• Imaging Science in Dentistry
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• v.39 no.1
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• pp.41-49
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• 2009

Purpose: To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. Materials and Methods: After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. Results: In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Conclusion: Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.109-118
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• 1991

The author studied the age distribution, etiology, affected site and several radiographic features of periapical granulomas, cysts, and abscesses. The material consisted of 928 films obtained from the patients who were diagnosed and treated under the diagnosis of periapical granulomas, cysts, and abscesses during the past 8 years (1979-1986) at the Infirmary of Dental School, Chosun University. The obtained results were as follows: 1. The order of incidence was as follows: periapical abscess (67.2%), granuloma, and cyst. 2. The age distribution revealed the highest incidence around the age of 30 and relatively higher incidence over the age of 60 in the case of periapical abscess and granuloma. 3. In the frequency of location: Periapical abscesses occured most frequently in the mandibular molars. Granulomas showed relatively higher incidence in maxilla than in mandible. Cysts were most common in the maxillary anterior teeth. 4. The mean diameter of dental granuloma was 5.9㎜, however, all dental granulomas were less than 9.3㎜ in diameter. The mean diameter of periapical cyst was l3.8㎜. 5. Periapical cyst revealed well circumscribed radiolucent lesions and 77.8% of the lesion showed white line. 86.0% of dental granuloma showed well circumscribed border, 54.5% sclerosis on surrounding bone and 38.5% partial white line. Periapical abscess revealed diffuse radiolucent lesion, 89.6% of the lesions had sclerosis on surrounding bone, and 38.0% sinus tract.

• Imaging Science in Dentistry
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• v.47 no.1
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• pp.25-31
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• 2017

Purpose: The aim of this study was to compare the diagnostic accuracy of previously trained endodontists in the detection of artificially created periapical lesions using cone-beam computed tomography (CBCT) and digital periapical radiography (DPR). Materials and Methods: An ex vivo model using dry skulls was used, in which simulated apical lesions were created and then progressively enlarged using #1/2, #2, #4, and #6 round burs. A total of 11 teeth were included in the study, and 110 images were obtained with CBCT and with an intraoral digital periapical radiographic sensor (Instrumentarium dental, Tuusula, Finland) initially and after each bur was used. Specificity and sensitivity were calculated. All images were evaluated by 10 previously trained, certified endodontists. Agreement was calculated using the kappa coefficient. The accuracy of each method in detecting apical lesions was calculated using the chisquare test. Results: The kappa coefficient between examiners showed low agreement (range, 0.17-0.64). No statistical difference was found between CBCT and DPR in teeth without apical lesions (P=.15). The accuracy for CBCT was significantly higher than for DPR in all corresponding simulated lesions(P<.001). The correct diagnostic rate for CBCT ranged between 56.9% and 73.6%. The greatest difference between CBCT and DPR was seen in the maxillary teeth (CBCT, 71.4%; DPR, 28.6%; P<.01) and multi-rooted teeth (CBCT, 83.3%; DPR, 33.3%; P<.01). Conclusion: CBCT allowed higher accuracy than DPR in detecting simulated lesions for all simulated lesions tested. Endodontists need to be properly trained in interpreting CBCT scans to achieve higher diagnostic accuracy.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.277-287
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• 1990

The purpose of this study was to estimate the diagnostic availability of the common periapical lesions by using computer. The author used a domestic personal computer and rearranged the applied program appropriately with RF (Rapid File), a program to answer the purpose of this study, and then input the consequence made out through collection, analysis and classification of the clinical and radiological features about the common periapical lesions as a basic data. The 256 cases (Cyst 91, Periapical granuloma 74, Periapical abscess 91) were obtained from the chart recordings and radiographs of the patients diagnosed or treated under the common periapical lesions during the past 8 years (1983-1990) at the infirmary of Dental School, Chosun University. Next, the clinical and radiographic features of the 256 cases were applied to RF program for diagnosis, and the diagnosis by using computer was compared with the hidden final diagnosis by clinical and histopathological examination. The obtained results were as follows: 1. In cases of the cyst, diagnosis through the computer program was shown rather lower accuracy (80.22%) as compared with accuracy (90.1 %) by the radiologists. In cases of the granuloma, diagnosis through the computer program was shown rather higher accuracy (75.7%) as compared with the accuracy (70.3%) by the radiologists. 2. In cases of periapical abscess, the diagnostic accuracy was shown 88% in both diagnoses. 4. The average diagnostic accuracy of 256 cases through the computer program was shown rather lower accuracy (81.2%) as compared with the accuracy (82.8%) by the radiologists. 5. The applied basic data for radiographic diagnosis of common periapical lesions by using computer was estimated to be available.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.463-468
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• 1993

The purpose of this study was to evaluate the effects of Vitapex on the periapical lesions. Thirteen single-rooted teeth from ten patients who visited the SNU hospital were endodontically treated with Vitapex and Gutta percha cone, and radiographically and clinically evaluated for a period of 1 to 6 months. The results were as follows : 1. The loss of clinical symtoms was observed in all 13 teeth. 2. The reduction of size of periapical lesions in radiographs was observed in 10 teeth. The periapical lesions of remaining 3 teeth also look better in the radiographs. 3. All 13 teeth showed the reduction of radiolucency. 4. The gradual resorption of Vitapex over the root apex was observed.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.279-290
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• 1994

The purpose of this study was to compare the diagnostic accuracy of periapical radiographs and their digitized images for the detection of simulated interproximal carious lesions. A total of 240 interproximal surfaces was used in this study. The case sample was composed of 80 anterior teeth, 80 bicuspids and 80 molars which were prepared in order to distribute the surfaces from carious free to those containing simulated carious lesions of varying depths (0.5㎜, 0.8㎜, and 1.2㎜). The periapical radiographs were taken by paralleling technique and film used was Kodak Ektaspeed(E group). All radiographs were evaluated by five dentist to recognize the true status of simulated carious lesion. They were asked to give a score of 0, 1, 2, or 3. Digitized images were obtained using a commercial video processor(FOTOVIX Ⅱ- XS). And the computer system was 486 DX PC with PC Vision and frame grabber. The 17' display monitor had a resolution of 1280×1024 pixels(0.26㎜ dot pitch). But the one frame of the intraoral radiograph has a resolution of 700×480 pixels and each pixel has a grey level value of 256. All the radiographs and digital images were viewed under uniform subdued lighting in the same reading room. After a week the second interpretation was performed in the same condition. The detection of lesions on the monitor was compared with the finding of simulated interproximal carious lesions on the film images. The results were as follows: 1. When the scoring criteria was dichotomous ; lesion present and not present 1) The overall sensitivity, specificity and diagnostic accuracy of periapical radiographs and their digital images showed no statistically significant difference. 2) The sensitivity and specificity according to the region of teeth and the grade of lesions showed no statistically significant difference between periapical radiographs and their digital images. 2. When estimate the grade of lesions ; score 0, 1, 2, 3 1) The overall diagnostic accuracy was 53.3% on the intraoral films and 52.9% on digital images. There was no significant difference. 2) The diagnostic accuracy according to the region of teeth showed no statistically significant difference between periapical radiographs and their digital images. 3. The degree of agreement and reliability 1) Using gamma value to show the degree of agreement, there was similarity between periapical films and digital images. 2) The reliability of each twice interpretation of periapical films and digital images showed no statistically significant difference. In all cases P value was greater than 0.05, showing that both techniques can be used to detect the incipient and moderate interproximal carious lesions with similar accuracy.

• The Journal of the Korean dental association
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• v.50 no.4
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• pp.196-202
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• 2012

Radiographic diagnosis of periapical lesions is based on many factors, including anatomical limitations such as thickness of the cortical bone; positioning of the apical abscess to the cortical bone; and is complicated by proximity to other anatomical structures and neighboring teeth. With conventional radiographs, these structures are often superimposed. Dental CBCT with its associated geometric accuracy offers accurate visualizations of the complex relationships and boundaries between teeth, related anatomical features, and their associated pathology. Its images also provide us internal tooth morphology, periodontal ligament space, the presence or absence of periapicl lesions in association wi th critical anatomical structures and maxillary sinus involement. Using 3 D imaging makes it easier for clinicians to detect, diagnosis, and develop highly effective treatment plans. Now, 4 cases of periapical and periodontal pathosis with CBCT images are to be presented including periapical abscess, furcation involvement, periapical pathosis involving maxillary sinus, and osteomyelitis. CBCT analyze specific area of interest and provides the highly detailed anatomical information. It also facilitates earlier and more accurate diagnosis, and treatment planning decisions and more predictable outcome.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.19 no.1
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• pp.55-64
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• 1989

The purpose of this study was to clarify that scintigram was a more effective method than radiogram in the early detection of periapical lesion. Periapical lesions were produced artificially by the opening of the pulp chambers of the lower right 3rd and 4th premolars in 6 dogs. The serial bone scintigrams using 99m-Tc-MDP and periapical radiograms were taken weekly. The uptake counts of the 99-Tc-MDP in the experimental side were compared with those in the control side. The periapical radiograms were interpreted with the joint evaluation by three dental radiologists. The following results were obtained; 1. The radioactivity in the experimental side was increased at the Ist week except one animal in which the radioactivity was increased at the 2nd week. 2. It was observed that increasing amount of radioactivity per week was prominent from the 1st day of experiment to the Ist week, and the 3rd week to the 4th week. 3. The radiographic evidence of the periapical lesions was observed at the 3rd week and became more apparent at the 4th week. 4. Histologically, proliferation of blood vessels and infiltration of chronic inflammatory cells were observed at the 1st week and osteoblasts were found after the 3rd week.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.19-30
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• 1982

This study was performed to elucidate the histopathologic distribution of immunoglobulins, particularly IgA, IgG and IgM in the periapical lesions, including 22 periapical granulomas and 18 periapical cysts. The immunoperoxidase staining method using reagents manufactured and supplied by Danish DAKO company was employed in this study. In comparison with the immunohistochemical methods, this method was proved to be reliable and convinient one to detect immunoglobulins in the tissue. The following results were obtained: 1. In the 22 periapical granulomas, IgG was found in 20 cases (90.9%), IgA in 16 cases (72.7%) and IgM in 19 cases (86.3%). 2. In the 18 periapical cysts, IgG was found in 16 cases (88.8%), IgA in 13 cases (72.2%) and IgM in 15 cases (83.3%). 3. The distribution of immunoglobulins both in periapical granulomas and periapical cysts was in great diversity according to the lesion and area. 4. More immunoglobulins were found in the exudative area with moderate or severe infiltrations of plasma cells and lymphocytes and less concentration of immunoglobulins were seen in the area with leukocytes infiltration and tissue destruction. 5. The area with collagenolysis and reparative activity contained more abundant IgG and IgM than IgA in periapical granulomas. 6. IgG was dominant in the granulomatous connective tissue and immunoglobulins were not easily found in the fibrous capsule in periapical cysts.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.200-211
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• 1999

The periapical response to injury is a complex interaction of inflammatory, immune, neural, vascular and synthetic activity. TGF-${\beta}$ is a potent modulator of proliferation and differentiation in various tissue, seems to lead to an increase in extracellular matrix. MMP are a family of proteolytic enzyme that mediate the degradation of extracellular matric macromolecules, but little is known about theirs possible role in periapical tissue. The purpose of this study is to investigate the differential expression of TGF-${\beta}$ and MMP-1 in tooth follicle, periapical abscess, granuloma and cyst. The expression of TGF-${\beta}$ and MMP-1 in Periapical tissue was evaluated by immunohistochemical staining and Western blot analysis. Correlationship among the periapical lesions were stastically analyzed. The degree of MMP-1 expression in periapical abscess was higher than in any other periapical lesion, and stastically significant. TGF-${\beta}$ expression is the prominent in granuloma than other periapical lesion, which was stastically significant. The increased expression of MMP and TGF-${\beta}$ was not co-related with inflammatory cell infiltration degree of the periapical cyst. The expression degree of MMP and TGF-${\beta}$ was not co-related with periapical abscess and cyst, but expression of MMP and TGF-${\beta}$ showed strong positive co-relationship with periapical granuloma, which was stastically significant. TGF-${\beta}$ expression by Western blot analysis was prominent in granuloma and cyst, and similar to the results by imunohistochemistry. MMP-1 expression is less than TGF-${\beta}$, but there is not extreme difference between periapical lesion. These results suggest that TGF-${\beta}$ and MMP may be involved in tissue remodeling and has an important role in progress or mediation of periapical lesions.