Unless a dental procedure is very minor or the tooth being filled has no nerve it is very necessary to be numb before treatment.
Many people worry more about the injection than any other part of dental treatment. Will it hurt? Will it work? How long will it take for things to come back to normal?
While it is impossible to guarantee that nothing will be felt during an injection there are things which can be done to make the procedure as comfortable as possible.
Scary? It doesn’t need to be! Illustrated: An injection syringe with vibrator and some surface anaesthetic paste.
First, the needles used must be very sharp so that they glide almost imperceptibly through the skin rather than puncture a hole in it. This may sound obvious but just like anything else needles are made in different qualities. The more expensive ones tend to give better results.
The use of a surface anaesthetic paste before starting may be helpful in some areas of the mouth. Needles are designed for single patient use and while nowadays no dentist would consider re-using a needle on another patient in a situation where a single patient needs 2 or 3 injections on the same appointment it’s worth changing the needle each time as the point quickly dulls.
One of the things that can cause discomfort is the rush of cold liquid from the injection into the tissues. In the winter injection solution can become very cold indeed and warming it to about body temperature before injecting can greatly improve the experience.
Possibly the main reason for painful injections is injecting too quickly. This causes the delicate tissues to tear apart, sometimes resulting in bruising or swelling. The recommendation is to inject at a rate of a millilitre per minute. Since injection cartridges hold about 2 millilitres of solution that’s how long a painless injection should take: about 2 minutes. The more slowly the liquid goes in the less you will feel it.
Vibration confuses nerves so that they are less able to transmit pain signals. Fitting a simple vibrator to the injection syringe is yet another method that can result in the procedure becoming much more comfortable.
After the injection has been given it needs time to work. As a rule of thumb 2 minutes is about right for an upper tooth while lower teeth can take twice that long to go numb. It’s essential the clinician waits long enough before starting for the injection to work.
If a tooth really won’t go numb after one injection a second one will normally do the trick. This second injection will normally be completely painless as the skin it goes into will already be numb.
How long will it take for the injection to wear off? This depends on the type of chemical used, the position of the injection and variation among individuals but normally the skin will come back to normal after about 2-hours though some people stay numb for up to 6 hours. During this period great care needs to be taken to avoid biting the lips, tongue or cheeks or scalding them with hot drinks.
Giving comfortable injections is a skill that any clinician can learn but it does require time, patience and attention to detail. However, learning these techniques are of enormous benefit to the patients we serve.