• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.301-307
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• 2012

50-year-old female and 50-year-old male were referred to the department of the oral and maxillofacial surgery of Kyungpook national university dental hospital with asymptomatic lesions on their posterior mandibular body areas. They were discovered incidentally on panoramic radiographs during routine dental examination. Physical examination revealed no remarkable findings. Each panoramic radiograph showed well defined radiolucent lesions without hyperostotic border on their posterior mandibular body area. At first they were diagnosed as benign tumors because they looked like multilocular pattern and one of the patient showed discontinuity of mandibular canal within the lesion. CT scans demonstrated well demarcated and irregular lingual depression filled with fat tissue and they were diagnosed as developmental salivary gland defects. One of the lesion showed no change on follow-up panoramic radiograph after 4 months. Developmental salivary gland defects resembling benign tumor are atypical cases and it is suggested that confirmatory imaging using CT or MRI should be taken.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.7-13
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• 1991

An anatomic radiolucency called medial sigmoid depression can be observed on a number of panoramic and mandibular oblique lateral views in the ramus just below and anterior to the mandibular sigmoid notch. The radiolucency may be unilateral or bilateral. Seventy-eight mandibles of dry skulls were visually examined and radiographed by panoramic machine. The observable incidence, the location center, and the mean size of the medial sigmoid depression were studied. Additionally, the radiographic incidence of the depression was determined using 500 panoramic radiographs. Normal anatomic radiolucent areas in the jaws are encountered often in the radiographs taken for the usual dental practice purpose. Some of these radiolucencies can be misdiagnosed as pathologic entities. But in most cases, the size, location, and appearance of the radiolucent area, and the presence or absence of symptoms can lead one to the correct diagnosis before surgery is undertaken. And this can be secured if diagnosticians are aware of the common and varied appearances of the normal anatomic radiolucencies A depression in the ramus just below and slightly anterior to the most inferior aspect of mandibular sigmoid notch shows occasionally foramen-like or notch-like radiolucency on some panoramic and oblique lateral views. This radiolucency was named medial sigmoid depression by Langlais et a1. in 1983. Since there're no reports about this medial sigmoid depression after that, (The author retrieved the Mediline from 1983 to 1990: Cambridge scientific abstracts, (7200 Wisconsin Ave Bethesda MD 20814 U.S.A.) National Library of Medicine) the author studied the size and the location of the depression of the mandible specimens, and determined the relationship between the observable anatomic incidence and its reproducibility on the radiographs.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.191-200
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• 1998

This study was intended to perform the influence of condyle positional change after surgical correction of skeletal Class III malocclusion after orthognathic surgery in 37 patients(male 13, female 24) using computed tomogram that were taken in centric occlusion before, immediate after, and long term after surgery and lateral cephalogram that were taken in centric occlusion before, 7 days within the period of intermaxillary fixation, at the 24 hours later removing intermaxillary fixation and long term after surgery. 1. Mean intercondylar distance was $84.42{\pm}5.30mm$ and horizontal long axis of condylar angle was $12.79{\pm}4.92^{\circ}$ on the right, $13.53{\pm}5.56^{\circ}$ on the left side. Condylar lateral poles were located about 12mm and medial poles about 7mm away from the reference line(AA') on the axial tomogram. Mean intercondylar distance was $83.15{\pm}4.62mm$ and vertical axis angle of condylar angle was $76.28{\pm}428^{\circ}$ on the right, $78.30{\pm}3.79^{\circ}$ on the left. 2. In amount of set back, We found the condylar change(T2C-T1C) which had increasing tendency in group III (amount of setback : 10-15mm). but there was no statistical significance(p>0.05). 3. There was some correlation between condylar change(T2C-T1C) and TMJ dysfunction. It seemed that postoperative condylar change had influenced postoperative TMJ dysfunction, through there was no statistical significance (p>0.05). As we have observed the change of condylar axis in the group that complained of TMJ dysfunction in cases of large amount of mandibular setback. So we consider that the more trying to conserve condylar position will decrease occurrence rate of post operational TMJ dysfunction.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.4
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• pp.315-323
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• 2005

For reconstruction of the bony defect, distraction osteogenesis has many advantages in comparison with bone graft. However, it needs long consolidation period for sufficient bone maturity. This study is performed to evaluate the effect of PRP injection into the distracted mandible on bone formation in rabbits. Twelve house rabbits, weighing 2 kg, were used. All animals underwent bilateral mandibular osteotomy under general anesthesia. A internal distractor divice was positioned along a plane perpendicular to the line of osteotomy. After 5 days of latency period, distraction osteogenesis was started at a rate of 1 mm/day for 9 days which was distracted 9 mm totally. After completion of distraction, 0.5 ml of PRP which collected in rabbit blood was injected into the distracted mandible on experimental group, whereas no injection was done in control group. Macroscopical, radiographical, and histological, and histomorphometric examinations were performed 2, 4 and 8 weeks after distraction. All animals showed distracted mandible and severe anterior cross-bite. In radiographical findings 2 weeks after distraction, more radiopacity in the distracted gap was found in experimental group than that of control group. At 4 weeks after distraction, distracted bone was similar to normal bone in experimental group. In histological findings, 1) At 2 weeks after distraction, number of osteoblasts and angiogenesis in the distracted gap was found in experimental group than that of control group. 2) At 4 weeks after distraction, more active and distinct bone in the distracted gap was found in experimental group than that of control groups. 3) At 8 weeks after distraction, more dense and matured lamellated bone in the distracted gap was found in experimental group than that of control group. In histomorphometrical findings 8 weeks after distraction, more bone formation was observed in experimental group than control group (p<0.01). These results indicate that administration of PRP into the distracted mandible can promote bone formation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.5
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• pp.407-416
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• 2008

Purpose: The aim of the present study is to evaluate the effect of repetitive distraction and compression on new bone formation during distraction period. Materials and methods: Sixteen healthy rabbits, weighing about 2.5kg, were used in this experiment. A unilateral mandibular osteotomy was performed in the left mandible and the distractor(Track 1 $plus^{(R)}$, Gebruder Martin $GmbH^{(R)}$, Germany) was fixed with four screws (Cross driver screw $TI^{(R)}$, Gebruder Martin $GmbH^{(R)}$, Germany). After 4 days, the mandibles were distracted at a rate of 0.6mm/day for 10 days to obtain the amount of 6mm distraction in the control group(n=4). In the experimental group A(n=6), they were distracted at a rate of 1.2mm/day for 5 days and then compression of 0.6mm length and distraction of 0.6mm per 12 hours were carried out as counter direction for 5 days, relatively. In the experimental group B(n=6), distraction of 1.2mm length and compression of 0.6mm length per 12 hours were repeated for 10 days to obtain the amount of 6mm distraction finally. The experimental animals were sacrificed at 2 and 4 weeks after surgery and block specimens were obtained. With histologic and histomorphometric analysis, we observed the histologic changes of the cells and bone formation after H-E and Masson- Trichrome staining and then, measured Bone Deposition Rate with TOMORO $ScopeEye^{TM}$ ver. 3.5(Olympus, Japan), Results: Histologically, new bone formation was examined in all experimental groups and the control. But, the ability of bone formation of the experimental group A was somewhat better than any other groups. On the histomorphometric analysis, Bone Deposition Rate was higher in the experimental group A$(50.67{\pm}4.36%)$ than in the control group$(45.94{\pm}3.97%)$ and in the experimental group B$(42.68{\pm}5.70%)$. These data showed significant differences statistically(p<0.05). Conclusion: These results show that the distraction osteogenesis using repetitive compression and distraction force in the early consolidation period may be effective for new bone formation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.27.1-27.9
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• 2019

Background: Implants are becoming the first choice of rehabilitation for tooth loss. Even though they have a high success rate, failures still occur for many reasons. The objective of this study is to analyze the reasons for recurring failure at the same site and the results of re-implantation. Methods: Thirteen patients (11 males and 2 females, mean age 60 ± 9.9 years) who experienced implant surgery failure at the same site (same tooth extraction area) two or more times in the Department of Oral and Maxillofacial Surgery, Seoul National University Bundang Hospital, between 2004 and 2017 were selected. The medical records on a type, sites, diameter, and length of implants; time and estimated cause of failure; and radiographs were reviewed. Data were collected and analyzed retrospectively, and the current statuses were evaluated. Results: A total of 14 implants experienced failure in the same site more than two times. Twelve implants were placed in the maxilla, while 2 implants were placed in the mandible. The maxillary molar area was the most common site of failure (57.1%), followed by the mandibular molar, anterior maxilla, and premolar areas (14.3% each). The first failure occurred most commonly after prosthetic treatment (35.7%) with an average period of failure of 3.8 months after loading. Ten cases were treated as immediate re-implantation, while the other 4 were delayed reimplantation after an average of 3.9 months. The second failure occurred most commonly after prosthetic treatment (42.9%), with an average of 31 months after loading; during the healing period (42.9%); and during the ongoing prosthetic period (14.3%). In 3 cases (21.4%), the treatment plan was altered to an implant bridge, while the other 11 cases underwent another implant placement procedure (78.6%). Finally, a total of 9 implants (64.3%) survived, with an average functioning period of 60 months. Conclusions: Implants can fail repeatedly at the same site due to overloading, infection, and other unspecified reasons. The age and sex of the patient and the location of implant placement seem to be associated with recurring failure. Type of implant, bone augmentation, and bone materials used are less relevant.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.2 no.1
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• pp.39-44
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• 2006

Cerebral palsy(CP) is one of the most common motor disease, due to brain injury during fetal and neonatal development which results in neuromotor paralysis and associated neuromuscular symptoms. Features of CP include motor disability due to the lack of muscle control, often accompanied by sensory disorders, mental retardation, speech disorders, hearing loss, epilepsy, behavior disorders, etc. There are increasing chances of treatment of dental patients with cerebral palsy, as the occurrence of CP is increasing with the decrease in infant mortality and an increase in immature birth and premature birth and also, there is a trend to pursue of higher quality of life. Reports on the relationship between CP and maxillofacial deformity are uncommon, but it is well known that the unbalance and discontrol of the facial muscles, lip, tongue and the jaws leads to malocclusion and temporomandibular joint disorders, and statistics show that class 2 relationship of the jaws and open bite is frequently reported. However, it is difficult to perform maxillofacial deformity treatment, which consists of orthodontic treatment, maxillofacial surgery and muscle adaptation training, due to difficulties in communication and problems of muscle adaptation caused by difficulties in motor control which leads to a high recurrence rate. This case report is to trearment of maxillofacial deformity in CP patient. A 26 year old female patient came to the department with the chief complaint of prognathism of the mandible and facial asymmetry. According to the past medical history, she was diagnosed as cerebral palsy 1 week after birth, classified as GMFC, classII accompanied with left side torticollis. The patient's intelligence was moderate, and there were no serious problems in communication. For two years time, the patient underwent lingual frenectomy, pre-operation orthodontic treatment and then bimaxillary orthognathic surgery to treat mandibular prognathism and facial asymmetry followed by rehabilitatory exercise of facial muscle. After 6 months of follow up, there was a good result. This is to report to the typical signs and symptoms of DFD in CP patient and the limitation of the usual method of the treatment of DFD in CP patient with literature review.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.34.1-34.14
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• 2015

Background: Over the past 30-40 years, various carbon implant materials have become more interesting, because they are well accepted by the biological environment. The traditional carbon-based polymers give rise to many complications. The polymer complication may be eliminated through carbon fibres bound by pyrocarbon (carbon/carbon). The aim of this study is to present the long-term clinical results of carbon/carbon implants, and the results of the scanning electron microscope and energy dispersive spectrometer investigation of an implant retrieved from the human body after 8 years. Methods: Mandibular reconstruction (8-10 years ago) was performed with pure (99.99 %) carbon implants in 16 patients (10 malignant tumours, 4 large cystic lesions and 2 augmentative processes). The long-term effect of the human body on the carbon/carbon implant was investigated by comparing the structure, the surface morphology and the composition of an implant retrieved after 8 years to a sterilized, but not implanted one. Results: Of the 16 patients, the implants had to be removed earlier in 5 patients because of the defect that arose on the oral mucosa above the carbon plates. During the long-term follow-up, plate fracture, loosening of the screws, infection or inflammations around the carbon/carbon implants were not observed. The thickness of the carbon fibres constituting the implants did not change during the 8-year period, the surface of the implant retrieved was covered with a thin surface layer not present on the unimplanted implant. The composition of this layer is identical to the composition of the underlying carbon fibres. Residual soft tissue penetrating the bulk material between the carbon fibre bunches was found on the retrieved implant indicating the importance of the surface morphology in tissue growth and adhering implants. Conclusions: The surface morphology and the structure were not changed after 8 years. The two main components of the implant retrieved from the human body are still carbon and oxygen, but the amount of oxygen is 3-4 times higher than on the surface of the reference implant, which can be attributed to the oxidative effect of the human body, consequently in the integration and biocompatibility of the implant. The clinical conclusion is that if the soft part cover is appropriate, the carbon implants are cosmetically and functionally more suitable than titanium plates.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.3
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• pp.176-183
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• 2011

Introduction: Very high aggressiveness and recurrence are important clinical characteristics of ameloblastoma compared to the other benign tumors. Therefore, an accurate diagnosis and treatment plan is important. This study examined the association of the clinical findings and recurrence based on the radiological findings of ameloblastoma. In recurrent cases, these results are expected to help in the diagnosis and treatment of ameloblastoma to examine the relevance with the clinical characteristics and radiological features. Materials and Methods: For a clinical (gender, age) and radiological (location, internal pattern, size, perforation, border pattern, impacted tooth, root resorption) evaluation, this study examined 156 cases of 147 patients diagnosed with ameloblastoma, who had been treated and in most cases regularly checked at the department of oral and maxillofacial surgery, Kyungpook National University Hospital, between January 1993 and December 2009. For a recurrent rate evaluation, a more than 3 years follow-up period is needed. Accordingly, 116 patients diagnosed with ameloblastoma between January 1994 and December 2007 were investigated. Results: The recurrence rate in all cases was 6.1% but was 7.8% in cases with follow-up periods more than 3 years. The male-to-female ratio was 3:2, showing a slight male predilection. Ameloblastoma had a peak occurrence in the second decade of life followed by the fourth decade of life. The mandibular angle area is the most frequent site of ameloblastoma (50.8%) in the jaws. Six cases of unilocular (7.8%) and 3 cases of multilocular (7.7%) ameloblastomas recurred. Seven cases of smooth (10%) and 2 cases of irregular (4.3%) ameloblastomas recurred. No cases of ameloblastomas without perforation of the cortical bone (0%) and 9 cases with a perforation of cortical bone (11.1%) recurred. Four cases of the ameloblastomas with impacted teeth (11.4%) and 5 cases of ameloblastomas without impacted tooth (6.2%) recurred. Seven cases of ameloblastomas with root resorption (10.9%) and 2 cases of ameloblastomas without root resorption (3.8%) recurred. Conclusion: A multiple smooth margin, unilocular ameloblastoma with an impacted tooth, root resorption tends to recur more easily. Therefore, they need to be treated more carefully and require a a longer follow-up.

• Imaging Science in Dentistry
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• v.46 no.1
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• pp.25-31
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• 2016

Purpose: This study was performed to evaluate condylar surface changes and remodeling after orthognathic surgery using three-dimensional computed tomography (3D CT) imaging, including comparisons between the right and left sides and between the sexes. Materials and Methods: Forty patients (20 males and 20 females) who underwent multi-detector CT examinations before and after surgery were selected. Three-dimensional images comprising thousands of points on the condylar surface were obtained before and after surgery. For the quantitative assessment of condylar surface changes, point-to-point (preoperative-to-postoperative) distances were calculated using 3D processing software. These point-to-point distances were converted to a color map. In order to evaluate the types of condylar remodeling, the condylar head was divided into six areas (anteromedial, anteromiddle, anterolateral, posteromedial, posteromiddle, and posterolateral areas) and each area was classified into three types of condylar remodeling (bone formation, no change, and bone resorption) based on the color map. Additionally, comparative analyses were performed between the right and left sides and according to sex. Results: The mean of the average point-to-point distances on condylar surface was $0.11{\pm}0.03mm$. Bone resorption occurred more frequently than other types of condylar remodeling, especially in the lateral areas. However, bone formation in the anteromedial area was particularly prominent. No significant difference was found between the right and left condyles, but condylar surface changes in males were significantly larger than in females. Conclusion: This study revealed that condylar remodeling exhibited a tendency towards bone resorption, especially in the lateral areas. Condylar surface changes occurred, but were small.