Photo of Topical Anaesthetics in different flavours

Topical Anaesthesia (or “numbing gel” in dentist-speak) is used to numb the gums or other tissues before an injection, so that you can’t feel the needle glide in.

  • Topical Anaesthetic is put on tissues like gums or skin and numbs the surface of the tissue
  • Local Anaesthetic is injected with a needle

How does it work?

Cotton-Tip Applicators

Numbing gel contains an anaesthetic agent, most commonly benzocaine (usually at a concentration of 20%). A cotton swab or q-tip is used to apply a small amount of gel to the injection site.

Does it really work?

Yes it does, but there’s a slight snag. Even though numbing gel usually produces an effect within 30 seconds, it needs to be left on for 2 to 3 minutes for best effect 1. So if you read somewhere that “the numbing gel doesn’t work for me”, it’s probably because it wasn’t left on for long enough. So it’s important to leave it on for long enough, especially in sensitive areas like the palate.

Does the numbing gel guarantee a comfortable injection?

Actually, most discomfort during injections is due to the local anaesthetic being given too quickly. It is important to give it slowly and steadily to avoid any discomfort (although this also depends on which area is being numbed – some areas are much more sensitive than others). Especially in days gone by, some dentists used pretty blunt needles, which hurt. So if it’s been a long time since you last had an injection, you may be pleasantly surprised.

When searching for a dentist who gives comfortable injections, make sure you alert them to your fear when you first contact them, and ask them how they can help.

You could also see if a dentist in your area offers the Wand.

What types of topical anaesthetic are there?

Photo of numbing gels in different flavors

Topical anaesthetic comes in lots of forms (sprays, patch, ointment, solution). The ingredients are the same, but they are good for different purposes. Gel is good for numbing the gums prior to an injection. Spray is good if you are prone to gagging, and can be used before x-rays, for example.

Numbing gel is available from many companies, and sometimes comes in yummy flavours like strawberry, mint, cherry, banana, berry, tropical fruit, and bubble gum.

I’ve heard about a numbing gel that can be used instead of injections. Is this true?

Topical anaesthetics are good for numbing the gums, but they’re no use for numbing the actual teeth. This is because they only numb soft tissues. Topical anaesthetics doesn’t really affect the nerves that transmit sensations from your teeth to your brain. To put these nerves to sleep, a local anaesthetic needs to be used.

For some people, topical anaesthetics can be a useful alternative to local anaesthetics for deep cleaning (also known as scaling and root planing), depending on how sensitive your teeth and gums are, and whether or not injections cause you a lot of stress.

Oraqix (2.5% lidocaine and 2.5% prilocaine) is a non-injectable gel anaesthetic that is put into the space where the teeth meet the gums in order to numb the soft tissues. HurriPAK is a 20% benzocaine solution that is sold as a needle-free periodontal anesthetic kit with a plastic syringe and disposable plastic tips, but it only lasts for 15 minutes. Cetacaine Topical Anaesthetic (Cetylite, NJ, USA) contains 14% benzocaine, 2% butamben, and 2% tetracaine-hydrochloric acid, and comes with a similar kit including the solution, a syringe, and applicator tip.

My dentist doesn’t use the numbing gel. What should I do?

Some dentists are really good at giving painless injections even without numbing gel. This is especially true for upper back teeth and lower front teeth. But if you’d like the numbing gel, just ASK if they have it! It’s not impolite to do so, nobody is going to get upset if you say something along the lines of “I’m worried that the prick might hurt. I’ve read about this numbing gel, could you use something like that?”.

I’m allergic to ester “caines” like benzocaine.

Allergy to ester “caines” is more common compared to the amide “caines” used in injections. Luckily, because benzocaine is not absorbed into the body system, any allergic reaction is usually localised to the spot where the contact occurs. But if you have a known allergy to benzocaine, let your dentist know. An alternative topical anaesthetic is lidocaine. The reason why benzocaine is the topical anaesthetic of choice is the risk of accidental overdose is lower with esters compared to amides (especially on larger areas).

Further Reading

Needle Phobia – This page also provides information on topical anaesthetics for IV sedation, including Ametop and EMLA cream.

The information on this page has been provided by Dental Fear Central. Last reviewed on March 30, 2019. We welcome your feedback on our information resources.

References

  1. H.S. Lee (2016). Recent advances in topical anaesthesia. J Dent Anesth Pain Med. 2016 Dec;16(4):237-244.