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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.

Many techniques can be used for anaesthetizing different region of the maxilla. Supraperiosteal (local) infiltration and regional nerve blocks are the commonly used ones.

Supraperiosteal / Local Infiltration

This is the most common technique used to obtain pulpal anesthesia on a target tooth. In this technique, the needle is bevelled towards the bone, inserted in the mucobuccal fold above the apex of a tooth and advanced until it touches the bone. The needle is then withdrawn a little and the solution is released from the syringe at the rate of 30s/ml to allow the solution to deposit at the surrounding of the nerves. Placing the needle below the periosteum may cause more painful experience and discomfort to the patient.

Local infiltration is considerably very easy to perform with a high success rate. However, when several tooth requires anesthesia  or there is an acute inflammation or infection in the area of injection, it is highly suggested to opt for regional nerve blocks.

Regional Nerve Block

• Maxillary Nerve (V2) block

The maxillary branch (V2) is the second branch of trigeminal nerve. It is effective in anesthetizing all maxillary teeth on one side, bone underlying each teeth, buccal periodontium,, soft tissue, hard palate and part of soft palate, skin of lower eyelid, nose, cheek and upper lip with just a single injection.  It can be achieved with several approaches.

• High-Tuberosity approach

To perform this approach, the patient is positioned supine or semi-supine with his/her mouth partially open and the soft tissue is retracted using the index finger. The needle is then inserted into the mucobuccal fold at 45 degree distal to second molar. The needle is then advanced  posteriorly, superiorly and medially about 30 mm. Anaesthetic solution is then deposited.

• Posterior Superior Alveolar Nerve Block

Posterior superior alveolar nerve innervates the molar teeth of the maxilla, except for the maxillary first molar which only its distobuccal root is innervated by posterior superior alveolar nerve (The mesiobuccal root is innervated by middle superior alveolar nerve). Hence, to anaethetize maxillary first molar, and extra injection (usually infiltration) is required to ensure both roots are well-anaesthetized.

In this approach a short needle is used. This is to prevent distal insertion of the needle which may lead to haematoma. The site of injection is on the mucobuccal fold over the second molar. The needle is then inserted, advanced 16mm upwards, inwards and backwards, followed by the deposition of anesthesia solution.

• Middle Superior Alveolar Nerve Block

Middle superior alveolar nerve innervates the premolar teeth of maxilla, as well as the mesiobuccal root of the maxillary first molar. This block is injected near to the root apex of the premolar tooth / mesiobuccal root apex of the first molar.

• Anterior Superior Alveolar Nerve Block

Anterior Superior Alveolar Nerve Block innervates the maxillary incisors and canine teeth. This block is delivered into the mucobuccal fold adjacent to the tooth, which is near to the root apex.

• Infraorbital Nerve Block

Infraorbital nerve innervates the mucosa and skin surface of one half of the upper lip and part of the skin of the lateral side of the nose. One needs to locate the infraorbital foramen by palpating the infraorbital notch with index finger, then moving down from the notch where convexity of the bone can be felt, indicating the roof of the infraorbital foramen. As one continue palpating inferiorly a concavity is felt. This is the infraorbital foramen. Mild soreness that felt by the the patient when pressing against the foramen. Once the location is identified. A long needle is attended from the mucobuccal fold of the apex of the first premolar, inserted and advanced upwards till it reaches nearby to the infraorbital foramen with approximately half of the needle depth (16mm). The anesthetic solution can be deposited once the needle is in the target area, and one can feel the solution is slowly deposited beneath the finger on the foramen site. To increase the diffusion of the solution into the foramen, firm pressure is maintained with pressing over the injection site around 1 or 2 minutes. The needle is inserted  with an angled position, which is away from the bone; the solution is deposited when the needle is advanced  through the tissue to reduce the pain and prevent tearing of the periodontium.

• Nasopalatine Nerve Block

Nasopalatine nerve mainly innervates mucosa surrounding the incisive papilla and the gingiva margins of the maxillary incisors. This block is aimed to anesthesize the anterior portion of the hard palate, bilaterally mesial to the first premolars. 0.2-0.5ml of anesthetic solution is usually injected into area adjacent to the incisive papilla. However, the nasopalatine nerve block is an extremely painful injection because the soft tissue in this area is dense, adheres firmly to the underlying bone. To reduce the pain, one can anesthetize the dental papilla by inserting the needle between centrals labially, through it to the palatal side near the foramen to deposit  a little solution as to numb the surrounding tissue before the main injection is given.

• Greater Palatine Nerve Block

Greater palatine nerve innervates the bone and palatal soft tissues as far anterior as first premolar. This block is aimed to anesthetize the posterior portion of the hard palate and the overlying tissue near to the greater palatine foramen. The foramen can be located by palpating the area distal to the maxillary second molar. In this approach, 0.5 ml of anesthetic solution is used to block the nerve.