Healing pattern of experimental soft tissue lacerations after application of novel topical anesthetic agents - an experimental study in rabbits.

Topical anesthetics based on a combination of 2.5% lidocaine and 2.5% prilocaine are efficient in eliminating pain from needle stick when placed on skin and oral mucosa. This suggests their application in soft tissue lacerations before suturing to enable pain-free exploration and suturing of traumatic lacerations without prior injection needle stick. The aim of the present study was to study the healing of experimental oral lacerations after topical anesthetic substances were placed in the lacerations. Thirty-six standardized incisions were made bilaterally in the lower and the upper labial mucosa of nine white New Zealand rabbits. All wounds were intentionally contaminated with saliva to simulate laceration wounds in trauma situation. EMLA cream and Oraqix thermosetting gel were applied into 30 lacerations and six lacerations were left untreated as control. In some lacerations the topical anesthetic agent was left in the wound, while in others they were rinsed off by saline before suturing the laceration wound. The rabbits were then killed after 3 days, 2 weeks and 4 weeks of healing and the lips were processed for histological evaluation. Similar normal histological healing patterns were seen in wounds in which EMLA and Oraqix were applied compared with control lacerations at all stages of healing. No adverse tissue or foreign body reactions were seen in any of the lacerations. We conclude that EMLA and Oraqix can be used in oral mucosal lacerations prior to suturing without the risk of adverse tissue reaction.