will feel movement and pressure when the tooth is being removed, but it shouldn’t hurt- the size and shape of the roots and the density of your jaw will affect how much ‘pushing’ and 'pressure' you feel. The reason for this is, anaesthetic only works on nerve fibres, not on pressure fibres (proprioceptors).
Infection can sometimes neutralize the anaesthetic to the point where we can’t get the tooth numb. If you have a large abscess, whilst the ideal solution for removing the infection, is removing the source i.e. the tooth, antibiotics and draining the abscess (if possible) may be needed first, then another appointment to extract the tooth a week later.
If this situation happens whilst in the chair, as very occasionally it does, the procedure may need to be abandoned, suitable antibiotics prescribed and an appointment made for you to come back in a week.