[Topical application of local anesthetics and opioids after elective tooth extraction]

The aim of this study was to provide evidence for the peripheral effect of opioids in oromaxillary procedures and to investigate whether postoperative morphine sulfate plus lidocaine administered as a local spray achieve better analgesic efficacy than lidocaine applied alone. The double-blind randomized study included 60 patients. The patients exhibited neither preoperative pain nor inflammation (tooth extractions) and when pain occurred received as alternative medication diclofenac retard 50 mg or tramadol. Side effects were documented. No differences between the two groups were observed in the demographic data, visual and numeric analog scale in the first 24 h, or in the consumption of analgesics. Since the patients presented in a pain-free state at the time of surgery, apparently no activation of the peripheral opioid receptors occurs. Thus, a peripheral effect of opioids could not be demonstrated in this model.