Investigation Of The Effect Of Low-intensity Pulsed Ultrasound On Promoting Dogs' Periodontal Tissues Repair In BIO-GIDE Membrance Guided Periodontal Tissue Regenerated Surgery

Paradentosis is a chronic bacterial infectious disease. It mainly shows destruction of periodontal tissue, leading to tooth depression and missing teeth,etc.In particular,Guided Tissue Regeneration (GTR) was needed if there were periodontal tissue defecting evidences ,depth of pocket (PD) deepened , local bacteria plaque controlled difficult。Conventional treatment was difficult to cure in the periodontal disease of root bifurcation more than degreeⅡ. However, this surgery had some limitations,such as strict indications,highly technical operation in surgery,slow and limited effects in regenerative repair. So a new complementary therapy is needed to be digged out.As a safe and non-invasive treatment,LIPUS (Low Intensity Pulsed Ultrasound), certificated by the FDA,plays a significant role in promotion of fracture healing and treatment of bone nonunion. In addition,preliminary study found that LIPUS could promote the regeneration of alveolar bone and increase the optical density and paturity of the alveolar bone. It prompted that LIPUS as adjunct treatment of GTR surgery in paradentosis treatment would be used in potential application.Objects of this study were the bilateral mandibular third and fourth premolars of 8 adult male Beagle dogs. We established the periodontal disease of root bifurcation degreeⅡmodels by removing alveolar bone rapidly,ligating teeth using stainless steel silk and feeding them with high sugar and high viscosity .The dogs were randomly selected into 2 time groups(6 weeks control group and 8 weeks control group ). In each group,the number of the teeth was 24. They were randomly selected into 4 groups,which were periodontal flap surgery group , GTR(Bio-Gide collagen membrane+canine autologous bone graft)surgery group,periodontal flap surgery +LIPUS group , LIPUS joint GTR(Bio-Gide collagen membrane+canine autologous bone graft)surgery group. In this experiment,on the dog 's same side,if a tooth had been selected as the experimental one after LIPUS irradiation, ipsilateral other experimental teeth were not elected to non-LIPUS exposure group. The aim of this was to avoid the adjacent tissue of LIPUS.For 6 weeks and 8 weeks treatment,2 control groups were selected from each time groups. The real-time fluorescence quantitative PCR detection had been done about the number of total bacteria of periodontal pocket and porphyromonas gingivalis - the periodontal pathogens which were accepted on the currently.Eight weeks after the model was established,it showed that depth of pocket (PD) deepened and attachment loss(AL) became apparent. The real-time fluorescence quantitative PCR detection showed that the number of total bacteria of periodontal tissue and P. g had increased more than the former model. There were significant differences(P < 0.05). So it confirmed the similarity of the pathogenic bacteria between building model's periodontal pocket and paradentosis of human and the rationality of the building model. It offered a good platform for the study of the effect of Low-intensity pulsed ultrasound united GTR technique on promoting periodontal tissue repair.Clinical index of periodontal examination results showed that the control groups of GTR—Simple GTR And LIPUS United GTR had better results than the control groups of no-GTR. It shows that depth of pocket (PD),AL and sulcus bleeding index(SBI) had grown down. There were significant differences(P<0. 05). But there were no significant differences (P<0.05) between the groups of LIPUS irradiation and non-LIPUS irradiation. The same between the groups of 6 weeks controlled and 8 weeks controlled.There were no significant differences among interclass and between the groups of 6 weeks controlled and 8 weeks controlled prompted that LIPUS united GTR surgery was safe because it may not increase the local pathogen. But it required further study in whether having the effect of inhibition to P.g and what were the effect of the other periodontal pathogenic bacteria.The result of histologic qualitative observation showed a good periodontal restoration in GTR surgery group. The repair of alveolar bone regeneration was significant. The new periodontal attachment formated. In the LIPUS united GTR surgery group,we could see the proliferation of new cementum and the repair of alveolar bone. We also saw less infiltration of inflammatory cells.It was higher than the group of GTR in bone paturity and bone density. Complete prothetic peridental membrane had been found.Micro-CT test results showed that the new alveolar bones' height of GTR group and GTR+LIPUS GTR+LIPUS irradiation group were higher than the group of non-GTR group from two-dimensional measurements in the same processing time,The root exposure was relatively low,There were significant differences(P<0. 05).The new alveolar bones' height of LIPUS irradiation group was higher than the simple GTR group. The root exposure became lower. The new alveolar bones' height of LIPUS irradiation group was higher than the periodontal flap surgery group. The root exposure became lower. There were significant differences(P<0.05). There were no significant differences in measure index between the group of 6 weeks and 8 weeks( P > 0.05 ) . From three-dimensional measurements in the same processing time,BV,BS,Tb. N of the GTR group and GTR+LIPUS irradiation group were higher than the group of non-GTR. BV,BS,Tb. N of the GTR+LIPUS irradiation group were higher than the group of GTR. BV,BS,Tb. N of the LIPUS irradiation group were higher than the periodontal flap surgery group. There were significant differences(P<0. 05). There were no significant differences among groups about Tb. Th. (P>0. 05). The Tb. N of 8 weeks was higher than 6 weeks in the same control group. There were no significant differences for other parameters in different time(P>0. 05).In summary, this study found that simple LIPUS irradiation might increase the number,volume and area of new alveolar bone trabeculae.It could improve the repair ability of GTR surgery to alveolar bone and increase the optical density and paturity of the alveolar bone if LIPUS united GTR surgery did not increase the number of local P. g.Observing the histological slices,we can see that LIPUS may have the effect of prompting cementum and periodontal ligament repair and reducing the local tissue inflammatory cells infiltration. It suggests that certain parameters LIPUS as the adjunct therapy to GTR surgery has potential clinical application prospects in treating root bifurcation degree Ⅱ.