Anesthetic Efficacy of Meperidine in Teeth With Symptomatic Irreversible Pulpitis

Achieving adequate pulpal anesthesia in mandibular teeth is always a challenge. Supplementary injections and using drugs in combination are some methods implemented to overcome this hurdle. In this randomized clinical trial, use of meperidine in conjunction with lidocaine in intraligamentary injection did not exhibit significant improvement in anesthesia.Key Words: Periodontal ligament, Meperidine, Irreversible pulpitis, Dental anesthesiaThe failure rate of the inferior alveolar nerve block (IANB) in some experimental studies has been reported up to 75%.^1–4 This lack of success has even increased to a maximum of 81% in some recent studies.^5–7 To overcome this shortcoming, dental clinicians have actively sought measures to improve the patients'' anesthesia during different dental procedures. Apart from the anatomical variations mentioned in the applied anatomy of injections,⁸ several authors have attempted to modify the anesthetic technique,^9–12 and others have compared different anesthetic agents¹³ or their concentrations¹⁴ to improve their efficacy.Activating the opioid receptors peripherally in inflammatory conditions has become a new trend in research to manage postoperative pain.¹⁵ Synergy between local anesthetics and opioids has become an interesting field of research recently.¹⁶ Opioids are frequently added to local anesthetics in a variety of surgical procedures, eg, intrathecal application for minor surgery.¹⁷ Meperidine or its derivatives, eg, pethidine (meperidine chloride) or norpethidine (Pethidine Intermediate B) are agonists of μ-opioid receptors, which block the pathway of pain signals to the trigeminal nucleus. They also activate peripheral opioid receptors and block sodium channels.^17–22 Despite controversy regarding the use of meperidine as an anesthetic,²² recent studies have demonstrated its benefits over prilocaine in arthroscopy with local anesthesia,¹⁶ nasal packing removal,²³ etc.However, only a few studies have investigated the dental anesthetic efficacy of such combinations.^24,25 The effect of the addition of meperidine to lidocaine in IANB for pain management in normal teeth²⁴ and also in teeth with irreversible pulpitis²⁵ has been studied. The aim of our study was to compare the efficacy of local anesthetics with and without meperidine for intraligamentary supplemental injection for teeth with irreversible pulpitis. Our null hypothesis stated that the addition of meperidine to standard lidocaine with epinephrine does not improve the efficacy of supplemental intraligamentary anesthesia in teeth with symptomatic irreversible pulpitis. The specific objectives were to randomly allocate volunteers with complete soft tissue anesthesia following an IANB, yet having positive pulp response, into 2 groups, and then compare the efficacy of lidocaine with epinephrine plus meperidine with that of lidocaine with epinephrine plus an equal volume of sterile water for supplemental periodontal ligament anesthesia.