Overview

Local anaesthetics are topical analgesics and shall not be mixed up with anaesthetics that switch off consciousness. They affect the nerve cells by stabilizing the cell membrane and thereby complicating depolarization (= reduction or cancellation of tension on the separating layer) and as a result suppress the transmission of a pain stimulus. Local anaesthetics are almost entirely used for pain elimination during operations and for pain therapy. The most best-known application is used in dentistry where the dentist injects an anaesthetic so he can, for example, pull a tooth out. Two classes of local anaesthetics are distinguished between: a) the ester-type (historically) which only lasts shortly and represents a relatively high rate of allergisation, for example, Procaine, Tetracaine; b) the amide-type (modern), for example, Articaine, Bupivacaine, Lidocaine, Prilocaine, Ropivacaine. In dentistry in Europe, Articain is used in over 90 % of all applications. Epinephrine is mostly used as an addition. Depending on the phinephrine content, different durations of action can be expected, for example, 1. Without addition of epinephrine: approximately 10 min; 2. With addition of epinephrine 1:200 000: approximately 45 min; 3. With addition of epinephrine 1:100 000: ca. 75 min. The commercially available local anaesthetics are offered in cartridges, snap-off ampoules and multiple-dose vials. 75 % of those anaesthetics are cartridges. This International Standard gives specific performance requirements for single-use dental cartridges of 1,0 ml, 1,7 ml, 1,8 ml and 2,2 ml nominal capacity for use with local anaesthetics. It specifies tests for leakage, plunger movement, extractable volume and underfilling, and lists general overall dimensions to ensure that the cartridge will fit dental cartridge syringes complying with ISO 9997 and ISO 21533. Labelling requirements are also specified. Dental cartridge syringes are specifically manufactured for dentistry. The long design of the cartridge syringes, combined with narrow cartridge syringes, and special injection needles, allows the dentist to inject in a neat manner. He can hold his hand well outside the mouth, even when he sets the injection far back in the mouth (for example, in the area of the wisdom tooth). A shorter syringe would require that he had to put half of this hand into the patient's mouth which would obstruct illumination and the field of vision. The International Standard has been prepared by ISO/TC 106/SC 4/WG 10 "Dental injection systems" (secretariat: BSI, Great Britain), together with CEN/TC 55 "Dentistry" (secretariat: DIN). The responsible committee at DIN is Working Committee NA 014-00-23 AA "Dental medical instruments" of NADENT. The standard describes a colour coding system for the anaesthetic agent and the concentration in the cartridge (for example 2 % Lidocaine = red) and another colour coding system for the vasoconstrictor and its concentration (for example Epinephrine 1:200 000 = orange). The revision of the standard contains now also -in addition to the previously usual volumes of 1,8 ml and 2,2 ml - cartridges with smaller volumes, for example, 1,7 ml and 1,0 ml. Smaller volumes are more suitable for children, since they require a smaller dose due to the smaller body mass so the anaesthetic does not last for long after the treatment. The effect of the local anaesthetics mainly depends on the concentration. This means: the thicker the myelin sheath (the sheath covering the nerve) the more ingredient molecules are required for blocking the nerves.

Document: references other documents

Responsible national committee

NA 014-00-23 AA - Dental medical instruments  

Responsible european committee

CEN/TC 55 - Dentistry  

Responsible international committee

ISO/TC 106/SC 4 - Dental instruments