• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.19-25
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• 2011

Objectives: The purpose of this retrospective study was to evaluate the success rate of intentionally replanted mandibular second molar with C-shaped canal configurations and to access the impact of preoperative periapical lesion on the success of intentional replantation procedure. Materials and Methods: This retrospective chart review study evaluated 52 intentionally replanted mandibular second molar teeth treated at Seoul National University Dental Hospital Department of Conservative Dentistry from January 2005 to December 2007. Seventeen teeth were lost for the follow-up, and another 6 teeth did not meet inclusion criteria of C-shaped root canal configurations. Healing outcome such as success, uncertain healing, and failure after follow-up was evaluated by clinical criteria and radiographs. Results: The overall success rate was 72.4% for the 29 intentionally replanted C-shaped mandibular second molars. The success rate of replanted teeth with preoperative periapical lesions was similar to that of replanted teeth which have no periapical lesions. Conclusions: Therefore, root canal treatment failure on C-shaped mandibular second molar can be predictably treated by intentional replantation regardless of the presence of periapical lesion.

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.31-35
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• 2014

Purpose: This study was performed to investigate the effect of image enhancement of periapical radiographs according to the diagnostic task. Materials and Methods: Eighty digital intraoral radiographs were obtained from patients and classified into four groups according to the diagnostic tasks of dental caries, periodontal diseases, periapical lesions, and endodontic files. All images were enhanced differently by using five processing techniques. Three radiologists blindly compared the subjective image quality of the original images and the processed images using a 5-point scale. Results: There were significant differences between the image quality of the processed images and that of the original images (P< 0.01) in all the diagnostic task groups. Processing techniques showed significantly different efficacy according to the diagnostic task (P< 0.01). Conclusion: Image enhancement affects the image quality differently depending on the diagnostic task. And the use of optimal parameters is important for each diagnostic task.

• Restorative Dentistry and Endodontics
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• v.41 no.2
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• pp.137-142
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• 2016

We report a case of large radicular cyst progression related to endodontic origin to emphasize proper intervention and follow-up for endodontic pathosis. A 25 yr old man presented with an endodontically treated molar with radiolucency. He denied any intervention because of a lack of discomfort. Five years later, the patient returned. The previous periapical lesion had drastically enlarged and involved two adjacent teeth. Cystic lesion removal and apicoectomy were performed on the tooth. Histopathological analysis revealed that the lesion was an inflammatory radicular cyst. The patient did not report any discomfort except for moderate swelling 3 days after the surgical procedure. Although the patient had been asymptomatic, close follow-ups are critical to determine if any periapical lesions persist after root canal treatment.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.271-278
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• 1987

The purpose of the present study was to investigate associations between periapical and bitewing techniques by assessing the crestal alveolar bone. This article also reports the ability of these two techniques to correctly detect evidence of interproximal dental caries, and comparison between the interproximal overlapping of teeth. Bitewing and periapical radiographs were used from posterior quardants of 243 dental students in Seoul National University. The distance from cemento-enamel junction to the alveolar crest (CEJ-AC) was measured for each proximal surface from the distal of cuspid to the distal of second molar. Data were arranged according to the proximal surface examined, and bitewing and periapical measurements were compared using paired tests. The obtained results were as follows: 1. In maxilla, a significant t ratio with a P value of 0.05 or less reached for 100% and in mandible, reached for 94%. 2. The anatomic limitations imposed on periapical radiographic technique, most often result in somewhat foreshortened radiographic images. This situation would tend to be accentuated by the anatomical restrictions of the hard palate. 3. Consequently, since the significant differences frequently exist between measurements obtained from bitewing and periapical techniques, it is important to define which technique is used. 4. The number of the interproximal overlapping was the largest medial side of the maxillary second molar, while the smallest at the distal side of the mandibular second premolar. And the overall number of the interproximal overlapping was more (538) in the periapical technique than in the bitewing technique (372). 5. The interproximal dental carious lesions were detected more (74) on the bitewing films than on the periapical ones (23). The fact was resulted from the small number of interproximal overlapping and relative easi- ness of obtaining horizontal angulation in taking the bitewing radiographs.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.1-12
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• 1999

Bacterial infection of the pulp results in the development of a periapical lesion with the concomitant resorption of periapical bone. The cytokines are believed to play an important role in this matter. The purpose of this study was to find the relationship among the presence of black pigmented bacteria, the levels of cytokines(TNF-${\alpha}$, -${\beta}$, IL-$1{\beta}$, and TGF-${\beta}1$), and the amount of bone resorption in periapical and pulpal diseases. For the purpose, the patients were grouped into chronic apical pathosis, acute apical pathosis, acute pulpitis, and a healthy control group. Root canal samples were taken from periapical tissue exudates during routine endodontic treatment, and the venous blood was taken from each patients. The samples were processed to measure local and systemic levels of the cytokines using enzyme linked immunosorbent assay(ELISA). Bacterial content of Porphyromonas endodontalis, Porphyromonas gingivalis, and Prevotella nigrescens were measured by indirect immunofluorescence method and the size of the periapical lesions were measured from the radiographs. The following results were obtained: 1. The levels of bone resorptive cytokines(TNF-${\alpha}$, TNF-${\beta}$, and IL-$1{\beta}$) in exudates from acute and chronic apical pathoses were significantly higher than those from acute pulpitis and the normal pulps(p<0.05). 2. IL-$1{\beta}$ were the highest among the bone resorptive cytokines in apical pathoses. However, no statistical difference between acute and chronic lesions were found(p>0.05). 3. The levels of TGF-${\beta}1$ in exudates from acute pulpitis and chronic apical pathoses were significantly higher than those from acute apical pathoses and the normal pulps(p<0.05). However, there were no significant correlations among the levels of bone resorptive cytokines. 4. The levels of TNF-${\beta}$ in serum were significantly higher than those from the exudates while serum TGF-${\beta}1$ concentrations were significantly lower(p<0.05). 5. Exudates from the canals in which the P. nigrescens were detected showed significantly higher levels of IL-$1{\beta}$ than those from the canals without the microorganism(p<0.05). 6. There were no significant correlations among the levels of the cytokines, the amount of bone destruction, and the presence of acute and chronic symptoms(p>0.05).

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.309-325
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• 1997

In order to set the lasing variables and evaluate, clinically, the therapeutic effects of a pulsed Nd:YAG laser on oral lesion, the author applied the laser energy from a fiberoptic delivered, free running, pulsed Nd:YAG laser (wavelength 1064nm, Pulse duration 120$\mu$sec, fiber diameter 200$\mu$m/320$\mu$m) to 22 cases of oral soft tissue lesions and 6 cases of oral hard tissue lesions. The obtained results were as follows : 1. The effective excision with contact mode and the effective hemostasis of accompanied bleeding with noncontact mode were occurred by lasing on oral soft tissue lesions with fiber diameter of 320$\mu$m under the variables of 2.0~4.0W and 20~50Hz which were controlled into high power/low pulses for excision, low power/high pulses for hemostasis, low power in granulation tissue and high power in fibrous tissue according to therapeutic goals and tissue conditions. 2. About 50% of decreasing effect on hypersensitivity was occurred by lasing with non-contact and contact mode on cervical abrasion which caused dentinal hypersensitivity with fiber diameter of 320$\mu$m under the variables of 0.7 - 1.0W and 10Hz which were applied 2~3 times with 1 week interval. 3. The effective sterilization of infected root canal and lesion of periapical abscess was occurred by lasing with contact and spiral modes on wall of root canal and periapical abscess with fiber diameter of 200$\mu$m of which the tip was placed about 1mm shorter than root canal length under the variables of 1.OW and 10Hz.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.83-89
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• 1991

This study was performed to simulate various sizes of periapical lesions and condensing osteitis in bone and to clarify that condensing osteitis would give a greater radiographic contrast because of the more radiopacity immediately adjacent to the lesion and what the lamina dura on radiogram is in bone. For this study, two dry and wet human adult mandible and a cadaver were used. Each mandible was sectioned longitudinally to split lingual and buccal cortical plates to gain better access to the apex of tooth. Lesions were gradually enlarged and bordered with tooth ash that burned out at 950℃ for the reproduction of condensing osteitis in sequence. The serial radiograms were taken under the constantly maintained condition and compared with the actual lesions.

• Imaging Science in Dentistry
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• v.35 no.4
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• pp.199-202
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• 2005

Purpose : To report the incidence of radiological findings from screening panoramic radiographs and verify the validity of the panoramic radiography for screening purposes. Materials and Methods : Six thousand one hundred and sixty panoramic radiographs taken from the patients visiting the Health Promotion Center of CNUH were selected for this retrospective study. Panoramic radiographs were examined into the following pathologic conditions : the presence of periodontal bone loss, dental caries, periapical radiolucencies, retained roots, impacted supernumerary teeth, impacted third molars, odontoma, cystic lesions other than radicular cyst, sialoliths, and mixed radiolucent-radiopaque lesions. Number of pathologic conditions and Prevalence values were recorded. Results: The prevalences of pathologic conditions were $72.9\%$ of periodontal bone loss, $32.2\%$ of dental caries, $11.9\%$ of periapical radiolucencies, $10.8\%$ of retained roots, $0.4\%$ of root fracture, $1.0\%$ of impacted supernumerary teeth, $1.0\%$ of impacted third molars, $0.06\%$ of odontoma, $0.08\%$ of cystic lesion other than radicular cyst, $0.2\%$ of prolonged retention of deciduous tooth, $0.1\%$ of sialolith, and $0.04\%$ of mixed radiopaque and radiolucent lesion. Conclusion : Although the panoramic radiograph should not be used to replace intraoral radiographic and clinical examinations, this study showed that many dental pathologic conditions could be detected on panoramic radiographs. The panoramic radiograph might serve as a diagnostic aid in dental health evaluation programs.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.276-283
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• 2011

Recently, undifferentiated stem cells which exist in dental papillae of immature permanent teeth were newly discovered and these stem cells appear to be the origin of ameloblasts associated with the formation of root dentin. When treating immature permanent teeth, the preservation of these stem cells induce the continuous formation of the root. Therefore, it is reported that minimal invasion to periapical region in immature permanent teeth with periapical inflammation resulted in good-healing pattern in clinical and radiographic examination. In this case, a 10 year-old boy(mandibular right premolar) and a 8 year-old girl(maxillary left premolar) who visited the department of pediatric dentistry at Chosun University Dental Hospital were diagnosed with pulp necrosis and periapical abscess in clinical and radiographic examination. Endodontic instrumentation to the periapical region was limited and MTA(Mineral Trioxide Aggregate) was applied into the pulp canal. The periodic checks showed healing of periapical abscess and the development and growth pattern of roots. In permanent teeth with pulp necrosis and periapical abscess, preservation of pulp and dental papillae in the periapical region showed good prognosis during the periodic examinations. Therefore, a lot of clinical examination and long-term evaluation of conservative pulp treatment in immature permanent teeth are expected to be necessary.

• Restorative Dentistry and Endodontics
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• v.47 no.4
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• pp.41.1-41.20
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• 2022

Objectives: This study compared the clinical and radiological outcomes of regenerative endodontic procedures (REPs) using blood clots (BCs), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) through intraoral periapical radiography (IOPAR) and cone-beam computed tomography (CBCT). Materials and Methods: Forty-five single-rooted necrotic teeth with periapical pathology were randomly allocated to receive BC, PRP, or PRF as an individual scaffold. Outcomes were evaluated in 35 teeth in 23 patients with a follow-up period of 12-24 months through qualitative IOPAR scoring and quantitative CBCT measurements. Healing of periapical lesions and in immature teeth, changes in the apical foramen diameter (AFD), root wall thickness (RWT), and root length (RL) were assessed. A p value less than 0.05 was considered to indicate statistical significance. Results: All teeth were asymptomatic except 1 in the PRP group. Periapical lesion healing was seen in all except 2 teeth in the BC group and 3 in the PRP group. Both IOPAR and CBCT revealed no significant differences in bone healing or changes in AFD, RWT, and RL among the 3 groups. A positive pulp sensibility response to the cold test was seen in 2 teeth in the BC group, but none to the electric pulp test. Intracanal calcification (ICC) was evident in more teeth in the BC group than in the PRP and PRF groups, and was also significantly higher in immature teeth. Conclusions: Our results revealed that BC, PRP, and PRF have similar potential as scaffolds in REPs, and ICC may be a concern for long-term outcomes.