Dental Anaesthesia in English: From Injection to Sedation

An anaesthetic is the drug; anaesthesia is the state it produces. Add two spellings — British anaesthesia, American anesthesia — and you have the single commonest error in this topic.

This list covers 75 terms: delivery techniques, drugs, consumables, the effect and its loss, levels of sedation, patient anxiety and complications.

Who this is for

  • Patients — asking about pain control and declaring an allergy
  • Clinicians and assistants — running an anaesthesia protocol in English
  • Students — the pharmacology and techniques as examined

Word list to learn

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Word
local anesthesia ˈləʊkəl ˌænəsˈθiːziə
local anesthetic ˈləʊkəl ˌænəsˈθetɪk
topical anesthetic ˈtɒpɪkəl ˌænəsˈθetɪk
anesthetic gel ˌænəsˈθetɪk dʒel
anesthetic spray ˌænəsˈθetɪk spreɪ
injection ɪnˈdʒekʃən
infiltration ˌɪnfɪlˈtreɪʃən
buccal infiltration ˈbʌkəl ˌɪnfɪlˈtreɪʃən
nerve block nɜːv blɒk
inferior alveolar nerve block ɪnˈfɪəriər ælˈviːələ nɜːv blɒk
mental nerve block ˈmentəl nɜːv blɒk
lingual nerve block ˈlɪŋɡwəl nɜːv blɒk
intraligamentary injection ˌɪntrəlɪɡəˈmentəri ɪnˈdʒekʃən
intraosseous injection ˌɪntrəˈɒsiəs ɪnˈdʒekʃən
intrapulpal injection ˌɪntrəˈpʌlpəl ɪnˈdʒekʃən
computer-controlled delivery kəmˈpjuːtə kənˈtrəʊld dɪˈlɪvəri
lidocaine ˈlaɪdəkeɪn
lignocaine ˈlɪɡnəkeɪn
articaine ˈɑːtɪkeɪn
mepivacaine məˈpɪvəkeɪn
prilocaine ˈpraɪləkeɪn
bupivacaine bjuːˈpɪvəkeɪn
benzocaine ˈbenzəkeɪn
epinephrine ˌepɪˈnefrɪn
adrenaline əˈdrenəlɪn
vasoconstrictor ˌveɪzəʊkənˈstrɪktə
felypressin ˌfelɪˈpresɪn
anesthetic cartridge ˌænəsˈθetɪk ˈkɑːtrɪdʒ
carpule ˈkɑːpjuːl
needle gauge ˈniːdəl ɡeɪdʒ
short needle ʃɔːt ˈniːdəl
long needle lɒŋ ˈniːdəl
needle bevel ˈniːdəl ˈbevəl
aspiration ˌæspəˈreɪʃən
onset time ˈɒnset taɪm
duration of action djʊˈreɪʃən əv ˈækʃən
profound anesthesia prəˈfaʊnd ˌænəsˈθiːziə
pulpal anesthesia ˈpʌlpəl ˌænəsˈθiːziə
soft tissue anesthesia sɒft ˈtɪʃuː ˌænəsˈθiːziə
numb nʌm
wear off weər ɒf
lip numbness lɪp ˈnʌmnəs
tongue numbness tʌŋ ˈnʌmnəs
failed anesthesia feɪld ˌænəsˈθiːziə
hot tooth hɒt tuːθ
sedation sɪˈdeɪʃən
conscious sedation ˈkɒnʃəs sɪˈdeɪʃən
oral sedation ˈɔːrəl sɪˈdeɪʃən
inhalation sedation ˌɪnhəˈleɪʃən sɪˈdeɪʃən
nitrous oxide ˈnaɪtrəs ˈɒksaɪd
laughing gas ˈlɑːfɪŋ ɡæs
intravenous sedation ˌɪntrəˈviːnəs sɪˈdeɪʃən
midazolam mɪˈdæzəlæm
diazepam daɪˈæzɪpæm
general anesthesia ˈdʒenərəl ˌænəsˈθiːziə
anesthetist əˈniːsθətɪst
nil by mouth nɪl baɪ maʊθ
recovery rɪˈkʌvəri
dental anxiety ˈdentəl æŋˈzaɪəti
dental phobia ˈdentəl ˈfəʊbiə
needle phobia ˈniːdəl ˈfəʊbiə
vasovagal syncope ˌveɪzəʊˈveɪɡəl ˈsɪŋkəpi
fainting ˈfeɪntɪŋ
allergic reaction əˈlɜːdʒɪk riˈækʃən
anaphylaxis ˌænəfɪˈlæksɪs
maximum recommended dose ˈmæksɪməm ˌrekəˈmendɪd dəʊs
overdose ˈəʊvədəʊs
toxicity tɒkˈsɪsəti
hematoma ˌhiːməˈtəʊmə
post-injection trismus pəʊst ɪnˈdʒekʃən ˈtrɪzməs
paresthesia ˌpærəsˈθiːziə
lip biting lɪp ˈbaɪtɪŋ
pain threshold peɪn ˈθreʃhəʊld
pain control peɪn kənˈtrəʊl
pain relief peɪn rɪˈliːf

Useful phrases

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Phrase
I'm going to give you an injection now.
You'll feel a small scratch.
Are you allergic to any anaesthetic?
The last time I was numbed, it didn't work properly.
Tell me if you feel any pain and I'll give you more.
Raise your hand if you need me to stop.
Is your lip starting to feel numb?
The numbness will last two or three hours.
Be careful not to bite your lip or cheek while it's numb.
Don't drink anything hot until the feeling comes back.
Can I have something to help me relax?
We can offer sedation if you're very anxious.
I'm very nervous about the needle.
Would you like a topical gel before the injection?

Dental Anesthesia: Fear of the Needle, Numbness and Sedation

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Patient
Before we start — I'm quite nervous about the injection.
Dentist
That's very common. Dental anxiety and needle phobia affect a lot of people — we'll go at your pace.
Patient
Will the local anesthetic hurt?
Dentist
I'll put a topical anesthetic gel on the gum first, so the needle is barely noticeable.
Patient
How long does it take to work?
Dentist
The onset time is usually two to five minutes for an infiltration, a little longer for a nerve block.
Patient
Which one will I need today?
Dentist
For a lower molar I'll give an inferior alveolar nerve block, so your lip and tongue will go numb as well.
Patient
How long will the numbness last?
Dentist
Soft tissue anesthesia can last three to four hours, and it will wear off gradually.
Patient
Can I eat afterwards?
Dentist
Wait until the numbness has gone — while the lip is numb, lip biting happens very easily.
Patient
What if I still feel pain during the treatment?
Dentist
Raise your left hand and I'll stop. If the anesthesia is not profound enough, I can top it up.
Patient
Is there anything for the anxiety itself?
Dentist
We offer inhalation sedation with nitrous oxide — laughing gas. You stay awake but much more relaxed.
Patient
Are there side effects from the adrenaline in the anesthetic?
Dentist
Your heart may beat faster for a minute. It is harmless and passes quickly.

Common mistakes

Avoid these common mistakes

Wrong The dentist gave me an anesthesia before the filling.
Correct The dentist gave me an anesthetic before the filling.

Two nouns from one root with different grammar. Anesthesia is the condition or the technique — uncountable, so no article a: under anesthesia, local anesthesia, profound anesthesia. Anesthetic is the substance — countable: an anesthetic, several anesthetics, a topical anesthetic. The clean pairing is that a clinician administers an anesthetic in order to achieve anesthesia. The adjective form is also anesthetic, as in anesthetic cartridge.

Wrong I would prefer narcosis for this extraction.
Correct I would prefer general anesthesia for this extraction.

Narcosis in English means a drug-induced state of stupor or unconsciousness in a general, often toxicological sense, and its commonest collocation is nitrogen narcosis in diving medicine. It is not the clinical term for surgical sleep. That is general anesthesia. Several European languages use a cognate for the surgical sense — German Narkose, Russian наркоз, Polish narkoza — which makes this one of the most persistent false friends in medical English.

Wrong The nurse will make you an injection now.
Correct The nurse will give you an injection now.

The verb is give or, more formally, administer: give an injection, administer a local anesthetic, deliver the block. Make an injection implies manufacturing the syringe contents. This is a calque shared across many languages — Russian сделать укол, French faire une piqûre, Spanish poner una inyección, Polish zrobić zastrzyk — and it survives well into advanced English. Colloquially patients say a jab in Britain and a shot in America.

Wrong In the United States the anaesthetist is the doctor in charge.
Correct In the United States the anesthesiologist is the doctor in charge.

This is a genuine professional pitfall, not a style choice. In British usage an anaesthetist is a fully qualified physician. In American usage the physician is an anesthesiologist, and an anesthetist — normally a certified registered nurse anesthetist — is an advanced-practice nurse. The spelling splits the same way: British anaesthesia, anaesthetic, anaesthetist with the ae digraph; American anesthesia, anesthetic, anesthesiologist without it. Most international journals follow the American forms.

Wrong How long until the anesthetic finishes?
Correct How long until the anesthetic wears off?

Wear off is the fixed collocation for a drug losing its effect over time: the numbness will wear off in two to four hours, the anesthetic has not worn off yet. Finish and end suggest a scheduled stop rather than a gradual decline. Learn the neighbours at the same time: kick in for beginning to work, top up for adding more, last for duration, and wear off for the tail. Together they cover almost every chairside exchange about numbness.

About This List

Anaesthetic and anaesthesia: drug and state

An anaesthetic is a substance: the dentist gave me a local anaesthetic. Anaesthesia is the absence of sensation: under general anaesthesia. You inject an anaesthetic, never "inject anaesthesia".

Spelling follows the variety: British anaesthesia and anaesthetic, American anesthesia and anesthetic. The drugs split the same way — lignocaine (BrE) and lidocaine (AmE) are one drug, as are adrenaline and epinephrine.

The rest of the formulary: articaine, mepivacaine, prilocaine, bupivacaine, and topical benzocaine. A vasoconstrictor — epinephrine or felypressin — is added to prolong the effect.

Infiltration versus block: why the lower jaw is harder

Infiltration works where bone is porous enough for solution to diffuse through to the root. In the maxilla that is enough, so a buccal infiltration does the job.

Mandibular bone is dense and solution will not cross it. That is why the lower jaw needs a nerve block — anaesthetising the nerve trunk before it enters bone: the inferior alveolar nerve block, with a mental or lingual nerve block when needed.

Supplementary techniques for difficult cases: intraligamentary injection, intraosseous injection, intrapulpal injection, and computer-controlled delivery.

Consumables: an anesthetic cartridge or carpule, a needle of a given needle gauge — short or long needle — its needle bevel, and aspiration before depositing, to avoid an intravascular injection.

Why anaesthesia fails

The effect is described by four parameters: onset time, duration of action, profound anaesthesia when it is complete, and wear off when it goes. Pulpal anaesthesia and soft tissue anaesthesia are separate achievements — the lip can be numb while the tooth is not.

Failed anaesthesia is common enough to have a named cause: a hot tooth, irreversibly inflamed pulp that resists a standard block. Patients report lip numbness and tongue numbness as side effects rather than goals.

Sedation: four levels

  1. oral sedation — a tablet before the appointment
  2. inhalation sedation — nitrous oxide, also laughing gas
  3. intravenous sedation — midazolam or diazepam
  4. general anaesthesia — unconsciousness, with an anaesthetist present

The first three are conscious sedation: the patient stays awake. General anaesthesia brings nil by mouth beforehand and recovery afterwards.

Anxiety belongs here too: dental anxiety, dental phobia, needle phobia, and possible vasovagal syncope — fainting.

Complications: allergic reaction and anaphylaxis, maximum recommended dose, overdose, toxicity, hematoma, post-injection trismus, paresthesia, and lip biting — chewing a numb lip, a particular risk in children.

Usage notes

  • Numb is an adjective and a verb: my lip is numb, we'll numb it first; the noun is numbness
  • Freezing is the North American lay word for local anaesthesia: is the freezing wearing off?
  • Wear off is the standard phrasal verb — not go away or finish
  • Shot is American for an injection; jab is British and informal
  • Narcosis is not a synonym for general anaesthesia in English, though its cognate is in several other languages
  • Block works as noun and verb, but to block a nerve and a nerve block are not interchangeable in a sentence

Frequently Asked Questions

Anesthesia is the state or the technique and is uncountable — local anesthesia, under general anesthesia, profound anesthesia. Anesthetic is the drug and is countable — a local anesthetic, two anesthetics, a topical anesthetic. A clinician administers an anesthetic in order to produce anesthesia.

Both are correct in their own systems. American English drops the digraph: anesthesia, anesthetic, anesthesiologist. British English keeps it: anaesthesia, anaesthetic, anaesthetist. Most international journals follow the American spelling. Whichever you choose, keep it consistent across a document.

An infiltration deposits anesthetic beside the tooth itself, so it numbs a small area and works well in the maxilla, where bone is porous. A nerve block targets a nerve trunk further back and numbs everything it supplies — the inferior alveolar nerve block covers the mandibular molars, half the tongue and the lower lip. That is why block anesthesia produces much wider lip numbness.

A hot tooth is a tooth with irreversible pulpitis that is difficult to numb. Inflammation lowers the pH of surrounding tissue and alters nerve excitability, so a standard block may fail. Clinicians respond with supplementary techniques — intraligamentary injection, intraosseous injection or, as a last resort, intrapulpal injection.

It depends entirely on the country. In the UK an anaesthetist is a consultant physician. In the US the physician is an anesthesiologist, while an anesthetist is normally a certified registered nurse anesthetist, an advanced-practice nurse. Using the wrong title in a job application or referral letter is a real error, not a stylistic one.

Adrenaline, called epinephrine in American usage, is a vasoconstrictor. It narrows local blood vessels, which slows absorption of the anesthetic, deepens and prolongs the effect, and reduces bleeding in the surgical field. Where it is contraindicated, the alternatives are felypressin or a plain cartridge with no vasoconstrictor.

Soft tissue anesthesia usually outlasts pulpal anesthesia, so the lip and tongue stay numb after the tooth is comfortable again — commonly two to four hours, longer with bupivacaine. The phrasal verb is wear off: the numbness will wear off by this evening. Warn patients about lip biting while sensation is absent, which matters most in children.

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