• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.167-172
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• 2009

The maxilla rarely undergoes necrosis due to its rich vascularity. Maxillary necrosis can occur due to bacterial infections such as osteomyelitis. viral infections such as herpes zoster and fungal infections such as mucormycosis, aspergillosis etc. Herpes zoster is a common viral infection, the oral soft tissue manifestations of which are widely known and recognized. Extremely rare complications such as osteonecrosis, and secondary osteomyelitis in maxilla were observed. But, reports of spontaneous tooth exfoliation and jaw osteonecrosis following herpes zoster infection in the distribution of the trigeminal nerve are extremely rare in the literature. We report a case of maxillary necrosis by herpes zoster in an uncontrolled diabetic patient. There was extensive necrosis of the buccal and palatal mucoperiosteum and exposure of the alveolar bone. This patient was successfully treated using a removal of necrotic bone and nasolabial flap. We briefly discuss different diseases which can lead to maxillary necrosis and a review. Analysis of the pathogenesis of herpes zoster and bone necrosis are discussed.

• The Journal of the Korean dental association
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• v.52 no.4
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• pp.192-202
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• 2014

Bisphosphonate(BP) significantly influence the hone remodeling process. Increasing number of patients with osteoporosis and metastatic bone disease need high dose or long term bisphosphonate therapy. Major adverse effect is jaw bone necrosis and now the bisphosphonate-related necrosis of the jaw(BRONJ) is the major concern of dental practitioner. This study intended to perform the review of the current understandings concerning the pathophysiology of BRONJ. Even though pathophysiological mechanism of BRONJ is not clearly elucidated but now suggested as largely two different concepts; so-called "inside-out" or "outside-in" theory. Inside-out theory emphasize the osteonecrosis of the jaw is the initial major event and subsequent infection and inflammation is the second event that accompanies bone exposure and death of overlying mucosa. However, in "outside-in" theory, infection or inflammation initiated by traumatized oral epithelium is the major event of BRONJ. Both theory would be partially explain BRONJ. Recent research reveals the immune modulating effect and influence of microcrack accumulation by BP. These findings and those of others might explain the missing part of outside-in theory.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.744-749
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• 2018

Dapsone, an antibiotic, has been used to cure leprosy. It has been reported that dapsone has anti-inflammatory activity in hosts; however, the anti-inflammatory mechanism of dapsone has not been fully elucidated. The present study investigated the anti-inflammatory effects of dapsone on bone marrow cells (BMs), especially upon exposure to lipopolysaccharide (LPS). We treated BMs with LPS and dapsone, and the treated cells underwent cellular activity assay, flow cytometry analysis, cytokine production assessment, and reactive oxygen species assay. LPS distinctly activated BMs with several characteristics including high cellular activity, granulocyte changes, and tumor necrosis factor alpha ($TNF-{\alpha}$) production increases. Interestingly, dapsone modulated the inflammatory cells, including granulocytes in LPS-treated BMs, by inducing cell death. While the percentage of Gr-1 positive cells was 57% in control cells, LPS increased that to 75%, and LPS plus dapsone decreased it to 64%. Furthermore, dapsone decreased the mitochondrial membrane potential of LPS-treated BMs. At a low concentration ($25{\mu}g/mL$), dapsone significantly decreased the production of $TNF-{\alpha}$ in LPS-treated BMs by 54%. This study confirmed that dapsone has anti-inflammatory effects on LPS-mediated inflammation via modulation of the number and function of inflammatory cells, providing new and useful information for clinicians and researchers.

• Korean Journal of Artificial Intelligence
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• v.12 no.1
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• pp.1-6
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• 2024

Recently, various techniques are being applied through the development of medical AI, and research has been conducted on the application of super-resolution AI models. In this study, evaluate the results of the application of the super-resolution AI model to brain CT as the basic data for future research. Acquiring CT images of the brain, algorithm for brain and bone windowing setting, and the resolution was downscaled to 5 types resolution image based on the original resolution image, and then upscaled to resolution to create an LR image and used for network input with the original imaging. The SRCNN model was applied to each of these images and analyzed using PSNR, SSIM, Loss. As a result of quantitative index analysis, the results were the best at 256×256, the brain and bone window setting PSNR were the same at 33.72, 35.2, and SSIM at 0.98 respectively, and the loss was 0.0004 and 0.0003, respectively, showing relatively excellent performance in the bone window setting CT image. The possibility of future studies aimed image quality and exposure dose is confirmed, and additional studies that need to be verified are also presented, which can be used as basic data for the above studies.

• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.29-37
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• 2016

The paper presents a research project on the tensile properties of RPC mixed with both steel and polypropylene fibers after exposure to $20-900^{\circ}C$. The direct and the indirect tensile strength (in bending) were measured through tensile experiment on dog-bone specimens and bending experiment on $40{\times}40{\times}160mm$ prisms. RPC microstructure was analyzed using scanning electron microscope. The results indicate that, steel fibers can significantly improve the tensile performance of hybrid fiber-reinforced RPC, whereas polypropylene fibers have no obvious effect on the tensile performance. With increasing temperature, the flexural and axial tensile strength of hybrid fiber-reinforced RPC substantially decrease linearly, which attributes to the deteriorating microstructure. Based on the experimental results, equations are established to express the decay of the flexural and tensile strength with increasing temperature.

• Journal of Environmental Health Sciences
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• v.16 no.1
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• pp.55-65
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• 1990

This study was carried out to investigate the effects on sister chromatid exchanges (SCEs) and chromosome aberrations in PHA or LPS stimulated mouse spleen and bone marrow lymphocytes after an acute whole body irradiation. Frequencies of sister chromatid exchanges were significantly increased with the increased dose(from zero to 400tad) but there was no differences between B-cell and T-cell. By times, the maximum induced SCE levels was observed at 12 hours after irradiation and then returned to base level at one day in 100rad group and three day in 400rad group. There was a significant difference in chromosome aberration with increasing exposure. X-ray irradiated chromosome aberration was long lived relative to SCE. This results show that counting the incidence of SCE may not provide a sensitive system for detecting X-ray exposure.

• Journal of Periodontal and Implant Science
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• v.45 no.6
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• pp.229-237
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• 2015

Purpose: The aim of this study was to determine the clinical feasibility of using dehydrothermally cross-linked collagen membrane (DCM) for bone regeneration around peri-implant dehiscence defects, and compare it with non-cross-linked native collagen membrane (NCM). Methods: Dehiscence defects were investigated in twenty-eight patients. Defect width and height were measured by periodontal probe immediately following implant placement (baseline) and 16 weeks afterward. Membrane manipulation and maintenance were clinically assessed by means of the visual analogue scale score at baseline. Changes in horizontal thickness at 1 mm, 2 mm, and 3 mm below the top of the implant platform and the average bone density were assessed by cone-beam computed tomography at 16 weeks. Degradation of membrane was histologically observed in the soft tissue around the implant prior to re-entry surgery. Results: Five defect sites (two sites in the NCM group and three sites in the DCM group) showed soft-tissue dehiscence defects and membrane exposure during the early healing period, but there were no symptoms or signs of severe complications during the experimental postoperative period. Significant clinical and radiological improvements were found in all parameters with both types of collagen membrane. Partially resorbed membrane leaflets were only observed histologically in the DCM group. Conclusions: These findings suggest that, compared with NCM, DCM has a similar clinical expediency and possesses more stable maintenance properties. Therefore, it could be used effectively in guided bone regeneration around dehiscence-type defects.

• Parasites, Hosts and Diseases
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• v.55 no.4
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• pp.433-437
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• 2017

Pentastomiasis, a zoonotic parasite infection, is typically found in the respiratory tract and viscera of the host, including humans. Here, we report for the first time an extremely rare case of intraosseous pentastomiasis in the human maxilla suffering from medication related osteonecrosis of the jaw (MRONJ). A 55-year-old male had continuously visited the hospital for MRONJ which had primarily developed after bisphosphonate and anti-neoplastic administration for previous bone metastasis of medullary thyroid cancer. Pain, bone exposure, and pus discharge in the right mandible and left maxilla were seen. Osteolysis with maxillary cortical bone perforation at the left buccal vestibule, palate, nasal cavity, and maxillary sinus was observed by radiologic images. A biopsy was done at the left maxilla and through pathological evaluation, a parasite with features of pentastome was revealed within the necrotic bone tissue. Further history taking and laboratory evaluation was done. The parasite was suspected to be infected through maxillary open wounds caused by MRONJ. Awareness of intraosseous pentastomiasis should be emphasized not to be missed behind the MRONJ. Proper evaluation and interpretation for past medical history may lead to correct differential diagnosis and therapeutic intervention for parasite infections.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.591-604
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• 1996

The present study evaluates the effects of dura mater barrier membranes In class III furcation defects on the regeneration of periodontal tissues in dogs. Experimental class III furcation defects were created surgically by removing alveolar bone horizontally down to 4mm from CEJ in mandibular premolars of adult dogs. Dura mater barrier membranes were applied bucco-lingually in the test group, and flap surgery only with no membranes in the control group. The healing was evaluated clinically and histologically after 8weeks. Clinically, the test group showed slight exposures of the membranes, while the control group showed no furcation exposure, The test specimens showed new bone formation coronal to the notch, while the control specimens had new bone formation up to the level of the notch. New cementum was observed in both groups. The test specimens showed functional arrangements of connective tissue fibers between new bone and new cenentum, while irregular arrangements were observed in the controls. No root resorption or ankylosis were observed in either groups,These results suggest that dura mater resorbable barrier membranes on class III furcation defects may be effective in regeneration of alveolar bone and peridontal ligament.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.4
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• pp.477-497
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• 1994

The purpose of this study was to investigate the effect of timing of implant insertion on osseointegration after tooth extraction. Fifteen mongrel dogs, weighing 15kg or more, were used. The lower right 1st, 2nd, 3rd, 4th premolars and 1st molar were extracted under general anesthesia. Implants were inserted at 2, 4, and 8 weeks after extraction of the teeth, being designated as 2-, 4-, and 8-week groups, respectively. Results obtained were as follows. 1. Macroscopically there was neither an infection at the implant site nor an exposure of the implant. 2. Histologically the surrounding bone of the implant was less mature in the 2-week group than in the 4- and 8-week groups. 3. The implant-bone contact ranged from 75 to 82%, with no significant differences among the groups. No increase in the implant-bone contact was found with increasing healing periods from 4 to 12 weeks after implant insertions. 4. The average depth (0.64mm) of the fibrous connective tissue ingrowth in the 2-week group was slightly deeper than those in the 4- (0.51mm) and 8-week (0.53mm) groups at 12 weeks after implant insertion. 5. the implant-bone interfacial bond strengths were 73.05 kgf in the 2-week group, 69.71 kgf in the 4-week group and 73.76 kgf in the 8-week group. No significant difference was noted in pullout force among the groups. The degree of confidence of interfacial bone strength was highest in the 8-week group, followed by the 4- and 2-week groups. These results indicate that at least 4 weeks of healing period will be required before implant is to be inserted following tooth extraction.