Local Anaesthetic in Dentistry: Nerve Supply and Administration

Flashcards covering nerve supply in dentistry, components of local anaesthetic, administration techniques, patient care, equipment, and safety protocols based on lecture notes.

What are the three main branches of the Trigeminal Nerve (CN V) and their primary functions?

The Ophthalmic (V1) and Maxillary (V2) branches are sensory, while the Mandibular (V3) branch is both sensory and motor.

Which foramen does the Mandibular branch of the Trigeminal nerve enter through, and what structures are protected by the lingula?

The Mandibular branch enters through the Mandibular Foramen, and it protects the Lingual nerve and Inferior alveolar nerve.

What specific area does the Long Buccal nerve supply sensation to?

The Long Buccal nerve supplies sensation to the buccal gingiva only.

What specific area does the Lingual nerve supply sensation to?

The Lingual nerve supplies sensation to the lingual gingiva only.

Which nerve supplies sensation to the lower lip, buccal mucosa, and chin, and through which foramen does it exit?

The Mental nerve, branching off the Inferior Alveolar Dental Nerve (IDN), supplies sensation to these areas and exits through the Mental foramen at the apices of the premolars.

What are the main branches of the Maxillary nerve (V2) relevant to dental anaesthesia?

The main branches are the Posterior superior alveolar, Middle superior alveolar, and Anterior superior alveolar nerves.

Which nerves supply the palatal region, and through which foramina do they enter?

The Nasopalatine nerve enters through the Incisive foramen, and the Greater palatine nerve enters through the Greater palatine foramen, supplying the soft palate.

How is 'anaesthesia' typically defined, and what does local anaesthetic in dentistry actually achieve for the patient?

Anaesthesia is defined as 'LOSS OF ALL SENSATION,' but in dentistry, local anaesthetic typically achieves 'LOSS OF PAIN ONLY,' allowing the patient to still feel pressure and vibration while remaining conscious. It should technically be referred to as 'local analgesia'.

How do local anaesthetics work to prevent pain during dental procedures?

Local anaesthetics work by blocking the electrical transmissions of sensations from the site of stimulation (e.g., tooth or surrounding tissues) along sensory neurons to the brain, preventing the information about painful procedures from reaching the brain.

Who is responsible for deciding and confirming the selection of local anaesthetic equipment, and who is responsible for setting it up?

The operator (dentist) is responsible for deciding and confirming the selection, while the Dental Nurse is responsible for setting up the equipment.

Where should the sharps bin be placed for dismantling the syringe and needle after use?

The sharps bin should be placed next to the operator on the worktop.

What are the five standard components found in a local anaesthetic cartridge?

The five components are: Anaesthetic agent, Sterile water, Buffering agent, Preservative, and Vasoconstrictor.

What is the role of the vasoconstrictor in a local anaesthetic solution, and what is the commonest one used?

The vasoconstrictor prolongs the action of anaesthesia by closing blood vessels, preventing the anaesthetic from being carried away too quickly. Adrenaline (epinephrine) is the commonest vasoconstrictor used.

In which medical conditions should adrenaline (epinephrine) not be used as a vasoconstrictor in local anaesthetics?

Adrenaline cannot be safely used in patients with High BP, Heart disease, or an overactive thyroid gland because it is a potent cardiac stimulant.

What alternatives to adrenaline can be used as vasoconstrictors, and for which patient group is Felypressin contraindicated?

For medically compromised patients, a 'plain' cartridge (no vasoconstrictor) can be used, or Citanest with Octapressin or Felypressin. Felypressin is contraindicated in pregnant patients due to its contractive action on the uterus, which can induce labor.

How can a Dental Nurse support an anxious patient during the delivery of local anaesthetic?

The Dental Nurse can support the patient by discussing prior to treatment, confirming with the operator, demonstrating positive body language, engaging in encouraging chat, holding the patient's hand, and using positive reinforcement like 'almost done, well done!'

What are topical anaesthetics, and why are they used in dentistry?

Topical anaesthetics are gels, creams, or sprays applied to the surface of the mucous membrane before injecting local anaesthetic. They are used to anaesthetize the surface, reducing the discomfort of the needle and improving patient comfort.

What are the four main administration techniques for local anaesthetics in dentistry?

The four methods are Infiltration, Nerve block, Intra-ligamentary, and Intra-osseous.

What is the purpose of the thumb ring on an aspirating syringe, and what action should be taken if blood is aspirated?

The thumb ring allows the operator to 'draw back' (aspirate) to ensure the needle has not penetrated a blood vessel. If blood is aspirated, the needle should be removed, realigned, and a tiny quantity of LA delivered before re-aspirating and continuing if no blood is present.

What is the relationship between the gauge number and the internal diameter of a dental needle?

The larger the gauge number, the smaller the internal diameter of the needle.

For an extraction of an upper permanent central incisor, which nerves typically need to be anaesthetised?

The Superior anterior alveolar nerve and the Naso-palatine nerve.

For the extraction of an upper first premolar tooth, which nerves typically need to be anaesthetised?

The Middle superior alveolar nerve and the Greater palatine nerve.

For the surgical removal of an upper third permanent molar tooth, which nerves typically need to be anaesthetised?

The Posterior superior alveolar nerve and the Greater palatine nerve.

For the extraction of a lower permanent central incisor tooth, which anaesthetic techniques can be administered?

Either an Inferior dental nerve block or buccal and lingual infiltration injections can be administered.

For the extraction of a lower right first molar, which nerves typically need to be anaesthetised?

An Inferior dental nerve block, the Lingual nerve, and the Long buccal nerve.

What specific area does a Posterior Superior Alveolar (PSA) nerve block anaesthetise?

A PSA nerve block anaesthetises the upper 6 distal, 7, 8 and their buccal gingiva.

What specific area does a Greater Palatine nerve block anaesthetise?

A Greater Palatine nerve block anaesthetises the palatal gingiva only of teeth 4, 5, 6, 7, 8.

What specific areas does a Mandibular Inferior Dental Nerve (IDN) block anaesthetise?

An IDN block anaesthetises all lower teeth, the buccal gingiva of teeth 5, 4, 3, 2, 1, the lower lip, and the chin.

What is the safest technique for re-sheathing a dental needle after use?

The one-hand scoop technique is the safest method for re-sheathing. The needle sheath should be placed in a device to hold it firmly and upright, allowing the syringe to be held by its back end while the needle is re-sheathed, keeping fingers away.

What immediate steps should be taken if an inoculation (needlestick) injury occurs with a contaminated needle?

Immediately stop, remove the glove, squeeze the injury area under running tap water to encourage bleeding, dry it, and apply a waterproof dressing. Then, inform the dentist/practice manager, record in the accident book, check the patient's medical history, and contact an occupational health nurse for advice.

What post-operative advice should the Dental Nurse give to a patient after receiving local anaesthetic?

Patients should be advised that sensation will be lost for several hours, to avoid eating or drinking until full sensation returns (to prevent biting or burning), to avoid chewing directly on newly restored teeth, and that a tingling sensation indicates the anaesthetic is wearing off (paraesthesia). They should also be informed that an IDN block or intraligamentary injection may cause local tenderness.