Local Anaesthetic in Dentistry
Local Anaesthetic in Dentistry
- Last updated January 21, 2026
✅ Objectives
By the end of these revision notes, you should be able to:
- Explain the mode of action and chemistry of local anaesthetic in dentistry
- Identify common formulations used in dentistry
- Discuss potential adverse effects of local anaesthetic
Chemistry and Classification
Local anaesthetics comprise of the same basic structure including:
- A lipophilic aromatic ring – this allows passage of the LA through cell membranes
- An intermediate linkage – this is either an amide or ester
- A hydrophilic amine group – this allows ionisation and water solubility
Amide LAs are the standard local anaesthetic used in dentistry (for example, lidocaine, articaine, prilocaine. Ester LAs, including procaine, are rare in dental practice and are usually used as topical agents.
Mode of Action
Local anaesthetics work by blocking voltage-gated sodium ion channels within nerve fibres. The non-ionised form is lipid soluble and able to penetrate lipid membranes. Therefore, the more non-ionised drug available at physiological pH, the more potent the local anaesthetic is.
The ionised form then binds to sodium ion channels and prevents influx of sodium ions. This prevents depolarisation and stops action potentials.
All nerve fibres will be impacted in the region – initially small fibres but then larger fibres as well.
Components in Local Anaesthetic
Dental local anaesthetic cartridges usually have multiple components including, but not limited to:
- Vasoconstrictor
- This is typically either adrenaline or felypressin
- Advantages – delayed removal of anaesthetic from site, rapid onset of anaesthesia, prolongs anaesthetic effect, reduces operative bleeding
- Disadvantages – prolonged anaesthesia may be unpleasant for some patients, may lead to unwanted systemic effects from adrenaline
- Reducing agents – this prevents the vasoconstrictor from oxidising
Formulations of Local Anaesthetic
🚨 Access Restricted
Subscribe to access ALL revision notes and cheat sheets!
We provide a wide range of revision notes and cheat sheets to help you study and prepare for exams! To access all we have to offer, head over and subscribe to ExamineDental now to supercharge your revision!
and then