By delivering adequate local anaesthesia, clinicians can perform invasive procedures such as extractions, sub-gingival scaling and deep restorations on patients in a pain-free manner. This ensures the delivery of superior patient care.
STEP 1| Select the correct anaesthetic
Depending on the duration of your procedure, you may opt for anaesthetics with different acting times. The most commonly used is the intermediately acting lignocaine with adrenaline. If patients are allergic to sulphites, adrenaline containing drugs often contain metabisulfites and should be avoided. Hence, these patients will use prilocaine with felypressin.
Short Acting - Use in dentistry may be limited
🌟Articaine
Use in dentistry may be limited
Articaine 4% (40mg/mL) has a maximum dose of 7mg/kg
🌟Lidocaine
Use in dentistry may be limited
🌟Prilocaine
Use in dentistry may be limited
Prilocaine 4% (40mg/mL) has a maximum dose of 6mg/kg
🌟Mepivacaine
Use in dentistry may be limited
Mepivacaine 3% (30mg/mL) has a maximum dose of 1.8mL (3 - 6 years old), 2.7mL (6 - 14 years old), 4.4mL (15 - 17 years old), 6.6mL (adult)
Do not use in children younger than 3 years old
Intermediate Acting - first-line use in dentistry
🌟Lignocaine with adrenaline
First line for routine dental procedures
Do not use in patients with allergies to sulphites, because adrenaline - containing solutions use metabisulfites as a preservative.
Lidocaine 2% (20mg/mL) with adrenaline 1:80000 (12.5 micrograms/ mL) has a maximum dose of 7mg/kg
Maximum number of cartridges = weight (kg) x 7 ÷20 ÷2.2
🌟Prilocaine with felypressin
First line for routine dental procedures when adrenaline is contraindicated
Prilocaine 3% (30mg/mL) with felypressin 0.03 international units/ mL (0.54 micrograms/ mL), and Prilocaine 3% (30mg/mL) with 1:300000 (3.3 micrograms/ mL) have a maximum dose of 9mg/kg
Maximum number of cartridges = weight (kg) x 9 ÷30 ÷2.2
🌟Articaine with adrenaline
Risk of prolonged permanent anaesthesia
For infiltration only - do not use for regional blocks (injections close to the inferior alveolar, lingual and mental nerves
Articaine 4% (40mg/mL) with adrenaline 1:100 000 (10 micrograms/ mL) and Articaine 4% (40mg/mL) with adrenaline 1:200 000 (5 micrograms/ mL) have a maximum dose of 7mg/kg
Do not use in children younger than 4 years old
Do not use in patients with allergies to sulphites, because adrenaline - containing solutions use metabisulfites as a preservative.
🌟Mepivacaine with adrenaline
Do not use in children younger than 3 years old
Do not use in patients with allergies to sulphites, because adrenaline - containing solutions use metabisulfites as a preservative.
Mepivacaine 2% (20mg/mL) with adrenaline 1: 100000 (10 micrograms/ mL) has a maximum dose of 1.8mL (3 - 6 years old), 2.7mL (6 - 14 years old), 4.4mL (15 - 17 years old), 6.6mL (adult)
Long Acting
🌟Ropivacaine
Useful for situations in which prolonged anaesthesia (e.g. 12 - 18 hours) is required, postoperative pain, and refractory acute dental pain
Concentrations up to 0.5% can be used in children
🌟Bupivacaine
Similar indications to ropivacaine
More cardiotoxic than ropivacaine
Cardiac toxicity may manifest before neurological toxicity
do not use in children younger than 12 years old
🌟Bupivacaine with adrenaline (epinenephrine)
Similar indictions to ropivacaine
More cardiotoxic than ropivacaine
Cardiac toxicity may manifest before neurological toxicity
do not use in children younger than 12 years old
STEP 2| Select the Administration Method
Before you administer the anaesthetic, recall the basic anatomy and innervation of the different teeth.
When it comes to local anaesthesia, it can be administered as an infiltration or as a field block. Selecting the right administration route will depend on the procedure and purpose of the procedure.
TOPICAL ADMINISTRATION OF ANAESTHETIC
Before the administration of an infiltration or block, it is essential to apply topical anaesthetic. Analgesia will be achieved in 3 minutes following topical cream application.
INFILTRATION
Often, only a single tooth requires analgesia. In these cases, only the terminal branches of the nerve rather than the entire nerve needs to be anaesthetised. Hence, an injection known as an infiltration is delivered near the site. Analgesia will be achieved in 2 - 3 minutes following an infiltration injection.
Infiltrations CAN be used to numb all maxillary teeth. This is because the anterior portion of the mandible is very thin and allows anaesthetic to penetrate.
Infiltrations CAN be used to numb all mandibular anterior and canine teeth. This is because the anterior portion of the mandible is very thin and allows anaesthetic to penetrate.
Infiltrations CAN be used to numb mandibular premolars. However, the rate of successfully infiltrated lower second premolars is 50% only.
Infiltrations CANNOT be used to numb the mandibular molars. This is because the
buccal mandibular bone surrounding mandibular molars is very dense and cannot allow for the anaesthetic to penetrate.
There are several regions to deliver infiltration.
buccal: This will anaesthetise the pulp of of the tooth, as well as the buccal wall. Often this is indicated for extractions, sub-gingival scaling and deep restoration.
lingual/ palatal: needle enters the root apex of the tooth on the lingual or palatal wall. This is indicated on top of a buccal injection for extractions.
intra-ligamentary: directly into the periodontal ligament space via papilla. This helps to achieve 40 - 60 minutes of profound anaesthesia.
intra-pulpal: directly into the root canal upon opening the access cavity in endodontic treatment
FIELD BLOCKS
A block is indicated when multiple structures or teeth need analgesia. This can include procedures involving multiple restorations, extractions and sub-gingival scaling within the same quadrant. Analgesia will be achieved in 5 minutes following a block.
Maxillary block
The relevant instructions for blocks in the maxilla can be found below.
Anterior Superior Alveolar Nerve Block
Middle Superior Alveolar Nerve Block
Posterior Superior Alveolar Neve Block
Posterior Superior Alveolar Neve Block
Infraorbital Nerve Block
Greater Palatine Nerve Block
Mandibular block
The relevant instructions for blocks in the mandible can be found below.
Buccal block
Incisive/ Mental Block
Inferior Alveolar Nerve Block
Consider the following lines to obtain it for mandibular molars.
Primary: Inferior alveolar nerve block
First line supplementary: Use supplementary Gow-Gayes block if necessary as a first line supplementary technique.
Second line supplementary: buccal infiltration, lingual infiltration
Third line supplementary: intra-osserous, intra-ligamentary, intra-pulpal
Hot tooth syndrome
A tooth can be described as hot and unable to be treated. This usually applies to the mandibular molars. The pulp has been diagnosed with irreversible pulpitis. It is recommended to use an intra-ligamentary or intra-osseous injections to administer LA.
Recommend for the patient to take Nurofen before appointment to facilitate LA. Ibuprofen administration 400mg 1 hour before giving LA, increases the chances of analgesia by 1.85x.
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