Preliminarily Clinical Study Of Partial Odontoectomy Extraction Of Impacted Lower Third Molar Close Toinferior Alveolar Nerve

Objective:Combined with cone beam computed tomography imaging examination, through the measurement and analysis on the postoperative pain, dentine hypersensitivity,infection and residual tooth tissue movement of partial odontoectomy, preliminarily explore the common problems and the influencing factors after surgey of partial odontoectomy so as to provide reference significance for clinical.Method:Between September 2012 and September 2014,patients presenting to the Integrated Department of The Affiliated Stomatological Hospital of Nanchang University, for removal of impacted mandibular third molars. This study selected the40 cases of patients, 18 patients are male, 22 patients are female, the mean age of the patients was 29.6 years old(SD, 6.0), the youngest patient was 20 years old, and the oldest was 40 at the time of the investigation. 44 impacted mandibular third molars,23 in left side, 21 in right side, 17 horizontal impaction and 27 mesioangular impaction.The main predetermined inclusion criteria was that the root of impacted mandibular third molars touched or compressing with the superior and Inferior cortical line of the inferior alveolar nerve canal with cone beam computed tomography scanning. Postoperative 24 hours and 7 days of partial odontoectomy, the patients need the further consultation to record the postoperative pain,dentine hypersensitivity and infection.Take cone beam computed tomography scanning again at 6th month after surgey and measure the migration of residual tooth tissue. After completely departed from the inferior alveolar nerve canal, remove the residual tooth tissue, and detect the sensory function of inferior alveolar nerve one week postoperative. Statistical analysis was performed with SPSS 19.0 software. The level of significance was set at P<0.05, a=0.05. Additionally, multivariate linear regression analysis was applied to postoperative pain and the movement of the residual tooth.logistic regression analysis was applied to dentine hypersensitivity.Result:1.44 impacted molars have no infection after partial odontoectomy.Postoperative no cases of inferior alveolar nerve deficit were noted after remove the residual tooth tissue.2. the proportion of patients who presented postoperatively with pain was 31.8%(14/44) in 24 hours postoperative, the mean pain VAS score was 1.4(SD, 2.2),Significant associations were found between postoperative pain and status of eruption and depth of impacted by multivariate linear regression analysis(p<0.05). The postoperative pain with impaction in low and unerupted is severer than the high and erupted. No cases of postoperative pain was noted on the 7th day after surgery.3. 79.5%(35/44) of dentine hypersensitivity were reportd on the 24 hours after surgery, the sensitivity score of 1,2 and 3 accounts for 9.1%, 36.4%, and 34.1%,respectively. There was a highly significant association between dentine hypersensitivity and status of eruption, impacted depth and dental pulp exposure by logistic regression analysis(p<0.05). The sensitivity degree with dental pulp exposure is severer than non-exposure after surgery, while the sensitivity degree with the high and the unerupted impaction is lighter than the low and the erupted. The dentine hypersensitivity incidence is reduced to 27.3%(12/44) on the 7th day after surgery, the sensitivity score of 1 and 2 accounts for 18.2%(8/44) and 9.1%(4/44),respectively.4. All the residual tooth tissues departed from inferior alveolar nerve canal, the mean movement is 2.5mm(SD, 0.6mm) in the 6th month postoperative, There was a highly significant association between the movement and the age by multivariate linear regression analysis(p<0.05), the elder the age is, the movement is smaller,while the younger the age is, the movement is bigger.Conclusions1. The extraction of partial odontoectomy is easy and simple on operation,and the postoperative complication is little.2. 2.Partial odontoectomy is a preferable technique for patients who run a risk of injury to the inferior alveolar nerve during mandibular third molar surgery with mesioangular and horizontal impacted.