• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.6
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• pp.352-357
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• 2016

Objectives: This study aimed to evaluate the stability of prosthetic screws from three types of craniofacial prostheses retention systems (bar-clip, ball/O-ring, and magnet) when submitted to mechanical cycling. Materials and Methods: Twelve models of acrylic resin were used with implants placed 20 mm from each other and separated into three groups: (1) bar-clip (Sistema INP, São Paulo, Brazil), (2) ball/O-ring (Sistema INP), and (3) magnet (Metalmag, São Paulo, Brazil), with four samples in each group. Each sample underwent a mechanical cycling removal and insertion test (f=0.5 Hz) to determine the torque and the detorque values of the retention screws. A servo-hydraulic MTS machine (810-Flextest 40; MTS Systems, Eden Prairie, MN, USA) was used to perform the cycling with 2.5 mm and a displacement of 10 mm/s. The screws of the retention systems received an initial torque of 30 Ncm and the torque values required for loosening the screw values were obtained in three cycles (1,080, 2,160, and 3,240). The screws were retorqued to 30 Ncm before each new cycle. Results: The sample was composed of 24 screws grouped as follows: bar-clip (n=8), ball/O-ring (n=8), and magnet (n=8). There were significant differences between the groups, with greater detorque values observed in the ball/O-ring group when compared to the bar-clip and magnet groups for the first cycle. However, the detorque value was greater in the bar-clip group for the second cycle. Conclusion: The results of this study indicate that all prosthetic screws will loosen slightly after an initial tightening torque, also the bar-clip retention system demonstrated greater loosening of the screws when compared with ball/O-ring and magnet retention systems.

• Korean Journal of Cleft Lip And Palate
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• v.3 no.1
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• pp.1-9
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• 2000

목적 : 치조파열 환자에 있어서 이차 치조골 이식술을 시행한 후 그 결과를 알아보고자 방사선학적 분석을 통하여 평가하였다. 본 연구의 목적은 수술전 골결손부 인접치아의 치조정 높이와 수술후 골결손부 인접치아의 치조정 높이를 근심측과 원심측에서 각각 측정함으로써 치조정의 높이가 과연 통계적으로 유의성 있게 증가하는지와 치조골 이식술의 성공률이 치조열의 너비와 상관관계가 있는지의 여부를 알아보는 것이다. 환자 및 방법 : 1991년부터 1999년까지 서울대학교병원 구강악안면외과에서 자가장골 채취 후 분쇄피질망사골 형태 또는 block 피질망상골 형태로 이식한 편측성 치조열을 가진 환자 중 최소한 6개월이 경과한 환자 56명을 연구대상으로 하였고 두 술자에 의해 시술되었다. 수술전 골결손부 인접치아의 치조정의 높이와 치조열의 너비 및 수술후 이식한 골의 높이와 절흔의 양은 치과용 파노라마 방사선 사진을 이용하여 측정하였고, 치조열의 너비는 모델이나 환자의 골결손부 근심치아의 근원심 폭경을 이용하여 환산하였다. 그리고 이식한 골의 높이와 절흔의 양을 1995년 Long이 제시한 방법으로 측정하여 술전의 측정치와 비교하였다. 결과 : 치조열의 너비는 평균 6.9mm(1.9mm-12.1mm) 였다. 근심에서의 치아는 골이식 당시 중절치가 52개(92.9%), 측절치가 4개(7.1%)였고, 49명의 환자에서 완전맹출을, 6명의 환자에서 부분맹출(측절치 2개, 중절치 4개)을 보였다. 원심측에서의 치아는 골이식 당시 측절치가 25개(44.6%), 견치가 29개(51.8%), 소구치가 2개(3.6%)였고, 완전 맹출이 32.1%, 부분 맹출이 57.2%, 미맹출이 10.7%로서 완전히 맹출하기 전에 골이식한 경우가 67.9%였다. 모든 환자에 있어서 bony bridge가 나타났고, 절흔이 인접치 아래로 연장되지 않았으며, 치조골 이식술 후 oronasal fistula를 보인 환자는 한 명도 없었으므로 성공률은 100%였다. 술후 근심측에서의 치조정의 높이는 근심측 치아 치근길이의 79%(평균), 원심측에서의 치조정의 높이는 원심측 치아 치근길이의 87%(평균)로서 통계적으로 유의성 있게 증가하였다. 결론: 이차 치조골 이식술을 시행한 후 치조정의 높이는 골결손부 근심측과 원심측에서 모두 유의성있게 증가하였고, 근심측에서보다 원심측에서 통계학적으로 더 유의성 있게 증가하였다. 치조열의 너비와 절흔의 양, 치조정의 높이 및 치조골이식 성공률과는 유의성 있는 관련성이 없었다.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.1
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• pp.40-46
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• 2014

Treacher Collins syndrome (TCS) is autosomal dominant disorder that occurs approximately 1 in 25,000 to 50,000 live births. The main signs of syndrome are hypoplasia of facial bone and microtia. One in third of them is associated with cleft palate and often shows dental hypoplasia. TCS patients need several number of surgery with general anesthesia throughout their life time for recovery of function and esthetic. Endotracheal intubation of TCS patient is very difficult due to microstomia, retrognathia, choanal stenosis, and decreased oropharyngeal airway. Therefore, general anesthesia of adolescent TCS patient with immature incisor roots has high risk of causing dental trauma. This case is regarding TCS patient who was referred to the Department of Pediatric Dentistry, Yonsei University for avulsed upper left central incisor during endotracheal intubation. The purpose of this report is to emphasize the usefulness of mouth guard to prevent dental trauma when endotracheal intubation is needed for TCS patient.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.766-770
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• 2008

Gingival fibromatosis is a rare condition characterized by varying degrees of gingival hyperplasia. Gingival fibromatosis usually occurs as an isolated disorder or can be associated with a variety of other syndromes. It usually appears at the time of eruption of permanent dentition but, can develop at the time of eruption of the primary dentition and rarely at birth. It may deform palatal contour and subsequently restrict the tongue movement, resulting in interference during speech and mastication. In addition, it incapacitates maintenance of normal lip closure. A 14-month-old girl visited the department of pediatric dentistry, Yonsei University Dental Hospital, for the congenital gingival overgrowth. There was no one in the family, who showed similar pattern of gingival growth. The intraoral clinical examination revealed generalized severe gingival enlargement throughout the maxillary and the mandibular arches. Enlarged gingival tissue was pink and had firm consistency. She was referred for chromosomal analysis, which confirmed absence of any known syndrome. Under local anesthesia, "Punch-biopsy" was performed on the labial area, and the specimen was histologically diagnosed as gingival fibromatosis. For she did not have any medical problem nor familiar history, she was diagnosed as having idiopathic gingival fibromatosis. Regarding her age and behavior, close follow-up was decided.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.6
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• pp.478-482
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• 2011

Purpose: Free flap reconstruction is performed on defects including benign and malignant tumors as well as trauma in the department of oral and maxillofacial surgery, but there are few reports of free flap reconstruction cases for oral cancer in patients in Korea. Methods: This study was designed to retrospectively analyze surgical outcomes and complications of 164 free-flap reconstructions performed at the Oral Oncology Clinic, National Cancer Center, during 2002~2011. A total of 164 free flaps were performed for reconstruction of oral and maxillofacial defects which were caused by oral cancer and osteoradionecrosis in 155 patients. Results: The present study had 162 successful cases and 2 failed cases for a total of 164 cases. The study had a success rate of 98.8% for free-flap reconstructions. Flap donor sites included radial forearm free flap (n=93), fibula osteocutaneous free flap (n=25), anterolateral thigh flap (n=18), latissimus dorsi myocutaneous flap (n=16) and other locations (n=12). Postoperative medical complications were generally pneumonia and delirium. Postoperative local complications occurred including partial flap necrosis, delayed wound healing of the donor site, infection of the recipient site and salivary fistula. The incidence of postoperative complications and patient-related characteristics including age, sex, smoking, history of radiotherapy, hypertension (HTN) and diabetes Mellitus (DM) were retrospectively analyzed. Patient age ($P$=0.003) and DM ($P$=0.000) and HTN ($P$=0.021) were significant risk factors for complications overall. Conclusion: The present study had no mortality and confirms that free-flap reconstructions are extremely reliable in achieving successful results.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.6
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• pp.497-504
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• 2011

Purpose: Patients who had a subcondylar fracture with a displaced or deviated condylar segment were treated with a retromandibular approach (RMA) or an endoscope-assisted transoral approach (EATA) in our department of oral and maxillofacial surgery. The clinical results of the approaches were compared. A comparative study of specific approaches for subcondylar fractures has not been published before in Korea. Methods: Twenty-one patients with subcondylar fractures of the mandible were included. Ten patients were treated with the retromandibular approach and 11 were treated with an endoscope-assisted transoral approach. We examined patient age, gender, fracture sites, classifications, period of maxillomandibular fixation, facial nerve (FN) or greater auricular nerve (GAN) injuries, maximal mouth opening, deflection, occlusal changes, number of plates, follow-up period, and other complications. Preoperative computed tomography and pre-operative, post-operative, and follow-up panoramic views were taken of each patient. Results: Mean maximal mouth openings were similar between the two approaches. FN and GAN injuries were more frequent in the RMA group but the deflective rate with mouth opening was higher in the EATA than that in RMA group. Two cases of post-operative infection occurred in the EATA group, and occlusal changes were observed in one case for both approaches. Conclusion: The RMA offers more direct access and visualization of the surgical field but it can cause scars and retractive injuries of the FN and GAN. But, EATA did not result in consequent nerve injuries or scars postoperatively, but unfavorable fractures such as $medial$ $override$ condyles were more difficult to reduce endoscopically. Except cases of an expected difficult reduction, the treatment of choice for a displaced subcondylar fracture may be an EATA.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.453-460
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• 2009

Background and Purpose: Vascular endothelial growth factor (VEGF)-C, VEGF-D and their tyrosine kinase receptor, VEGF receptor (VEGFR)-3 are recently known to have lymphangiogenic activities in various tumor types. Oral mucosal squamous cell carcinoma (OMSCC) easily metastasizes to cervical lymph nodes, so we determined the expression levels of VEGF-C, VEGF-D and VEGFR-3 in oral squamous cell carcinoma. Materials and Methods: We performed Western blot analyses with 4 OMSCC cultured tumor cell lines (SCC9, KB, YD-10B, YD-38), and with 7 surgical specimens of OMSCC for the detection of VEGF-C, VEGF-D and VEGFR-3 proteins. Expression of VEGF-C mRNA as well as mRNA for VEGFR-3 in 4 OMSCC cell lines (KB, SCC-4, SCC-9, YD-10B) was investigated by RT-PCR. We also measured VEGFC/VEGF-D protein concentrations in the media and protein concentration of VEGFR-3 in cell lysates of 4 OMSCC cell lines (SCC9, KB, YD-10B, YD-38) using commerical ELISA kits. Finally, we performed immunoprecipitation for the detection of VEGF-C in cell lysates of 4 OMSCC cells (KB, SCC-4, SCC-9, YD-10B) and real-time RT-PCR for the quantification of VEGF-C mRNA. Results: In the result of Western blotting with cell lysates of 4 OMSCC cells, we could not detect the protein expression of VEGF-C, VEGF-D, and VEGFR-3. But, all tumor tissues demonstrated VEGF-C and VEGFR-3. VEGF-C mRNA was detected at various levels in 4 OMSCC cell lines. Moreover, OMSCC cells secreted VEGF-C, not VEGF-D and VEGFR-3 was also detected in cell lysates of OMSCC by ELISA. Immunoprecipitation and real-time RT-PCR revealed VEGF-C was also expressed in 4 OMSCC cell lines. Conclusion: Taken together, tumor cells of OMSCC secrete VEGF-C, not VEGF-D. And VEGFR-3 is expressed tumor cells as well as OMSCC tumor tissues, needs further study.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.302-309
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• 2002

In order to improve the success rate of implants, various implant designs have been developed. Although there have been enough efforts to handle the surface of the implant with careful choice of material and mechanics so that the bone and the implant can be tightly joined together, they have still failed to play the role of periodontal ligaments of the natural teeth in the past. The role of periodontal ligaments is very important since it can improve the initial stability of implant by absorbing the impacts. The purpose of this study is, thus, to test the possibility of alleviating the impact when the surface of the implant was coated with chitosan, a natural polymer, and making sure that the coated material stayed on. Then, the condition of newly developed bone formation and the degree of inflammation in response was closely observed in the surface level. In the main experiment, Chitosan coated implant ($3.3mm{\times}7mm$) was implanted on both the right and the left side of rabbit's femur. The animals were each sacrificed on the $1^{st}$, $2^{nd}$, $3^{rd}$, $7^{th}$, $14^{th}$, $21^{st}$ and 28th day. The process was observed under an light microscope after the Toluidin Blue staining. From the experiment, it was found that the chitosan was evenly distributed on the surface of the screws, and the implant was adjoined with adjacent bone. There was a sign of inflammation on the $3^{rd}$ day, but on the $14^{th}$ day, the formation of woven bone and newly formed bones were noticed. Also, chitosan filled the gap was formed between the implant and the newly formed bone. The implant, the chitosan and the newly formed bone were forming one unit as a result. Therefore, it was found that chitosan coated implant could absorbe the impact in the initial stage of implant.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.15-24
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• 2001

The purpose of this study is to evaluate the tissue response in applying of various bone substitutes included toothash-plaster mixture, resorbable hydroxylapatite (HA) and demineralized freeze-dried bone and to show the clinical usefulness of toothash-plaster mixture for the repair of craniomaxillofacial bone defect. For this experiment, 100 Sprague-Dawley rats weighing 200gm or more were used. There were four experimental groups: group I, toothash-plaster mixture; group II, demineralized freeze-dried bone; group III, resorbable HA; and group IV, control group. A full thickness, round bone defect measuring 10mm in diameter was created in the midcranium, and the substitutes cited above were embedded in the experimental rats based on their group assignment. Blood clot was filled in the rats assigned to the control group. Experimental rats were sacrificed on the 1st, 3rd, 5th, 8th, 12th and 24th week after implantation and stained with the hematoxylineosin, Masson's Trichrome, using Van Gieson's stain method, and were examined under light microscope. The results were as follows: 1. In all the groups, prominent inflammatory reaction and the infiltration of multinucleated giant cells were noted during the early stage. Gradual healing decreased this reaction. 2. Among the rats in the experimental group II, which were given demineralized freeze-dried bone implants, active formation of new bone traveculae manifested. Chondroid tissues appeared, and it was suggested that the defect was filled with newly formed bone by virtue of osteoinductive activity. On the 12th week after the experiments, most of the defect was filled with newly formed bone trabeculae. 3. In experimental groups I and III, it was noted that HA manifested a healing process similar to that characterized by the toothash-plaster mixture, but inflammatory reaction was more prominent in experimental group I. Active osteoblasts were observed along the periphery of osteoid tissues, while newly formed bone trabeculae appeared adjacent to the implanted materials three weeks later. Formation increased to the extent that newly formed bone trabeculae fused directly with the host bone. Increase in new bone ingrowth into the filling materials was revealed by both experimental groups. 4. In the control group, new bone formation adjacent to the host bone was observed, but most of the defect was filled with mature connective tissue 24 weeks after the experiments.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.78-82
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• 2001

Background : The coronal incision is versatile surgical approach to upper and middle region of the facial skeletal including the zygomatic arch. The advantages of coronal approach are minimal injury of facial tissue including facial nerve and satisfactory cosmetic result by hidden scar at hair. But wide exposure of scalp, its disadvantages are operation time and massive blood loss. Methods : Thirty patients undergoing elective surgery were divided 3 groups. Group I used only coronal approach, group II used coronal with subciliary approach and group III used coronal with subciliary and intraoral approach. And then retrospected of the preoperative, postoperative red blood cell count, hemoglobin(Hb), hematocrit, transfused red blood cell units and platelet cell units, and the amount of infused crystalloids and colloids, and postoperative hemovac count was estimated. Results: 1. Red blood cell count were decreased in all groups at immediated postoperation and decreased in all group of postoperative first day and decreased in group I, II but increased group III of postoperative third day. 2. Hemoglobin and hematocrit were decreased in all group at immediated postoperation and decreased in all group of postoperative first day and decreased in group I, II., but increased group III postoperative third day. 3. Platelet was decreased in all group at immediated postoperation, and decreased in group II, III but increased in group I of postoperative first day and decreased in group I but increased group II, III of postoperative third day. 4. Mean postoperative hemovac mean drainage group I of first day is $48.63{\pm}21.12ml$ and second day is $23.92{\pm}19.53ml$ and third day is $7.82{\pm}5.32ml$ and group II of first day $60.45{\pm}22.65ml$ and second day is $22.14{\pm}13.21ml$ and third day is $7.32{\pm}6.25ml$. III group of first day $58.16{\pm}10.13ml$ and second day is $21.27{\pm}11.72ml$ and third day is $7.13{\pm}4.90ml$. 5. Infusion of group I is mean PRC $1.08{\pm}0.91$ pint, FFP $1.03{\pm}0.75$ pint, crystalloid $2562.23{\pm}1345.53ml$ and group II is mean PRC $1.05{\pm}0.89$ pint, FFP $1.71{\pm}0.78$, crystalloid $2650.47{\pm}1096.36ml$ and group III is mean PRC $1.79{\pm}1.45$ pint, crystalloid $3295.43{\pm}1472.432ml$.