• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.98-106
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• 2008

The purpose of this study was to evaluate whether intracanal irrigation method could affect the adhesion between intracanal dentin and root canal filling materials (Gutta-percha/AH 26 sealer and Resilon/Epiphany sealer). Thirty extracted human incisor teeth were prepared. Canals were irrigated with three different irrigation methods as a final rinse and obturated with two different canal filling materials (G groups: Gutta-percha/AH 26 sealer, R groups: Resilon/Epiphany sealer) respectively. Group G1, R1-irrigated with 5.25% NaOCl Group G2, R2-irrigated with 5.25% NaOCl, sterile saline Group G3, R3-irrigated with 5.25% NaOCl, 17% EDTA, sterile saline Thirty obturated roots were horizontally sliced and push-out bond strength test was performed in the universal testing machine. After test, the failure patterns of the specimens were observed using Image-analyzing microscope. The results were as follows. 1. Gutta-percha/AH 26 sealer groups had significantly higher push-out bond strength compared with the Resilon/Epiphany sealer groups (p < 0.05). 2. Push-out bond strength was higher when using 17% EDTA followed by sterile saline than using NaOCl as a final irrigation solution in the Resilon/Epiphany sealer groups (p < 0.05). 3. In the failure pattern analysis, there was no cohesive failure in Group G1, G2, and R1. Gutta-percha/AH 26 sealer groups appeared to exhibit predominantly adhesive and mixed failure patterns, whereas Resilon/Epiphany sealer groups exhibited mixed failures with the cohesive failure occurred within the Resilon substrate.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.463-472
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• 2002

Bacterial lipopolysaccharide (LPS) plays a major role in stimulating the synthesis and release of the principal osteoclast-activating cytokines, namely, interleukin 1 and tumor necrosis factor-$\alpha$ from immune cells. Although rnonocytes/macrophages are the main producers of these cytokines, recent evidence has indicated that polymorphonuclear leukocytes (PMN) have the ability to release IL-1 and TNF-$\alpha$. Calcium hydroxide has been shown to be an effective medicament in root canal infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)$_2$ may also be the result of direct inactivation of LPS. The purpose of this study was to investigate whether treatment of Porphyromonas endodontalis LPS with calcium hydroxide alters its biological action as measured by human PMN secretion of IL-1 and TNF-$\alpha$, and it was compared with Escherichia coli LPS. P. endodontalis ATCC 35406 was cultured in anaerobic condition, and LPS was extracted using the hot-phenol water extraction method and purified. Purchased E. coli LPS was also purified. 100 $\mu\textrm{g}$/ml of each LPS in pyrogen free water were incubated with 25mg/ml Ca(OH)$_2$ at 37$^{\circ}C$ for 7 days. The supernatants were subjected to ultrafiltration, and the isolates were lyophilized and weighed. PMNs were obtained from peripheral blood by centrifugation layered over Lymphoprep. The cells were resuspended (4$\times$10$^6$ cells/ml) in RPMI 1640 followed by treatment with various concentrations of LPS (0, 0.1, 1, 10$\mu\textrm{g}$/ml) for 24 hours at 37$^{\circ}C$ in 5% $CO_2$ incubator. The supernatants of cells were collected and the levels of IL-1$\alpha$, IL=1$\beta$ and TNF-$\alpha$ were measured by enzyme-linked immunosorbent assay. The results were as follows ; 1. The levels of IL-1$\alpha$, IL-1$\beta$, TNF-$\alpha$ from PMN treated with each LPS were significantly higher than those released from unstimulated PMN of the control group (p<0.05). 2. The levels of all three cytokines released from PMN stimulated with each calcium hydroxide treated LPS were significantly lower than those released from PMN stimulated with each untreated LPS (p<0.05), while they were not significantly different from those released from unstimulated PMN of the control group (p>0.05) 3. The levels of secretion for all three cytokines were affected in a dose-dependent manner in PMN stimulated with each LPS (p<0.05), but not in PMN stimulated with each calcium hydroxide treated LPS (p>0.05). 4. The levels of all three cytokines released from PMN stimulated with p. endodontalis LPS were significantly lower than those released from PMN stimulated with E coli LPS (p<0.05).

• Imaging Science in Dentistry
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• v.32 no.3
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• pp.167-173
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• 2002

Purpose : To evaluate clinical and radiographic differential diagnosis between ameloblastoma and odontogenic keratocyst (OKC) using clinical data, plain radiographs, and CT. Materials and Methods: 25 cases of ameloblastoma and 44 cases of OKC diagnosed in biopsy, were selected from the files stored in Department of Oral and Maxillofacial Radiology, Seoul National University Dental Hospital from 1999 to 2001, and evaluated using following criteria: sex and age, location, shape, border to normal bone tissue, effect to adjacent tissues, homogeneity in the lumen of the lesion, response of the cortical bone, long-to-short length (LIS) ratio of the lesion, and expansion angle of the cortex. Results: Ameloblastoma and OKC were seen most frequently in third decades and no statistical significance was noted between both sexes. Ameloblastoma occurred most frequently in mandibular angle and ramus area (68%) and OKC at the maxillary molar (34.1 %), and mandibular angle and ramus area (43.2%). The root resorption of the adjacent teeth, mandibular canal displacement, and the impaction of teeth were seen more frequently in ameloblastoma than in OKC. The LIS ratio measured in CT was largest in maxillary OKC cases, followed by mandibular ameloblastoma, and mandibular OKC (1.2, 1.8 and 2.4 respectively). The expansion angle of the cortex shows a statistically significant difference between ameloblastoma (48.8°) and OKC (31.5°). Conclusion : The numeric morphology (LIS ratio) and expansion angle of the cortical bone of the lesion measured in computed tomography can be used to differentiate the ameloblastoma and odontogenic keratocyst.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.249-256
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• 2012

Cone beam computed tomography (CBCT) has become widely available in recent years and is recognized as an important diagnostic tool for varies disease and condition of the orofacial structure. Clinician is easy to determine adequate treatment plan for pediatric patients by using CBCT. CBCT is used in Chonbuk National University Dental Hospital since 2005. This research presents clinical application of CBCT on patients visiting department of pediatric dentistry in Chonbuk National University Dental Hospital from Jan, 2005 to July, 2011. 1. Total number of patients taken CBCT is 252, and total number of area taken CBCT is 279. 2. An age group form 9 years to 12 years showing 53% was highest and percentage of 6~8 years showed 24%. 3. Chief complaints for CBCT taking are position and shape of impacted teeth (49.1%), mesiodens (19.4%), supernumerary teeth (7.9%), position and root canal shape of erupting teeth (7.2%), cyst (5.4%), inflammatory lesion (3.9%), odontoma (3.9%), tumor (2.2%), and et al. 4. Treatments are extraction (29.7%), orthodontic traction and leveling (24.0%), follow up (16.5%), refer to other professional part (11.5%), endodontic treatment (3.9%), surgical removal (2.9%), malsupialization (3.9%), enucleation (1.1%), and fail to follow up (5.0%), and et al.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.80-87
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• 2017

Purpose: The aim of this study was to assess the physical properties of a novel resin-based endodontic sealer, Any-Seal, in comparison with AH Plus Jet. Materials and Methods: Flow, radiopacity and compressive strength were examined according to ISO 6876/2001. For flow test, 0.05 mL of sealer was placed between glass plate and 100 g weight were applied. Ten minutes after mixing the sealers, the load was removed and the diameters of the compressed sealer discs were measured. For radiopacity, 10 mm diameter and 1 mm thickness sample were fabricated and took radiograph with an aluminum step-wedge and analyzed using imaging program. For compressive strength test, $4mm{\times}6mm$ cylindrical specimen was fabricated and tested after 24 hours and 1 week using Universal testing machine. Results: Both tested sealers were consistent with ISO 6876/2001 in the flow and radiopacity test. The flow values of both sealers were not significantly different (P > 0.05). AH Plus Jet had significantly higher radiopacity (P < 0.05). AH Plus Jet showed higher compressive strength at both time intervals (P < 0.05). Conclusion: Any-Seal showed low compressive strength until after 1 week, so its physical and biological aspect should be evaluated more before clinical use.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.1-18
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• 1996

There are many advantages when using IIF and DNA probe methods over anaerobic culture method in that they are time-and effort-saving, more precise and more sensitive. Furthermore, in IIF and DNA probe methods, the detection is possible only with small amount of bacteria, the quantitative analysis is possible, and the cell viability is not necessary. The purpose of this study is to observe the incidence of P.endodontalis by carrying out anaerobic culture, IIF and colony lift using DNA probe method respectively, and to compare these 3 methods in terms of effectiveness and sensitivity in order to identify the most effective detection method. 30 teeth with at least one clinical symptoms, with single canal, and with pulp necrosis were sampled. For sampling bacteria, access cavity was prepared after disinfecting tooth and its surroundings. Then the paper point was inserted up to the periapical area, leave there for a while, and finally it was placed into PRAS Ringer's sol. and PBS sol. In anaerobic culture method, P.endodontalis was identified by biochemical tests after subculturing black and brown colonies which were produced after 7 days of incubation on BAP and Brucella BAP in anaerobic chamber. To identify P.endodontalis in IIF method, species-specific polyclonal rabbit-antisera of P.endodontalis(ATCC 35406) was reacted with sampled PBS sol. dispensed onto glass slide, and then P.endodontalis was examined by phase contrast microscopy after incubating with Goat anti-rabbit lgG conjugated to Fluorescein isothiocyanate. For colony lift using DNA probe method, membranes were laid over colonies on the surface of BAP and were hybridized with cloned DNA probe of P.endodontalis. The existence of P.endodontalis was then identified by the methods of chemiluminescent detection and color metric detection. Black colony was found in 11 teeth out of 30 teeth and P.endodontalis was detected in 6 teeth (20 %) by anaerobic culture method, 16 teeth (53 %) by IIF method, and 7 teeth (23 %) by DNA probe method. IIF method is significantly better in detecting P.endodontalis than DNA probe method and anaerobic culture method. There was no significant differences between DNA probe method and anaerobic culture method. There was significant correlation between the formation of black colony and the existence of P.endodontalis. The probability of detecting P.endodontalis when black colony being present is 2.89 times higher than when not being present. There was significant relationship between the foul odor of clinical symptoms and P.endodontalis. The sensitivity of existing P.endodontalis when foul odor being present was 93.75 %, while the specificity of not existing P.endodontalis when foul odor not being present was 28.57 %. These results suggested that the probes of P.endodontalis will be used to decide the method and prognosis in endodontic treatments.

• 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).

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.49-54
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• 1999

Ko, Lim found some differences in the concentrations of bone resorptive cytokines, especially IL-$1{\alpha}$ and IL-$1{\beta}$ in periapical lesions and inflamed pulps. And they suppose that these differences may be due to the type of cells which produce each cytokine. The purpose of this study was to analyze the human odontogenic cysts & cystic fluid for their contents of IL-$1{\alpha}$, IL-$1{\beta}$ and TNF-$1{\alpha}$ and to compare the concentrations of each cytokine according to the cytokine producing cells. The cystic tissues used in this experiment, were obtained from periapical surgery or cyst enucleation surgery. Cystic fluid was obtained from root canal during routine endodontic therapy(n=5). Cystic tissues were subdivided into two groups, inflammatory radicular cyst group(n=15) and developmental odontogenic keratocyst group(n=3). Normal periapical tissues of extracted third molar(n=5) were also obtained to be used as control group. Each specimen was incubated in 0.5ml homogenizing buffer (0.1mol/L potassium chloride, 0.02mol/L TRIS;pH=7.6) for two hours and then homogenized with glass homogenizer. Each specimen was centrifuged in a microcentrifuge for 3 minutes, and supernatants were extracted. The concentrations of cytokines were measured with R&D ELISA kit. The data were analyzed by Mann-Whitney U test for the differences among the diseases and t test for the correlations among each cytokine. Following results were obtained ; 1. For IL-$1{\alpha}$ and IL-$1{\beta}$, all experimental groups showed significantly higher concentrations of each cytokine than the control group (p<0.05). 2. In radicular cysts, the concentrations of IL-$1{\alpha}$ were higher than IL-$1{\beta}$, but not stastically significant (p>0.05). In odontogenic keratocysts, the concentrations of IL-$1{\alpha}$ were significantly higher than IL-$1{\beta}$ (p<0.05). In cystic fluid, the concentration of IL-$1{\beta}$ was significantly higher than IL-$1{\alpha}$ (p<0.05). 3. Between odontogenic keratocysts and radicular cysts, the concentrations of IL-$1{\alpha}$ were significantly higher in odontogenic keratocysts than in radicular cysts (p<0.05). 4. For TNF-${\alpha}$, only cystic fluid group showed significantly higher concentrations than the control group (p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.18-25
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• 2005

Traumatic bone cyst is a nonodontogenic cyst without epithelial-linig which contains fluid in it's cavity, and it is limited by bone walls with no evidence of infection. Traumatic bone cyst is asymptomatic and appears more frequently in the second decade. Gender distribution is approximately equal, although males are affected slightly often than females. Radiographically the lesion shows a well demarcated radiolucent lesion of variable size and the lesion may have scalloped margins. The adjacent teeth to traumatic bone cyst remains vital. Traumatic bone cyst is usually treated by surgical exploration and currettage of the lesion. In the first case of this case report, the patient was refered from the local dental clinic for the radiolucent area under the left mandibular first molar. From the panorama radiograph at the first visit, the radiolucent area of the left mandible showed a well defined scalloped margin and identified as traumatic bone cyst. In the second case, the patient have visited for the chief complaint of swelling and abcess of right maxillary second premolar. In the radiographic check up with panorama radiograph, the radiolucent lesion with well demarcated scalloped margin was found in the right mandible body, and identified as traumatic bone cyst. In the first case, overinstrumentation was done through the mesial root canal to irrigate the lesion. In the second case, not any treatment was done, and watched the progression of the lesion. And in both cases, after two month, the radiolucency and the size of the lesion has decreased to show healing in progress.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.95-104
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• 2018

Purpose: The purpose of this study is to analyze the factors affecting the longevity of failed prosthesis and the success rate of the prosthesis based on the data evaluated with the newly developed Korean Academy of Prosthodontics (KAP) criteria. Materials and methods: Evaluation was performed in the restored prosthesis for patients who visited the prosthodontics department of the 13 dental university hospitals and general hospitals. The status of the prosthesis was classified into four categories: Good, Fair, Bad, Worst. The success was recorded if only the category was classified in 'good'. The mean duration of failed prostheses and the success rate through Kaplan-Meier method were analyzed. Results: A total of 1,804 cases of prosthesis were evaluated: 810 cases of fixed dental prostheses (FDP), 519 cases of Removable Dental Prostheses (RDP), and 475 cases of implant prosthesis. The mean duration of failed FDP was $11.41{\pm}0.30years$ and the median was 10 years. The mean duration of failed RDP was $8.18{\pm}0.29years$ and the median was 7 years. The mean duration of failed implant prosthesis was $7.99{\pm}0.30years$ and the median was 7 years. The factors related to the failure were as follows: number of units, abutments, abutments treated with root canal, and plaque index in FDPs; treated and opposing dentition in RDPs; the number of implants, duration of use, and plaque index in implant prostheses. Conclusion: The average duration of failed prosthesis was 11.41 years for FDPs, 8.18 years for RDPs, and 7.99 years for implant prosthesis, according to the evaluation with newly developed KAP criteria.