Providing the patient with an adequate anesthetic regime in terms of location, depth and duration is essential to the performance of the absolute majority of the procedures conducted daily by the dentist. The operative choices must be legitimately based on the preferences (of the clinician and also of the patient), on the repeatability in terms of effectiveness and, in addition, must be supported by scientific evidence.
Evaluations of this order become even more delicate in some particularly controversial areas. This is the case, for example, of the inferior alveolar nervous block, whose classic technique is flanked by some that differ in success rates and anatomical distribution of the anesthetic effect. Among these, the techniques of Gow-Gates and Vazirani-Akinosi should be mentioned.
Consider, however, the most unfavorable clinical condition to the onset of local anesthesia; i.e., the state of irreversible pulpitis.
At the top of the pyramid of evidence are placed systematic reviews of the literature with meta-analysis: this category includes the study recently published by Nagendrababu and colleagues in the Journal of Endodontics, aimed precisely at comparing the effectiveness of different methods in the management of irreversible pulpitis. The work also includes a trial sequential analysis. The TSA combines a calculation of the amount of information (cumulative sample size of all the trials included) of the meta-analysis with a threshold of statistical significance. It is a useful tool for quantifying the statistical reliability of meta-analysis data by adjusting significance levels for scattered data and repetitive tests on accumulated data.
Starting from more than a thousand studies collected from the databases PubMed, EBSCOhost (Dentistry & Oral Sciences Source), Cochrane Central Register of Controlled Trials and Scopus, updated in June 2019, five randomized clinical trials were led to qualitative and quantitative evaluations, two of which were classified as low bias risk.
Statistical analysis has shown the absence of significant differences between the two main alternative clinical techniques, namely the conventional lower alveolar nerve block and the method of Gow-Gates, undergoing irreversible pulpitis. The cumulative success rate was also deemed low. In both cases, therefore, the resulting clinical recommendation is the use of additional anesthesia. The quality of evidence for the comparison between these two techniques was judged to be moderate by the reviewers.
However, it was not possible to complete the meta-analysis by including the Vazirani-Akinosi technique. A further data that emerges from the study is, therefore, the need to set up new randomized clinical trials well set up, investigating more techniques, with or without additional anesthesia, providing stronger evidence.