Anesth Essays Respect

Successful local anesthesia is required for control of pain during dental procedures. Anesthesia should also occur with a low rate of additional complications, such as positive aspiration, swelling and so on. The inferior alveolar nerve block is the most commonly used block during oral surgery. However, this block has a comparatively high failure rate29, mainly because of inter-patient anatomic variations. Therefore, various other nerve blocks were utilized over time to improve the success rate of anesthesia. The G-G and V-A methods discussed in this paper have been the most important alternatives. They differ from the conventional IANB technique in terms of the location of the injection point. From the analysis of the RCTs included above, it can be concluded that G-G and V-A techniques enjoy several advantages over IANB techniques when utilized during mandibular third molar extraction. The results suggest that they may be a useful alternative to IANB with regard to an increase in anesthetic success and a decrease in clinically dangerous positive aspiration.

Some studies even suggest that these alternative techniques may decrease the incidence of certain complications such as swelling and pain in the injection area. With respect to these ancillary advantages of the alternative techniques, however, not enough research has been done to conclude via meta-analysis that G-G or V-A can de facto reduce such complications.

The meta-analysis has, however, uncovered one enigma: the analgesic onset time of both G-G and V-A is longer than of IANB. The reasons for this are not clear. But because they differ from the IANB technique principally in terms of the location of various injection points, one could hypothesize that a slower onset time might be a result of different anatomic factors associated with different injection areas. Among these factors could be differences in nerve distribution, in blood flow condition, or even in soft tissue conditions associated with distinct injection areas.

In IANB the anesthetic is injected in the pterygo-submandibular space, the posterior boundary of which is the parotid gland, exterior the ramus of the mandible, interior and inferior the medial pterygoid, superior the external pterygoid, and anterior the masseter. The G-G method consists somewhat of a type of “high” inferior alveolar nerve block anesthesia, whose anesthetic is injected principally at the mandibular condylar region. In the V-A approach, the anesthetic is injected into the upper part of the pterygo-mandibular space, so that the three branches of the mandibular nerve (the inferior alveolar, lingual and buccal nerves) are anesthetized.

It should also be pointed out that, due to various confounding variables, such as types and concentrations of anesthetic substances adopted in these seven RCTs, as well as differential levels of experience on the part of those administering the anesthesia, it is not possible to formulate absolute conclusions concerning their properties of onset time, success rate and positive aspiration rate. Four of the studies used lidocaine, one adopted articaine and two did not describe the drug type. ALLEN L 1896 conducted local anesthesia with administration of 8 ml 2% lidocaine in V-A while using 2.3 ml in the IANB group. Fei Wang 2002 utilized 3 ml 2% lidocaine in both the IANB and the G-G groups. Jieping Yang 2013 utilized 3–5 ml 2% lidocaine in both the IANB and the G-G groups. Jiacai He 2000 used 2 ml 2% lidocaine in both IANB and V-A. Martinez, G 2003 used 1.8 ml 4% articaine in both IANB and V-A. Jizhong Lv 2009 and Diandian Li 2009 did not provide specific details about anesthetic types and concentrations in each group. Apart from these variations among the studies, the issue of different concentrations of epinephrine also arises. Martinez, G 2003 ALLEN L 1896 and Jieping Yang 2013 adopted a 1:100,000 concentration of epinephrine. Jiacai He 2000 also added an unspecified amount epinephrine in the anesthesia. The remaining three RCTs had no information on this matter. It is true that previous research showed that the concentration of epinephrine does not influence the anesthetic success rate of IANB30. However, there is not enough evidences to indicate whether epinephrine concentration will affect the anesthetic effectiveness and safety of the G-G and V-A methods. Variations in these factors might lead to a higher index of heterogeneity, which could arguably weaken the results of this meta-analysis.

Despite the presence of these limitations, however, this meta-analysis has successfully compared intervention and control techniques under similar conditions. It seemed both logical and valid to pool together data from these studies. On the other hand, further studies should be undertaken that would take into consideration variables such as anesthetic and epinephrine types and concentrations to verify these findings.

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