Combined Delivery of Two Different Bioactive Factors Incorporated in Hydroxyapatite Microcarrier for Bone Regeneration

BACKGROUND@#The delivery of growth factors using a carrier system presents a promising and innovative tool in tissue engineering and dentistry today. Two of the foremost bioactive factors, bone morphogenetic protein-2 and vascular endothelial growth factor (VEGF), are widely applied using a ceramic scaffold. The aim of this study was to determine the use of hydroxyapatite microcarrier (MC) for dual delivery of osteogenic and angiogenic factors to accelerate hard tissue regeneration during the regenerative process. @*METHODS@#Two MCs of different sizes were fabricated by emulsification of gelatin and alpha-tricalcium phosphate (a-TCP).The experimental group was divided based on the combination of MC size and growth factors. For investigating the in vitro properties, rat mesenchymal stem cells (rMSCs) were harvested from bone marrow of the femur and tibia. For in vivo experiments, MC with/without growth factors was applied into the standardized, 5-mm diameter defects, which were made bilaterally on the parietal bone of the rat. The animals were allowed to heal for 8 weeks, and samples were harvested and analyzed by microcomputed tomography and histology. @*RESULTS@#Improved proliferation of rat mesenchymal stem cells was observed with VEGF loaded MC. For osteogenic differentiation, dual growth factors delivered by MC showed higher osteogenic gene expression, alkaline phosphatse production and calcium deposition. The in vivo results revealed statistically significant increase in new bone formationwhen dual growth factors were delivered by MC. Dual growth factors administered on a calcium phosphate matrix showed significantly enhanced osteogenic potential. @*CONCLUSION@#We propose this system has potential clinical utility in providing solutions for craniofacial bone defects, with the added benefit of early availability.

Combined Delivery of Two Different Bioactive Factors Incorporated in Hydroxyapatite Microcarrier for Bone Regeneration

BACKGROUND@#The delivery of growth factors using a carrier system presents a promising and innovative tool in tissue engineering and dentistry today. Two of the foremost bioactive factors, bone morphogenetic protein-2 and vascular endothelial growth factor (VEGF), are widely applied using a ceramic scaffold. The aim of this study was to determine the use of hydroxyapatite microcarrier (MC) for dual delivery of osteogenic and angiogenic factors to accelerate hard tissue regeneration during the regenerative process. @*METHODS@#Two MCs of different sizes were fabricated by emulsification of gelatin and alpha-tricalcium phosphate (a-TCP).The experimental group was divided based on the combination of MC size and growth factors. For investigating the in vitro properties, rat mesenchymal stem cells (rMSCs) were harvested from bone marrow of the femur and tibia. For in vivo experiments, MC with/without growth factors was applied into the standardized, 5-mm diameter defects, which were made bilaterally on the parietal bone of the rat. The animals were allowed to heal for 8 weeks, and samples were harvested and analyzed by microcomputed tomography and histology. @*RESULTS@#Improved proliferation of rat mesenchymal stem cells was observed with VEGF loaded MC. For osteogenic differentiation, dual growth factors delivered by MC showed higher osteogenic gene expression, alkaline phosphatse production and calcium deposition. The in vivo results revealed statistically significant increase in new bone formationwhen dual growth factors were delivered by MC. Dual growth factors administered on a calcium phosphate matrix showed significantly enhanced osteogenic potential. @*CONCLUSION@#We propose this system has potential clinical utility in providing solutions for craniofacial bone defects, with the added benefit of early availability.

The influence of bone graft procedures on primary stability and bone change of implants placed in fresh extraction sockets / 대한악안면성형재건외과학회지

BACKGROUND: This study was to evaluate the effect of bone graft procedure on the primary stability of implants installed in fresh sockets and assess the vertical alteration of peri-implant bone radiographically. METHODS: Twenty-three implants were inserted in 18 patients immediately after tooth extraction. The horizontal gap between the implant and bony walls of the extraction socket was grafted with xenografts. The implant stability before and after graft procedure was measured by Osstell Mentor as implant stability quotient before bone graft (ISQ bbg) and implant stability quotient after bone graft (ISQ abg). Peri-apical radiographs were taken to measure peri-implant bone change immediately after implant surgery and 12 months after implant placement. Data were analyzed by independent t test; the relationships between stability parameters (insertion torque value (ITV), ISQ abg, and ISQ bbg) and peri-implant bone changes were analyzed according to Pearson correlation coefficients. RESULTS: The increase of ISQ in low primary stability group (LPSG) was 6.87 ± 3.62, which was significantly higher than the increase in high primary stability group (HPSG). A significant correlation between ITV and ISQ bbg (R = 0.606, P = 0.002) was found; however, age and peri-implant bone change were not found significantly related to implant stability parameters. It was presented that there were no significant peri-implant bone changes at 1 year after bone graft surgery. CONCLUSIONS: Bone graft procedure is beneficial for increasing the primary stability of immediately placed implants, especially when the ISQ of implants is below 65 and that bone grafts have some effects on peri-implant bone maintenance.

Histological Analysis of In Vitro Co-Culture and In Vivo Mice Co-Transplantation of Stem Cell-Derived Adipocyte and Osteoblast

Many researchers have focused on the role of adipocytes in increasing efficient bone tissue engineering and osteogenic differentiation of stem cells. Previous reports have not reached a definite consensus on whether adipocytes positively influence in vitro osteogenic differentiation and in vivo bone formation. We investigated the adipocyte influence on osteogenic differentiation from adipose-derived stromal cells (ADSCs) and bone formation through histological analysis in vitro and in vivo. Using the direct co-culture system, we analyzed the influence of adipocytes to promote the differentiation fate of ADSCs. Using co-transplantation of ADSC-derived adipocytes and osteoblasts into the dorsal region of mice, the osteogenesis and bone quality were determined by histological morphology, radiography, and the measurement of the Ca²⁺ concentration. The adipocyte negatively affected the osteoblast differentiation of ADSCs in the in vitro system and induced osteogenesis of osteoblasts in the in vivo system through co-transplantation. Interestingly, in the co-transplanted adipocytes and osteoblasts, the bone formation areas decreased in the osteoblast only group compared with the mixed adipocytes and osteoblast group 6 weeks after transplantation. Conversely, co-transplantation and osteoblast transplantation had similar degrees of calcification as observed from radiography analysis and the measurement of the Ca²⁺ concentrations. Our results revealed that adipocytes inhibited osteoblast differentiation in vitro but enhanced the efficacy of osteogenesis in vivo. In addition, the adipocytes controlled the activity of osteoclasts in the newly formed bone tissue. Our approach can be used to reconstruct bone using stem cell-based tissue engineering and to enhance the understanding of the role adipocytes play.

Demineralized dentin matrix combined with recombinant human bone morphogenetic protein-2 in rabbit calvarial defects

OBJECTIVES: The aim of this study was to compare the osteogenic effects of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) in rabbit calvarial defects with DDM and anorganic bovine bone (ABB) combined with rhBMP-2. MATERIALS AND METHODS: Four round defects with 8-mm diameters were created in each rabbit calvaria. Each defect was treated with one of the following: 1) DDM, 2) ABB/rhBMP-2, or 3) DDM/rhBMP-2. The rhBMP-2 was combined with DDM and ABB according to a stepwise dry and dip lyophilizing protocol. Histological and microcomputed tomography (µCT) analyses were performed to measure the amount of bone formation and bone volume after 2- and 8-week healing intervals. RESULTS: Upon histological observation at two weeks, the DDM and ABB/rhBMP-2 groups showed osteoconductive bone formation, while the DDM/rhBMP-2 group showed osteoconductive and osteoinductive bone formation. New bone formation was higher in DDM/rhBMP-2, DDM and ABB decreasing order. The amounts of bone formation were very similar at two weeks; however, at eight weeks, the DDM/rhBMP-2 group showed a two-fold greater amount of bone formation compared to the DDM and ABB/rhBMP-2 groups. The µCT analysis showed markedly increased bone volume in the DDM/rhBMP-2 group at eight weeks compared with that of the DDM group. Notably, there was a slight decrease in bone volume in the ABB/rhBMP-2 group at eight weeks. There were no significant differences among the DDM, ABB/rhBMP-2, and DDM/rhBMP-2 groups at two or eight weeks. CONCLUSION: Within the limitations of this study, DDM appears to be a suitable carrier for rhBMP-2 in orthotopic sites.

Calcifying epithelial odontogenic tumor (CEOT) in palate: report of a case

A calcifying epithelial odontogenic tumor (CEOT) was first described as a separate entity in 1955 by Pindborg, and has since been referred to as Pindborg tumor. CEOT is characterized by the presence of squamous-cell proliferation, calcification and amyloid deposits, and accounts for only 1% of all odontogenic tumors. CEOT is a benign, though occasional locally invasive, slow-growing neoplasm. It is located either intraosseously or extraosseously, and is usually associated with an unerupted permanent tooth. A 24 year-old female visited our clinic, presenting with a palatal swelling and intra-oral ulcer. After an incisional biopsy, the lesion was confirmed to be odontogenic tumor. A tumor resection and reconstruction surgery with tongue flap were performed.

The Effect of PRF and PRP for New Bone Formation of beta-TCP in Skull of White Rabbit

Effect of bovine bone (Bio-Oss(R)) and platelet rich plasma, platelet poor plasma on sinus bone graft in rabbit

Maxillary sinus lift and bone graft are used to reconstruct atrophic maxilla molar area for endosseous dental implants. Many different grafting materials and techniques can be used for maxillary sinus bone graft. Bio-Oss(R) has been proposed as bone substitute and successfully utilized as osteoconductive filler. Platelet rich plasma (PRP) is an autologous material with many growth factors, such as PDGF, TGF-beta, IGF, VEGF, facilitating bone healing process. And Platelet poor plasma (PPP) is the by-product in procedure of producing PRP. Six rabbits were used as experimental animal. Both maxillary sinus were grafted with Bio-Oss(R) and PRP, and Bio-Oss(R) and PPP. Rabbits were sacrificed at 4, 8 and 12 weeks. The grafting sites were evaluated by histomorphometric analysis. As a result, using PRP showed excellent bone formation in the early stage, but no further significant effect after that. In late stage, the ability of bone formation of using PRP was even worse than using PPP. The further studies need to be considered in this case.

BONE REGENERATION WITH ADIPOSE TISSUE-DERIVED MESENCHYMAL STEM CELL AND HA/TCP

BONE REGENERATION WITH INJECTABLE MPEG-PCL DIBLOCK COPOLYMER AND BONE MARROW MESENCHYMAL STEM CELL

A study on the osteogenic differentiation of adipose-derived adult stem cell

Hsp27 expression in osteoblast by thermal stress

Pleiotrophin effects on binding and subsequent osteogenesis of human mesenchymal stem cells

Hsp27 modulation of implant-associated metal ion cytotoxicity of osteoblastic cells

Changes of serum alkaline phosphatase after enucleation of cysts in the jaws

This study was to analyze the changes of levels of alkaline phosphatase before and after enucleation of jaw cysts combined with bone grafting, and to evaluate biochemically the effectiveness of the early detection of bone healing and infection as a prognostic marker. Eighteen patients (13 males, 5 females) with cystic lesions of the jaws were divided into two groups. The bone graft group underwent enucleation and bone graft. The control group underwent only enucleation. Both groups were measured levels of ALP before surgery, and plus-minus 4 weeks postoperatively. The more discriminating results were obtained in the bone graft group. The results were as follows : 1. Levels of ALP after enucleation of jaw cysts were decreased in all patients with and without bone graft. 2. The bone graft group showed more marked decrease in variation of levels of ALP than the control group.(p=0.008) This should be considered as a result of increased osteoblastic activity and new bone formation. 3. Such variation could be used as a prognostic marker for bone healing after cyst operation. In the cost/benefit ratio, measurement of ALP activity could be useful as a convenient procedure in routine clinical practice.

The experimental study for influence of fibrin glue during healing phase after making artificial bone defect

Decompression of dentigerous cyst in children: Report of cases

Hsp27 contributes to estrogen regulation of osteoblast apoptosis

Estrogen may promote osteoblast/osteocyte viability by limiting apoptotic cell death. We hypothesize that hsp27 is an estrogen- regulated protein that can promote osteoblast viability by increasing osteoblast resistance to apoptosis. The purpose of this study was to determine the effect of estrogen treatment and heat shock on TNF alpha- induced apoptosis in the MC3T3-E1 cell line. Cells were treated with 0 - 100 nM 17betaestradiol (or ICI 182780) for 0 - 24 hours before heat shock. After recovery, apoptosis was induced by treatment with 0 - 10 ng/ml TNF alpha. Hsp levels were evaluated by Northern and Western analysis using hsp27, hsp47, hsp70c and hsp70i - specific reagents. Apoptosis was revealed by in situ labeling with Terminal Deoxyribonucleotide Transferase (TUNEL). A 5 - fold increase in hsp27 protein and mRNA was noted after 5 hours of treatment with 10 - 20 nM 17beta estradiol prior to heat shock. Increased abundance of hsp47, hsp70c or hsp70i was not observed. TUNEL indicated that estrogen treatment also reduced (50%) MC3T3-E1 cell susceptibility to TNF alpha-induced apoptosis. Treatment with hsp27-specific antisense oligonucleotides prevented hsp27 protein expression and abolished the protective effects of heat shock and estrogen treatment on TNF alpha-induced apoptosis. Hsp27 is a determinant of osteoblast apoptosis, and estrogen treatment increases hsp27 levels in cultured osteoblastic cells. Hsp27 contributes to the control of osteoblast apoptosis and may be manipulated by estrogenic or alternative pathways for the improvement of bone mass.

Clinical Study of Cyst in the Jaws

The purpose of this study is to find the histopathological pattern of cysts. We reviewed the hospital chart, out-patient chart, roentgenogram, histopathologic report and operation report of 152 patients who had been diagnosed as cyst and treated at the department of Oral and Maxillofacial Surgery of Korea university hospital between Jan. 1, 1995 and Dec. 31, 1998. And then we studied clinically with regard to pathological classification, age and sex distribution, anatomical distribution and so on. The results were as follows : 1. In pathologic classification, radicular cyst (97cases, 64%), dentigerous cyst (35cases, 23%), odontogenic keratocyst (8cases, 5.3%) were dominant among cases of cyst. 2. The pattern of age distribution in cases of radicular cyst, dentigerous cyst and odontogenic keratocyst was similar to that found in previous studies. The peak incidence was in the second decade (27%) and third decade (29%) in overall cases. 3. The male-to-female ratio was 1.9 : 1. 4. Radicular cyst occured most frequently in the maxillary incisor teeth area, dentigerous cyst in mandibular wisdom teeth area, and odontogenic keratocyst in mandibular molar area.

Evaluation of skeletal stability after BSSRO in skeletal class III with anterior open bite

OR = 1mm). Serial lateral cephalometric radiographs were taken within 2 weeks preoperatively, within 1 week postoperatively and at a follow up period that ranged from 7 to 24 months postoperatively. All cephalometric radiographs were traced and digitized using the Quick ceph image Pro for analysis. And then, horizontal and vertical changes of reference points(B point, Pogonion, L1) were assessed by the linear measurements in millimeters on both axes. The results were as follows: 1. Mean horizontal relapses were 0.67+/-0.93mm (11%) at B point (P0.05). 3. The mean angular change of occlusal plane to SN was 0.24+/-1.19 (P>0.05) and that of mandibular plane to SN was 1.03+/-1.85 (P<0.05). 4. There was correlation between the extent of preoperative overbite and the postsurgical relapse at B point and Pogonion. 5. There was no correlation between the amount of surgically produced horizontal movement and the postoperative horizontal relapse at B point.