| Objective:To evaluate the condition of implant-bone interface of simultaneous dental implantation after the mandibular non-vascularized bone graft and to observe the angiogenesis in the region of bone grafts by means of SPECT/CT fusion imaging and ground section of grafted bone with dental implants.Methods:Six local healthy crossbred dogs were chosen as the experimental animals. After one week of suitably breeding, the animal model of non-vascularized bone graft and simultaneous dental implantation was prepared. Under the condition of general anesthesia for each animal, the incision was made along the inferior border of the mandible with surgical instruments, then, the osteotomy of rectangular bone cutting which formed the3cm*2cm-size mandibular defect was performed on one side of the mandible. The free bone block was replanted in the original site within15-20mins, simultaneously3dental implants were placed in the grafted bone with the spacing of5mm. The wound was sutured carefully at last. Another3dental implants were inserted on the other side of the mandible without using osteotomy. The anti-infection treatment was routinely carried out post-operation. All the animals were received99Tcm-MDP740～925MBq via intravenous drip, and examined by the SPECT/CT fusion imaging3hours later at1week,4weeks,8weeks,12weeks of healing, and the radioactivecounting of the region of interest (ROI) and the CT value of bone graft area were compared between experimental and control groups, respectively. The specimens were detached after the animals were killed at12weeks. After the observation of the gross specimens and X-ray examination, ground sections of grafted bone with dental implants were made and stained with methylene blue-basic fuchsin and(or) toluidine blue for histological and histomorphometric analyses to acquire the data about the implant-bone interface, bone-to-implant contact ratio and miner·alized bone area of dental implants. Statistical analysis was conducted with SPSS13.0software package.Results:1. There were no bleeding, swell, ulceration and suppurating happened in the tissue around all the implants, and the implants had no loose, falling off and shift. All the implants healed well by the semi-quantitaive analysis of the analysis on the radioactivecounting of the region of interest and the CT value at the implant region. The X-ray showed the direct bone-to-implant contact and no area of low density which indicated successful plants.2. The SPECT/CT fusion imaging showed not only the information of the coronal, sagittal and horizontal plane of the implant and mandible which indicated the three-dimensional positions of the implant and mandible and the density of the implant-bone interface, but also the level of radionuclide accumulation at the base of exact anatomic localization.3. Radioactivecounting of ROI in the experimental side was significantly higher than the control side at4weeks, and no statistical difference at1week,8weeks and12weeks with the paired t test; CT value at the bone interface of experimental side was significantly lower than the control side at1week,4weeks and8weeks, but no statistical difference at12weeks.4. The histological observations of ground section of bone with dental implant showed the new bone, the grafted bone and the host bone combined. There were much woven bone which contacted directly with the implant surface at the implant-bone interface. Also, the red new trabeculae arranging in cords, the discrete blue osteoblast and the rare intramedullary canal of bone were distinguished in the histological examination with the methylene blue-basic fuchsin staining; and the deep blue new bone arranging in cords which had undefined margin with the old bone and the discrete osteoblast were clearly observed in the microscopic field of vision with toluidine blue stain. The mean of the bone-to-implant contact ratio and mineralized bone area was82.33%and76.63%for the experimental side; and86.61%and78.89%for the control side. There were no statistical differences between the experimental side and the control side with the paired t test.Conclusions:1. The experiment showed the high success rate of simultaneous dental implantation after the mandibular non-vascularized bone graft in the proper condition.2. The SPECT/CT fusion imaging can judge the success of the dental plant. Since the SPECT/CT fusion imaging reflected the implant-bone interface early and offer three-dimensional information of the implant and mandible, it had a practical value of the clinical application.3. The implant-bone interface was showed exactly with the combination of SPECT/CT fusion imaging and ground section of bone with dental implant.4. The histological examination of ground section of bone with dental implant by the methylene blue-basic fuchsin stain and toluidine blue staining stain can visually show the mineralization degree and differentiation state of the bone which judged the skeletal maturity exactly. |
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