• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.3
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• pp.153-157
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• 2009

Recently, an increasing number of bisphosphonate related osteonecrosis of the jaw(BRONJ) is being reported. A guideline has been already established in the US, but it does not seem to be fully recognized by clinicians in Korea. Therefore, a survey study was done to inform and have clinicians realize the seriousness of BRONJ. 1,341 practitioners were randomly selected out of 13,405 practitioners(by Feb of 2008, KDA) in Korea. A questionnaire was given to them between May to July in 2008. Questions were designed to investigate each respondent's experience term years in the clinic, occupation, speciality, awareness on risk of bisphosphonate, experience on treating osteonecrosis patients, awareness about the guideline on BRONJ suggested by AAOMS and whether if they ask about bisphosphonate medication history to patients before invasive treatment. 45.1% of the clinicians have reported on experiencing delayed healing on bone exposed site after extraction both in the maxilla and the mandible. However, clinicians have asked the patients whether if they are on bisphosphonate or not in only 15.1% of these cases. 56.5% of the clinicians simply knew about BRONJ but only 28.9% of the clinicians were aware that bisphosphonate can cause osteonecrosis after invasive dental treatment. Only 19.3% knew about the contents of guideline on BRONJ and 57.2% were aware of the seriousness of BRONJ. Clinicians with shorter clinical experience term were more aware of BRONJ and the guideline on BRONJ than the experienced clinicians. But awareness of the possibility of BRONJ after invasive dental treatment were about the same regardless of their clinical experience. The results show that Korean clinicians need to be more aware about BRONJ. Data on BRONJ cases in Korea should be collected and provided with additional education to let Korean clinicians know and be more aware about BRONJ.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.114-120
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• 2007

The augmentation of soft tissue defects is one of the critical problems in the oral and maxillofacial surgery. Various types of graft materials, both autologous and non-autologous, have been used for the augmentation of soft tissue in the facial region. However, it is not easy to choose an ideal material for soft tissue augmentation because each has its advantages and disadvantages. An ideal graft material should meet the following criteria : it should not leave a scar at the area from which it was taken; should have less likelihood of causing infection; should feel natural after implanted; and should be not absorbed. Among the materials meeting these criteria, human dermis and artificial dermis are commonly used for clinical purposes. The present study was aimed to investigate and compare the resorption rate and the histological change following the use of the autologous dermis, the human homogenous dermis $Alloderm^{(R)}$, and the artificial dermis $Terudermis^{(R)}$ to reconstruct the soft tissue defect. Twenty mature rabbits of either sex, weighing about 2 ㎏, were used. Each rabbit was transplanted with the autologous dermis, $Alloderm^{(R)}$, and $Terudermis^{(R)}$ size $1{\times}1-cm$ at the space between the external abdominal oblique muscle and the external abdominal oblique fascia. They were then divided into 4 groups (n=5 each) according to the time elapsed after the surgery: 1, 2, 4, and 8 weeks. The resorption rate was calculated by measuring the volume change before and after the transplantation, and H-E stain was preformed to observe the histological changes. The resorption rate after 8 weeks was 21.5% for the autologous dermis, 16.0% $Alloderm^{(R)}$, and 36.4% $Terudermis^{(R)}$, suggesting that $Alloderm^{(R)}$ is the most stable while $Terudermis^{(R)}$ is the most unstable. In microscopic examinations, the autologous dermis graft was surrounded by inflammatory cells and showed foreign body reactions. The epidermal inclusion cyst was observed in the autologous dermis graft. $Terudermis^{(R)}$ and $Alloderm^{(R)}$ demonstrated neovascularization and the progressive growth of new fibroblast. The results suggest that $Terudermis^{(R)}$ and $Alloderm^{(R)}$ can be availably for substituting the autologous dermis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.131-138
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• 2007

The purpose of this study was to observe the effect of calcium and vitamin D to the titanium implant osseointegration in animal model. 32 rats, 10 weeks of age, were divided into two group: additional calcium and vitamin D supplementation group and a control group. Titanium screw implant(diameter, 2.0mm; length, 3.5mm; pitch-height 0.4mm) were placed into tibia of 32 rats, 16 in the control group and 16 in the experimental group. The rats were sacrificed at different time interval(1, 2, 4, and 8 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with osteocalcin and osteopontin antibody. Histopathologically findings, newly formed bone was seen at 1 weeks and became lamellar bone at 2 weeks, and mature trabecullar bone was seen at 4 weeks experimental group. In control group, thickness of regenerated bone increased till 4 weeks gradually and trabecullar bone was seen at 8 weeks. By histomorphometric analysis, bone marrow density was increased significantly at 1 and 2 weeks in experimental group compared to control group. Osteocalcin immunoreactivity was strong at 1 week experimental group and reduced after 4 weeks gradually. But it was continuously weakly from 1 to 4 weeks in control group. Osteopontin immunoreactivity was very strong in newly formed bone from 2 to 8 weeks experimental group. And the amount of osteopontin expression was more abundant in experimental group. The results of this study suggest that calcium and vitamin D supplementation promotes bone healing around dental implants

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.1
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• pp.36-48
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• 2008

To repair bone defects in the oral and maxillofacial field, bone grafts including autografts, allografts, and artificial bone are used in clinical dentistry despite several disadvantages. The purpose of this study was to evaluate new bone formation and healing in rat calvarial bone defects using hydroxyapatite (HA, $Ca_{10}[PO_4]_6[OH]_2,\;Bongros^{(R)}$, Bio@ Co., KOREA) and tricalcium phosphate (${\beta}-TCP,\;Ca_3[PO_4]_2$, Sigma-Aldrich Co., USA) mixed at various ratios. Additionally, this study evaluated the effects of type I collagen (Rat tail, BD Biosciences Co., Sweden) as a basement membrane organic matrix. A total of twenty, 8-week-old, male Sprague-Dawley rats, weighing 250-300g, were divided equally into a control group (n=2) and nine experimental groups (n=2, each). Bilateral, standardized transosseous circular calvarial defects, 5.0 mm in diameter, were created. In each experimental group, the defect was filled with HA and TCP at a ratio of 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 0:100 with or without type I collagen. Rats were sacrificed 4 and 8 weeks post-operation for radiographic (standardized plain film, Kodak Co., USA), histomorphologic (H&E [Hematoxylin and Eosin], MT [Masson Trichrome]), immunohistochemical staining (for BMP-2, -4, VEGF, and vWF), and elementary analysis (Atomic absorption spectrophotometer, Perkin Elmer AAnalyst $100^{(R)}$). As the HA proportion increased, denser radiopacity was seen in most groups at 4 and 8 weeks. In general radiopacity in type I collagen groups was greater than the non-collagen groups, especially in the 100% HA group at 8 weeks. No new bone formation was seen in calvarial defects in any group at 4 weeks. Bridging bone formation from the defect margin was marked at 8 weeks in most type I collagen groups. Although immunohistochemical findings with BMP-2, -4, and VEGF were not significantly different, marked vWF immunoreactivity was present. vWF staining was especially strong in endothelial cells in newly formed bone margins in the 100:0, 80:20, and 70:30 ratio type I collagen groups at 8 weeks. The calcium compositions from the elementary analysis were not statistically significant. Many types of artificial bone have been used as bone graft materials, but most of them can only be applied as an inorganic material. This study confirmed improved bony regeneration by adding organic type I collagen to inorganic HA and TCP mixtures. Therefore, these new artificial bone graft materials, which are under strict storage and distribution systems, will be suggested to be available to clinical dentistry demands.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.1
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• pp.3-10
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• 2014

Objectives: Although nerve growth factor (NGF) could promote the functional regeneration of an injured peripheral nerve, it is very difficult for NGF to sustain the therapeutic dose in the defect due to its short half-life. In this study, we loaded the NGF-bound heparin-conjugated fibrin (HCF) gel in the NGF-delivering implants and analyzed the time-dependent release of NGF and its bioactivity to evaluate the clinical effectiveness. Materials and Methods: NGF solution was made of 1.0 mg of NGF and 1.0 mL of phosphate buffered saline (PBS). Experimental group A consisted of three implants, in which $0.25{\mu}L$ of NGF solution, $0.75{\mu}L$ of HCF, $1.0{\mu}L$ of fibrinogen and $2.0{\mu}L$ of thrombin was injected via apex hole with micropipette and gelated, were put into the centrifuge tube. Three implants of experimental group B were prepared with the mixture of $0.5{\mu}L$ of NGF solution, $0.5{\mu}L$ HCF, $1.0{\mu}L$ of fibrinogen and $2.0{\mu}L$ of thrombin. These six centrifuge tubes were filled with 1.0 mL of PBS and stirred in the water-filled beaker at 50 rpm. At 1, 3, 5, 7, 10, and 14 days, 1.0 mL of solution in each tubes was collected and preserved at $-20^{\circ}C$ with adding same amount of fresh PBS. Enzyme-linked immunosorbent assay (ELISA) was done to determine in vitro release profile of NGF and its bioactivity was evaluated with neural differentiation of pheochromocytoma (PC12) cells. Results: The average concentration of released NGF in the group A and B increased for the first 5 days and then gradually decreased. Almost all of NGF was released during 10 days. Released NGF from two groups could promote neural differentiation and neurite outgrowth of PC12 cells and these bioactivity was maintained over 14 days. Conclusion: Controlled release system using NGF-HCF gel via NGF-delivering implant could be an another vehicle of delivering NGF to promote the nerve regeneration of dental implant related nerve damage.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.1
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• pp.21-26
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• 2014

Objectives: The purpose of this article is to analyze the incidence, demographic distribution, type, and etiology of mandible fractures that were treated by the Department of Oral and Maxillofacial Surgery in Kyung Hee University Dental Hospital from January 2002 to December 2012. Materials and Methods: This was a descriptive and analytic retrospective study that evaluated 735 patients that were treated for mandible fracture. Results: This study included 1,172 fractures in 735 patients. The ratio of male to female patients was 5.45 : 1; the maximum value was in patients between 20 and 29 years (38.1%) and the minimum in patients over 70 years old. The monthly distribution of facial fractures peaked in the fall and was lower during winter. No specific correlation was identified based on the annual fracture distribution. Among the 735 fracture patients, 1.59 fracture lines were observed per patient. The most frequent site was the symphysis, which accounted for a total of 431 fractures, followed by the angle (348), condyle (279), and body (95). The symphysis with angle was the most common site identified in combination with fracture and accounted for 22.4%, followed by symphysis with condyle (19.8%). The angle was the most frequent site of single fractures (20.8%). The major cause of injury was accidental trauma (43.4%), which was followed by other causes such as violence (33.9%), sports-related accidents (10.5%), and traffic accidents (10.1%). Fracture incidents correlated with alcohol consumption were reported between 10.0%-26.9% annually. Conclusion: Although mandible fracture pattern is similar to the previous researches, there is some changes in the etiologic factors.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.1
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• pp.99-107
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• 2008

Objective : The objective of this review was to provide reliable comparative results regarding the effectiveness of any interventions either open or closed that can be used in the management of fractured mandibular condyle Patients and Methods : Research of studies from MEDLINE and Cochrane since 1990 was done. Controlled vocabulary terms were used. MeSH Terms were "Mandibular condyle" AND "Fractures, bone". Only comparative study were considered in this review using the "limit" function. According to the criteria, two review authors independently assessed the abstracts of studies resulting from the searches. The studies were divided according to some criteria, and following were measured: Ramus height, condyle sagittal displacement, condyle Towns's image displacement, Maximum open length, Protrusion & Lateral excursion, TMJ pain, Malocclusion, and TMJ disorder. Results : Many studies were analyzed to review the post-operative result of the two methods of treatment. Ramus height decreased more in when treated by closed reduction as opposed to open reduction. Sagittal condyle displacement was shown to be greater in closed reduction. Condyle Town's image condyle displacement had greater values in closed reduction. Maximum open length showed lower values in closed reduction. In protrusive and lateral movement, closed reduction was less than ORIF. Closed reduction showed greater occurrence of malocclusion than ORIF. However, post-operative pain and discomfort was greater in ORIF. Conclusion : In almost all categories, ORIF showed better results than CRIF. However, the use of the open reduction method should be considered due to the potential surgical morbidity and increased hospitalization time and cost. To these days, Endoscopic surgical techniques for ORIF (EORIF) are now in their infancy with the specific aims of eliminating concern for damage to the facial nerve and of reducing or eliminating facial scars. Before performing any types of treatment, patients must be understood of both of the treatment methods, and the best treatment method should be taken on permission.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.6
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• pp.274-282
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• 2013

Objectives: The posterior maxillary region often provides a limited bone volume for dental implants. Maxillary sinus elevation via inserting a bone graft through a window opened in the lateral sinus wall has become the most common surgical procedure for increasing the alveolar bone height in place of dental implants in the posterior maxillary region. The purpose of this article is to assess the change of bone volume and the clinical effects of dental implant placement in sites with maxillary sinus floor elevation and autogenous bone graft through the lateral window approach. Materials and Methods: In this article, the analysis data were collected from 64 dental implants that were placed in 24 patients with 29 lacks of the bone volume posterior maxillary region from June 2004 to April 2011, at the Department of Oral and Maxillofacial Surgery, Inha University Hospital. Panoramic views were taken before the surgery, after the surgery, 6 months after the surgery, and at the time of the final follow-up. The influence of the factors on the grafted bone material resorption rate was evaluated according to the patient characteristics (age and gender), graft material, implant installation stage, implant size, implant placement region, local infection, surgical complication, and residual alveolar bone height. Results: The bone graft resorption rate of male patients at the final follow-up was significantly higher than the rate of female patients. The single autogenous bone-grafted site was significantly more resorbed than the autogenous bone combined with the Bio-Oss grafted site. The implant installation stage and residual alveolar height showed a significant correlation with the resorption rate of maxillary sinus bone graft material. The success rate and survival rate of the implant were 92.2% and 100%, respectively. Conclusion: Maxillary sinus elevation procedure with autogenous bone graft or autogenous bone in combination with Bio-Oss is a predictable treatment method for implant rehabilitation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.6
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• pp.263-268
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• 2013

Objectives: The interforminal region, between the mandibular foramen, is known as a relatively safe area that is free of anatomic structures, such as inferior alveolar nerve, submandibular fossa, and lingual side of the mandible is occasionally neglected for its low clinical importance. Even in the case of a severely constricted alveolus, perforation of the lingual cortical bone had been intended. However, anterior extension of the inferior alveolar canal, important anatomic structure, such as concavity of lingual bone, lingual foramina, and lingual canal, has recently been reported through various studies, and untypical bleeding by perforation of the lingual plate on implantation has also been reported. Therefore, in this study, we performed radiographic and statistical analysis on distribution and appearance frequencies of the lingual foramina that causes perforation of the mandibular lingual cortical bone to prevent complications, such as untypical bleeding, during surgical procedure. Materials and Methods: We measured the horizontal length from a midline of the mandible to the lingual foramina, as well as the horizontal length from the alveolar crest to the lingual foramina and from the lingual foramina to the mandibular border by multi-detector computed tomography of 187 patients, who visited Dankook University Dental Hospital for various reasons from January 1, 2008 to August 31, 2012. Results: From a total of 187 human mandibles, 110 (58.8%) mandibles had lingual foramina; 39 (20.9%) had bilateral lingual foramen; 34 (18.2%) had the only left lingual foramen; and 37 (19.8%) had the only right lingual foramen. Conclusion: When there is consistent bleeding during a surgical procedure, clinicians must consider damages on the branches of the sublingual artery, which penetrate the lingual foramina. Also, when there is a lingual foramina larger than 1 mm in diameter on a pre-implantation computed tomography, clinicians must beware of vessel damage. In order to prevent these complications and progress with a safe surgical procedure, a thorough radiographic examination before the surgery is indispensable. Further, clinicians should retract lingual flap definitely to confirm the shape of the lingual bone and existence of the lingual foramina.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.4
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• pp.240-249
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• 2020

Objectives: Although the side effects of radiation therapy vary from mucositis to osteomyelitis depending on the dose of radiation therapy, to date, an experimental animal model has not yet been proposed. The aim of this study was to develop an animal model for assessing complications of irradiated bone, especially to quantify the dose of radiation needed to develop a rat model. Materials and Methods: Sixteen Sprague-Dawley rats aged seven weeks with a mean weight of 267.59 g were used. Atraumatic extraction of a right mandibular first molar was performed. At one week after the extraction, the rats were randomized into four groups and received a single dose of external radiation administered to the right lower jaw at a level of 14, 16, 18, or 20 Gy, respectively. Clinical alopecia with body weight changes were compared and bony volumetric analysis with micro-computed tomography (CT), histologic analysis with H&E were performed. Results: The progression of the skin alopecia was different depending on the irradiation dose. Micro-CT parameters including bone volume, bone volume/tissue volume, bone mineral density, and trabecular spaces, showed no significant differences. The progression of osteoradionecrosis (ORN) along with that of inflammation, fibrosis, and bone resorption, was found with increased osteoclast or fibrosis in the radiated group. As the radiation dose increases, osteoclast numbers begin to decrease and osteoclast tends to increase. Osteoclasts respond more sensitively to the radiation dose, and osteoblasts are degraded at doses above 18 Gy. Conclusion: A standardized animal model clinically comparable to ORN of the jaw is a valuable tool that can be used to examine the pathophysiology of the disease and trial any potential treatment modalities. We present a methodology for the use of an experimental rat model that incorporates a guideline regarding radiation dose.