Needle-free injection (synonyms: syringe without needle, jet injection, Injex method; engl. : jet injection) is an injection system the size of a ballpoint pen, with which the anesthetic for local anesthesia is not applied with a hypodermic needle, but by building up high pressure under the mucosa (oral mucosa) for a short time. Syringe phobia (fear of injections) is a common problem in dentistry. It can result in a considerable restriction of a patient’s ability to be treated: out of fear of the injection, children as well as adult patients forego anesthesia (anesthetization). As a result, therapy may have to be interrupted or even stopped more frequently, and only the most necessary treatment measures are carried out. Even secondary diseases caused by omitted dental visits and treatments are accepted by the patient. The Injex system from Rösch AG Medizintechnik originates from insulin therapy (treatment of diabetes) and has been transferred to the dental field.
Indications (areas of application)
The procedure has its crucial area of application in anxiety patients of all ages whose fear of dental treatment is fixed on conventional local anesthesia (local anesthesia) with a cannula (syringe). Here psychological inhibitions can be reduced and in many cases the patient can be given a painless treatment. However, the indication is limited to the treatment of the upper jaw and in the lower jaw to the incisor region, as the depth of effect is not sufficient for the posterior region of the lower jaw. Before the procedure
Before the procedure is performed, the patient should be informed about the various local anesthetic options with their advantages and disadvantages. In particular, he should be prepared for the short-term pressure during the application, which would otherwise unsettle him, which in turn could make the treatment more difficult.
The procedure
A spring is integrated into the system’s pen-sized injector. By briefly pressing a trigger, mechanically driven by spring force, the drug is released from a hair-thin micro orifice in a fraction of a second. If the injector is positioned correctly, i.e. with sufficient contact pressure applied at right angles to the area to be anesthetized, the drug passes directly through the mucosa (mucous membrane) into the underlying tissue. The anesthetic effect occurs more quickly with needle-free injection than with conventional infiltration anesthesia, in which the local anesthetic is injected directly into the tissue in the surgical area). Tissue damage at the site of application is no greater than with the insertion of a cannula; in fact, the pressure-driven fluid jet is even thinner than a fine injection cannula. Advantages:
- Needle-free procedure
- This removes the basis of a phobia of syringes tied to the puncture: Fear reduction
- Faster onset of action
- All commercially available anesthetics can be used in the injector of the system
- Pen-like appearance, also thereby reduction of syringe anxiety.
- Gentle on the skin because the drug jet delivered through a micro orifice is even thinner than a hypodermic needle (0.18 mm compared to at least 0.25 mm)
- Tissue-sparing: pressure and speed are adjusted so that the anesthetic is applied into the submucosal fatty tissue (under the mucosa) without causing damage to vessels, nerve fibers, and muscles
- Safe to use, as there is no risk of injury if a patient makes defensive movements, as may well be the case with conventional anesthesia at some point
- Safer also for dental staff, as the number of needlestick injuries and the resulting risk of infection are reduced
- Application is almost painless, even if a short-termDruckgefühl can not be avoided
- Low injection volume, thereby risk of side effects lower
Disadvantages:
- Low injection volume (maximum 0.5 ml), which means that sufficient depth of anesthesia cannot be achieved in every case
- The procedure should be considered only as a substitute for dental infiltration anesthesia.It cannot replace a conduction anesthesia, for example, for the posterior teeth of the mandible, because the mandibular bone, which is very massive in this area, cannot be penetrated.
After the procedure
The Injex system is reusable. The activation of the spring is done by means of a reset box. To work hygienically, sterile disposables are used to refill the system with anesthetic.
Possible complications
Complications rarely occur due to the safety of the procedure. Apart from the possibility of drug intolerance, which needle-free injection has in common with all other local anesthetic procedures, the following complications may be observed:
- Hematoma (bruise) in the application area, e.g., due to tilting of the angle of application.
- Due to the small injection volume can not always be achieved sufficient pain inhibition
- Wet Shot: when the injector is placed on the injection site with insufficient contact pressure or at the wrong angle, the full dose of anesthetic is not administered, the risk of hematoma and bleeding is increased
Contraindications
Allergy to the anesthetic or any of the additives.
