• Imaging Science in Dentistry
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• v.53 no.3
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• pp.217-220
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• 2023

Purpose: This pilot study was conducted to evaluate half-value layer (HVL) measurements obtained using a semiconductor dosimeter for intraoral radiography. Materials and Methods: This study included 8 aluminum plates, 4 of which were low-purity (less than 99.9%) and 4 high-purity (greater than 99.9%). Intraoral radiography was performed using an intraoral X-ray unit in accordance with the dental protocol at the authors' affiliated hospital: tube voltage, 60 kVp and 70 kVp; tube current, 7 mA; and exposure time, 0.10 s. The accuracy of HVL measurements for intraoral radiography was assessed using a semiconductor dosimeter. A simple regression analysis was performed to compare the aluminum plate thickness and HVL in relation to the tube voltage (60 kVp and 70 kVp) and aluminum purity (low and high). Results: For the low-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the thickness of the aluminum plate (X), with Y=1.708+0.415X (r=0.999, P<0.05) and Y=1.980+0.484X (r=0.999, P<0.05), respectively. Similarly, for the high-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the plate thickness(X), with Y=1.696+0.454X (r=0.999, P<0.05) and Y=1.968+0.515X (r=0.998, P<0.05), respectively. Conclusion: This pilot study examined the relationship between aluminum plate thickness and HVL measurements using a semiconductor dosimeter for intraoral radiography. Semiconductor dosimeters may prove useful in HVL measurement for purposes such as quality assurance in dental X-ray imaging.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.375-385
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• 1992

This is a report of adenoid cystic carcinoma occurred in the palate in 30-year-old patient with a complaint of exophytic mass. The authors diagnosed it as adenoid cystic carcinoma by the clinical examination, radiographic findings and histopathological findings. The obtained results are as follows: 1. In clinical examination, asymptomatic exophytic mass of palate was observed. 2. In radiographic findings, soft tissue mass infiltrated the left maxillary sinus, nasal cavity, infraorbital fossa, hard palate, pterygopalatine fossa and pterygoid plate, and enhanced soft tissue mass was also observed in CT. 3. In histopathological findings, tubular and solid patterns of glandular structures were observed and the infiltration of tumor cells into the nerve fibers was also observed. 4. Two years after radical surgery, radiation therapy and chemotherapy, the perineural spread to orbital area was observed. 5. Much longer follow-up than 5 years is needed for early diagnosis of recurrence and distant metastasis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.1
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• pp.1-6
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• 1993

The maxillary squamous cell carcinoma is major part of maxillary malignant tumor. The treatment of maxillary malignancy tumor is the maxillectomy in combination with radiation therapy and chemorherapy. When tumor invasion is occured to the orbit, orbital exenteration is required. But if the periosteum of the orbital floor is intact, the orbit can be preserved. There are many orbital floor reconstruction materials for the prevention of ptosis of the orbital content. The patients on this paper were diagnosised as squamous cell carcinoma on maxilla, we performed the partial maxillectomy including the orbital floor, and we used temporalis muscle-coronoid process flap for the reconstruction of the orbital floor after partial maxillectomy and obtained good esthetic and functional results, as followed. 1. We obtained sufficient flap width for defect of orbital floor. 2. It permits good blood supply and no necessary other donor site. 3. It gives a solid base for the support the globe and the orbital floor. 4. It gives minimal postoperative morphorogical defect and functional disturbance.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.291-309
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• 2000

Statement of problem. There were several studies on the effects of irradiation to peri-implant bone tissue. However, no clear biological effect of irradiation on peri-implant bone tissue was reported yet. Purpose. This study compared the effect of irradiation on the surrounding tissue of a HA-coated implant fixture with controls. Material and methods. 6 Steri-Oss implants were implanted into the femur of 6 mongrels. The implanted dogs were divided into three groups and received irradiation. After 1 month, 2months and 4 months healing period, the histologic examination and mobility test and digital radiographic imaging analyses were performed to compare the control and experimental group respectively. Results. The irradiated group showed slower healing than control group in light microscopic observations. The mobility test demonstrated significant less number (Periotest) in control group than that of irradiated groups. The digital radiographic imaging analysis showed that the bone density of irradiated group was higher than control group. Conclusion. Generally, control group showed favorable biological response and less mobility than irradiated group. The conflict result of bone density value were measured by the digital radiographic imaging analysis. The digital radiographic imaging analysis needs more research in future.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.6
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• pp.547-550
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• 2001

Acinic cell carcinoma is a rare salivary gland carcinoma, usually being found in the parotid gland and is uncommon in the other major and minor salivary glands. The tumor cells consist of either serous or mucous acinar cells with few ductal or myoepithelial cell elements. The tumor is a low-grade malignancy with slow growth potential. Surgical therapy depends on tumor size and the extent of infiltration into neighboring tissues. Superficial parotidectomy or total parotidectomy is the initial method of therapy in case of acinic cell carcinoma on parotid gland. When regional neck lymph nodes are involved, the operation is combined with a neck dissection, or with radiation therapy. In the short follow up period, acinic cell carcinoma has good prognosis with 5 year survival rate after surgery is over 80%. In the long-term follow-up, however, there is a tendency to increase in recurrence or metastasis. We experienced a case of acinic cell carcinoma of parotid gland in a 57-year-old female, so we report it with literatures review.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.437-445
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• 1995

The purpose of this study was to evaluate the equivalent and effective dose, and estimate radiation risk to the critical organs of head and neck region from the use of adult and child mode in panoramic radiography. The results were as follows. 1. The salivary glands showed the highest equivalent and effective dose in adult and child mode. the equivalent and effective dose in adult mode were 837μSv and 20.93μSv, those in child mode were 462μSv and 11.54μSv, respectively. 2. Total effective doses to the critical head and neck organs were estimated 34.21μSv in adult mode, 20.14μSv in child mode. From these datas, the probabilities of stochastic effect from adult and child mode were 2.50x10/sup -6/ and 1.47x10/sup -6/. 3. The other remainder showed the greatest risk of fatal cancer. The risk estimate were 4.5 and 2.7 fatal malignancies in adult and child mode from million panoramic examinations. The bone marrow and thyroid gland showed about 0.1 fatal cancer in adult and child mode from these examinations.

• Imaging Science in Dentistry
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• v.35 no.2
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• pp.87-90
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• 2005

Purpose : The purpose of this study was to investigate variability of doses with same exposure parameters and evaluate radiographic density according to the variability of doses. Materials and methods Twenty-eight MAX-GLS (Shinhung Co, Seoul, Korea), twenty-one D-60-5 (DongSeo Med, Seoul, Korea), and eleven REX-601 (Yoshida Dental MFG, Tokyo, Japan) dental x-ray machines were selected for this study Surface doses were measured under selected combinations of tube voltage, tube current, exposure time, and constant distance 42 cm from the focal spot to the surface of the Multi-O-meter (Unfors Instruments, Billdal, Sweden). Radiographic densities were measured on the films at maximum, minimum and mean surface doses of each brand of x-ray units. Results With MAX-GLS, the maximum surface doses were thirteen to fourteen times as much as the minimum surface doses. With D-60-S, the maximum surface doses were three to eight times as much as the minimum surface doses. With REX-601, the maximum surface doses were six to ten times as much as the minimum surface doses. The differences in radiographic densities among maximum, mean, and minimum doses were significant (p<0.01). Conclusion : The surface exposure doses of each x-ray machine at the same exposure parameters were different within the same manufacturer's machines.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.2
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• pp.62-66
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• 2014

Osteoradionecrosis is one of the most serious complications of patients receiving radiation therapy. It is characterized by hypovascularity, hypocellularity, and hypoxia-inducing necrosis of bone and soft tissue following delayed healing. In this case, a 72-year-old man was referred to the Department of Oral and Maxillofacial Surgery complaining of trismus following extraction three months before first visit. He had a history of right tonsillectomy, radical neck dissection and radiotherapy performed due to right tonsillar cancer seven years prior. After the diagnosis of osteoradionecrosis on right mandibular body and angle, conservative antibiotic therapy was used first, but an orocutaneous fistula gradually formed, and extensive bony destruction and sequestrum were observed. Sequestrectomy, free particulated iliac bone and umbilical fat pad graft were performed via a submandibular approach under general anesthesia. Preoperative regular exams and delicate wound care led to secondary healing of the wound without vascularized free flap reconstruction.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.461-466
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• 2016

Dental caries is an important dental disease among children and adolescents that can continue for a lifetime. Early detection of dental caries in deciduous dentition is significant because it can influence the permanent teeth. It is also critical to prevent dental caries by performing fluoride treatment and pit-and-fissure sealant for high-risk children. Various methods have been developed for the early detection of dental caries; however, many studies are still seeking to discover more effective methods. In general, visual examination and radiographic images are used, but these techniques have several limitations such as errors and radiation exposure. In this study, clinical application of the newly developed DIAGNOcam caries identification device and its possible applications were examined. DIAGNOcam was applied to diagnose dental caries in the posterior teeth of patients in the Department of Pediatric Dentistry, and it was confirmed that it could be used to detect proximal caries, the margin of restoration, and the extent of dental caries lesions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.505-509
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• 2011

Epithelial-myoepithelial carcinoma (EMC) is a low-grade malignant salivary gland neoplasm that was first described in 1972. EMC occurs in the older age group, there is a female predilection and mainly involves the parotid gland. Most authors recommend superficial parotidectomy as a treatment for low-grade malignant tumor in the superficial lobe of parotid gland. The treatment of epithelial-myoepithelial tumors typically includes surgical excision aimed at achieving a R0 resection. This paper reports a case of EMC of the parotid gland treated only by a conservational surgical excision. The lesion was exposed by the retromandibular approach and detached. After the parotid gland envelop was exposed, the mass was observed and was easy to remove due to capsulation. The preoperative diagnosis was a pleomorphic adenoma on the left parotid gland. The tumor was removed surgically with a conservative extracapsular dissection. The postoperative diagnosis was EMC, so superficial parotidectomy or radiation therapy was considered. Nevertheless, the patient was observed and no additional treatment was attempted because the patient was old and a successfully excision of the tumor had been achieved.