The criteria defined below refer to the recommendations provided by the American Dental Association (ADA) and also approved by the American Academy of Pediatric Dentistry (AAPD). The ADA is proposing its own general standards in the field of local anaesthesia in dentistry, adapting them to the real-life situation and to the specific demands of pediatric patients. The objective will hence remain that of ensuring effective and lasting local anaesthesia, compatible with the performance of clinical procedures.
A precaution of primary importance in syringe assembly is to ensure there is effective aspiration before injection. Thus, needles which will allow this procedure to be performed must be selected. Needles with a larger diameter are subject to less distortion when passing through soft tissues. The precise internal diameter, measured in terms of its Gauge, and expressed as an inverse proportion, is considered. The values range from 23 to 30 Gauge. As regards the length, 32 mm, 20 mm or 10 mm needles are commonly used, the first two simply being defined as “long” or “short” in practice. The insertion depth varies according to the technique and also according to the age and build of the subject.
However, rupture of the needle, though a rare complication, must be considered. It basically occurs when the needle is inserted too deep (up to the needle hub area) and is even more likely if it was previously bent, or if the patient moves following its insertion. This last variable is significant when dealing with pediatric patients. It is most likely to happen when performing regional anaesthesia, inferior alveolar nerve block, in which the needle penetrates deeper into the tissues; this approach can be avoided in many cases thanks to the proven efficacy of intraligamentary anaesthesia.
Local anaesthesia and children at the dentist: which compound should be chosen?
As regards the choice of which compound to use, as already stated that this must be compatible with clinical timeframes. In this regard, it is inadvisable to subject children to prolonged sessions in the chair which might jeopardise their future collaboration. For the same reason long-acting anaesthetics should be avoided. Compounds with a less prolonged effect should therefore be preferred, administered over several short sessions (if necessary). Care also needs to be taken in the opposite direction. The use of rapidly-eliminated drugs could, in fact, more easily lead to their accumulation in the blood. In this sense, paradoxically, ADA advises that particular care should be taken when using local anaesthetics without a vasoconstrictor. The fundamental criterion to be used is therefore the maximum dose of drug which should not be exceeded. This information is calculated on the patient’s weight (or body mass index). The AAPD also provides recommendations for each compound which can be converted into the number of cartridges.