Inferior alveolar nerve anaesthesia

Inferior alveolar nerve block (abbreviated to IANB, and also termed inferior alveolar nerve anesthesia or inferior dental block) is a nerve block technique which induces anesthesia (numbness) in the areas of the mouth and face innervated by one of the inferior alveolar nerves which are paired on the left and right side. These areas are the skin and mucous membranes of the lower lip, the skin of the chin, the lower teeth and the labial gingiva of the anterior teeth, all unilaterally to the midline of the side on which the block is administered. However, the long buccal nerve is not anesthetized by an IANB and therefore an area of buccal gingiva (gums on the cheek side) of the lower posterior teeth will retain normal sensation unless that nerve is also anesthetized, via a long buccal nerve block. The inferior alveolar nerve is a branch of the mandibular nerve, the third division of the trigeminal nerve. This procedure attempts to anaesthetise the inferior alveolar nerve prior to it entering the mandibular foramen on the medial surface of the mandibular ramus.

Administration of anesthesia near the mandibular foramen causes blockage of the inferior alveolar nerve and the nearby lingual nerve by diffusion (includes supplying the tongue). This causes patients to lose sensation in:

Another symptom is harmless numbness and tingling of the body of the tongue and floor of the mouth, which indicates that the lingual nerve, a branch of the mandibular nerve, is anesthetized. Another symptom that can occur is “lingual shock” as the needle passes by the lingual nerve during administration. The patient may make an involuntary movement, varying from a slight opening of the eyes to jumping in the chair. This symptom is only momentary, and anesthesia will quickly occur.

There are a number of techniques that are commonly used to achieve inferior alveolar nerve anesthesia. The most commonly used techniques involve an attempted block of an entire portion of the inferior alveolar nerve:

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