하악에 발생한 45예, 상악에 발생한 1예로 총 46예의 법랑모세포종이 연구되었다 환자의 평균연령은 34세였으며 성별에 따른 차이는 없었다. 가장 흔한 징후는 악골 또는 안면의 종창이었다. 소구치-대구치-하악지 부위를 침범한 예가 20예(43.5％)였다. 다방성 병소가 26예(56.5％)에서 발견되었다. 방사선학적 형태는 환자의 연령이나 조직학적 형태와는 상관관계가 없었다. 단방형 형태는 주로 젊은 환자에서 발견되었으며 10대에 호발하는 상관관계를 나타내었다(P<0.05). 근치 또는 보존적 수술로 치료를 받은 분석 가능한 18명의 환자에서 재발율은 33.3％를 나타내었다. 다방성 형태(36.4％)학적 행태를 명확하게 예측하기 위해서는 좀 더 상세한 임상 및 방사선학적 변수가 첨가되어야 할 것으로 사료되었다.

The purpose of this study was to obtain some informations for the radiographic differential diagnosis between odontogenic keratocyst and unicystic ameloblastoma in the mandible. The author compared and analysed the clinico-radiographic features of 48 cases of odontogenic keratocyst and 32 cases of unicystic ameloblastoma. The obtained results were as follows : 1. Odontogenic keratocyst and unicystic ameloblastoma occurred the most frequently in the 2nd and 3rd decades, and both lesions occurred with slight predilection in males. The most frequent lesional site was molar area in odontogenic keratocyst(50.0％) and mandibular angle and ramus area in unicystic amelobla-stoma(71.9％). 2. Cortical thinning and expansion were observed with similar occurrences in odontogenic keratocyst(77.l％) and in unicystic ameloblastoma(72.9％). 3. Typical undulating lesional border was observed more frequently in odontogenic keratocyst(79.2％) than in unicystic ameloblastoma(46.9％). 4. Well-defined lesional outline occurred more frequently in odontogenic keratocyst(97.9％) than in unicystic ameloblastoma(53.1％). 5. Root resorption of adjacent teeth occurred more frequently in unicystic ameloblastoma(65.2％) than in odontogenic keratocyst(18.8％) respectively, but loss of lamina dura was frequently observed in odontogenic keratocyst(79.2％). And tooth displacement occurred more frequently in odontogenic keratocyst(50.0％) than in unicystic ameloblastoma(17.4％). 6. Displacement of mandibular canal occurred more frequently in odontogenic keratocyst(75.0％) than in unicystic ameloblastoma(61.5％). 7. Inhomogeneous lesional radiolucency occurred more frequently in unicystic ameloblastoma(53.l％) than in odontogenic keratocyst(39.6％).

The organ or tissue doses were determined with head and neck phantom measurement for multiple axial scans (36 slices), multiple coronal scans (13 slices), 3 types of single axial scans(orbit, maxillary sinus and mandibular canal) and single coronal scan (maxillary sinus). For each scan sequence 30 TLDs were placed in selected sites(16 internal sites and 14 external sites) in a tissue-equivalent phantom. The exposure was made at 120kVp, 500mAs with 5 mm slice width. The results were as follows : 1. In multiple axial scans, the greatest effective dose recorded was that delivered to the thyroid glands(2.77 mSv) and the least was that received by the skin(0.05 mSv). From these data, stochastic effects were 202.2x10/sup -6/ and 3.7×10/sup -6/, respectively. 2. In multiple coronal scans, the greatest effective dose recorded was that delivered to the salivary glands(0.58 mSv) and the least was that received by the skin(0.01 mSv). From these data, stochastic effects were 42.2×10/sup -6/ and 0.7×10/sup -6/, repectively. 3. Among single axial scans, the greatest effective dose recorded was that delivered to the salivary gland(0.38 mSv) in maxillary sinus scan. From this data, stochastic effect was 27.7×10/sup -6/. 4. In single coronal scan, the greatest effective dose recorded was that delivered to the salivary gland(0.01 mSv). From this data, stochastic effect was 1.0×10/sup -6/. 5. The equivalent dose measured that delivered to the lens of the eyes was 69.64 mSv in multiple axial scan, 39.32 mSv in multiple coronal scan and 36.77 mSv in single axial scan(orbit).

This study was performed to determine the each location of lesions in the maxillary sinus and to evaluate the relationship between the floor of the antrum and the apical regions of teeth by the comparison of the panoramic view and panoramic sinus view. For this study, experimentally with two dry skulls, jelly balls of 8mm and 15mm in diameter containing a short wire for the radiopacity similar to the cyst and clinically 5 patients having mucosal cyst in the antrum and 10 patients having periapical lesion of molar were used. The experimental cystic lesions were simulated with jelly ball being attached in turn to each wall of the antrum. The radiolucent periapical lesions of upper molars were formed by using round bur and the radiopaque periapical lesions were simulated by filling the former lesions with lead foil. Each panoramic view and each panoramic sinus view of the experimental lesions and patients were obtained by using panoramic machine and analyzed. The obtained results were as follows : 1. On the panoramic sinus view, the innominate line was approximately coincided with the most lateral portion of the antrum and the posterior wall appeared as the narrow area at the mesial side of the innominate line. The anterior wall occupied totally the mesial side of the innominate line, and the medial wall occupied the mesial half of the antrum. 2. In all cases of experimental cystic lesion attached to each wall of the antrum, the location of each lesion was able to be determined by applying Tube shift technic. 3. The palatal root and mesiobuccal root of the molar appeared as being transposed each other mesiolaterally on the panoramic and panoramic sinus views. 4. The panoramic sinus view was superior to the panoramic view in revealing the relationship between the floor of the antrum and the periapical lesion.

The purpose of this investigation was to compare the direct digital radiographic system with film-based digital imaging system using Ektaspeed and Ektaspeed Plus film with respect to image characteristics and detectability and evaluate the sensor noise with the use of subtraction method. Direct digital radiographic system which used was Sens-A-Ray system(Regam Medical Systems, Sundsvall, Sweden) and film-based digital imaging system was composed of Macintosh II ci computer, high resolution Sony XC-77 CCD camera and intraoral x-ray film(Kodak Ektaspeed film, Kodak Ektaspeed Plus film). Images were taken by using CCD sensor of Sens-A-Ray system, Ektaspeed film and Ektaspeed Plus film with variable exposure time(0.06s, 0.1s, 0.16s, 0.2s, 0.3s, 0.4s, 0.5s, 0.6s, O.8s, LOs), 5 times at each exposure time. And then ektaspeed films and ektaspeed plus films were digitized using CCD camera. Image groups were divided into 3 groups; Sens-A-Ray group(direct digital radiographic system), Ektaspeed group and Ektaspeed Plus group (film-based digital imaging system) They were assessed by the following three aspects; image density, image contrast and detectability and sensor noise of Sens-A-Ray system was also evaluated. The results were as follow : 1. S group showed higher density than E , EP group except at the low exposure time(p<0.01). 2. S group showed higher contrast than E,EP group except at the high exposure time(p<0.01). 3. All groups showed good detectability at the each proper exposure time. Lowest exposure time which shows maximum detectability in S,EP group(0.5s) was lower than that in E group(0.6s). 4. Sensor noise of Sens-A-Ray system generally increased according to exposure time. On the basis of the above results, it was considered that Sens-A-Ray system could show higher speed, higher contrast than Ektaspeed, Ektaspeed Plus film except at too high and low exposure time and the same detectability as the conventional intraoral film.

The purpose of this study was to investigate the early irradiation changes on the ultrastructure of the capillary endothelial cell in the rat submandibular glands. For the study, 110 Sprague-Dawley strain male rats were singly irradiated to their neck regions with the doses of 2Gy, 5Gy, and 10Gy by 6MV X -irradiation, and sacrificed on the 3 hours, 6 hours, 12 hours, 1 day, 3 days, 7 days, and 14 days after irradiation. The authors observed the histologic and ultrastructural changes of the capillary endothelial cell using the light and electron microscopes. The results were as follows: I. In the light microscopic examination, the capillary dilation was observed on the 6 hours group and the capillary density was slightly increased on the 12 hours group after 2Gy and 5Gy irradiation. And luminal size and capillary density were decreased on the 3 days and the 7 days groups after irradiation, after then, they were recovered. But capillary density was still decreased on the 14 days group after 10Gy irradiation. 2. In the transmission electron microscopic examination, the mild proliferation of cytoplasmic process of the endothelial cell and reduction in luminal size were observed on the 3 hours group after irradiation. After then, endothelial swelling, marked proliferation of cytoplasmic process, thickened basal lamina, and numerous pinocytotic vesicles were observed after the 1 day group after irradiation. Thickened basal lamina and numerous pinocytotic vesicles were still observed until the 7 days group after irradiation. These changes were recovered to normal on the 14 days group after 2Gy and 5Gy irradiation, but not after 10Gy irradiation. 3. In the scanning electron microscopic examination, the dilation of conduits and constriction, and meandering were observed on the 1 day group after 10Gy irradiation. These changes were observed with increased coarseness of the surface of the vascular resin casting on the 3 days group after irradiation. 4. From the above results, endothelial swelling, proliferation of cytoplasmic process, and thickening of the basal lamina appeared before the 6 hours group after irradiation. And these changes may also induce the increase of the capillary number and luminal size, after then, capillary permeability was increased via the increase of the number of pinocytotic vesicles. The changes were observed earlier and more apparent with the increase of the irradiation doses under the dose of 10Gy irradiation.

The radiographic findings of soft tissue calcification in the oral and maxillofacial area was analysed using panoramic, skull P-A and intraoral radiographs in 250 patients. The obtained results were as follows ; 1. Salivary stone had the highest rate of occurrence at 46％(116 cases), followed by lymph node calcification(97 cases), phleholith(21 cases), multiple miliary osteoma(15 cases), antrolith(l case), vessel calcification(l case) and cysticercosis(1 case). 2. The prevalence of salivary stone was slightly higher in females, on the right side and in the middle-aged group and was especially higher in the submandibular gland(83％). The majority of them were round-shaped, homogeneously radiopaque and associated with sialodochitis. 3. The prevalence of lymph node calcification was higher in the female and old-aged group. Irregular shape and radiopaque bodies were seen in the cervical area, bilaterally. 4. The prevalence of phlebolith was slightly higher in the male, and the third decade group. The radiopaque bodies were 4-8 mm in diameter and had laminated appearance. 5. The prevalence of multiple miliary osteoma was higher in old-aged females. The numerous doughnut-shaped radiopaque bodies, sized 2-4 mm in diameter, were seen bilaterally in the cheek and were usually associated with the edentulous ridge.

The aim of this study was to evaluate clinician's detectability in the diagnosis of bone loss in the bifurcation of mandibular molars on periapical radiographs and Digital images. Periapical radiographs were obtained of the first molars in 2 dry mandibles after preparation of bony defects corresponding to degree I, degree II and degree III buccal furcation involvements. The radiographs were randomly presented to 39 clinicians(1 oral radiologist, 4 periodontist, 34 general dentists) who were asked to determine the presence or absence of bone loss. Periapical films were digitized with a TV camera. Digital images were assessed by 15 clinicians(1 oral radiologist, 4 periodontist, 10 general dentists). I. the overall diagnostic accuracy of Digital images for detection of bone loss in the bifurcation of mandibular molars was higher than that of the periapical radiographs. 2. the largest increase in diagnostic accuracy was found between lesion grade II and III on both radiographs and Digital images(P<0.05). 3. there was no significant difference between the standard state and the controlled contrast state on Digital images. 4. the overall diagnostic accuracy of I radiologist and 4 periodontists was better than that of the general dentists for detecting bifurcation involvements.

The purpose of this study was to investigate the changes of the shape of the panoramic innominate line and also to examine the relation of the panoramic innominate line to maxillary posterior wall according to positional changes in panoramic radiographs of the patients who had no pathoses in the maxillary sinus and adjacent bony structures. Thus these panoramic radiographs were obtained and evaluated in standard, forward 10mm, backward 10mm, chin down 10°, and chin up 10° positions. And the following results were obtained : 1. Panoramic innominate lines were not changed in shape according to various positional changes in panoramic radiography. 2. The panoramic innominate line was observed to be more clear images and decreased distance to the posterior wall of maxillary sinus at forward 10mm and chin down 10° positions. And the panoramic innominate line was observed more blurred images and increased distance to the posterior wall of maxillary sinus at backward 10mm and chin up 10° positions.

Forty-four cases of developmental salivary gland defects in 43 patients were analysed radiologically. The obtained results were as follows ; 1. It occurred more frequently in males(86 ％) than in females(14 ％). The age distribution of patients ranged from 20 to 74 years with the average being 52.7 years. 2. All but one were located between the angle of the mandible and the molar tooth. Only one patient showed bilateral occurrence. 3. The shape of the defect was ovoid(15 cases), round(10 cases), or half-ovoid(5 cases) 4. Their size ranged from 5 x 6 mm to 16 x 30 mm with the average around 9 x 14 mm. 5. Twenty-eight cases appeared to be surrounded partially(1/3 - 2/3) by a hyperostotic border. The thickness of the hyperostotic border varied ; thick(14 cases), moderate(l1 cases), thin(9 cases), or mixed(6 cases) 6. Thirteen cases were in contact with the superior border of the mandibular inferior cortex, 11 cases partially eroded the cortical plate, and 7 cases showed discontinuity of the mandibular inferior cortex. 7. Twenty-three cases were located below the mandibular canal, 13 cases overlapped the mandibular canal, and 2 cases showed slight deviation of the mandibular canal.

A number of panoramic radiographic images of the condylar head taken at various horizontal angulations were compared. A small artificial osteophyte was attached to the eight different portions of the condylar head and a small hole was created in four different portions of the condylar head. Three oral and maxillofacial radiologists evaluated the panoramic condylar images. The results were as follows : 1. Osteophytes in the superomedial, anterocentral and anterolateral portions could be detected easily, but those in the lateral, superolateral and medial portions were very hard to identify. 2. The greater the condylar horizontal angle, the easier it was to detect an osteophyte. But there was no statistically significant difference except between 0 and 40 degrees of horizontal angulation. 3. Holes in the anterocentral and superocentral portions could be detected easily, but those in the lateral and medial portions were very hard to identify. There were no differences between the various condylar horizontal angles.

The arteriovenous malformation, an uncommon lesion, is a direct communication between an artery and a vein that bypasses the intervening capillary bed. The authors experienced two cases of arteriovenous malformation in 17-year-old and 18-year-old female patients who had suffered from mandibular pain and gingival bleeding. As a result of careful analysis of clinical and angiographic radiological examinations, we diagnosed them as arteriovenous malformations, and the results were as follows : 1. Main clinical symptoms were dull pain and gingival bleeding on the mandibular body area, and reddness, pain on palpation, thrill and palpitation in the lesional sites were also observed. 2. Radiographically, well-defined radiolucent lesions with multiple osteolytic defects were observed. In radio-nuclide scan, increased uptakes of radioisotope were observed in the lesional sites. 3. Increased venous shunt supplied by the facial, lingual and inferior alveolar arteries was observed in angiography. After embolotherapy was performed, no recurrence was reported during 3 to 6 months follow up.

종양유발성 골연화증은 종양에 의하여 생성된 활동성 펩티드호르몬과 유사한 물질이 골이나 위장관에 작용하여 칼슘대사와 인대사의 변화를 일으키거나, 정상적인 비타민 D대사에 장애를 일으킴으로써 2차적으로 발생되는 대사성 질환으로 알려져 있다. 이의 발생빈도는 매우 낮으며, 임상적으로는 체중과 신장의 감소, 전신적인 골격의 동통 및 근무력증과 병적 골절이 동반되어 나타난다. 방사선사진에서는 골소주의 전반적인 소실, 피질골의 비박, 위골절, 치조백선의 소실 등을 보이고, 실험실 소견에서는 혈청인의 농도와 신세뇨관에서 인의 재흡수율의 감소 및 혈청 알칼리성 인산화효소 농도의 상승이 관찰된다. 본질환은 종양이 제거되면 별도의 부가적인 치료 없이도 임상적, 방사선학적 소견 및 실험실 소견의 뚜렷한 개선을 보이므로 이의 치료에 있어서 정확한 진단이 매우 중요하다. 저자들은 전신적인 동통과 근무력증을 주소로 내원한 환자들에게서 발생된 종양유발성 골연화증 3예를 경험하였기에 문헌고찰과 함께 이를 보고하는 바이다.

Desmoplastic variant of ameloblastoma is a new and unusual variant of ameloblastoma with extensive stromal desmoplastic proliferation. The authors experienced a case of desmoplastic variant of ameloblastoma with moderate-defined radiolucency on the right maxillary anterior area in 62-year-old female. As a result of careful analysis of clinical, radiological, histopathological examinations, we diagnosed it as desmoplastic variant of ameloblastoma, and the following results were obtained : 1. Main clinical symptoms were nontender bony swelling with normal intact overlying mucosa on the right maxillary anterior area. 2. Radiographically, moderate-defined, multilocular radiolucency on the right maxillary anterior area were shown, and severe cortical bony thinning and expansion to labial and palatal sides were also observed. And this lesion was shown to be extended to the right nasal cavity. 3. Histopathologically, follicle-like epithelial islands with densely abundant collagenous stroma were morphologically compressed.

Few cases of florid osseous dysplasia has been described as a condition that characteristically affects the jaws. It usually manifests as multiple radiopaque masses distributed throughout the jaws. Confusion exists about the relationship of florid osseous dysplasia, gigantiform cementoma, chronic sclersing osteomyelitis, sclerosing osteitis or multiple enostosis. Authors experienced a case of florid osseous dysplasia of the jaws in 52-year-old female on the basis of clinical, radiographic and histopathologic findings. The characteristic features are as follows : 1. In clinical examination, there was no clinical sign and symptoms except extracted area. And there was no facial asymmetry. 2. Radiograms show round or lobular dense radiopaque masses surrounded by radiolucent bands in lower molar teeth area bilaterally. And slight increased radiopacities in maxillary molar teeth area bilaterally. There was no expansion or thinning of buccal and lingual cortical bones. There is no displacement or resorption of involved teeth. In right side of mandible, mandibular canal is displaced inferiorly due to mass. 3. Photomicrograms show densely mineralized sclerotic acellular masses with empty lacunae. Pattern is suggestive of cementum, although it could be considered sclerotic bone. In the periphery, lesion consisting of moderately cellular fibrous tissue in which globular calcified products are deposited.