• 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.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.313-318
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• 2008

Dens invaginatus is a rare malformation resulting from invagination of the enamel before calcification has occurred. It is mostly found in permanent maxillary lateral incisors and mandibular teeth are rarely affected by this anomaly. The malformation is estimated to affect between 0.04 % and 10 % of people and has been associated with other abnormalities such as taurodontism, microdontia, gemination and dentinogenesis imperfecta. Dens invaginatus is classified in three types with respect to the depth of invaginatus and has a broad spectrum of morphologic variations. Invagination frequently allows the entry of irritants and microorganism, which usually lead to caries, pulp infection and pulp necrosis. Root canal treatment on such invaginatus tooth may present severe problems because of its complex anatomy of the tooth. Therefore, the early diagnosis of such malformation is crucial and preventive approach is strongly recommended.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.543-549
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• 2000

Gutta-percha와 근관sealer를 사용한 근관 충전은 가장 많이 이용되고 성공률이 높은 방법이지만, 현재 사용되는 모든 근관sealer는 미세누출을 나타낸다. 따라서 더 효과적인 근관 폐쇄를 이루기 위한 재료 및 방법들이 연구되어왔다. 이중 상아질 접착제는 근관 충전재와 함께 사용되어 미세누출을 감소시키지만, 근관 내에 사용하기에 술식이 복잡하고 기술이 요구된다. 본 연구의 목적은 gutta-percha와 레진계 근관 sealer로 충전한 근관에서 self-etching primer를 미리 도포한 경우와 도포하지 않은 경우의 치근단 미세누출을 비교하고, self-etching primer를 도포함에 있어 근관 내에 적용하는 방법에 따른 미세누출을 비교하는 것이다. 또한 근관sealer와 상아질 계면을 주사전자현미경으로 관찰하여, 이 결과를 미세누출과 관련시켜보고자 하였다. 36개의 발거된 사람의 단근치에서 치관부를 절단, 제거하고 ProFile로 근관 형성한 후, 무작위로 선택하여 4개의 군으로 분류하였다. 1군에서는 주사기와 30게이지 주사 바늘로 self-etching primer를 근관 내에 적용하였고, 2군에서는 self-etching primer를 paper point에 적셔 근관 내에 적용하였다. 3군에서는 self-etching primer를 적용하지 않았다. 1, 2, 3군의 치아를 gutta-percha와 AH26 sealer를 사용하여 continuous wave 충전법으로 충전한 후 치근단공 주위 3mm를 제외한 치근변에 nail polish를 2회 도포하였고, 4군(음성 대조군)은 치근면 전체에 도포하였다. 1군과 2군에서 각각 2개의 치아는 주사전자현미경적 관찰을 위해 준비하였다. 모든 치아를 Methylene Blue 수용액에 48시간동안 침적, 수세한 후 치아 장축에 평행하게 양분하여 10배의 실물확대현미경 하에서 치근단 색소 침투를 관찰하였다. Self-etching primer를 도포한 군과 도포하지 않은 군 사이에는 평균 미세누출량에 유의한 차이가 없었다. 주사 바늘로 적용한 군과 paper point로 적용한 군 사이에도 평균 미세누출량에 유의한 차이가 없었다. 상아질과 근관 sealer계면의 주사전자현미경 관찰 결과 일부분에서 긴밀한 접착 관계를 나타내었고, 다른 부분에서는 간극을 나타내었다.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.585-601
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• 1994

The purpose of this study was to evaluate the ability of several intracoronal base materials to prevent cervical leakage of a bleaching agent into the dentinal tubules and along the root canal. In this study, thirty-two anterior teeth were used. After lingual access was prepared in each tooth, tooth was instrumented with a step-back technique to a Nos. 40-50 using K-type files. All teeth were obturated with a lateral condensation technique. Excess gutta percha was removed with a warm instrument to the facial level of the CEJ. Teeth were divided into four groups : Teeth in control group were not filled with base material. Teeth in groups 1, 2, and 3 had 2mm of gutta percha removed with a warm instrument, then Dycal, Fuki II LC and Z-100 were filled with palstic instruments on the top of the gutta percha respectively. All teeth were bleached for 7 days, fresh bleach was added for another 7 days, then a 10 % methylene blue dye was placed inside the access preparation. They were stored at $37^{\circ}C$ and $100^{\circ}C$ humidity for 5 days. Each tooth was sectioned perpendicular to the long axis using a diamond disk. Initial cuts were made at the most coronal level of facial and lingual CEJ's, then another cuts continued appically in the levels of 0.5mm, 1.5mm, and 2.0mm respectively. The amount of dye leakage through the dentinal tubules was determined at each cut section. In addition, when the cut specimen was determined to be last penetration of any dye, this level was recorded as depth of apical leakage from the coronal terminus of the gutta percha, Dycal, Fuji II LC and Z-100. The acquired data were analyzed by Tukey's Multiple Range Test adn Cochran-Mantel-Haenszel Test to see if there was any statistically significant difference in dye penetration and linear apical leakage among the groups. The results were as follows : 1. Control group at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 AND 3 at level of 2.0mm showed the least dye penetration through the facial or lingual dentinal tubules, but there were no significant difference among three groups. 2. Group 2 at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 and 3 at level of 2.0mm showed the least dye penetration through the proximal dentinal tubules, but there were no significant difference among control group, group 2, and group 3. 3. Group 1 showed the greatest dye penetration through the facial or lingual and proximal dentinal tubules at all levels, and there were significant difference with other three groups. 4. Control group and group 1 showed 2mm apical dye leakage at facial or lingual and proximal aspects, group 2 showed 1.5mm, and group 3 showed 0.5mm.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.200-206
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• 2014

PURPOSE. This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane-or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS. Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate-and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (${\alpha}$=0.05). RESULTS. Mean fracture resistance for the eight groups (in Newton) were G1: $1200{\pm}169^a$, G2: $360{\pm}93^b$, G3: $632{\pm}196^c$, G4: $692{\pm}195^c$, G5: $917{\pm}159^d$, G6: $1013{\pm}125^{ad}$, G7: $959{\pm}148^d$, G8: $947{\pm}105^d$ (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION. Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

• Restorative Dentistry and Endodontics
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• v.17 no.2
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• pp.343-354
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• 1992

The purpose of this study was to analyze the relationship between linear and volumetric measurements of apical dye penetration in canals obturated by various kinds of methods. The canals of 108 roots without crown were conventionally prepared and randomly assigned to four group. The canals of group I a2 were obturated by lateral condensation with sealer, group II a2 by thermoplasticized low-temperature ($70^{\circ}C$) gutta-percha with sealer, group III by Thermafil endodntic obturation with sealer and group IV by injection-molded thermop-lasticized guttapercha One mm of root apex was exposed to a 2 % methylene blue solution at $7^{\circ}C$or 10 days, and the quality of apical seals was assessed by measuring the leakage linearly and volumetrically. The obtained results were as follows: In linear measurements, group II showed significanty less leakage than group III, I and group III also showed less than group N, but no statistically significant difference was demonstrated between the others. In volumetric measurements, group II showed significantly less leakage than group I and II, and no significant differnce from group III. There was a weak significant correlation between the linear measurement and the volumetric measurement(r=0.3391, P<0.001).

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.102-111
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• 2005

The purpose of this study was to assess the incidence of flare-ups among patients who received endodontic treatment and to examine the correlation with pre-operative and operative variables. Analysis was in two aspects (a) overall incidence of flare-ups as expressed by a percentage of all patients visits and (b) percentage of flare-ups that occurred as related to various factors suck as patient demo-graphics, diagnosis, and treatment procedures. 1. From the 840 teeth which were examined in this study, the total number of flare-ups was 13. 2. As to gender of patients, there was no significant difference in flare-ups. 3. As to tooth groups, there was no significant difference in flare-ups. 4. In the teeth with pre-operative symptom, there was a statistically significant higher incidence of flare-ups than the teeth without it. 5. In the teeth with apical periodontitis, there was a statistically significant higher incidence of flare-ups. 6. As to pulp and periapical status. non-vital teeth had a higher incidence as compared with vital teeth, irreversible pulpitis. 7. Multi-visit treatment resulted in the higher incidence of flare-ups than one visit treatment. 8. Re-treatment procedures had a statistically significant higher incidence of flare-ups than root canal treatment. In this study, overall percentages of flare-ups was $1.55\%$. It showed a statistically significant higher incidence related to pre-operative symptom, apical periodontitis, and re-treatment. There was no significant difference in flare-ups related to gender, tooth groups, and fistula.