• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.75-82
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• 2008

Purpose: The purpose of this study was to evaluate exophytically vertical bone formation in the mandibular premolar area of beagle dogs by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with human demineralized freeze-dried bone. Materials and Methods: Four one-year old beagle dogs were divided into control and experimental group. All mandibular premolars were extracted and surgical vertical defects of 5 mm in height were created in the extracted sockets. At 8 weeks after the extraction, TR e-PTFE membrane sized with 8 mm in length, 5 mm in width, and 4 mm in height was placed on the decorticated mandible, fixed with metal pins and covered with full-thickness flap and assigned as control group. In experimental group, decorticated mandibule was treated with TR e-PTFE membrane and human demineralized freeze-dried bone. The animals were sacrificed at 16 weeks after the regenerative surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. Results: Average of new bone formation was 38% in the control group, whereas was 25% in the experimental group (p<0.05). Average of connective tissue formation was 42% in the experimental group, whereas was 30% in the control group (p<0.05). The lamellar bone formation with haversian canals was observed in the both groups. In the experimental group, the particles of human demineralized freeze-dried bone were observed after 16 weeks and complete resorption of graft was not observed. Conclusion: On the basis of these findings, we conclude that titanium reinforced e-PTFE membrane may be used alone for vertical guided bone regeneration, but demineralized freeze-dried bone has no additional effect on vertical guided bone regeneration.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.163-175
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• 2004

This study was performed to evaluate bone formation in the calvaria of rabbit by the concept of guided bone regeneration with titanium mesh membrane and demineralized freeze-dried bone. The animal was sacrificed at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after the surgery. Non-decalcified specimens were processed for histologic analysis. 1. The titanium mesh but the biocompatibility was excellent the cell-occlusiveness was feeble. 2. The cell-occlusiveness was feeble and also the soft tissue growth of the upper part of the newly-formed bone after operating was excellent in early stage. 3. The maintenance ability of the space for the GBR very was excellent. 4. The titanium mesh the tissue-integration was superior the wound fixation ability excellent. 5. The demineralized freeze-dried bone did not promote the bone regeneration. 6. With the lapse of time, formation quantity of the bone some it increased, it increased quantity very it was feeble. Within the above results, the titanium mesh for the guided bone regeneration was excellent, the dεmineralized freeze-dried bone confirmed does not promote bone regeneration.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권4호
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• pp.278-286
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• 2011

Introduction: This study examined the predictability of new bone formation in the pneumatized maxillary sinus using only fibrin-rich blocks with concentrated growth factors as an alternative to bone grafts. Materials and Methods: Maxillary sinus augmentation was performed in thirty-three patients with a deficient alveolar bone height (mean 3.9 mm). All patients were treated consecutively with sinus membrane elevation via the lateral window approach and panoramic radiograms and cone-beam computed tomograms were taken to evaluate the remaining bone height and the new bone formation in the maxillary sinus, before and after surgery. Four biopsy specimens were taken at the time of implant consolidation (after an average of five months healing) and were stained by H & E and Trichrome staining. Results: None of the patients had postoperative complications during implant consolidation. After an average of 5 months since sinus augmentation, newly formed bone was observed in all cases by a radiographic evaluation. In 4 biopsy samples, newly formed bone was observed along the floor of the replaced bony window. The osteoblast lining and well distinguished Osteocytes in the lacunas were observed in the newly formed bone. Of the 74 implants (4 different surfaced implants - resorbable blast media-surfaced (RBM), Hydroxyapatite (HA) coated, acid-etched, sintered porous-surfaced implant) placed, one RBM implant failed. The success rate was 98.6% after a mean of 15 months. Discussion: These results suggest that maxillary sinus augmentation using fibrin rich block with concentrated growth factors is a successful and predictable technique.

• Toxicological Research
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• 제22권3호
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• pp.253-266
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• 2006

Bone is a dynamic tissue that is constantly being remodelled. Resolution of bone and formation of new bone are closely linked, so that bone mass remains constant. With age, this process becomes unlinked with an imbalance in bore resorption and formation that results in a net loss of bone. Especially, osteoporosis is a disease characterized by low bone mass with age. One form of aging-related primary osteoporosis is postulated with the reduction of circulating estrogen, rapid bone loss occurs as a result of enhanced bore remodelling with an excess of resorption over bore formation. The oxidative stress is also involved in the pathogenesis of osteoporosis. Oxidative stress by cytokines, such as IL-a and TNF-${\alpha}$, inhibits osteoblast function in vitro and stimulates osteoblast apoptosis resulting in an imbalance in bore remodelling. The present article reviews the current perspectives on the interaction between bone remodelling and factors such as estrogen and oxidative stress, providing an interpretation of bone diseases in a view of molecular mechanisms.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권1호
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• pp.49-58
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• 2008

Objective: The Purpose of the study was to investigate the bone morphogenic protein expression of rhBMP-2(recombinant human bone morphogenic protein-2) as singnaling molecule and ${\beta}-TCP$(Tricalcium phosphate) as a bone substitute and carrier medium of rhBMP-2. Materials and Methods: 16 rabbits divided into 2 group of each 8 rabbit. Two standardized bone defect, round bilateral defect was made in the cranium of the 8 rabbit of first group, and was grafted with $150{\sim}500{\mu}m$ diameter ${\beta}-TCP$ 0.25g in one side, which was soaked with rhBMP-2, and autogenous bone was grafted on another side as a positive control. Second group of 8 rabbit, only ${\beta}-TCP$ was grafted with same size and same manner. After 2, 4, 8, and 12 weeks, specimen was taken for microscopic immunohiostochemical and histomorphometric analysis. Result: Grafting ${\beta}-TCP$ with rhBMP show the early formation of the bone regenerative factor (BMP-4) and more quantity of new bone formation than only use of ${\beta}-TCP$ (8,12 week), even show less new bone formation than autogenous bone. Conclusion : The experimental study result that ${\beta}-TCP$ graft combination with rhBMP-2 as a delivery system is an effective with osteoinductive capacity and biodegradable properties, so that provide clinical availibility of composite use in reconstruction of bony defect.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권1호
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• pp.28-39
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• 2007

The purpose of this study is to evaluate the regenerative capacity of reconstruction in the atrophied posterior maxilla by comparing bone graft procedures and alveolar distraction osteogenesis (ADO) techniques. We performed the autogenous iliac bone graft (AGB group, 5 specimens in 3 patients), and the combination (Mixed group, 3 specimens in 3 patients) of the autogenous and deproteinized bovine bone ($Bio-Oss^{(R)}$, Geistlich Co., Switzerland) as the ratio of 2:1 in the sinus floor elevation procedures. ADO procedures using $TRACK^{(R)}$ (KLS Martin Co., Germany) were also performed to augment vertical alveolar height in atrophied posterior maxilla (ADO group, 5 specimens in 4 patients). Newly generated bone tissues were obtained with the 2.0mm diameter trephine bur (3i Co., USA) during implant fixture installation after 5-7 months. Routine histolomorphological observation, immunodot blot assay for quantitative evaluation, and immunohistochemical staining with antibodies to MMP-1, -9, -10, TIMP-1, -2, and BMP-2, -4 were all carried out. Lamellar bone formation was well shown in all specimens and new bone formations of ADO group increased than those of other procedures. In immunohistochemical staining, the strong expression of BMP-2 was shown in all specimens, and immunodot blot assay showed that bone formation is accompanied by the good induction of factors associated with angiogenesis and appeared more increased amount of osteogenic and angiogenic factors in ADO group. ADO is the most effective technique for new bone formation compared to sinus floor elevation with autogenous or mixed bone graft in the atrophied posterior maxilla. In the quantitative immunodot blot assay, the regenerated bone after ADO showed more increased products of VEGF, BMP-2, PCNA and MMP-1 than those after the other procedures, and these findings were able to be confirmed by immunohistochemical stainings.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.273-288
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• 2006

The purpose of this study was to evaluate exophytically vertical bone formation in rabbit calvaria by the concept of guided bone regeneration with a custom-made porous titanium membrane combined with bone graft materials. For this purpose, a total of 12 rabbits were used, and decorticated calvaria were created with round carbide bur to promote bleeding and blood clot formation in the wound area. Porous titanium membranes (0.5 mm in pore diameter, 10 mm in one side, 2 mm in inner height) were placed on the decorticated calvaria, fixed with metal pins and covered with full-thickness flap. Experimental group I was treated as titanium membrane only. Experimental group II, III, IV was treated as titanium membrane with BBM, titanium membrane with DFDB and titanium membrane with FDB. The animals were sacrificed at 8 and 12 weeks after surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. 1. Porous titanium membrane was biocompatable and capable of maintaining the regeneration space. 2. At 8 and 12 weeks, all groups demonstrated exophytic bone formation and there was a statistical significant difference among different groups only at 12 weeks. 3. The DFDB group revealed the most new bone formation compared to other groups (p<0.05). 4. At 12 weeks, DFDB and FDB groups showed the most significant resorption of graft materials (p<0.05). 5. The BBM was not resorbed at all until 12 weeks. 6. The fixation metal pin revealed excellent effect in peripheral sealing. On the basis of these findings, we conclude that a porous titanium membrane may be used as an augmentation membrane for guided bone regeneration, and DFDB as an effective bone forming graft material. The fixation of the membrane with pin will be helpful in GBR technique. However, further study is required to examine their efficacy in the intraoral experiments.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권4호
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• pp.312-321
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• 2007

Purpose: Distraction osteogenesis has been applied to the maxillofacial implantology and good experimental and clinical results have been reported. However, histologic studies of implants placement on distraction osteogenesis of atrophic alveolar ridges are scarce. In this study, we compare the bone formation between in the transport part and in the distraction part by histomorphometric analysis. Materials & methods: Three adult beagle dogs were served as experimental subjects. The 2 premolars and 1st molar were extracted on the Lt. side of mandible in each beagle dog. After one month later, osteotomy was performed and distraction device was adapted. Distraction was performed with gradual incremental separation of two bone pieces at a rate of 1.0mm per day for 5 days. During consolidation phase, new bone was formed in the distraction zone between the separated bone pieces. 5 weeks after distraction phase, 3 implants were placed in each beagle dog. The implants were inserted through transport part and distraction part and inferior basal bone. The animals were sacrificed at 2 weeks, 4 weeks, and 12 weeks after implant placement. BIC and BA of implants on distraction part and transport part were measured histomorphometrically. Results: BIC, BA increased after implant placement as time goes by passes and new bone formation was slightly higher in transport part than in distraction part at 2 weeks, 4 weeks after implant placement. At 12 weeks after implant placement, BIC, BA of were 74%, 61% in transport part and 77%, 59% in distraction part, therefore there were no difference in BIC and BA between transport part and distraction part at 12 weeks after implant placement.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권1호
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• pp.12-16
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• 2012

Purpose: The purpose of this study is to evaluate the effect of exposure of hydroxyapatite coating on the amount of bone formation and stability in the dogs. Methods: In this study, hydroxyapatite coated implants (HAPTITE) was placed over the femur bone surface of four dogs about 1 mm. The experimental group was divided into 4 weeks group of 8 implants and 8 weeks group of 8 implants, and then they were sacrificed. The stability of implants was evaluated twice with Osstell$^{TM}$ mentor (Osstell AB, Goteborg, Sweden) at right after placement and sacrifice. The amount of bone formation was evaluated through histomorphometric examination. Results: The stability of implants was in normal range, and tended to increase as time goes by. Mean percentages of new bone formation rates were $90.5{\pm}6.6$ at uppermost 1 mm bone level adjacent to soft tissues (level 1) and $92.9{\pm}4.1$ at next 1 mm bone level (level 2) in 4 weeks group, $90.1{\pm}11.5$ at level 1 and $95.9{\pm}2.3$ at level 2 in 8 weeks group. Mean percentages of bone-implant contact rates were $85.1{\pm}10.8$ at level 1 and $88.1{\pm}13.8$ at level 2 in 4 weeks group, $88.5{\pm}14.4$ at level 1 and $95.3{\pm}3.1$ at level 2 in 8 weeks group. There was no statistically significant difference of new bone formation rate and bone-implant contact rate between uppermost 1 mm bone level adjacent to soft tissues and next 1 mm bone level. However, there was no significant difference in bone formation between 4 and 8 weeks groups. Conclusion: These results suggested that exposed hydroxyapatite coated implants to soft tissue showed favorable bone formation and implant stability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권6호
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• pp.613-619
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• 2000

The purpose of the present study was to investigate the effect of Bioactive glass on bone regeneration in the experimental mandibular bone defects. Five rabbits, weighing about 2.0kg, were used. Three artificial bone defects, $5{\times}5{\times}5mm$ in size, were made at the inferior border of the mandible. In the experimental group 1, the bone defect was grafted with $Biogran^{(R)}$ and covered with $Bio-Gide^{(R)}$ resorbable membrane. In the experimental group 2, $Biogran^{(R)}$ was grafted only. In the control group, the bone defect was filled with blood clot and was spontaneously healed. The animals were sacrificed at 1, 2, 4, and 8 weeks after the graft. Microscopic examination was performed. Results obtained were as follows: In the control group, the osteoid tissue was observed at week 1 and the bone trabeculi were connected each other and matured at week 2. The lamellar bone formation appeared at week 4, and the amount of bone tissue was increased at week 8. In the experimental group 1, the fibrous tissue was filled between the granules of Bioactive glass and the cartilage formation was found adjacent to the normal bone at week 1. The bone tissue was formed between the granules at week 2, while the amount of bone tissue increased and the lamellar bone formation was observed at week 4. The lamellar bone was increased at week 8. Histologic findings were Similar between the experimental groups 1 and 2, although the amount of Bioactive glass granules lost was increased in the latter. These results suggest that new bone formation is found around the Bioactive glass granules grafted into the bone defects, and the membrane plays a role in keeping the granules and preventing the fibrous tissue invasion.