Research progress on "sandwich" osteotomy to increase alveolar bone / 口腔疾病防治

@#Lack of alveolar bone height is a major challenge for dental implants. In recent years, the use of "sandwich" osteotomy to increase alveolar bone height has become a topic of discussion within the research community. In theory, "sandwich" osteotomy is a U-shaped osteotomy in the bone defect area, to preserve the blood supply of the mucoperiosteal on the lingual side and to create an artificial "four-wall bone bag" to build a favorable space for osteogenesis and to increase the height of the alveolar bone. Histological studies have shown that the osteogenesis speed of "sandwich" osteotomy is fast, and the bone is good. Sandwich osteotomy is suitable for buccal-lingual alveolar bone height defects less than 50% of the implant length or for unilateral defects more than 50% of the implant length. In the operation of "sandwich" osteotomy, the horizonal incision should be 10-12 mm below the crest of the buccal alveolar ridge. The design of the osteotomy line should ensure the height of the osteotomy block and that the mandibular canal does not sustain damage and that it fits the shape of the bone defect. There was no significant difference in the osteogenic effect of different types of bone graft materials used for "sandwich" osteotomy. The osteotomy block was rigorously fixed by a titanium plate, titanium nail, implant and other materials, and finally, the intraoperative area was tensioned and sutured. The effect of bone augmentation was evaluated and compared with other bone augmentation techniques; the evaluation showed that sandwich osteotomy was better for moderate vertical bone defects. This technique is highly sensitive and postoperative transient sensory loss is common. With advances in technology, the application of digital technology and ultrasonic bone knives, the risk of complications is greatly reduced and advances in digital osteotomy will promote apply of "sandwich" osteotomy, which will become a popularized technique for clinical alveolar bone augmentation.

Effect of human tooth bone graft materials on proliferation and differentiation of mice mononuclear macrophage RAW264.7 / 中国修复重建外科杂志

Objective: To investigate the effect of human tooth bone graft materials on the proliferation, differentiation, and morphology of macrophages, and to understand the biocompatibility and cytotoxicity of human tooth bone graft materials. Methods: Fresh human teeth were collected to prepare human tooth bone graft materials, the adhesion of mouse mononuclear macrophages RAW264.7 to human bone graft materials was observed under confocal microscopy. Scanning electron microscopy was used to observe the morphology of human tooth bone graft materials, OSTEONⅡ synthetic highly resorbable bone grafting materials, and untreated tooth powder (dental particles without preparation reagents). Different components of the extract were prepared in 4 groups: group A (DMEM medium containing 10% fetal bovine serum), group B (human tooth bone graft materials), group C (OSTEONⅡ synthetic highly resorbable bone grafting materials), group D (untreated tooth powder without preparation reagents). The 4 groups of extracts were co-cultured with the cells, and the cytotoxicity was qualitatively determined by observing the cell morphological changes by inverted microscope. The cell proliferation and differentiation results and cell relative proliferation rate were determined by MTT method to quantitatively determine cytotoxicity. The cell viability was detected by trypanosoma blue staining, and tumor necrosis factor α (TNF-α ) and interleukin 6 (IL-6) expressions were detected by ELISA. Results: Scanning electron microscopy showed that the surface of the human tooth bone graft material and the OSTEONⅡ synthetic highly resorbable bone grafting materials had a uniform pore structure, while the untreated tooth particle collagen fiber structure and the demineralized dentin layer collapsed without specific structure. Confocal microscopy showed that the cells grew well on human tooth bone graft materials. After co-culture with the extract, the morphology and quantity of cells in groups A, B, and C were normal, and the toxic reaction grades were all grade 0, while group D was grade 3 reaction. MTT test showed that the cytotoxicity of groups B and C was grade 0 or 1 at each time point, indicating that the materials were qualified. The cytotoxicity was grade 2 in group D at 1 day after culture, and was grade 4 at 3, 5, and 7 days. Combined with cell morphology analysis, the materials were unqualified. The trypanosoma blue staining showed that the number of cells in groups A, B, and C was significantly higher than that in group D at each time point ( P<0.05), but no significant difference was found among groups A, B, and C ( P<0.05). ELISA test showed that the levels of TNF-α and IL-6 in groups A, B, and C were significantly lower than those in group D ( P<0.05), but no significant difference was found among groups A, B, and C ( P<0.05). Conclusion: The human tooth bone graft materials is co-cultured with mice mononuclear macrophages without cytotoxicity. The extract has no significant effect on cell proliferation and differentiation, does not increase the expression of inflammatory factors, has good biocompatibility, and is expected to be used for clinical bone defect repair.

Experimental Study of the Repair of Rabbit Skull Defects with Allogeneic Tooth Derived Bone Graft Material / 中国医科大学学报

Objective To evaluate the osteogenesis of rabbit allogeneic tooth derived bone graft material by histological detection ,so as to provide quality and cheap repair materials for the repair of bone defects in dental implants. Methods The bone graft materials were prepared using rab?bits allogeneic extracted teeth. A total of 28 adult Japanese healthy rabbits were selected to establish the cranial defect model with three 8 mm diam?eter holes. The allogenic tooth derived bone graft material were implanted into the experimental group. The artificial bone repair material was used as the control group,and the control group did not receive any implantion. Tetracycline labeling was performed after operation,the specimens were taken at 4,8 and 12 weeks after operation,and then the gross observation,X?ray examination,preparation of hard tissue sections,and HE staining were carried out. Results Histological analysis at 4,8 and 12 weeks after operation showed that there was an increasing trend the new bone for?mation in both experimental group and the control group ,and the experimental group was better;the trabecular bone structure of the blank group was scarce and the change was not obvious. Conclusion Allogenic tooth derived bone graft materials can promote the repair of bone defect ,and the effect is better than that of artificial bone repair materials.

A Double Layers Technique for Maxillary Sinus Augmentation with Demineralized and Mineralized Bone Graft Materials

The comparative study: the regenerative effect depends on size of bone graft material in bone loss site around dental implant / 대한치주과학회지

PURPOSE: The purpose of this study is to investigate on the regenerative capacity by using different size of graft materials around bony defect around implant. MATERIAL AND METHODS: Dental implant fixtures(Bio-TIS, Korea) were placed into the tibia of 8 rabbits. After placement of implant, artificial defects were created for each group, and the size of bone graft materials were used according to each designated group. 4 weeks after surgery, 8 rabbits were sacrificed. The histologic and histomorphometrical study were done for comparison of the regenerative capacity using 80-90micrometer and 200~1000micrometer size of grafting materials of OCS-B(R). RESULT: Matured bone formation was significantly increased more in Group E1(80-90micrometer) than in Group E2(200~1000micrometer). Group E1(80-90micrometer) showed more significant augmentation in marginal length of graft material per unit area than Group E2(200~1000micrometer). Group E1(80-90micrometer) showed more interspace in graft material than Group E2(200~1000micrometer). Control group showed no new bone formation around and inside of implanted fixture. CONCLUSION: Small grafting material size has great influence on bone regeneration.

Histologic evaluation of the regenerated bone using bone graft materials / 대한치주과학회지

This study was performed to evaluate the effect of bone graft materials including demineralized freeze-dried bone, freeze-dried bone, deproteinized bovine bone on space-making capacity and bone formation in guided bone regeneration with titanium reinforced ePTFE membrane(TR-ePTFE). Adult male rabbits(mean BW 2kg) were used in this study. Intramarrow penetration defects were surgically created with round bur on calvaria of rabbits. TR-ePTFE membrane was adapted to calvarial defect and bone graft materials were placed. Animals were sacrificed at 2, 8, 12 weeks after surgery. Non-decalcified specimens were processed for histologic analysis and prepared with Villaneuva bone stain. The results of this study were as follows: 1. TR-ePTFE membrane was biocompatible and capable of maintaining the space-making. 2. Tissue integration was not good at TR-ePTFE membrane. Fixation was not enough. so, wound stabilization was not good. 3. In animals using deproteinized bovine bone, demineralized freeze-dried bone, bone formation was little. 4. In animals using freeze-dried bone, bone formation was better. Within the above results, bone formation may be inhibited when wound stabilizafion was not good.

Effect of bone graft materials on bone formation in guided bone regeneration using perforated titanium membrane / 대한치주과학회지

The purpose of the present study was to evaluate the effect of bone graft materials including deproteinized bovine bone(DBB), demineralized freeze-dried bone(DFDB), freeze-dried bone(FDB) on bone formation in guided bone regeneration using perforated titanium membrane(TM). 16 adult male rabbits(mean BW 2kg) were used in this study and 4 rabbits allotted to each test group. Intramarrow penetration(diameter 6.5mm) was done with round carbide bur on calvaria to promote blood supply and clot formation in the wound area. The test groups were devided into 4 groups as follows: TM only(test 1), TM +DBB(test 2), TM +DFDB(test 3), TM +FDB(test 4). Perforated titanium membrane was contoured in rectangular parallelepiped shape(0.5mm pore diameter, 10mm in one side, 2mm in inner height), filled the each graft material and placed on the decorticated carvaria. Perforated titanium membrane was fixed with resorbable suture materials. The animals were sacrificed at 2, 8 weeks after the surgery. Non-decalcified preparations were routinely processed for histologic analysis. The results of this study were as follows: 1. Perforated titanium membrane was biocompatible. 2. Perforated titanium membrane had capability of maintaining the space during the healing period but invasion of soft tissue through the perforations of titanium membrane decreased the space available for bone formation. 3. In test 1 group without bone graft material, the amount of bone formation and bone maturation was better than other test groups. 4. Among the graft materials, the effect of freeze-dried bone on bone formation was best. 5. In the test groups using deproteinized bovine bone, demineralized freeze-dried bone, bone formation was a little. The spacemaking capability of the membrane may be crucial for bone formation. The combined treatment with the perforated titanium membrane and deproteinized bovine bone or demineralized freeze-dried bone failed to demonstrate any added effect in the bone formation. Minimization of size and numbers of perforations of titanium membrane or use of occlusive titanium membrane might be effective to acquire predictable results in the vertical bone formation.