Dental anesthesia

Dental anesthesia (or dental anaesthesia) is the application of anesthesia to dentistry. It includes local anesthetics, sedation, and general anesthesia. In dentistry, local anesthetic medications are often used to control any potential pain that may occur with procedures. Local anesthetic injections are given in specific areas of the mouth, rather than the whole body. Although several different medications are available, the most commonly used local anesthetic to prevent pain in the area around a tooth is lidocaine (also called xylocaine). Lidocaine's half-life in the body is about 1.5–2 hours. The time it takes for the anesthetic medication to prevent pain in the area (speed of onset) and length of time that the area does not have painful sensations are considerations when choosing an appropriate approach to dental treatment. Other considerations include procedural considerations, the presence of inflammation, techniques used to administer the anesthetic medication, and adverse effects. In root canal treatment, for example, more Lidocaine is required than for a simple filling.

Maxillary anaesthesia

Local anaesthesia is deposited at the buccal (cheek) side of the maxillary alveolus which can diffuse through the thin cortical plate of the maxilla, then further into the pulp of the tooth in order to achieve dental anaesthesia effect.

Mandibular anaesthesia

Both regional block and infiltration techniques are considered the first choice injections for anaesthetising the mandibular teeth.

Different techniques are chosen based on different factors:

• Patient age
  • Infiltration anaesthesia is a preferable method to anaesthetise deciduous/ primary teeth in children. The method is similar to the maxillary buccal infiltration. Ensure the lip/ cheek is stretched in a lateral and inferior direction instead of superiorly and the needle is then penetrated 45' with the buccal cortical plate of the bone through the taut tissue of the muccobuccal fold.
• Tooth to be anaesthetised
  • Infiltration anaesthesia should be the first choice of method for pulpal and soft tissue anaesthesia of mandibular permanent incisors in adults. Regional block injections are sometimes ineffective due to crossover innervation from the opposite side of inferior alveolar nerve. It is recommended to deposit at least 0.5mL at each buccal and lingual site in the apical region of the tooth of interest. The use of infiltration anaesthesia with 4% articaine with 1:100,000 epinephrine in obtaining pulp anaesthesia of the mandibular permanent first molar is getting more common these days due to its successful formulation.

Regional block techniques

Inferior alveolar and lingual block

The inferior alveolar nerve block is probably one of the most common methods used by dentist to anaesthetise the mandibular teeth in adults. This technique aims to inject the needle and deposit local anaesthetic close the near to the nerve before it enters the mandibular foramen, which locates on the medial aspect of the mandibular ramus. This is to block the nerve transmission in the inferior alveolar nerve before entering into the bone through the mandibular foramen.