• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.353-359
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• 2010

Introduction: This study examined the effect of cyclosporine A (CsA) on the allogenic cranial bone graft in the mice. Materials and Methods: Twenty eight 12-week-old male ICR mice weighing 40 g were used. The experimental group was injected subcutaneously with CsA (10 mg/kg/day) diluted in Caster oil for 7 days prior to the graft until sacrifice. The control group was injected with the same solution without CsA. Two full-thickness bone defects with a diameter of 3 mm were made with a trephine bur in the parietal bone lateral to the sagittal suture. A calvarial defect of a mouse was grafted with allogenic calvarial bone disc from another mouse. The experimental and control groups were injected with CsA and the solution without CsA in the same manner before surgery, respectively. The mice were sacrificed at 1 week, 2 weeks and 4 weeks after the bone graft, respectively. Results: In the experimental group, fibrous connective tissues and small amounts of inflammatory cells were observed. At 2 weeks after the allograft in the experimental group, new bone formation in fibrous collagenous tissue and around the allogenic bone was noted. At 4 weeks after the allograft, new bone formation was active along and at the periphery of the mature allogenic bone. The proliferation of blood vessels increased in bone marrow. In the control group, fibrous tissues and inflammatory cells were observed around the allogenic bone and existing bone at 1 week. At 2 weeks after the allograft, the proliferation of blood vessels accompanied by inflammatory cells were scattered in the fibrous connective tissues. New bone formation around the allogenic and existing bone could be observed. At 4 weeks after the allograft, inflammatory cells were severely infiltrated around the allogenic bone. Osteoclasts were scattered along the allogenic bone and induced bone resorption. Conclusion: These results suggest that the daily administration of CsA (10 mg/kg/day) induces efficient immunosuppression without serious complications, and this protocol might be useful for the experimental model of allogenic bone grafts.

• Journal of Periodontal and Implant Science
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• v.38 no.sup2
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• pp.373-384
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• 2008

Purpose: The aim of this study is to compare the healing response of various Hydroxyapatite(HA) coated dental implants by Ion-Beam Assisted Deposition(IBAD) placed in the surgically created circumferential gap in dogs. Materials and methods: In four mongrel dogs, all mandibular premolars and the first molar were extracted. After an 8 weeks healing period, six submerged type implants were placed and the circumferential cylindrical 2mm coronal defects around the implants were made surgically with customized step drills. Groups were divided into six groups : anodized surface, anodized surface with 150nm HA and heat treatment, anodized surface with 300nm HA and heat treatment, anodized surface with 150nm HA and no heat treatment, and anodized surface with 150nm HA, heat treatment and bone graft, anodized surface with bone graft. The dogs were sacrificed following 12 weeks healing period. Specimens were analyzed histologically and histomorphometrically. Results: During the healing period, healing was uneventful and implants were well maintained. Anodized surface with HA coating and $430^{\circ}C$ heat treatment showed an improved regenerative characteristics. Most of the gaps were filled with newly regenerated bone. The implant surface was covered with bone layer as base for intensive bone formation and remodeling. In case that graft the alloplastic material to the gaps, most of the coronal gaps were filled with newly formed bone and remaining graft particles. The bone-implant contact and bone density parameters showed similar results with the histological findings. The bone graft group presented the best bone-implant contact value which had statistical significance. Conclusion: Within the scope of this study, nano-scale HA coated dental implants appeared to have significant effect on the development of new bone formation. And additional bone graft is an effective method in overcoming the gaps around the implants.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.4
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• pp.293-300
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• 2011

Purpose: Substance P is a well known neurotransmitter and has been known to mediate pain. Recently, it has been unveiled that substance P is involved in the recruitment of mesenchymal stem cells to wound sites. The purpose of this study was to exam bone formation when a combination of substance P and silk fibroin was used in a bone defect model. Methods: Twenty rabbits were used and 40 calvarial defects were formed. They were divided as 4 groups (unfilled control, silk only, silk+$10{\mu}g$/ml substance P; Sub10, and silk+$100{\mu}g$/ml substance P; Sub100). All animals were humanely sacrificed 4 or 8 weeks after grafting. The specimens were analyzed by micro-computerized tomography and histological analysis. Results: When compared to the unfilled control to silk only group, there was significant difference in bone mineral density (BMD) and the attenuation coefficient (AC) at 4 weeks ($p$=0.037 and 0.038, respectively). When compared Sub10 group to Sub100 group, there was significant difference in BMD and AC at 8 weeks ($p$=0.004 for all). Residual graft amounts were $52.1{\pm}15.8$%, $15.2{\pm}9.2$% and $9.0{\pm}3.3$% for silk only, Sub10, and Sub100 groups, respectively. When comparing the residual graft amount of silk only to sub10 or sub100, the differences were statistically significant ($p$ <0.001). Conclusion: The silk fibroin scaffold showed higher BMD and AC than the unfilled control. The combination graft with substance P and silk fibroin scaffold showed a faster graft degradation than with a silk fibroin scaffold only.

• Journal of Periodontal and Implant Science
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• v.45 no.3
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• pp.82-93
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• 2015

Purpose: This retrospective study evaluated the relationship between the timing of peri-implantitis diagnosis and marginal bone level after a 5-year follow-up of non-surgical peri-implantitis treatment. Methods: Thirty-three patients (69 implants) were given peri-implantitis diagnosis in 2008-2009 in Seoul National University Bundang Hospital. Among them, 31 implants from 16 patients were included in this study. They were treated non-surgically in this hospital, and came for regular maintenance visits for at least 5 years after peri-implantitis treatment. Radiographic marginal bone levels at each interval were measured and statistical analysis was performed. Results: Timing of peri-implantitis was one of the significant factors affecting initial bone loss and total bone loss not additional bone after peri-implantitis diagnosis. Patients with cardiovascular disease and diabetic mellitus were positively influenced on both initial bone loss and total bone loss. Patients who needed periodontal treatment after implant placement showed a negative effect on bone loss compared to those who needed periodontal treatment before implant placement during entire periods. Implant location also significantly influenced on amounts of bone loss. Mandibular implants showed less bone loss than maxillary implants. Among surgical factors, combined use of autogenous and xenogenic bone graft materials showed a negative effect on bone loss compared to autogenous bone graft materials. Use of membrane negatively affected on initial bone loss but positively on additional bone loss and total bone loss. Thread exposure showed positive effects on initial bone loss and total bone loss. Conclusions: Early peri-implantitis diagnosis led to early non-surgical intervention for peri-implantitis treatment, which resulted in the maintenance of the bone level as well as preservation of the implant.

• The Journal of the Korean dental association
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• v.50 no.12
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• pp.743-754
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• 2012

urpose : The purpose of this study was to evaluate the US II plus/GS II Osstem$^{(R)}$ implants through the study for the clinical success rate during the installation of the Osstem¢Á implants after bone graft. Materials and Methods : This study was researched in the 4 medical institutions: Chonnam National University, Chosun University, Bundang Seoul National University Hospital, and FM dental clinic from May, 2002 to September, 2009. Based on the total number of 60 patients whose treatment was the installation of the US II plus/GS II Osstem¢Á implants after bone graft, we evaluated success rate of implants. We analysis the distribution of patient's age and gender, edentulous area, bone type, fixture length and diameter, installation and loading time, donor site, bone graft material and method, antagonistic teeth, and survival and success rate. From these analyses we got the following results. Results : 1. In this study, the total number of patients who have been installed with US II plus implant was 27, and total of 52 implants were installed. The average age was 38.9, with 16 male, and 11 female patients. 2. The total number of patients who have been installed with GS II implant was 33, and total of 54 implants were installed. The average age was 49.7, with 24 male, and 9 female patients. 3. As for bone graft method, either autogenous bone or a mix of autogenous and heterogenous bone was used(88.4%) for US II plus. Chin, iliac, and Maxillary tuberosity were the donor sites for autogenous bone graft, and onlay method of bone graft was performed. 4. Allogenic bone or a mix of autogenous and heterogenous bone was used(77.8%) for GS II. Chin, ramus, and tibia were the donor sites for autogenous bone graft, and GBR method of bone graft was performed. 5. The duration from the installation of implants to setting of final prosthesis was average of 16 months and 10 months for US II plus and GS II respectively. Also, the final follow up period was average of 31 months and 28 months respectively. During this period, one GS II implant was removed from 1 patient due to failure of early osteointegration. 6. The survival rates were 100% and 98.1%, and success rates were 94.2% and 94.4% for US II plus and GS II implant respectively. Conclusion : On the evaluation of our clinical study, both US II plus and GS II Osstem¢Á implants showed the excellent clinical results after bone graft.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.611-619
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• 2017

Objective : In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis. Methods : A validated 3-dimensional, nonlinear ligamentous cervical segment (C3-7) finite element model was used. This study simulated a single-level ACDF at C5-6 with a cylindroid interbody graft. The variables were the properties of the incorporated interbody graft (cancellous bone [Young's modulus of 100 or 300 MPa] to cortical bone [10000 MPa]) and the contact area between the vertebra and interbody graft (Graft-area, from 10 to $200mm^2$). Interspinous motion between the flexion and extension models of less than 2 mm was considered solid fusion. Results : The minimal Graft-areas for solid fusion were $190mm^2$, $140mm^2$, and $100mm^2$ with graft properties of 100, 300, and 10000 MPa, respectively. The minimal Graft-areas were generally unobtainable with only the formation of InGBB after the use of a commercial stand-alone cage. Conclusion : ExGBB may be formed to compensate for insufficient InGBB. Although various factors may be involved, solid fusion with less formation of ExGBB may be achieved with refinements in biomaterials, such as the use of osteoinductive cage materials; changes in cage design, such as increasing the area of polyetheretherketone or the inside cage area for bone grafts; or surgical techniques, such as the use of plate/screw systems.

• Imaging Science in Dentistry
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• v.44 no.3
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• pp.213-220
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• 2014

Purpose: This study was performed to determine the efficacy of observers' prediction for the need of bone grafting and presence of perioperative complications on the basis of cone-beam computed tomography (CBCT) and panoramic radiographic (PAN) planning as compared to the surgical outcome. Materials and Methods: One hundred and eight partially edentulous patients with a need for implant rehabilitation were referred for preoperative imaging. Imaging consisted of PAN and CBCT images. Four observers carried out implant planning using PAN image datasets, and at least one month later, using CBCT image datasets. Based on their own planning, the observers assessed the need for bone graft augmentation as well as complication prediction. The implant length and diameter, the need for bone graft augmentation, and the occurrence of anatomical complications during planning and implant placement were statistically compared. Results: In the 108 patients, 365 implants were installed. Receiver operating characteristic analyses of both PAN and CBCT preoperative planning showed that CBCT performed better than PAN-based planning with respect to the need for bone graft augmentation and perioperative complications. The sensitivity and the specificity of CBCT for implant complications were 96.5% and 90.5%, respectively, and for bone graft augmentation, they were 95.2% and 96.3%, respectively. Significant differences were found between PAN-based planning and the surgery of posterior implant lengths. Conclusion: Our findings indicated that CBCT-based preoperative implant planning enabled treatment planning with a higher degree of prediction and agreement as compared to the surgical standard. In PAN-based surgery, the prediction of implant length was poor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.2
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• pp.77-84
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• 2013

Objectives: This study evaluated implant success rate, survival rate, marginal bone resorption of implants, and material resorption of sinus bone graft in cases wherein tapered body implants were installed. Materials and Methods: From September 2003 to January 2006, 20 patients from Seoul National University Bundong Hospital, with a mean age of 54.7 years, were considered. The mean follow-up period was 19 months. This study covered 50 implants; 14 implants were placed in the maxillary premolar area, and 36 in the maxillary molar area; 24 sinuses were included. Results: The success rate was 92%, and the survival rate was 96.0%. The mean amount of sinus augmentation was $12.35{\pm}3.27$ mm. The bone graft resorption rate one year after surgery was $0.97{\pm}0.84$ mm; that for the immediate implantation group was $0.91{\pm}0.86$ mm, and that for the delayed implantation group was $1.16{\pm}0.77$ mm. However, the difference was not statistically significant. The mean marginal bone resorption one year after restoration was $0.17{\pm}0.27$ mm (immediate group: $0.12{\pm}0.23$ mm; delayed group $0.40{\pm}0.33$ mm); statistically significant difference was observed between the two groups. Conclusion: Tapered body implant can be available in the maxillary posterior edentulous ridge which sinus bone graft is necessary.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.4
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• pp.359-362
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• 2011

Purpose: This study evaluated the clinical applications of implant placement and guided bone regeneration using a mineralized bone allograft and a barrier membrane derived from ox pericardium Methods: From January 2007 to June 2009, among the patients who received an implant at Chosun University Dental Hospital, patients were selected if they were treated with guided bone regeneration (GBR) with simultaneous implant placement or GBR prior to implant placement. The selected patients were sorted according to the materials and membranes used in GBR, and the implant survival rate was recorded by clinical examination and reviewing the medical records and the radiographs. Each study list was analyzed by SPSS (version 12.0, SPSS Inc., USA) software and the survival rate was verified by Chi-square tests. $P$ values less than 0.05% were deemed significant. Results: 278 implants were placed on a total of 101 patients and 8 implants resulted in failure. Three implants failed among 15 implants with only a mineralized bone allograft. No failure was shown among the 74 implants placed with mineralized bone allograft and a barrier membrane derived from ox pericardium. One group of 4 implant placements showed failure among the 102 implants placed with a mineralized bone allograft and another bone graft material. The group that had a barrier membrane derived from ox pericardium with a mineralized bone allograft or other bone materials showed no implant failure. Three failures were shown among the 21 implants placed with only bone graft and not using a membrane. The group with membranes other than a barrier membrane derived from ox pericardium showed 5 failures among 170 implants. Conclusion: The implant survival rate of the group with GBR using a mineralized bone allograft was 96.3%, which meant there was little difference compared to the groups of another bone graft materials (98.9%). The implant survival rate of the group without a membrane-was 85.7% and it showed a significant difference compared to the group using a barrier membrane derived from ox pericardium (100%) and the group using another membrane (97.1%).

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.671-689
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• 1994

The purpose of this study was to compare effects of various bone grafts on periodontal regeneration of alveolar bone defects in dogs. Seven adult dogs aged 12 to 18 months were used in this study. Experimental alveolar bone defects were created surgically with a #1/2 round bur at the furcation area of the buccal surface of the mandibular 3rd, 4th premolars and 1st molar. Each experimental alveolar bone defects were grafted with dense hydroxyapatite, natural coral, and decalcified freeze-dried bone, and respectively divided into DHA, NC, DFDB group. An area without bone graft was divided into control group. At 1,2,4,6, and 12 weeks, dogs were serially sacrificed and specimens were prepared with Hematoxylin-Eosin stain and Mallory stain for light microscopic evaluation. The results of this study were as follows : 1. In control group, the matrix change of granulation tissue was observed at 1 week. And in experimental groups, the appearance of connective tissue around graft materials was loosely formed at 1 week, but densely formed at 2 weeks. 2. In every group, the slight formation of new trabecular bone was seen from remaining bone at 1 week. 3. The DHA and NC particles were gradually encapsulated by new trabecular bone from remaining bone, and the osteoid tissue was directly induced from DFDB particles. 4. The presence of osteoblasts was first observed at 1 week in control group and at 2 weeks in NC group, but at 6 weeks in DHA group. 5. In DHA group, the resorption of particles was not observed until 12 weeks. But in NC and DFDB group, the particles were resorbed at 6 weeks and replaced by new bone. And the amount and size of particles were reduced, and their border represented irregular form. In summary, in three experimental groups the inflammatory or foreign body reaction were slight, but the regeneration of new osteoid tissue and the matrix change of dense connective tissue fiber were observed. Especially, NC and DFDB materials were considered as the biocompatible graft materials which were effective in the regenertion of new bone.