| Objective: The effect of bone regeneration and its potential effect on the second molar were observed by comparing the extraction of mandibular impacted wisdom tooth with autologous dental granules in the extraction fossa and the naturally healed tooth extraction nest.Methods: A total of 45 wisdom teeth were selected from 42 patients who were asked to remove the mandibular horizontal or proximal impacted wisdom teeth and whose second molars were shown to have bone defects on curved surface tomograms from October to July 2017.The patients were randomly divided into two groups.Group A was implanted with autologous dental granules as experimental group and B group as blank control group.Group A,18 wisdom teeth,group B,24 patients,27 wisdom teeth.The patients in group A and B were examined for the depth of diagnosis and the loss of attachment at the buccal,middle and lingual sides of the distal and middle sides of the second molar before operation,and the mean values of three points were taken.The height of the distal bone of the second molar(that is,the distance from the top of the alveolar ridge to the occlusal plane)and the bone density of the second molar were measured.In group A,18 patients with wisdom tooth extraction were treated with autologous dental granules machine.The extracted wisdom teeth were made into autologous dental granules and implanted in the extraction fossa near the distal middle root of the second molar.The height of the second molar was fixed with gelatin sponge at the margin of the distal enamel cementum of the second molar.Suture wound,thread compression hemostasis group B patients after wisdom tooth extraction routine cleaning extraction nest,blood clot filled with extraction nest,suture wound,compression hemostasis.The patients were told to remove the thread for 7 days,to record the pain,swelling and bleeding time after operation,to determine whether there was infection or dry groove disease,and to ask the patient to return to the hospital 6 months after the operation,and the second molar was examined by the operator.The depth of probing and loss of attachment in the middle and lingual sides were compared with those before operation,and the distance from the top of the alveolar ridge to the occlusal plane of the mandibular second molar was examined by a curved surface tomograph.The difference between the bone height and the bone height before operation was taken as the regenerated bone mass,and bone regeneration was compared to measure the bone mineral density.Results: 1.All 42 patients in group A and B were disconnected 7 days after operation.The wounds healed normally.All 42 patients had mild to moderate pain and swelling on2 ~ 3 days.After oral anti-inflammatory drugs or infusion,the patients were better.There was no intraoral bleeding after operation.Two patient in group A had significant swelling on the second day after operation,and six patients in group B had swelling and pain after operation.Patients in group A without socket occurrence and 2 patients with dry socket in group B.2.A review six months later showed that:In the experimental group,18 wisdom teeth had good healing,and the second molar had no obvious retraction in the distal gingiva and no discomfort in cold stimulation.There was no significant loosening of the second molars in 15 patients with?°loosening in 3 patients.In the control group,27 wisdom teeth were healed well,of which 4 patients had gingival recession in the second molar,1.5 mm distal to the buccal side of the distal root,sensitive to cold stimulus,and 2.5 mm in the distal buccal side of the second molar in 2 patient and sensitive to cold stimulus.The second molars of 8 cases were loosened ?°and 4 cases of the second molars ?°loosened,while the other cases of the second molars were not obviously loosened.3.A review six months later showed that:Taking the height from the crest of the second molar to its occlusal plane as the bone height,it can be concluded that the height of the second molar distal alveolar bone in group A was 9.25±2.26 at 6 months after operation,which was significantly higher than that of the preoperative alveolar bone height of 15.70±2.60.The difference was statistically significant(P<0.01).The bone mineral density of the second molar was detected by the change of the distal gray level of the second molar on curved surface tomograph.The bone mineral density was 155.45±15.33 at 6 months after operation,which was significantly higher than that of the preoperative alveolar bone density137.73±21.04.The difference was statistically significant(P<0.01).At 6 months after operation,the depth of probing was 3.00±0.52,which was less than that of preoperation6.34±0.84.The difference was statistically significant(P<0.01).At 6 months after operation,the loss of attachment was 0.95±0.568,which was significantly lower than that before operation 4.18±0.90(P<0.01).In 17 cases,there was no periodontal bag in the distal part of the second molar,and one patient had a periodontal bag.Taking the height from the crest of the second molar to its occlusal plane as the bone height,it can be concluded that after the extraction of 27 wisdom teeth in group B at 6 months after operation,the height of the alveolar bone of the second molar was11.24±2.26,which was higher than that of the preoperative alveolar bone 12.90±1.91.The difference was statistically significant(P<0.01).The bone mineral density of the second molar was detected by the change of the distal gray level of the second molar on curved surface tomograph.The bone mineral density was 120.13±25.05 at 6 months after operation,which was not significantly higher than that of the preoperative alveolar bone density 117.47±22.78.There was no significant difference between the two groups(P>0.05).At 6 months after operation,the depth of exploration was 5.00±0.97,which was lower than that before operation5.74±1.01.The difference was statistically significant(P<0.01).At 6 months after operation,the loss of attachment was 2.83±0.94, which was lower than that before operation 3.60±0.97(P<0.01).In one case,the depth and attachment loss of the second molar were further deepened,and the bone height and bone mineral density were lower than those before operation.There were still more than3 mm periodontal pockets in the second molar of 27 patients,more than 7mm in 4patients,more than 5mm in 18 patients,and more than 4mm in 23 patients.4.Six months later,the depth of diagnosis,loss of attachment,alveolar bone regeneration and bone mineral density were compared between the two groups.we can see:There was no significant difference in the depth of exploration between group A and group B before operation(6.34±0.84vs5.74±1.01,P>0.05),but the depth of exploration in group A was significantly lower than that in group B(3.00±0.52vs5.00±0.97,P<0.01)after operation.There was no significant difference in preoperative attachment loss between group A and group B(4.18±0.90vs3.60±0.97,P>0.05),but the postoperative loss of attachment in group A was significantly lower than that in group B(0.95±0.57vs2.83±0.94,P<0.01).The amount of regenerated bone in group A was significantly higher than that in group B(6.45±0.56vs1.66±1.46,P<0.01).There was no significant difference in alveolar bone mineral density between group A and group B(137.73±21.04vs117.47±22.78,P>0.05)before operation,but the alveolar bone density in group A was significantly better than that in group B(155.45±15.33vs120.13±25.05,P<0.01)after operation.Conclusion: 1.After the extraction of impacted mandibular wisdom teeth,the second molar had periodontal bags in the distal part of the second molar,and the regenerated bone of alveolar bone was less,and the periodontal hidden trouble existed.2.After extraction of impacted mandibular wisdom teeth,autologous dental granules was implanted into the extraction fossa.The second molar could regenerate the periodontal tissue in the distal part of the second molar,without periodontal bag,and the elevation of alveolar ridge is ideal. 3.As a new bone graft material,autologous dental granules can promote bone regeneration.It is worth popularizing in clinic because it can promote reuse and it is taken from the waste teeth of patients. |
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