• Archives of Plastic Surgery
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• v.38 no.4
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• pp.438-444
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• 2011

Purpose: Adipose-derived stromal cells (ASCs) are readily harvested from lipoaspirated tissue or subcutaneous adipose tissue fragments. The stromal vascular fraction (SVF) is a heterogeneous set of cell populations that surround and support adipose tissue, which includes the stromal cells, ASCs, that have the ability to differentiate into cells of several lineages and contains cells from the microvasculature. The mechanisms that drive the ASCs into the osteoblast lineage are still not clear, but the process has been more extensively studied in bone marrow stromal cells. The purpose of this study was to investigate the osteogenic capacity of adipose derived SVF cells and evaluate bone formation following implantation of SVF cells into the bone defect of human phalanx. Methods: Case 1 a 43-year-old male was wounded while using a press machine. After first operation, segmental bone defects of the left 3rd and 4th middle phalanx occurred. At first we injected the SVF cells combined with demineralized bone matrix (DBM) to defected 4th middle phalangeal bone lesion. We used P (L/DL)LA [Poly (70L-lactide-co-30DL-lactide) Co Polymer P (L/DL)LA] as a scaffold. Next, we implanted the SVF cells combined with DBM to repair left 3rd middle phalangeal bone defect in sequence. Case 2 was a 25-year-old man with crushing hand injury. Three months after the previous surgery, we implanted the SVF cells combined with DBM to restore right 3rd middle phalangeal bone defect by syringe injection. Radiographic images were taken at follow-up hospital visits and evaluated radiographically by means of computerized analysis of digital images. Results: The phalangeal bone defect was treated with autologous SVF cells isolated and applied in a single operative procedure in combination with DBM. The SVF cells were supported in place with mechanical fixation with a resorbable macroporous sheets acting as a soft tissue barrier. The radiographic appearance of the defect revealed a restoration to average bone density and stable position of pharyngeal bone. Densitometric evaluations for digital X-ray revealed improved bone densities in two cases with pharyngeal bone defects, that is, 65.2% for 4th finger of the case 1, 60.5% for 3rd finger of the case 1 and 60.1% for the case 2. Conclusion: This study demonstrated that adipose derived stromal vascular fraction cells have osteogenic potential in two clinical case studies. Thus, these reports show that cells from the SVF cells have potential in many areas of clinical cell therapy and regenerative medicine, albeit a lot of work is yet to be done.

• Journal of Periodontal and Implant Science
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• v.46 no.3
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• pp.152-165
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• 2016

Purpose: This study investigated the effects of bone density and crestal cortical bone thickness at the implant-placement site on micromotion (relative displacement between the implant and bone) and the peri-implant bone strain distribution under immediate-loading conditions. Methods: A three-dimensional finite element model of the posterior mandible with an implant was constructed. Various bone parameters were simulated, including low or high cancellous bone density, low or high crestal cortical bone density, and crestal cortical bone thicknesses ranging from 0.5 to 2.5 mm. Delayed- and immediate-loading conditions were simulated. A buccolingual oblique load of 200 N was applied to the top of the abutment. Results: The maximum extent of micromotion was approximately $100{\mu}m$ in the low-density cancellous bone models, whereas it was under $30{\mu}m$ in the high-density cancellous bone models. Crestal cortical bone thickness significantly affected the maximum micromotion in the low-density cancellous bone models. The minimum principal strain in the peri-implant cortical bone was affected by the density of the crestal cortical bone and cancellous bone to the same degree for both delayed and immediate loading. In the low-density cancellous bone models under immediate loading, the minimum principal strain in the peri-implant cortical bone decreased with an increase in crestal cortical bone thickness. Conclusions: Cancellous bone density may be a critical factor for avoiding excessive micromotion in immediately loaded implants. Crestal cortical bone thickness significantly affected the maximum extent of micromotion and peri-implant bone strain in simulations of low-density cancellous bone under immediate loading.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.6
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• pp.371-381
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• 2022

Objectives: This study determined the effect of platelet-rich fibrin (PRF) on extraction socket bone regeneration and assessed the patterns and determinants of bone regeneration after the surgical extraction of impacted mandibular third molars. Materials and Methods: This prospective study randomly allocated 90 patients into two treatment groups: A PRF group (intervention group) and a non-PRF group (control group). After surgical extractions, the PRF group had PRF placed in the extraction socket and the socket was sutured, while the socket was only sutured in the non-PRF group. At postoperative weeks 1, 4, 8, and 12, periapical radiographs were obtained and HLImage software was used to determine the region of newly formed bone (RNFB) and the pattern of bone formation. The determinants of bone regeneration were assessed. Statistical significance was set at P<0.05. Results: The percentage RNFB (RNFB%) was not significantly higher in the PRF group when compared with the non-PRF group at postoperative weeks 1, 4, 8, and 12 (P=0.188, 0.155, 0.132, and 0.219, respectively). Within the non-PRF group, the middle third consistently exhibited the highest bone formation while the least amount of bone formation was consistently observed in the cervical third. In the PRF group, the middle third had the highest bone formation, while bone formation at the apical third was smaller compared to the cervical third at the 8th week with this difference widening at the 12th week. The sex of the patient, type of impaction, and duration of surgery was significantly associated with percentage bone formation (P=0.041, 0.043, and 0.018, respectively). Conclusion: Placement of PRF in extraction sockets increased socket bone regeneration. However, this finding was not statistically significant. The patient's sex, type of impaction, and duration of surgery significantly influenced the percentage of bone formation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.3
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• pp.228-236
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• 1992

This study was to designed to evaluate the reactions of mouse femoral bone to bone wax. In sixteen mice with a strain of I. C. R. mouse weighed approximately 300 to 850g 2.0~2.0mm sized bone defects were created by drilling. Half of mice were inserted by bone wax and the remainder serving as control without bone wax application. The mice were sacrificed 1, 2, 6, 8 weeks after operation and block specimens were prepared for light microscopy examination. The results obtained were as follows. 1. Histologic features of tissue reaction to bone wax were the presence of inflammatory cell infiltration and multinucleated giant cell. 2. Bone ear healing from the created margin were markedly impaired by the application of bone wax 3. New bone formation was markedly decreased in bone wax application.

• Journal of Korean Dental Science
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• v.6 no.2
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• pp.50-57
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• 2013

Purpose: Autogenous tooth bone graft is proven to be efficient. We evaluated the bone healing effect and clinical capabilities of autogenous tooth bone materials as a scaffold when growth factor is used together with this material. Materials and Methods: Subjects were those who needed implant placement and bone graft because of missing tooth or alveolar bone defect and who kept their autogenous tooth or needed extraction of other tooth. Group I included autogenous tooth bone graft with growth factor, whereas Group II had only autogenous tooth bone graft. We investigated the bone healing state through computed tomography taken just before surgery and 3 to 4 months after surgery to evaluate the effectiveness of bone graft. Group I had 9 patients, whereas Group II had 5 patients. We compared the pre- and post-operative increase of the Hounsfield unit and bone height by analyzing the computed tomography images. Result: Sinus bone grafts numbered 8 cases, and vertical ridge augmentation was performed together with 3 cases of these. Vertical ridge augmentation was performed in 2 cases, and horizontal ridge augmentation in 1 case alone. Socket graft was done in 3 cases. The post-operative mean value of the Hounsfield unit was 960 in Group I and 836.7 in Group II, but the increase was almost similar, i.e., 636.9 in Group I and 634.7 in Group II on the average. Increase of bone height was 7.6 mm in Group I and 11.1 mm in Group II on the average. This difference was attributable to the fact that most of the cases were sinus bone graft in Group II. Conclusion: In this study, we suggest the possibility of autogenous tooth bone graft materials as a scaffold besides their bone healing ability.

• Archives of Craniofacial Surgery
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• v.19 no.4
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• pp.270-274
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• 2018

Background: Nasal bone fractures occur frequently because the nasal bone is located at the forefront of the face. The goal of this study was to examine the cause, change in severity, change in incidence, and demographics of nasal bone fracture according to today's lifestyle. Methods: A total of 2,092 patients diagnosed as having nasal bone fractures at our department between 2002 and 2017 were included in this study. We retrospectively examined patients' medical records to extract information regarding age, sex, cause of injury, combined facial bone fractures, and related injuries such as skull base fracture, spinal cord injury, brain hemorrhage, and other bone fractures. Fracture severity was classified by nasal bone fracture type. Results: No statistically significant difference was found in annual number of patients treated for nasal bone fracture. The proportion of patients who underwent closed reduction was significantly decreased over time for those with nasal bone fractures caused by traffic accidents. However, it was not significantly changed for those with nasal bone fractures due to other causes. The number of patients with combined facial bone fractures increased over time. Incidences of severe nasal bone fracture also increased over time. Conclusion: The study suggested that there is a decrease in the frequency and increase in the severity of nasal bone fracture due to traffic accident. Many protective devices prevent nasal bone fractures caused by a small amount of external force; however, these devices are not effective against higher amounts of external force. This study highlights the importance of preoperative thorough evaluation to manage patients with nasal bone fractures due to traffic accident.

• Korean Journal of Cleft Lip And Palate
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• v.9 no.2
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• pp.71-78
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• 2006

The case records of 24 patients in Seoul National University Hospital who had bone grafting of 29 alveolar clefts between 2001 and 2004 were examined. Details were recorded of age, sex, preoperative orthodontictreatment, the time of bone grafting, the type of donor site, cleft width, functional load applicationand the success of grafting as established by lowest marginal bone levels. Using this results and review of literature, we concluded that secondary bone graft with iliac bone before canine eruption with root development of 1/2 to 1/3 provide more favorable results and the functional load introduced to the grafted bone lower the resorption rates.

• Archives of Craniofacial Surgery
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• v.22 no.5
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• pp.239-246
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• 2021

Background: Bone grafts can provide an optimal environment for permanent tooth to erupt and enhance the stability of the alveolar maxilla. Although autologous bone is an optimal source for osteogenesis, its inevitable donor site morbidity has led to active research on bone substitutes. This study was designed to evaluate the safety and feasibility of using biphasic calcium phosphate (BCP; Osteon) as a bone substitute in dogs. Methods: Bilateral third and fourth premolars of four 15-week-old mongrel dogs were used. All teeth were extracted except the third premolar of the right mandible, which was used as a control. After extraction of the premolars, each dog was administered BCP (Osteon), demineralized bone matrix (DBM; DBX), and no graft in the hollow sockets of the right fourth premolar, left fourth premolar, and left third premolar, respectively. Radiographs were taken at 2-week intervals to check for tooth eruption. After 8 weeks, each dog was sacrificed, and tooth and bone biopsies were performed to check for the presence of tooth and bone substitute particle remnants. Results: Four weeks after the operation, permanent tooth eruptions had started at all the extraction sites in each dog. Eight weeks after the operation, all teeth had normally erupted, and histological examination revealed BCP particles at the right fourth premolar. Conclusion: In all four dogs, no delay in the eruption of the teeth or shape disfigurement of permanent teeth was observed on gross inspection and radiologic evaluation. On histological examination, most of the BCP and DBM were replaced by new bone. Bone substitutes can be used as graft materials in patients with alveolar clefts.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.2
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• pp.158-164
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• 2008

Purpose : Recently, various materials were developed for enhancing bone formation capacity. Platelet rich plasma(PRP) is an autologous source with several growth factors and obtained by sequestering and concentrating platelets by gradient density centrifugation. This study was to evaluate the effect of PRP on healing of grafted bone. Materials and methods : Two blood samples were obtained and analysed for measuring platelet counts of normal blood and PRP. In experimental group, two defects of mandibular bone, 10mm in diameter and 4.0mm deep, were created in the mandible and immediately grafted with autogenous bone chips mixed with PRP. In control group, same bone defects were prepared and grafted with autogenous bone chips. Gelform was used for carrier of PRP. 2 weeks, 4 weeks, 8 weeks later, each group was evaluated with histologi-cal and histomorphometric analyses. Results : According to histological observation, experimental group was showed more anastomosing newly-formed woven bone having osteoblastic activation than control group. According to histomorphometric analysis, there were 9.11% more newly-formed bone volume in experimental group than control group at 2 weeks, 7.91% more at 4 weeks, 20.08% more at 8 weeks. Conclusion: Our results demonstrated PRP in autogenous bone graft could enhance the bone formation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.9-15
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• 2010

Aim of the study: As an injectable scaffold, MPEG-PCL diblock copolymer was applied in bone tissue engineering. In vivo bone formation was evaluated by soft X-ray, histology based on the rat calvarial critical size defect model. Materials and Methods: New bone formation was evaluated with MPEG-PCL diblock copolymer in rat calvarial critical size bone defect. No graft was served as control. 4, 8 weeks after implantation, gross evidence of bone regeneration was evaluated by histology and soft X-ray analysis. Results: The improved and effective bone regeneration was achieved with the BMP-2 and osteoblasts loaded MPEG-PCL diblock copolymer. Conclusion: It was confirmed that MPEG-PCL temperature sensitive hydrogels was useful as an injectable scaffold in bone regeneration.