The lower dental arch is a complex anatomical site from the point of view of innervation and, consequently, the approach to anesthesia. The posterior sites are normally approached with the lower alveolar nerve block, which intercepts the nerve before it enters the mandibular foramen. At the mandibular level, however, at least one other block technique can be used, i.e. dedicated to a nerve fiber of relevant caliber and precise course. In this case, reference is made to the mental/incisive nerve block. This is addressed to the same lower alveolar nerve trunk which, after having emitted a series of perforating branches during the course along the mandibular canal, comes out of the mental foramen, normally placed between the apexes of the two premolars. Therefore, this method, which consists of a buccal infiltration injection in the estimated site (indicated in this sense the radiographic finding) of the foramen, is an option to be considered in view of a treatment of an inferior premolar, precisely.
Starting from these assumptions, an interesting study recently published in Clinical Oral Investigation asked whether the mental/incisive nervous block, with the same anesthetic molecule, can be a perfect alternative to the lower alveolar nervous block in the treatment of lower premolars in the most unfavorable condition from the anesthesiologic point of view, irreversible acute pulpitis .
The study involved a total of 64 patients aged between 18 and 65 years, all reporting an established condition of irreversible pulpitis – response to cold tests and tests of electrical stimulation and active bleeding at the opening of the pulpal chamber – in one of the lower premolars. The study was set up as a randomized parallel double-blind clinical trial (observer and statistician). Each subject was randomly assigned to one of the two treatment groups; the procedures were conducted using a standardized technique by the same operator. In all cases, the same molecule (4% articaine with 1:100000 epinephrine) was used in the same quantity (1.8 mL, equal to a cartridge) with the same type of needle (27 Gauge per 31 mm). In all cases, the treatment was started 10 minutes after the onset of the symptom of lip numbness and the painful stimulus – and consequently the success of the anesthetic maneuver – was evaluated on a visual-analog scale.
The mental/incisor nerve block showed a significantly reduced onset time compared to the inferior alveolar nerve block, as well as a higher success rate (93.8% versus 81.2%), albeit in a statistically insignificant manner. The negative aspect was a significantly higher discomfort in the following 4 days. In virtue of the greater operational simplicity, however, it can be concluded with the indication in the first method as a valid alternative to the second in the treatment of lower premolars, even during irreversible acute pulpitis.