The main framework of endodontic urgency, i.e. the state of irreversible pulpitis, is also one of the strictest limits in the field of dental anesthesiology.
Obtaining an adequate pain control regimen, in fact, represents a fundamental requirement in the approach to a patient suffering this much. On the other hand, the acidic and hyperemic pulp environment has a negative effect on the pharmacokinetics of the anesthetic drug, both hindering concentration and encouraging early removal. Getting full pulpal anesthesia is therefore somewhat arduous.
Several clinical studies – some of which have appeared in this publication – have considered the problem, proposing extremely diverse clinical solutions: from increasing the volume administered, to changing the pharmacological drug, to premedication with oral analgesic drugs, up to administering additional anesthetic injection procedures.
The Zanjir working group recently conducted a systematic review of the literature on the subject, aiming to provide a complete evaluation from which to draw evidence-based indications on the safest and most effective clinical options. The results were published in late 2019 in an article that appeared in the Journal of Endodontics.
The research, updated in February 2018, mainly used the MEDLINE, Embase, Cochrane Central, CINAHL and Scopus databases to obtain a pool of over 2,000 records (674 once duplicates had been removed). Only randomized clinical trials were included, referring to lower molars in a state of irreversible pulpitis, approached with routine anesthesia methods, and endodontically treated without surgery. 133 full-texts were considered, 87 of which were excluded for not complying with the above criteria.
The remaining 46 studies were all qualitatively evaluated, then underwent network meta-analysis, a procedure indicated for simultaneously comparing different treatments, combining the direct and indirect evidence of the RCT sample.
Almost all the studies indicate that they evaluated samples of the adult population (18–68 years old), with the diagnosis of irreversible pulpitis (in the lower molars or premolars) made by cold test and/or electric pulp test. Most patients evaluated with a visual-analog scale (VAS) reported moderate to severe preoperative pain symptoms.
With regard to the approach, the most widespread primary local anesthesia technique is the inferior alveolar nerve block, followed by these techniques: Gow-Gates, Vazirani-Akinosi, vestibular infiltration, vestibular infiltration with or without lingual infiltration, intraligamentary anesthesia. Vestibular infiltration, intraligamentary, intraosseous and Gow-Gates, in this order, are the most used additional methods. To which are added, beyond the different anesthetic formulations, the different drugs used in premedication: NSAIDs, paracetamol, opiates. In total, there are 37 approaches in the 46 studies.
Overall, the authors admit to having evidence available with varying levels of quality, from very low to moderate. Buccal or vestibular infiltration with 4% articaine and 1:100000 adrenaline and intraosseous injection have proven to be effective for pulpal anesthesia in cases of irreversible pulpitis. Premedication with NSAIDs or opioids, potentially associated with paracetamol, can increase the effectiveness of these anesthetic procedures.