[Effects of GBR and Delayed Loading on Bone Ring Grafting with Simultaneous Implant Insertion: an Experimental Study on Beagle Dogs].

OBJECTIVE: To determine the effects of guided bone regeneration (GBR) and delayed loading on autogenous bone ring grafting. METHODS: Autogenous bone ring augmentation with simultaneous implant insertion was performed in the mandibular premolars region of six Beagle dogs. The Bone quality of four mandibular premolars [second premolar (P2) and fourth premolar (P4)] were detected using cone beam CT (CBCT). The P2s and P4s of bilateral mandible were extracted, with three extracting sites being randomly selected to create buccal defects and the remaining one serving as control. GBR and bone ring grafting with simultaneous implant insertion was performed on two of the three experimental sites with buccal defects 3 months later, while the other one was treated with bone ring grafting with simultaneous implant insertion. Routine implant placement was performed in the control group. Vertical bone resorption and sulcus deep around the implants were measured three months after occlusal loading with abutment. RESULTS: Three months after operations, 83.3% of bone rings grafts were successful and 100% of implants survived. Delayed healing appeared more in the dogs with GBR compared those treated with bone ring grafting with simultaneous implant insertion, resulting in an increase in vertical bone resorption. Compared with the control group, delayed loading had no effects on vertical bone resorption and the health of gingiva tissues after autogenous bone ring transplant. CONCLUSION: GBR is not a preferred procedure for bone ring grafts, which may increase the risk of delayed healing and site infections, leading to failure of implants. Healed bone ring grafts can resist loadings as normal.

[Imaging classification diagnosis and maxillary sinus floor augmentation of maxillary sinus cystic lesions].

Maxillary sinus cystic lesions can often be found in cone-beam computed tomography (CBCT) images. However, whether this change affects the implementation of maxillary sinus floor augmentation remains unclear. Combining the common cystic change performance of CBCT, image classification diagnosis of maxillary sinus cystic change was introduced, and the indications and surgical methods of maxillary sinus floor augmentation and postoperative radiographic changes of mucous were analyzed. This procedure may help clinicians evaluate the feasibility and methods of maxillary sinus augmentation in maxillary sinus cystic changes.

[Differentiation and functional expression of highly purified osteoclast-like cells in vitro].

OBJECTIVE: To establish a culture method for a large amount of highly purified osteoclast-like cells in vitro. To investigate the gene expression of some osteoclast marker enzymes. To lay the foundation for the further study of the signal path on the differentiation and formation of osteoclast-like cells. METHODS: The bone marrow mononuclear cells of rat were treated with 30 ng/mL macrophagecolony-stimulating factor (M-CSF) and 50 ng/mL receptor activator of NF-kappaB ligand (RANKL) and cultured for 6 days. After culturing, cells were evaluated by morphology observation, tartrate-resistant acid phosphatase (TRAP) staining, Giemsa staining, pit staining, and the gene expression of some osteoclast marker enzymes. RESULTS: The TRAP-positive mononuclear cells were more frequently observed than the multinucleated cells and pit staining could be seen on the dentine slice. The transcription expression of TRAP, matrix metalloproteinase-9 (MMP-9), membrane-type1-matrix metalloproteinase (MT1-MMP) and cathepsin K were detected by RT-PCR. CONCLUSION: The cooperation of M-CSF and RANKL could induce a large amount of highly purified osteoclast-like cells formation in rat bone marrow culture. The typical characteristics of osteoclast-like cells were demonstrated and the enriched osteoclast-like cells expressed TRAP, MMP-9, MT1-MMP and cathepsin K.