Hypoesthesia after IAN block anesthesia with lidocaine: management of mild to moderate nerve injury
A 36-year-old woman was presented to the department of conservative dentistry in Yonsei University, Dental College, Seoul, Korea. She received a root canal treatment for about five times before, but complained of spontaneous pain on the mandibular right second premolar. She had no specific medical history. The mandibular right second premolar was tested positive response to percussion, so it was diagnosed as previously initiated therapy, and symptomatic apical periodontitis. A nonsurgical root canal treatment was explained to the patient. She understood the treatment options and risk factors and signed the consent forms to proceed with the nonsurgical root canal treatment.\nOn the first day of the treatment, the IAN block anesthesia using 2% lidocaine (1:100,000 epinephrine, Huons Co., Ltd., Sungnam, Korea) was performed, and canal irrigation was done. Two days later, she called to our clinic and complained of feeling numb on her lower right lip and chin area. She also complained about feeling weird when chewing. Since hypoesthesia was suspected, we recommended her to visit our clinic as soon as possible. She visited our clinic two days after the call. She complained about dull sensation lasting on her lower right lip and chin area which is suspected to be a mental nerve innervations region. A Light touch test and pin prick test was performed and scored one-tenth comparing to the normal left side on her lip and chin. Hypoesthesia was diagnosed, so oral steroid was prescribed for a week and the patient was informed about the tapering procedure. Also, on the same day, mapping on the hypoesthetic region was performed ().\nAfter a week, she felt better but tickling sensation persisted on the region. Light touch test and pin prick test was again performed and scored one-half to two-thirds comparing to the left side. It was thought that healing was taking place, so additional medicine was not prescribed. At the 2 weeks follow up, the hypoesthesia was consistently getting better and 80 to 90 percent of sensation was recovered, compared to the left side. Five weeks after hypoesthesia was noticed, mapping was performed again (). Comparing with the first mapping, the hypoesthetic region was decreased in size. During this period, non-surgical root canal treatment was accomplished including several canal irrigation appointments.\nFour months later, she came to our office for a regular check-up. The hypoesthesia was completely resolved.