Profound anesthesia is the goal when treating patients who present to the dental office with symptoms of irreversible pulpitis. Inferior alveolar nerve block (IANB) is the standard injection technique used to achieve regional anesthesia for mandibular molar treatments. Studies have shown that the IANB technique fails in 30% to 90% of these cases.
To evaluate the effect of preop-erative oral ibuprofen on IANB with 2% mepivacaine containing 1:100,000 epinephrine for patients with symptomatic irreversible pulpitis, Noguera-Gonzalez et al from Universidad Autonoma de San Luis Potosi, Mexico, conducted a prospective, randomized, double-blind, placebo-controlled study.
The study included 2 study groups, each consisting of 25 patients who exhibited symptomatic irreversible pulpitis of a mandibular posterior tooth. The patients presented prolonged moderate or severe pain (>10 seconds) after cold testing and indicated their pain scores on a Heft-Parker visual analog scale. The patients received identically appearing capsules containing either 600 mg ibuprofen or gelatin placebo 1 hour before administration of IANB with 2% mepivacaine containing 1:100,000 epinephrine.
After 15 minutes, the anesthetic blockade was assessed by a 3-step examination (lip numbness, positive/negative response to cold testing and clinical discomfort during endodontic access). IANB success was defined as the absence of pain during any of these evaluations.
After IANB, all the patients reported lip numbness. Statistically significant differences were measured between the ibuprofen and placebo (p < .05); the IANB success rates were 72% (18/25) in the ibuprofen group and 36% (9/25) in the placebo group.
Table 1 indicates the pre- and post-operative pain in both treatment groups. At 24 hours, only 4 patients had moderate-to-severe pain (1 in the ibuprofen group and 3 in the placebo group). At 48 hours, no patients reported pain. No patient reported adverse effects or flare-ups from ibuprofen or placebo.
The results of this study allow for the following hypotheses:
■ Selection of mepivacaine over lidocaine may achieve superior levels of anesthesia during inflam-matory conditions, such as irrevers-ible pulpitis, especially when the expression of tetrodotoxin-resistant sodium channels is up-regulated.
■ Premedication with ibuprofen plays an important role in controlling the expression of prostaglandin E2 in peripheral and central tissues, where overexpression is observed during painful dental inflamma-tion. This factor might contribute to improved anesthetic blockade during painful clinical conditions.
■ Premedication with ibuprofen may indirectly enhance the effect of mepivacaine by reducing the expression of tetrodotoxin-resistant sodium channels.
Preoperative oral administration of ibuprofen significantly improved the efficacy of mepivacaine IANB in patients with symptomatic irreversible pulpitis.