Técnica De Anestesia: Akinosi

The Akinosi technique

This method, which is also known as the Vazirani-Akinosi closed-mouth technique, is useful when conventional block anaesthesia fails (fig. 2a,b). It is simpler than the Gow-Gates method, and uniquely for intra-oral approaches to the inferior alveolar nerve, it does not rely upon contacting a bony end-point. The patient has the mouth closed and the syringe, fitted with a35 mm needle, is advanced parallel to the maxillary occlusal plane at the level of the maxillary muco-gingival junction. The needle is advanced until the hub is level with the distal surface of the maxillary second molar, by which stage it will have penetrated mucosa at a higher level than with the direct approach to the nerve. At this point a cartridge of solution is deposited.

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[pic]The Gow-Gates and Akinosi techniques are both 'high' methods of blocking the inferior alveolar nerve; both anaesthetise the lingual nerve. In addition the Gow-Gates method will block conduction in the long buccal nerve (occasionally this also happens with the Akinosi technique).

The Gow-Gates and Akinosi methods are best reserved for those cases where the conventional block methods fail asthey can produce more complications than the standard approach. The higher the needle is inserted the closer it is to the maxillary artery and the pterygoid plexus. Contacting the maxillary artery can cause pain and produce blanching because of arteriospasm, laceration of vessels in the pterygoid plexus can cause an alarming haematoma which is controlled by firm pressure but may producepost-injection trismus which may last for weeks.

Other methods of anaesthetising man-dibular teeth include infiltration anaesthesia, incisive and mental nerve blocks, intraligamentary (or periodontal ligament), intra-osseous and intra-pulpal methods.

Infiltration anaesthesia

Buccal infiltration anaesthesia in the mandible can be effective in some areas. Indeed in children this may the preferredtechnique when treating the deciduous dentition.8 In adult patients buccal infiltrations may be effective in the mandibular incisor region.

Mental and incisive nerve block

When treating the lower premolar and anterior teeth a mental and incisive nerve block may overcome a failed inferior alveolar nerve block. When using this method 1.5 ml should be injected in the region of the mental foramenwhich is often located between the apices of the lower premolars (available radiographs can be used to accurately localise the foramen).

Intraligamentary and intra-osseous anaesthesia

These techniques rely on the same mechanism to achieve anaesthesia, namely deposition of solution in the cancellous bone of the alveolus. The intraligamentary method gains access to the cancellous space by theperiodontium, the intra-osseous technique by way of a perforation through the buccal gingiva. They can be used in either jaw.

Intraligamentary anaesthesia

This may be used both as a primary or a secondary technique. It has limitations as a principal method of anaesthesia (such as variable duration) but has been used to overcome failed conventional methods.9, 10

The technique is equallyeffective with conventional or specialised syringes. Glass cartridges are used in this method as the plastic type deform under the pressures produced.11

When administering intraligamentary injections the needle is inserted at the mesio-buccal aspect of the root and advanced until maximum penetration. A 12 mm 30 gauge is recommended although efficacy is independent of needle diameter.9, 10 Ideallythe bevel should face the bone although effectiveness is not impaired with different orientations.12 The needle does not penetrate deeply into the periodontal ligament but is wedged at the crest of the alveolar ridge. Around 0.2 ml of solution is injected per root. When using an ordinary dental syringe 0.2 ml is the approximate volume of the cartridge rubber bung. The injection must be delivered...