What is local anaesthesia?

Your dentist may need to numb a part of your mouth by injecting drugs in your gum or in the inside of your cheek. These drugs are known as local anaesthesia and they only numb the area near the injection site.

Today, the most common local anaesthesia is lidocaine. There are several others and they usually end in “caine.” Several people think that novocaine is the classic drug used for numbing local areas of your body. It was used before although it isn’t used nowadays. Other drugs last longer, are more effective, and cause lesser allergic reactions than novocain.

The numbing drug is only one part of the injection. The liquid in the shot can also have

• a type of drug referred to as a vasoconstrictor. It narrows the blood vessels and prolongs the numbness
• a chemical that will keep the vasoconstrictor from breaking down
• sodium hydroxide which helps in numbing
• sodium chloride which helps the drugs enter your blood

There are two kinds of shots that cause numbness. A block injection will numb an entire region of your mouth like a side of your upper jaw. An infiltration injection will numb a smaller area of your mouth.

If you need a numbing shot then your dentist will dry a part of your mouth with cotton or with air. Afterwards, the dentists will swab the area with gel in order to numb the skin. The dentist will then inject the drug that causes numbness. The needle can sting although several people do not feel the needle. The sting that they feel is usually caused by the liquid moving into the tissue. A numbing shot can last for several hours after the dental treatment. In fact, you may find it difficult to speak, eat, and drink. You should avoid biting on the numbed area and drinking from a straw. This can be messy and painful.

What are the side effects of local injections?

Local anaesthesia is the most common of the drugs used at the dentist’s office and side effects are very uncommon. One of the side effects that can happen is a haematoma. It is a blood-filled swelling that forms when an injection hits a blood vessel. Sometimes the side effects will cause numbing outside the targeted area. When this happens, your eyelid or your mouth can droop. When the drug wears off, you will recover. There are times when the vasoconstrictor drug causes your heart to beat faster. This may last for one minute or two minutes. Lastly, the needle could injure a nerve. This could cause numbness and pain for several weeks or even months. The nerve will heal through time.

What are some of the concerns with local injections?

It is uncommon to have an allergic reaction to local anaesthetics so you should let your dentist know about any of your allergies beforehand. You should also tell them about any medications you are taking and their corresponding dosages. Let them know both your over-the-counter medications and your prescription medications. Some of the drugs can interact with these local anaesthetic solutions.