Partial Coronectomy Combined With Orthodontic Extrusion Stepwise Approach Of Impacted Mandibular 3rd Molar Extraction: Case Report

Purpose:To investigate the safeness of stepwise approach of impacted mandibular 3rd molar extraction through coronectomy combined with orthodontic extrusion.The study was conducted by examining the post-operative pain,infection,and tactile sensation of the facial region and to show that this treatment modality was a mean to reduce post-operative complication and to provide better prognosis.Methods:All of the cases were collected from a certain implant center in Taiwan(2014.12~2016.12),and apparently they were all shared by a common chief complaint “ Ask for lower 3rd molar extraction”.10 cases were selected as study models through CT,PANO or PAF examination,which were shown to have IAN in close proximity to mandibular 3rd molar.They were 4 males and 6 females,with age range 21~63 years old,and average was 34.5 years of age.3 of them were mesial tipping impaction,and the other 7 cases were horizontal impaction.The treatment was conducted in a 2 steps approach.1st step: a partial coronectomy of the impacted mandibular 3rd molar was done,followed by attachment of orthodontic auxiliary to the remaining mandibular 3rd molar.The force exerted through the orthodontic appliance would gradually extrude the root tip away from IAN.A 3 days post-op follow-up was arranged to assess the post-op pain,the foreign body sensation and the damage of mucosa etc.A 7 days post-op follow-up was arranged to remove suture and to determine the status wound healing.Then an average of 2-3 week routine follow-ups were set-up to adjust the force of extrusion and to examine the relationship between IAN and the mandibular 2nd and 3rd molars both clinically and radiographically.2nd step:orthodontic appliance was removed and the remaining mandibular 3rd molar was extracted completely under local anesthesia.Appointment for suture removal 7 days post-op and the post-op pain and status of wound healing were also assessed.Test of tactile sensation of facial region was conducted 7 days,1 month,3 months and 6 months post-op respectively.Results:None of the cases showed any sign of post-op infection of the wound nor on the surrounding mucosa of anchorage tooth after the 1st step,and no facial paresthesia nor IAN damage was detected after the complete extraction.One case was presented with post-op pain and another one with post-op swelling.Once the 2nd step was done,test of tactile sensation of facial region was conducted 7 days,1 month,3 months and 6 months post-op respectively,and the results turned out to be normal in all 10 cases.Conclusion:The stepwise approach of impacted mandibular 3rd molar extraction had been proven to reduce the chance of IAN damage and improves the prognosis of the treatment.