• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.3
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• pp.175-180
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• 2004

In this study, three treatment options to replace two posterior missing teeth were investigated using three dimensional finite element analysis: two wide(${\phi}5.0mm$) implants(the experimental model I), two standard(${\phi}3.75mm$) implants(the experimental model II), and three standard(${\phi}3.75mm$) implants(the experimental model III). Two kinds of load case were applied ; 1) perpendicular on occlusal surface(axial load), parallel on occlusal surface(lateral load). 2) perpendicular on occlusal surface(3mm lateral to central point). The results obtained from this study were as follows; value of Von-mises stress (equivalent stress) was smallest in the two wide implant among the three experimental models. It was reported that the diameter is the efficient factor than osseointegrated surface area.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.6
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• pp.438-443
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• 2003

Purpose : This study evaluated the usefulness of resorbable plate and screw for treatment of maxillofacial bone fractures. Patients and methods : From july, 2000 to july, 2002, we used resorbable plates and screws($Biosorb^{(R)}$ FX, Bionix Inc, Finland) on 126 patients for treatment of maxillofacial bone fractures. Among them, 80 patients were capable of periodic following up to present season. We evaluated these patients with clinical, radiographic findings and subjective satisfaction. Results : 80 patients composed of 63 men and 17 women. Complication rates are 7.5%(6/80) recorded. 1 of bulging sensation, 3 of infection sign, 2 of the plate detachment were shown. The plates involved in such complications were removed. The other patients(92.5%) were not shown any problems. We could not find complete resorption of screw holes in the mandibular symphysis area even though two years later after surgery. Conclusion : Bioresorbable plates and screws are useful as fixation material at maxillofacial fractures although strength is thought to be weaker than titanium plate. But to reduce the possible complicaions, need to careful clinical and radiographical evaluations.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.3
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• pp.246-250
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• 2004

Uni- or bilateral mandibular hypoplasia can be associated with various syndromes or is acquired after early traumatic or inflammatory disease in the temporomandibular joint(TMJ). Early treatment is necessary to avoid consequent impairment of midfacial growth. The standard treatment of these malformations consists of the application of bone grafts which can lead to unpredictable growth, but the new procedure of bone lengthening which was presented by McCarthy et al. represents a limited surgical intervention and therefore open up a new perspective of treatment, especially in younger children with severe deformities. Patients with hemifacial microsomia and facial asymmetry have a vertically short maxilla, a tilted occlusal plane, and a short mandible. A 14-years-old boy with facial asymmetry, who was fractured on both condyle and mandibular symphysis before 8 years ago, was treated by mandibular ramus lengthening, symphysial widening and surgically assisted rapid palatal expansion with corticotomy. After allowing 1 week for the healing of the periosteum, the distraction was performed at the rate of 0.5-1.0mm per day for 7 days on maxilla and 14 days on mandible. The device was maintained on maxilla and mandible for 12 weeks following distraction. The difference in ramus and mandibular transverse deficiency were corrected and facial asymmetry was improved with complex distraction osteogenesis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.3
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• pp.251-254
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• 2004

Osteomyelitis is the inflammatory disease occured in the bone, involving a bone marrow, a Harversian system and the underlying cortical bone. Osteomyelitis is divided into acute and chronic osteomyelitis. Chronic osteomyelitis. is presented as a pain, swelling, pus discharge and radiographic change. The pathogenesis of osteomyelitis occcuring in the facial bone is predominately due to odontogenic microorgarnisms, Staphylococcus, resulted in odontogenic infection or post-traumatic infection. The mandible is the most commonly involved facial bone and the bones in the middle of third of the face is rare because of a abundant blood supply. Moreover, Osteomyelitis occuring in the zygoma is extremely rare. In our department, we report the case that osteomyelitis occuring in the zygoma with diabetes is resulted by odontogenic maxillary sinusitis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.6
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• pp.407-420
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• 2003

Purpose : The purpose of this study was to analyse the facial changes and factors contributing to then after bilateral sagittal split ramus osteotomy of mandibular prognathism. Materials and Methods : Forty patients with Class III dental and skeletal malocclusion who were treated with bilateral sagittal split ramus osteotomy were reviewed. Frontal and lateral cephalometric radiographs were taken preoperatively, immediate postoperatively and more than six months postoperatively in each patient. After tracing the cephalometric radiographs, various parameters were measured. Results : 1. Gonial angle at postoperative two days was decreased about $10.4^{\circ}$ than preoperatively and gonial angle at postoperative six months was increased about $6.8^{\circ}$ than postoperative two days. So, gonial angle at postoperative six months was decreased about $3.6^{\circ}$ than preoperative gonial angle. 2. Facial height postoperative two days was decreased about 0.8mm than preoperatively and facial height at postoperative six months was decreased about 0.7mm than postoperative two days. So, facial height at postoperative six months was decreased about 1.5mm than preoperative facial height. 3. Mandibular width postoperative two days was decreased about 1.0mm than preoperatively and mandibular width at postoperative six months was increased about 1.8mm than postoperative two days. So, mandibular width at postoperative six months was decreased about 2.8mm than preoperative mandibular width. 4. Amount of set back and mandibular plane angle were not influencing on relapse degree. Conclusion : It is thought that bilateral sagittal split ramus osteotomy in mandibular prognathic patients is effective to improve long face and steep gonial angle. More prudent operation and careful postoperative management is required to maintain stable face postoperatively. Further research for soft tissue changes and factors which are related with relapse is needed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.3
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• pp.234-236
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• 2004

Actinomycosis is a rare form of disease that is caused by Actinomyces such as A. israelii and A. bovis, which may take the form of chronic, purulent inflammation of deep tissue evolves with necrosis, formation of sinuses and fibrotic mass. This disease arises in the head and neck area mainly in 55% and other places like that chest and the gastrointestinal tract occurs in 45%. Actinomycosis can present in a variety of forms and may mimic other infections or even neoplasms. Our case was 44-year-old man having painful indurated mass in his left TMJ area, otorrhea in his left ear and trismus. He was treated with surgical excision and biopsy confirmed actinomycosis. And after that, he was cured successfully with antibiotic therapy. We report this case of actinomycosis that developed in the left TMJ area with review articles.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.168-173
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• 2006

The side effects of head and neck radiation therapy include mucositis, xerostomia, loss of taste, radiation caries, oral infection, osteoradionecrosis and trismus. When a patient is arranged to begin head & neck radiotherapy, oral pathologic lesions are examined and managed for the prevention of oral complications. The advanced odontogenic infection should be especially controlled before the radiotherapy and the patient must be instructed for proper oral prophylaxis. Generally the more conservative treatments, such as, scaling, restoration, endodontic treatment, are the care of choice and dental extraction is performed in advanced periapical and periodontal pathologic conditions. If the dental extraction should be done, the radiotherapy consequently will be delayed until there is epithelium covering the extraction socket, leaving no exposed bone. The cancer patient with severe emotional stress pray for the early radiation therapy, in spite of possibility of the recurrent odontogenic infectious lesions. So, the authors attempted to do the early radiation therapy by the conservative endodontic drainage and surgical incision & drainage without extraction of the infected teeth, and resulted in relatively good prognosis without the severe side effects of head and neck radiotherapy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.3
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• pp.139-143
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• 2016

Objectives: If teeth are missing, super-eruption of teeth in the opposing arch can occur in the area and can change the occlusal plane. When missing teeth are replaced with implants, the oral surgeon must determine whether or not the super-erupted teeth need to be treated in order to normalize the occlusal plane. In this study, we evaluated the clinical prognosis of dentition after implant placement and prosthetic treatment were completed in an occlusal plane altered by super-erupted teeth in the opposing arch without additional treatment of the super-erupted teeth. Materials and Methods: Twenty-two patients (9 males, 13 females) were treated with implants and prosthetics without addressing the super-erupted opposing dentition from April 2004 to August 2012 at Seoul National University Bundang Hospital. A total of 33 implants were placed. Values of crestal bone loss, survival rates, and surgical and prosthetic complications for an average of 29.6 months after prosthetic loading were recorded. Results: In one case, the cover screw was exposed after implant surgery. The mean crestal bone loss was $0.09{\pm}0.30mm$. Of the 33 implants, 31 survived, a survival rate of 93.94%. A prosthetic complication occurred in one case but functioned well after correction. Conclusion: Favorable clinical results from prosthetic complications, crestal bone loss, and implant survival rates were exhibited in implants next to a super-erupted opposing tooth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.3
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• pp.133-138
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• 2016

Objectives: To assess the association between muscle invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge and cervical lymph node metastasis on the basis of preoperative magnetic resonance imaging (MRI). Materials and Methods: Twenty-six patients with oral squamous cell carcinoma of the posterior mandibular alveolar ridge were evaluated by MRI. The associations between cervical lymph node metastasis and independent factors evaluated by MRI were analyzed. Overall survival was also analyzed in this manner. Representative biopsy specimens were stained with anti-podoplanin and anti-CD34 antibodies. Results: Mylohyoid muscle invasion was associated with cervical lymph node metastasis. A combinational factor of mylohyoid and/or buccinator muscle invasion was also associated with cervical lymph node metastasis. Cervical lymph node metastasis and masticator space invasion had a negative effect on overall survival. No lymphatic vessels were identified near the tumor invasion front within the mandible. In contrast, lymphatic vessels were identified near the front of tumor invasion in the muscles. Conclusion: This study demonstrates an association between muscular invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge and cervical lymph node metastasis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.3
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• pp.237-240
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• 2011

Epidermoid cysts presents as a nodular and fluctuant subcutaneous lesion beneath the skin and are most common in acne-prone areas of the head, neck and back. This cyst often arises after localized inflammation of the hair follicle and occasionally after the implantation of epithelium following trauma and surgery including a biopsy procedure. It is often associated with Gardner syndrome, particularly before puberty. The lesion is normally treated by a surgical excision or enucleation, and recurrence is uncommon. A 27 year old woman complained of a swelling of the left parotid gland when she visited our clinic. A cystic lesion was found in the left parotid gland from the high signal intensity on the MR images. Ultrasonography showed that the cystic lesion was heterogeneous echogenic. Six months earlier, botulinum toxin was injected in her left masseter muscles six months earlier and progressive swelling of the left parotid area was noticed four months after treatment. The lesion was surgically removed. It was encapsulated by a thin wall and filled mainly with keratin. The final diagnosis was an epidermoid cyst.