The pain associated with the injection procedure of local anesthesia is an essential component of dental anxiety and, therefore, a potential, strong, and unfavorable factor regarding the collaboration and therapeutic adherence of the dental patient. Some authors indicate in this procedure that it is the most painful procedure to all intents and purposes during the course of treatment.
This is why, in recent years, there has been a strong clinical interest (and also within the part of the patients themselves) in the methods of painless anesthesia.
One option, in this sense, is represented by the jet injection infusion method. A jet injection system consists of a piston connected to a spring system, capable of leading the anesthetic solution at high pressure into an extremely thin orifice.
From a practical point of view, the handpiece has different adapters for different intraoral sites (in fact, it is also suitable for subcutaneous anesthesia, even self-administered); once placed on the target site, the operator simply presses the plunger. Adapters are available for taking the liquid from the vial tube. The main advantage is the reduction of the risk of contamination, resulting from the failure to dispose of pungent material.
A Brazilian working group (Oliveira and colleagues) proposed to investigate one of these systems in terms of pain, latency time, and period of pharmacological efficacy, comparing it with a traditional injection procedure.
The survey involved a total of 41 subjects who needed middle-sized class-I restorations at the level of both upper first molars. A double-blind split-mouth study model was prepared. The measured outcomes were painful symptoms during the anesthetic procedure (measured by VAS), latency of pulpal anesthesia, and duration of anesthesia, both measured by electrostimulation of the second viable molar.
The results attest to the absence of significant differences in pharmacodynamic data (latency of 2 minutes for both methods, longer duration for the traditional injection procedure) and also the detection of pain data.
The conclusions of this study lead to a different orientation given the breadth of the panorama of painless dental anesthesia. The same authors refer, for example, to a previous study that compared the mean pain symptom related to a systematic jet injection without needle with the computer-controlled local anesthetic delivery (CCLAD) technique. The latter, although cannot be considered as a full-fledged needleless method, showed significantly less average pain relief.