• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.382-387
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• 2021

Objectives: Zygomatic complex (ZMC) fractures comprise up to 40% of all facial fractures. Misaligned bone fragments and misplaced fixation hardware traditionally detected postoperatively on plain radiographs of the skull might require re-operation. The intraoperative O-Arm (Medtronic, USA) is a three-dimensional (3D) computed tomographic imaging system. Materials and Methods: This retrospective single-center study evaluated the utility of O-Arm scanning during corrective surgeries for ZMC and zygomatic arch (ZA) fractures from 2018 to 2020. Three females and 16 males (mean age, 31.52 years; range, 22-48 years) were included. Fracture instability (n=6) and facial deformity (n=15) were the most frequent indications for intraoperative 3D O-Arm scan. Results: The images demonstrated that all fracture lines were properly reduced and fixed. Another scan performed at the end of the fixation or reduction stage, however, revealed suboptimal results in five of the 19 cases, and further reduction and fixation of the fracture lines were required. Conclusion: Implementation of an intraoperative O-Arm system in ZMC and ZA fracture surgeries assists in obtaining predictable and accurate results and obviates the need for revision surgeries. The device should be considered for precise operations such as ZMC fracture repairs.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.5
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• pp.415-423
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• 2005

Distraction osteogenesis (DO) is frequently used technique in reconstruction of bony defects resulted from tumor resection, congenital deformity, and trauma in the maxillofacial region. Although the histologic and ultrastructural changes associated with distraction osteogenesis have been extensively described, the exact changing of the surrounding tissues, such as nerve tissues, were still unclear. This study observed the histological changes and the expression of nerve growth factor (NGF) in the inferior alveolar nerve (IAN) after distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in eight mongrel dogs. Two animals were sacrificed at 7, 14, 28 and 56 days after completion of distraction, respectively. The distracted IAN and contralateral control nerve were harvested and processed for histological and innunohistochemical examinations. The signs of acute nerve injuries, such as demyelination and partial discontinuation of nerver fiber, were observed in the distracted IAN on 7 and 14 days after distraction. The initial remyelination and regeneration of distracted IAN were showed at 14 days after completion of distraction. At 56 days later, the histologic features of distracted IAN was similar to those of the normal control IAN. The expression of NGF was significantly increased in most distracted nerve tissues on 7, 14 and 28 days after distraction. On 56 days after distraction, the expression of NGF returned to the normal level. This study suggested that the acute IAN injury caused by mandibular distraction were mostly recovered during consolidation period. The NGF was seemed to be induced from Schwann cell and damaged nerve tissues, and it may have important roles in the initial healing of damaged nerves.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.5
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• pp.259-264
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• 2016

Objectives: We evaluated and recorded post-traumatic and postoperative neurosensory deficits of the inferior alveolar nerve (IAN) in mandibular fracture in order to identify associated risk factors. Materials and Methods: This was a prospective cohort study composed of 60 patients treated for mandibular fracture. The primary study variable was the change between the post-traumatic IAN neurosensory examination score and the score after fracture reduction. Risk factors were categorized as demographic, anatomic, fracture displacement, and treatment. Appropriate descriptive and bivariate statistics were computed. Results: Sixty patients with unilateral mandibular fracture reported within 24 hours of injury were evaluated over a one-year period. A post-traumatic neurosensory deficit was observed in 52 patients (86.7%), the percentage of which was reduced to 23.3% over the follow-up period. Abnormal postoperative neurosensory scores were significantly higher in angle fracture cases (33.3%) compared to body fracture cases (11.1%). When recovered and non-recovered neurosensory scores were compared by fracture location, 88.9% of body fracture cases showed significant recovery compared to 66.7% of mandibular angle fracture cases. Cases with less than 5 mm fracture displacement showed statistically significantly higher neurosensory recovery scores (90.6%) compared to those with more than 5 mm fracture displacement (60.7%). Conclusion: Use of a miniplate with mono-cortical screws does not play a role in increasing IAN post-traumatic neurosensory deficit. Early management can reduce the chances of permanent neurosensory deficit. Mandibular fracture displacement of 5 mm or more and fracture location were found to be associated with an increased risk of post-traumatic IAN neurosensory score worsening.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.3
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• pp.281-289
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• 1994

This is a clinical study on 235 inpatients who sustained a total of 350 mandibular fractures and who were treated in our department during the period of Oug., 1989 through Dec., 1993. The results obtained are as follows : 1. The mumber of patients has not been increased year after year. In respect of incidence, there were the highest frequency as 67 patients(28.5%) in 1991 and the least frequency as 16 patients(6.8%) in 1989 and the highest frequency as 28 patients(11.9%) in October and the least frequncy as 12 patients(5.2%) in February. 2. The age frequency was the highest in the second decade(30.6%). The youngest patient was 8 months and the eldest patient was 80 years and mean age was 27.8 years. The ratio of men to Wemen was 4 : 1. 3. The most frequent cause was fall down as 86 patients(36.6%) and the next was fist blow 4 as 75 patients(31.9%), traffic accident as 56 patients(23.9%) in order. 4. The most common location was symphysis as 141 numbers(40.3%) and the next was condyle as 96 numbers(27.4%), angle as 94 numbers(26.8%), body as 14 numbers(4.0%) in order. The sum of fracture sites were 350 and there were 1.49 fracture sites per one patient and multiple fractures occured in 100 patients(40.5%) of the 235 patients. The ratio of Left to Right except for symphysis was 1.71 : 1. 5. Among the 333 associated injuries, facial laceration was 136(57.9%) and tooth injury was 58(24.7%) and extremity was 31(13.2%). 6. Among the 350 mandibular fractures, complications after treatment occured in 51(14.6%) and infection as 20(5.7%) was the most frequent complication. 7. In respect of treatment of mandibular fracture, close reduction was 64 patients(27.2%) and open reduction was 164 patients(69.8%) and other were 7 patients(3.0%) of all and so open reduction was the most common in type of treatment.

• Restorative Dentistry and Endodontics
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• v.41 no.1
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• pp.63-67
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• 2016

During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.15 no.1
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• pp.27-40
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• 1985

This study was undertaken to observe the histopathologic changes in salivary gland of the white rats when exposed to megavoltage fractionated dose of cobalt-60 irradiation and 78 female white rats, weighing approximately 180gm, were divided into control and 3 experimental groups. Irradiation on experimental groups was delivered by using 6000 curies MeV ALCYON cobalt-60 teletherapy unit with exposure rate 183 rads per minute, in source skin distance 80cm, 600 rads every 3 days. In experimental groups, Group Ⅰwas irradiated of total dose 1200 rads for a period of 6 days, Group Ⅱ was irradiated of total dose 2400 rads for a period of 12 days and Group Ⅲ was irradiated of total dose of 4800 rads for a period of 24 days. The animals were sacrificed serially at 3 hours, 6 hours, 10 hours, 1st day, 4th day, 7th day after each completion of irradiation exposure. At sacrifice, salivary glands were excised and examined microscopically and electromicroscopically. The results were as follows: 1. The acinar cells of parotid and submaxillary gland showed damage varied with dose, 1200 rads resulted in very mild injury while 4800 rads caused most extensive injury. 2. The acinar cells of parotid and submandibular gland showed similar ultrastructural alterations, appeared as pleomorphic nucleus, decreased numbers and pleomorphism of secretory granules, distention of rough endplasmic reticulum, expansion and pallor appearance of mitochondria, and hypertrophy of Golgi complex. 3. Parotid serous cells were the most sensitive components, displaying morphological alterations of radiation damage as early as 3 hours, followed by submandibular seromucinous cells and secretory tubular cells. 4. The mucous cells of sublingual gland, as well as the whole ductal lining cells of each salivary gland, displayed no significant alterations. No evidence of microvascular injury through whole experimental groups indicated that microvascular impairment does not contribute to early salivary gland injury.

• The Journal of the Korean dental association
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• v.50 no.12
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• pp.763-770
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• 2012

The purposes of this work were to assess the cognition of the registered nurse(RN) on oral and maxillofacial emergency treatment and to compare cognition of the RN with that of the 119 emergency medical technician(EMT). 450 RNs who were working at each of secondary hospitals in Jeju province had responded to the questionnaire. Independent sample t-test and chi-square test were used to assess the state of RN on dental emergency treatment and to compare RN with EMT. The question 'education time on dentistry in formal education' that marked '0 hour' and '1-3 hours' were 73.3% and 20.0%, respectively. The question 'refresher training class on dentistry' that marked '0 hour' and '1-3 hours' were 92.9% and 6.7%, aggregately 99.6%. The results showed low score in the question 'reduction of temporo-mandibular joint(TMJ)'($1.67{\pm}0.857$), 'fixation of dislocated TMJ'($1.70{\pm}0.853$) and 'post-avulsed tooth treatment'($1.78{\pm}0.774$) by 5-point Likert scale. Likewise, the scores were $2.02{\pm}0.806$ in the question 'treatment of maxillofacial trauma', $2.76{\pm}1.061$ in the question 'emergent care of avulsed tooth', $2.70{\pm}1.095$ in the question 'treatment time of avulsed tooth' and $2.79{\pm}1.056$ in the question 'mouth guard', respectively. Compared to EMT, results of RN showed a statistically lower figure(p<0.05) in all items compared except the question 'medicine control', and the question 'doctor care in emergency room' was borderline(p=0.069). From this study, it is necessary for RN and student of nursing science to be educated on the oral and maxillofacial emergency treatment for the initial management of injuries. Authors suggest further co-study and nation-wide research with nursing care.

• Journal of Dental Anesthesia and Pain Medicine
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• v.18 no.6
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• pp.375-378
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• 2018

Endotracheal intubation is commonly associated with laryngeal injury that often resolves spontaneously without any complication. However, stenosis or granulomatous lesions are generally found on the tracheal wall or vocal process at the tube cuff level, caused by excessive cuff pressure. We present a case of fatal vocal cord granuloma leading to dyspnea following orthognathic surgery and sustained intubation for 14 hours.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.309-312
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• 2013

A retromolar canal is an anatomical variation in the mandible. As it includes the neurovascular bundle, local anesthetic insufficiency can occur, and an injury of the retromolar canal during dental surgery in the mandible may result in excessive bleeding, paresthesia, and traumatic neuroma. Using imaging analysis software, we evaluated the cone-beam computed tomography (CT) images of two Korean patients who presented with retromolar canals. Retromolar canals were detectable on the sagittal and cross-sectional images of cone-beam CT, but not on the panoramic radiographs of the patients. Therefore, the clinician should pay particular attention to the identification of retromolar canals by preoperative radiographic examination, and additional cone beam CT scanning would be recommended.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.125-130
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• 2009

For many years, intermaxillary fixation using arch bar has been operated in treatment of mandibular fracture patients. But it has many complications including injury of operators and assistants cause by wire, inflammation of periodontium. For that reasons alternatives are required; osteosynthesis technique using mini plate, intermaxillary fixation using IMF screws have been available. Treatment by arch bar fixation, however, is still valuable to treat craniomaxillary fracture patients. The purpose of this study is to know effect arch bar on periodontium and influence gingival gel on periodontium applied by arch bar. 40 mandibular fracture patients are monitored. 30 patients were applied by arch bar, 10 patients were not. And the former were classified by 3 categories; Nano vitamin and Mastic gel were applied to 10 patients respectively and any gingival gel was not used to 10 patients. Clinical attachment level, bleeding on probing and periodontal depth of each group were measured and compared before operation and on 2 weeks and 6 weeks after operation. Mann-Whitney U test was used to analyze result which leads to this conclusion. 1. Whether arch bar is applied or not, treatment of mandlbular fracture gave rise to gingivitis, but 6 weeks after operation, gingivitis is restored to the same level as the state before operation. 2. More severe gingivitis appeared when arch bar is applied to mandibular fracture than when it is not. 3. Both gingival gel used in this study can reduce gingivitis which can be caused by arch bar. 4. In this study, Mastic gel is more effective for prevent gingival inflammation cause by arch bar than nano vitamin. In regard to this result, gingivitis is considered to be available because it is reversible and does not induce periodontal disease. Gingival gel is regarded to be helpful for patients applied by arch bar to feel less discomfort.