• The Journal of the Korean dental association
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• v.10 no.8
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• pp.531-534
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• 1972

The author measured exothermic temperature of the 5 kinds of zinc phosphate cement and 3 kinds of copper phosphate cement during setting process. Cements were mixed on the glass slab with flexible steel spatula at room temperature (25.8℃) for one minute (spatulating speed was 100 strokes per minute) and placed in the incubator of which temperature was held at 37℃ and thermometer was inserted into the cement mass. The powder liquid ration was 3.0gm:1ml and 1.5gm:1ml. The results were as follows. 1) The heat generated after mixing these cements was under 47.22℃. 2) The range of thermal change of the zinc phosphate cements during setting process was wider than copper phosphate cements. 3) The exothermic temperature from the thin mix was higher than thick mix. 4) The exothermic temperature of the zinc phosphate cements was higher than copper phosphate cements.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.7 no.1
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• pp.43-48
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• 1977

The authors had observed a rare case of osteopetrosis from 8 years old male who had complained nasal obstruction at, Department of Dental Radiology, Kyung Hee University. In the serial roentgenograms the following results were revealed. 1. This osteopetrosis was considered to be malignant rather than benign. 2. In the skull, the greatest degree of radiopacity was found in the base. The pituitary fossa appeared to be small and posterior clinoid process revealed clubbing and thickening. 3. In the frontal and nasal bones were slightly enlarged with marked radiopacity and paranasal sinuses were obscured. 4. The maxilla was markedly affected and bony trabeculae were seen to be coarse and thickened but mandibular posterior segment slightly. 5. There were long retardation of the tooth eruption and physiologic resorption of the deciduous teeth, and tooth root revealed stunted and dwarfed appearance in the both jaws. 6. In this case, the thickened alveolar lamina dura was indistinguishable.

• Journal of the Korean Society of Visualization
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• v.22 no.2
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• pp.90-95
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• 2024

This study examined changes in airway airflow characteristics before and after extensive surgery for tongue cancer, which includes neck dissection and reconstruction. Pre- and post-operative CBCT scans were used to model 3D upper airways. Computational fluid dynamics (CFD) simulations analyzed airflow and pressure variations. Results showed a significant reduction in airway volume post-surgery, especially in the posterior tongue and epiglottis areas, leading to increased airflow velocity and complex vortex formations. Pressure drop analysis revealed that post-surgery, higher negative pressure is required for inhalation, indicating increased breathing effort. This suggests that the surgical removal of cancerous tissues and lymph nodes, along with reconstruction, alters airway geometry significantly, potentially impacting respiratory function. The findings highlight the clinical importance of assessing airway changes in tongue cancer surgery to anticipate and mitigate postoperative respiratory complications.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.93-99
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• 2010

Herpes zoster (HZ) is the secondary manifestation of an earlier infection with the varicella-zoster virus in one or more dermatomes. As reactivation of the virus is linked to an age-related diminished virus-specific and cell-mediated immunity, HZ develops mainly in elderly people. Acute zoster is painful, but does not incur lasting morbidity. Reactivation of the varicella-zoster virus in the trigeminal nerve (Herpes zoster) occur with severe pain and rash in the oro-facial region. The acute pain decreases as the rash begins to heal. Postherpetic neuralgia(PHN), the most frequent complication of herpes zoster, is usually defined as pain in the involved dermatome that is still present 3 month after rash onset. The clinical characteristics of PHN are, eposodic stabbing pain, burning pain and allodynia, with hypoesthesia and/or dysesthesia. $Neurometer^{(R)}$(neuroselective sensory nerve conduction threshold: sNCT, Automated current perception threshold: CPT, neurotron incorporated. Baltimore, Maryland. 21209 U.S.A.) is convenient, rapid and noninvasive, and allows objective assessment of sensory disturbance. This case is about the postherptic neuralgia patient assessed with $Neurometer^{(R)}$. From this case, we reviewed the pathophysiology and the treatment of PHN and recommend the assessment of pain intensity with $Neurometer^{(R)}$ as quantitative and objective method.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.544-549
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• 2009

Failure to use effective methods of reduction, fixation and immobilization may lead to osteomyelitis with the exposed necrotic bone, as the overzealous use of transosseous wires & plates that devascularizes bone segments in the compound comminuted fractures of mandible. Once osteomyelitis secondary to fractures has become established, intermaxillary fixation should be instituted as early as possible. Fixation enhances patient comfort and hinders ingress of microorganisms and debris by movement of bone fragments. Teeth and foreign materials that are in the line of fracture should be removed and initial debridement performed at the earliest possible time. Grossly necrotic bone should be excised as early as possible ; no attempt should be made to create soft tissue flaps to achieve closure over exposed bone. The key to treatment of chronic osteomyelitis of the mandible is adequate and prolonged soft tissue drainage. If good soft tissue drainage is provided over a long period, sequestration of infected bone followed by regeneration or fibrous tissue replacement will occur so that appearance and function are not seriously altered. Localization and sequestration of infected mandible are far better performed by natural mechanism of homeostasis than by cutting across involved bone with a cosmetic or functional defect. As natural host defenses and conservative therapy begin to be effective, the process may become chronic, inflammation regresses, granulation tissue is formed, and new blood vessels cause lysis of bone, thus separating fragments of necrotic bone(sequestra) from viable bone. The sequestra may be isolated by a bed of granulation tissue, encased in a sheath of new bone(involucrum), and removed easily with pincettes. This is a case report of the long-term conservative drainage care in osteomyelitis associated with mandibular fractures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.114-121
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• 2011

Introduction: The aim of this study was to demonstrate that the simulation surgery on rapid prototype (RP) model, which is based on the 3-dimensional computed tomography (3D CT) data taken before surgery, has the same accuracy as traditional orthograthic surgery with an intermediate splint, using an optoelectronic tracking navigation system. Materials and Methods: Simulation surgery with the same treatment plan as the Le Fort I osteotomy on the patient was done on a RP model based on the 3D CT data of 12 patients who had undergone a Le Fort I osteotomy in the department of oral and maxillofacial surgery, Seoul National University Dental Hospital. The 12 distances between 4 points on the skull, such as both infraorbital foramen and both supraorbital foramen, and 3 points on maxilla, such as the contact point of both maxillary central incisors and mesiobuccal cuspal tip of both maxillary first molars, were tracked using an optoelectronic tracking navigation system. The distances before surgery were compared to evaluate the accuracy of the RP model and the distance changes of 3D CT image after surgery were compared with those of the RP model after simulation surgery. Results: A paired t-test revealed a significant difference between the distances in the 3D CT image and RP model before surgery.(P<0.0001) On the other hand, Pearson's correlation coefficient, 0.995, revealed a significant positive correlation between the distances.(P<0.0001) There was a significant difference between the change in the distance of the 3D CT image and RP model in before and after surgery.(P<0.05) The Pearson's correlation coefficient was 0.13844, indicating positive correlation.(P<0.1) Conclusion: Theses results suggest that the simulation surgery of a Le Fort I osteotomy using an optoelectronic tracking navigation system I s relatively accurate in comparing the pre-, and post-operative 3D CT data. Furthermore, the application of an optoelectronic tracking navigation system may be a predictable and efficient method in Le Fort I orthognathic surgery.

• Journal of The Korean Dental Society of Anesthesiology
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• v.6 no.2 s.11
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• pp.103-112
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• 2006

Background: The purpose of this study was to compare the clinical safety and effect with and without additional submucosal midazolam to oral chloral hydrate and hydroxyzine when used for pediatric conscious sedation in a clinical dental environment. Methods: Thirty one cases of pediatric conscious sedations were performed in this study. Selection criteria included good health (ASA I), under 6 years old, 20 kg of body weight, uncooperative behavior and the need for sedation to receive dental treatment including anesthesia and restorative or surgical procedure for at least two teeth. In each visit, patients were randomly assigned into one of two groups; CH group: chloral hydrate (60 mg/kg), hydroxyzine (1 mg/kg), CH-M group: chloral hydrate (60 mg/kg). hydroxyzine (1 mg/kg) and submucoal midazolam (0.1 mg/kg). 50% nitrous oxide-oxygen was maintained during the sedation period Sedations were monitored using a pulse oximeter for estimating pulse rate (PR) and percutaneous oxygen saturation ($SpO_2$). Behavior response rated using Houpt's scale and need of restraint was assessed every 2 minutes through 30 minutes of operative procedure reviewing the videotape recording. Evaluation of overall behavior success was performed using modified overall behavior rate of Houpt's scale. Data was analyzed using t-test. Results: PR and $SpO_2$ for both groups remained within the normal values. The mean scores for sleep and movement of CH-M group were higher than those of CH group (P < 0.05). There were no significant difference in mean score for crying between two groups. The mean scores of overall behavior of CH-M group was higher than those of CH group (P < 0.01). Reinstraint of CH-M group was less required than that of CH group (P < 0.05). Conclusions: Oral chloral hydrate (60 mg/kg) and hydroxyzine (1 mg/kg) combined with submucosal injection of midazolam was safer and showed more improved sedation effect than oral chloral hydrate (60 mg/kg) and hydroxyzine (1 mg/kg) without midazolam for sedation of pediatric dental patients.

• Journal of Oral Medicine and Pain
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• v.36 no.3
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• pp.199-205
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• 2011

During root canal treatment, overinstrumentation with hand or mechanically driven files can perforate the mandibular canal, allowing the extrusion of endodontic sealers, dressing agents, and irrigant solutions out of the tooth and into the canal. The patient may report symptoms such as pain, hyperesthesia, hypoesthesia, anesthesia, dysesthesia and paresthesia. Such problems must be resolved as quickly as possible to avoid irreversible sequelae caused by certain neurotoxic materials that form part of endodontic sealants. Although there have been no controlled trials of treatment protocols involving endodontically related injuries to the inferior alveolar nerve, the normal therapeutic sequence for this complication is the control of pain and inflammation and, whenever possible, the surgical elimination of the cause. However, total resolution of pain and reduction in or disappearance of paraesthesia after a non-surgical management have been reported. Antiepileptic drugs such as gabapentin or pregabalin have been used for the treatment of neuropathic pain. This article describes a case of inferior alveolar nerve(IAN) damage after endodontic treatment of a mandibular right second molar and the treatment with non-surgical approach using prednisone and gabapentin medication, monitoring the patient's condition with clinical neurosensory examination and current perception threshold test(Neurometer).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.1
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• pp.63-79
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• 1993

To repair bony defects with tansplanted bone in the body, fresh autogenous bone is undoubtly, the most effective bone graft for clinical applications. But the demineralized bone has the matrix-induced bone formation which was suggested by Urist in 1965. Many authors assisted that demineralized bone powder induces phenotypic conversion of mesenchymal cells into osteoblasts, with high-density bone formation. The process of inducing differentiated cells becomes osteogenic properties. The purpose of this study was to evaluate the osteoinductive capacity of allogenic freeze-dried demineralized bone block (FDD, $7{\times}7mm$) and to compare FDD with the same sue of deep-frozen allogenic bone(DF), fresh autogenous bone (A) after implantation. The histological and ultrastructural features of tissue responses were examined after 1, 2, 4, 6, 8 weeks implantation of each experimental groups in the operative site of the New Zealand white rabbits. The results were as follows : 1. Inflammatory cell infiltration generally has appeared at 1 week, but reduced at 4 weeks in each group, but most severe in DF group. 2. Osteoblastic activity has increased for 4 weeks, but decreased at 6 weeks in each group and there was no significant difference among experimental groups. 3. New bone formation has begun at 1week, least activations in A groups, and showed the revesal line of bone formation among each group at 6 to 8 weeks. 4. Bone resorption has appeared at 1 week, but disappeared at 4 weeks in both A and DF groups, but more severe in DF than A groups. 5. In ultrastructural changs, the DF group have showed the most remarkable osteoclastic activities among experimental groups. 6. Osteoid or tangled collagen fibrils near the implanted sites were replaced by more mature, lamellated bony trabeculae during bone remodeling. There was little difference among each experimental groups. 7. During the convertion osteoblasts to osteocytes which embedded within the bone matrix, there was organ-less-poor cytoplasm, increased nuclear chromatin, abundant rough endothelial reticulum (RER) in each groups. From the above the findings, the DF group shored more bone resorption and foreign body reaction than FDD and A groups, and FDD group showed more new bone formation or osteoblastic activity than DF and A groups in early stage. There was no significant difference of cellular activities among the FDD DF, and A groups according to the time.

• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.406-414
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• 2014

PURPOSE. The objective of this study was to investigate the biologic effects of enamel matrix derivative (EMD) with different concentrations on cell viability and the genetic expression of human gingival fibroblasts (HGF) to zirconia surfaces. MATERIALS AND METHODS. Immortalized human gingival fibroblasts (HGF) were cultured (1) without EMD, (2) with EMD $25{\mu}g/mL$, and (3) with EMD $100{\mu}g/mL$ on zirconia discs. MTT assay was performed to evaluate the cell proliferation activity and SEM was carried out to examine the cellular morphology and attachment. The mRNA expression of collagen type I, osteopontin, fibronectin, and TGF-${\beta}1$ was evaluated with the real-time polymerase chain reaction (RT-PCR). RESULTS. From MTT assay, HGF showed more proliferation in EMD $25{\mu}g/mL$ group than control and EMD $100{\mu}g/mL$ group (P<.05). HGFs showed more flattened cellular morphology on the experimental groups than on the control group after 4h culture and more cellular attachments were observed on EMD $25{\mu}g/mL$ group and EMD $100{\mu}g/mL$ group after 24h culture. After 48h of culture, cellular attachment was similar in all groups. The mRNA expression of type I collagen increased in a concentration dependent manner. The genetic expression of osteopontin, fibronectin, and TGF-${\beta}1$ was increased at EMD $100{\mu}g/mL$. However, the mRNA expression of proteins associated with cellular attachment was decreased at EMD $25{\mu}g/mL$. CONCLUSION. Through this short term culture of HGF on zirconium discs, we conclude that EMD affects the proliferation, attachment, and cell morphology of HGF cells. Also, EMD stimulates production of extracellular matrix collagen, osteopontin, and TGF-${\beta}1$ in high concentration levels. CLINICAL RELEVANCE. With the use of EMD, protective barrier between attached gingiva and transmucosal zirconia abutment may be enhanced leading to final esthetic results with implants.