The conventional technique of lower alveolar block involves an area comprising, in addition to the lower arch quadrant, the anterior 2/3 of the tongue, the oral floor and the corresponding lingual covering tissues, normally excluding the vestibular soft tissue distal to the mental foramen. Therefore, the procedure requires co-administration of the long buccal nerve.
In the literature there is no full agreement about the volume of anesthetic solution to be administered: some authors say from 1/4 to 1/2 of the cartridge, others say to use 1.5 mL for the main administration, leaving a residue of 0.3 mL for the long buccal nerve. Malamed agrees with this last indication.
The variable success rate (described between 55 and 95% in the extraction of a dental tooth). Some authors would point out that inadequate anesthesia of the buccal nerve and insufficient volume of administration are among the causes of failure.
The anterior approach of the lower alveolar block involves the administration of the anesthetic within the pterygomandibular space, anterior to the mandibular foramen. Some authors have proposed to increase the volume of anesthetic solution from 1.8 mL (equal to a standard vial tube) to 2.7 mL.
A radiological study (on CT) by Okamoto showed that, through this technique, the anesthetic solution is able to diffuse beyond the tendon of insertion of the temporal muscle. The success rate for an extraction is approximately 75%.
Recently, Tsukimoto has proposed to investigate the effectiveness of the technique and the higher dosage of anesthetic, assessing the effective action on the area of the long buccal nerve and the success rate in general.
The study involved a total of 108 patients involved in the extraction of the third molar. In addition, ten volunteers underwent an evaluation by nuclear magnetic resonance imaging.
The success rate for the anterior approach with increased volume (2.7 mL) was 96%, a significantly higher figure than the standard quantity (67%). It is interesting that in the conventional technique the increase in dosage did not lead to a similar variation (78% against 81%).
The MRI study confirmed fluid distribution beyond the anterior surface of the temporal muscle insertion tendon.
In conclusion, the authors have indicated in the anterior approach to increased volume an alternative method of lower alveolar block, which is a technique that can increase the anesthetic efficacy in the extraction of the third molar. It guarantees rapid onset and involvement of the vestibular tissues innervated by the buccal nerve. The use of the technique can, therefore, be recommended in all oral surgery operations involving the posterior area of the mandible.