These same pages have highlighted the main limitations of the classical technique of lower alveolar nervous block: the element probably most discussed in the literature is the failure rate. Introducing her 2018 study (Anesthesia Progress), Sara Fowler highlights the painful potential of the injection procedure. One of the empirical methods to reduce the pain stimulus is to slow down the procedure, which results in a reduction in the pressure of diffusion of the anesthetic solution, with a positive return in terms of pain. The controversial aspect is the failure to overcome the dependence on the operator of the procedure: the operator, although an expert in practice, will not be able to ensure a perfect repeatability and, consequently, the results will be subject to a certain degree of variation.
One option to overcome this problem, ensuring control of the pressure ranges, is the computerized system of dental anesthesia, properly called Computer-Controlled Local Anesthetic Device (CCLAD). The main device in this category, the Wand STA has a basic setting that produces the administration of 1.4 mL of anesthetic solution in 4 minutes and 45 seconds, as well as faster programming.
Most studies agree to indicate the decrease of the pain symptom, with particular advantage in the approach to the pediatric patient.
The same working group, in a previous study, found inconsistent efficacy on several points of the oral cavity, experimenting with the conventional technique on the patient in a vertical and supine position. The authors, therefore, wanted to verify whether the equivalent method carried out using the CCLAD system could provide more consistent results.
The prospective randomized study, conducted at Ohio State University, involved 110 healthy and asymptomatic adult patients. Each patient received two administration sessions, two weeks apart, one in a vertical position (armchair angled at 75°, occlusal plane parallel to the floor) and one in a supine position (feet slightly raised from the head, trunk parallel to the floor).
VAS assessments of pain in the needle insertion and solution deposition phases were compared between the vertical and supine position using a repeated measurement variance analysis with post hoc tests. The authors proposed a biphasic administration protocol to further attenuate the stimulus.
The analysis demonstrated that there were no significant differences in pain during the lower alveolar nerve block procedure using CCLAD between supine and vertical positions. The computerized technique is indicated as a choice capable of reducing pain in the deposition phase of the anesthetic compared to the traditional syringe.