Objective To detect the effects of Yunnan Baiyao on receptor activator of NF-κB(RANK)/receptor activator of NF-κB ligand(RANKL)/osteoprotegerin(OPG) system by means of animal model that use Porphyromonas gingivalis(Pg) induce cal-varial to induce bone destroy .Methods Seventy-two male Kunming mouses were selected and randomly divided into model group , Yunnan Baiyao treatment group and control group .The animals of model group and Yunnan Baiyao treatment group were inoculated Pg at the midline of the scalp between the ears and the animals of the Yunnan Baiyao treatment group gastric perfusion Yunnan Baiyao after them inoculated Pg .Mouses were killed at 5 ,8 and 14 days after inoculation .For each data point ,killed eight mice(n=8) ,then detected the number of osteoclast of the calvaria and the change of RANKL mRNA ,OPGm RNA express .Results On the 5th ,8th and 14th day the number of osteoclast and the content of RANKL mRNA expression in the model group apparently higher than in the Yunnan Baiyao treatment group(P<0 .05) ,two groups also apparently higher than in the control group(P<0 .05) .A-bout OPG mRNA expression on the 5th ,8th and 14th day in the Yunnan Baiyao treatment group apparently higher than in the con-trol group and model group(P<0 .05) ,but on the 5th day the model group lower than the control group(P<0 .05) and on the 8th , 14 day the model group higher than the control group(P<0 .05) .Conclusion Yunnan Baiyao can cut regulation RANKL mRNA expression and raise regulation OPG mRNA expression to inhibit bone destruction and improve bone repair and inhibiting osteoclast product so as to inhibit bone destroy and improve bone repair .

Objective To investigate whether the abnormal stress could cause the ultrastructural change of the rats′condylar cartilage in vivo .Methods Fifty‐four SD male rats were randomly divided into condylar neck osteotomy operation(OO)group ,con‐dylar neck fracture operation(FO) group ,and control group ,with 12 rats in each group .Then the OO group rats ,FO group rats and control group rats were executed and sampled at 1st week ,3rd week and 5th week separately to observe the structure of condyle with light microscope(LM ) ,scanning electron microscope (SEM ) and transmission electron microscope (TEM ) .Results LM showed that the general condylar thickness of OO group and FO group were thinner than that of control group at 3rd and 5th week . SEM showed that the collagen and fibre were exposed in the OO group and FO group at 3rd week and 5th week ,the fibre was bro‐ken in the OO group at 5th week .TEM showed that the hypertrophic cell in OO group was more mature than those of FO group and control group at 3rd week .The arrange of fibre was disorder in OO group at 1st week ,the fibre was more disorder and there was even leak in OO group at 5th week .Conclusion The abnormal stress in vivo could result in the ultrastructural change of the rats′condyle ,and this change relates with the stess change degree and affects the growth and development of condyle .

Objective:To establish a computer-aided design and 3D printing system for precise implantation of micro implant anchorage, and accurately calibrate the position and direction of micro implant implantation.Methods:A retrospective selection was conducted on 15 patients (30 in total) who underwent micro implant implantation surgery from the Department of Stomatology, the Affiliated Hospital of Jiangnan University from November 2019 to November 2021, including 6 males and 9 females, aged (17.1±6.3)years old. The preoperative patient was photographed with cone beam computed tomography (CBCT) and the collected DICOM data format was output. A 3D scan was performed on the patient′s preoperative analysis model to obtain the STL file of the model scan. The CBCT data and model data were fitted and matched using 3Shape Implant Studio software, and the thickness of the guide plate, the amount of undercut compensation, and the size of the key component collar were designed. The 3D printer was used for printing after resizing. Using the assist method to implant micro implants, CBCT was taken postoperatively to compare the preoperative design with the postoperative results.Results:After fitting the postoperative CBCT with the designed CBCT of the micro implant, it was found that the micro implant was consistent with the preoperative design, maintained a safe distance and parallel to the adjacent tooth root, and did not damage the maxillary sinus and other areas. No detachment of the micro implant anchorage was observed 1 or 3 months after surgery. The application of assisted micro implant anchorage 3D guide plate was reliable, with accurate implantation position and direction, and can be implanted in most parts of the oral cavity.Conclusions:The use of computer-aided design and 3D printing system to create an assistive micro implant anchorage 3D guide plate can accurately locate the position and direction of the micro implant, which is worthy of clinical promotion and application.