• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.243-249
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• 2010

Tissue engineered bone (TEB) can replace an autogenous bone graft requiring an secondary operation site as well as avoid complications like inflammation or infection from xenogenic or synthetic bone graft. Adult mesenchymal stem cells (MSC) for TEB are considered to have various ranges of differentiation capacity or multipotency by the donor site and age. This study examined the effect of age on proliferation capacity, differentiation capacity and bone morphogenetic protein-2 (BMP-2) responsiveness of human bone marrow stromal cells (hBMSC) according to the age. In addition, to evaluate the effect on enhancement for osteoblast differentiation, the hBMSC were treated with Trichostatin A (TSA) and 5-Azacitidine (5-AZC) which was HDAC inhibitors and methyltransferase inhibitors respectively affecting chromatin remodeling temporarily and reversibly. The young and old group of hBMSC obtained from the iliac crest from total 9 healthy patients, showed similar proliferation capacity. Cell surface markers such as CD34, CD45, CD90 and CD105 showed uniform expression regardless of age. However, the young group showed more prominent transdifferentiation capacity with adipogenic differentiation. The osteoblast differentiation capacity or BMP responsiveness was low and similar between young and old group. TSA and 5-AZC showed potential for enhancing the BMP effect on osteoblast differentiation by increasing the expression level of osteogenic master gene, such as DLX5, ALP. More study will be needed to determine the positive effect of the reversible function of HDAC inhibitors or methyltransferase inhibitors on enhancing the low osteoblast differentiation capacity of hBMSC.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.1
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• pp.16-22
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• 2010

Purpose: The purpose of this study was not only to evaluate the relative mRNA expression of interleukin-$1{\beta}$(IL-$1{\beta}$), cyclooxygenase2 (COX-2) and prostaglandin E2 (PGE2) by RT-PCR analysis but to observe pattern of edema by light microscopic and electron microscope after topical apply of hyaluronic acid in inflammation-guided mouse. Material and methods: Mice of this study were devided into 4 groups: Control group (no inflammation guided), Positive control (inflammation guided + vaselin apply), Protopic group (inflammation guided + protopic apply), Hyaluronic group (inflammation guided + hyaluronic acid apply). Results: Hyaluronic group showed less expressions of IL-$1{\beta}$, COX-2, PGE2 than those of positive control & protopic group. Hyaluronic group revealed a decreased inflammation than positive control & protopic group in Light Microscope. Hyaluronic group appeared decreased edema of ear compare to positive control & protopic group in Elecron Microscope. Conclusion: It was considered that hyaluronic acid has an antiinflammatory effect for intercepting the gene expression of cytokines related to inflammation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.250-254
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• 2010

Introduction: This study evaluated the bone regenerative effect of silk fibroin mixed with platelet-rich fibrin (PRF) of a bone defect in rabbits. Materials and Methods: Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter: 8.0 mm). The silk fibroin mixed with PRF was grafted into the right parietal bone (experimental group). The left side (control group) was grafted only PRF. The animals were sacrificed at 4 weeks and 8 weeks. A micro-computerized tomography (${\mu}$CT) of each specimen was taken. Subsequently, the specimens were decalcified and stained for histological analysis. Results: The average value of plane film analysis was higher in the experimental group than in the control group at 4 weeks and 8weeks after surgery. However, the difference was not statistically significant.(P>0.05) The tissue mineral density (TMD) in the experimental group at 4 weeks after surgery was significantly higher than the control group.(P<0.05) Conclusion: Silk fibroin can be used as a scaffold of PRF for rabbit calvarial defect repair.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.1
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• pp.7-15
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• 2010

Complex human tissues harbor stem cells and precursor cells, which are responsible for tissue development or repair. Recently, dental tissues such as dental pulp, periodontal ligament (PDL), dental follicle have been identified as easily accessible sources of undifferentiated cells. These tissues contain mesenchymal stem cells that can be differentiate into bone, cartilage, fat or muscle by exposing them to specific growth conditions. In this study, the authors procured the stem cell from pulp, PDL, and dental follicle and differentiate them into osteoblast and examine the bone induction capacity. Dental pulp stem cell (DPSC), periodontal ligament stem cell (PDLSC), and dental follicle precursor cell (DFPC) were obtained from human 3rd molar and cultured. Each cell was analyzed for presence of stem cell by fluorescence activated cell sorter (FACs) against CD44, CD105 and CD34, CD45. Each stem cell was cultured, expanded and grown in an osteogenic culture medium to allow formation of a layer of extracellular bone matrix. Osteogenic pathway was checked by alizarin red staining, alkaline phosphatase (ALP) activity test and RT-PCR for ALP and osteocalcin (OCN) gene expression. According to results from FACs, mesenchymal stem cell existed in pulp, PDL, and dental follicle. As culturing with bone differentiation medium, stem cells were differentiated to osteoblast like cell. Compare with stem cell from pulp, PDL and dental follicle-originated stem cell has more osteogenic effect and it was assumed that the character of donor cell was able to affect on differential potency of stem cell. From this article, we are able to verify the pulp, PDL, and dental follicle from extracted tooth, and these can be a source of osteoblast and stem cell for tissue engineering.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.270-274
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• 2010

Introduction: Limited mouth opening is a representative clinical symptom of temporomandibular disorders (TMD) with anterior disc displacement without reduction (ADDWOR). Various treatment methods have been proposed for patients with ADDWOR. This study examined the clinical effectiveness of template therapy for patients with mouth opening difficulty due to the ADDWOR. Material and Methods: A total of 14 patients (female 12, male 2, average age: $29.1{\pm}14.4$), who had been treated in the template clinic, Sooncheonhyang University Bucheon Hospital, from January of 2006 to December of 2008, were enrolled in this study. The subjects were selected according to the following criteria: more than 2 weeks after the onset of locking, mouth opening range <35 mm, and confirmed ADDWOR without a synovial pathology by magnetic resonance imaging (MRI). All patients were treated with the template appliance, instructed to wear it while sleeping and exercise for at least 10 hours per day. The maximum mouth opening (MMO) range and pain recognition scores before and after template therapy were recorded and compared. A paired t-test and Wilcoxon's signed rank test were used for statistical analysis. Results: After the periodical follow up, significant improvement in the opening range was observed in the template treatment group. The average MMO range before treatment was $30.2{\pm}3.5mm$ and the average MMO after treatment and follow up was $47.1{\pm}4.7mm$. The mean amount of mouth opening increment was $16.9{\pm}5.4mm$ (P<0.01) and the pain recognition scores before and after treatment was also improved.(P=0.001) Conclusion: The template appliance proved to be efficient for the treatment of TMD with a closed lock and painful joint due to ADDWOR.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.275-279
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• 2010

Introduction: Guided bone regeneration (GBR) is a common procedure for the treatment of bone defects and bone augmentation. The nonresorbable barriers are well-documented barriers for GBR because of their stability and malleability. However, few GBR studies have focused on the different types of non-resorbable barriers. Therefore, this study examined the clinical results of different non-resorbable barriers for GBR; expanded polytetrafluoroethylene (e-PTFE) (TR-Gore Tex, Flagstaff, AZ, USA), and high-density polytetrafluoroethylene (d-PTFE) (Cytoplast membrane, Oraltronics, Bremen, Germany). Materials and Methods: The analysis was performed on patients treated with GBR and implant placement from January 2007 to October 2007 in the department of the Seoul National University Bundang Hospital. The patients were divided into two groups based on the type of non-resorbable barrier used, and the amount of bone regeneration, marginal bone resorption after prosthetics, implant survival rate and surgical complication in both groups were evaluated. Results: The implants in both groups showed high survival rates, and the implant-supported prostheses functioned stably during the follow-up period. During the second surgery of the implant, all horizontal defects were filled with new bone, and there was no significant difference in the amount of vertical bone defect. Conclusion: In bone defect areas, GBR with non-resorbable barriers can produce favorable results with adequate postoperative management. There was no significant difference in bone regeneration between e-PTFE and d-PTFE.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.309-313
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• 2010

The management of teeth in the line of a mandibular fracture is controversial despite the general agreement that most of these teeth can be preserved. Teeth should be retained if bony attachments are adequate for survival, the tooth is sound and important in maintaining fixation of the fractured segment of bone. Teeth should be removed if they are loose and interfere with the reduction of fragments, are devitalized and potentially a source of wound infection, are damaged beyond their usefulness or may become devital and interfere with healing by becoming infected. However, tooth removal will increase the level of trauma, extend the severity of the wound and require expensive prosthetic treatment. Therefore, it is very important to conserve infected teeth in the line of a mandibular fracture through early primary endodontic treatment (pulp extirpation, canal enlargement and canal opening drainage) and splinting. The basic principles underlying the treatment of pulpless teeth are those underlying general surgery. Therefore, debridement of the infected wound (pulp extirpation and canal enlargement), drainage (canal opening) and gentle treatment of the tissues (occlusal reduction and teeth splinting) are the principles of surgery. This is a representative case report of conservative care by the early endodontic drainage of infected teeth in the line of a mandibular fracture.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.609-616
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• 2007

Purpose: The aim of the present study was to evaluate the effect of Bio-Oss on bone formation in terms of healing period and type of membrane so that determine the most suitable condition for implant fixation in grafted maxilla. Material & Method: Forty-five biopsy specimens from graft site were evaluated. Sinus lift was performed in the patients with reduced alveolar bone height(less than 5mm). The specimen was taken at the time of implant fixation, which was performed at least 5 months after the sinus lift procedure. All specimens were stained with H&E and Trichrome staining and evaluated histomorphometrically. Result: The results showed that Bio-Oss particle was in direct contact with newly formed bone in all cases. In the present study, the amount of newly formed bone and the residual bone substitute material were not statistically different according to various membrane and different healing period. There was no difference between the histological feature of the specimen of 5 and 31 months. No statistical significance was detected between male and female. Conclusion: The result implies that Bio-Oss does not seem to be resorbed over time regardless of the type of the membranes. The further investigation is needed to clarify this issue with the extended period of follow-up.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.5
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• pp.217-223
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• 2013

Objectives: Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery. Materials and Methods: Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture. Results: Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible. Conclusion: Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.