• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.sup3
• /
• pp.299-304
• /
• 2016

Cytolethal distending toxin (CDT) is a secreted tripartite genotoxin produced by many pathogenic gram-negative bacteria. It is composed of three subunits, CdtA, CdtB and CdtC, and CdtB-associated deoxyribonuclease (DNase) activity is essential for the CDT toxicity. In the present study, to design a novel potentially antitumor drug against lung cancer, the possible mechanisms of cdtB anticancer properties were explored in the A549 human lung adenocarcinoma cell line. A recombinant plasmid pcDNA3.1/cdtB was constructed expressing CdtB of human periodontal bacterium Aggregatibacter actinomycetemcomitans and investigated for toxic properties in A549 cells and possible mechanisms. It was observed that plasmid pcDNA3.1/cdtB caused loss of cell viability, morphologic changes and induction of apoptosis. Furthermore, measurement of caspase activity indicated involvement of an intrinsic pathway of cell apoptosis. Consequently, the recombinant plasmid pcDNA3.1/cdtB may have potential as a new class of therapeutic agent for gene therapy of lung cancer.

• Journal of Periodontal and Implant Science
• /
• v.38 no.1
• /
• pp.103-108
• /
• 2008

Purpose: Studies reported controversial results about prognosis of root resection with 0%-38% failure rate. The purpose of this study is to consider clinical efficacy of root resection. Materials and Methods: This study reported three cases of root resection which were performed on different sites. In first case, lower right first molar showed pus discharge and 7 mm of probing pocket depth. It was diagnosed as fracture of mesial root. Hemisection of mesial root was performed. In second case, upper right first molar showed severe bone loss on disto-buccal root and 7 mm of probing pocket. Resection of disto-buccal root was performed In third case, lower left second molar showed severe bone loss on distal root including apex and 15mm of probing pocket depth. Hemisection of distal root was performed. Result: In these three cases of root resection, compromised molars were treated successfully and conserved. Conclusion: Root resection is a successful procedure treating compromised multi-rooted teeth and conserving teeth when proper case selection is performed.

• Restorative Dentistry and Endodontics
• /
• v.36 no.6
• /
• pp.465-476
• /
• 2011

In current endodontic practice, introduction of operating microscope, ultrasonic instruments, and microinstruments has induced a big change in the field of surgical retreatment. In this study, we aimed to offer key steps of endodontic microsurgery procedure compared with traditional root-end surgery, and to evaluate factors influencing success and failure based on published articles. Endodontic microsurgery is a surgical procedure performed with the aid of a microscope, ultrasonic instruments and modern microsurgical instruments. The microscope provides magnification and illumination - essential for identifying minute details of the apical anatomy. Ultrasonic instruments facilitate the precise root-end preparation that is within the anatomical space of the canal. Modern endodontics can therefore be performed with precision and predictability, thus eliminating the disadvantages inherent in traditional periapical surgery such as large osteotomy, beveled apicoectomy, inaccurate root-end preparation and the inability to observe isthmus. Factors influencing the outcomes of endodontic microsurgery may be diverse, but standardization of procedures can minimize its range. Among patient and tooth-related factors, periodontal status and tooth position are known to be prognostic, but there are only few articles concerning this matter. High-evidence randomized clinical trials or prospective cohort studies are needed to confirm these findings.

• The Journal of the Korean Society for Microbiology
• /
• v.35 no.3
• /
• pp.203-214
• /
• 2000

Porphyromonas gingivalis has been implicated in periodontal diseases. Accumulating evidence suggests that cardiovascular disease is the most prevalent medical problem in patients with periodontal diseases. In order to check the possibility that P. gingivalis is involved in coronary heart disease, the present study was performed to observe P. gingivalis adherence and invasion of human coronary artery endothelial cells (HCAEC) and production of cytokines and growth factors by HCAEC upon P. gingivalis infection. $^3H$-labeled P. gingivalis 381 was incubated with HCAEC for 90 min. The radioactivity of the washed HCAEC was a measure of the absorbed (adhering and invading) P. gingivalis. The absorption radioactivity of the HCAEC infected by P. gingivalis was determined to be 59.58% of the input bacterial cells. In contrast, the absorption radioactivity of the cells infected by S. gordonii Challis which was employed as a control was negligible (0.59%). DPG3, a P. gingivalis mutant defective of fimbriae, appeared to be impaired to some extent in capability of adherence/invasion as compared to that of the parental strain 381, showing 43.04% of the absorption radioactivity. The absorption radioactivity of the HCAEC infected by P. gingivalis 381 in the presence of excessive fimbriae at the concentrations of $50\;{\mu}g$ and $100\;{\mu}g/ml$ was 57.27 and 45.44%, respectively. Invasion of HCAEC by P. gingivalis 381 was observed by an antibiotic (metronidazole) protection assay and transmission electron microscopy (TEM). In the antibiotic protection assay, invasion by the bacterium was measured to be 0.73, 1.09, and 1.51% of the input bacterial cells after incubation for 30, 60, and 90 min, respectively. Invasion by DPG3 was shown to be 0.16% after 90-min incubation. In comparison of invasion efficiency at 90 min of the incubation, the invasion efficiency of DPG3 was 0.37% while that of its parental strain 381 was 2.54%. The immunoblot analysis revealed fimbriae of P. gingivalis did not interact with the surface of HCAEC. These results suggest that fimbriae are not the major contribution to the adherence of P. gingivalis to HCAEC but may be important in the invasion of HCAEC by the bacterium. The presence of cytochalasin D ($1\;{\mu}g/ml$) and staurosporine ($1\;{\mu}M$) reduced the invasion of HCAEC by P. gingivalis 381 by 78.86 and 53.76%, respectively, indicating that cytoskeletal rearrangement and protein kinase of HCAEC are essential for the invasion. Infection of P. gingivalis induced HCAEC to increase the production of TNF-${\alpha}$. by 60.6%. At 90 min of the incubation, the HCAEC infected with P. gingivalis cells was apparently atypical in the shape, showing loss of the nuclear membrane and subcellular organelles. The overall results suggest that P. gingivalis may cause coronary heart disease by adhering to and invading endothelial cells, and subsequently damaging the cells.

• The Korean Journal of Physiology and Pharmacology
• /
• v.10 no.5
• /
• pp.289-295
• /
• 2006

Sodium fluoride (NaF) has been shown to be cytotoxic and elicit inflammatory response in human. However, the cellular mechanisms underlying NaF-induced cytotoxicity in periodontal tissues have not yet been elucidated. This study is aimed to investigate the mechanisms of NaF-induced apoptosis in human gingival fibroblast (HGF). NaF decreased the cell viability of HGF in a dose- and time-dependent manner. NaF gave rise to apoptotic morphological changes including cell shrinkage, chromatin condensation, and DNA fragmentation. However, NaF did not affect the production of ROS. In addition, NaF augumented cytochrome c release from mitochondria into the cytosol, and enhanced caspase -9 and -3 activities., cleavage (85 kDa fragments) of poly (ADP-ribose) polymerase (PARP) and upregulation of voltage-dependent anion channel (VDAC) 1. These results demonstrated that NaF-induced apoptosis in HGF may be mediated with mitochondria. Furthermore, NaF elevated caspase-8 activity and upregulated Fas-ligand (Fas-L), suggesting involvement of death receptor mediated pathway in NaF-induced apoptosis. Expression of Bcl-2, an anti-apoptotic Bcl-2 family, was downregulated, whereas expression of Bax, a pro-apoptotic Bcl-2 family, was not affected in NaF-treated HGF. These results suggest that NaF induces apoptosis in HGF through both mitochondria- and death receptor-mediated pathway mediated by Bcl-2 family.

• Journal of Periodontal and Implant Science
• /
• v.33 no.4
• /
• pp.705-715
• /
• 2003

Procedures for treatment of molar furcation invasion defects range from open flap debridement, apically repositioned flap surgery, hemisection, tunneling or extraction, to regenerative therapies using bone grafting or guided tissue regenerative therapy, or a combination of both. Several clinical evaluations using regenerative techniques have reported the potential for osseous repair of treated furcation invasions. Regenerative treatment of maxillary molars are more difficult due to the multiple root anatomy and multiple furcation entrances therefore, purpose of this study was to evaluated histologically compomer and Ketac Silver as a barrier in the treatment of a bi-furcated maxillary premolar. Five adult beagle dogs were used in this experiment. With intrasulcular and crestal incision, mucoperiostcal flap was elevated. Following decortication with 1/2 high speed round bur, furcation defect was made on maxillary premolar. 2 month later one premolar was filled with compomer and the other premolar was filled with Ketac Silver. After 4, 8 weeks, the animals were sacrificed by vascular perfusion. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. Results were as follows. 1. Compomer & Ketac Silver restoration were encapsulated fine connective tissue. 2. In 4 weeks, compomer & Ketac Silver restoration slightly infiltrated inflammatory cells but not disturb the new bone or new cementum formation. 3. In 8 weeks, compomer & Ketac Silver restoration were less infiltrated iflammatory cell and encapsulated fine connective tissue. 4. Therefore, compomer & Ketac Silver filling to the grade III maxillary furcations with multiple root anatomy and multiple furcation entrances is possible clinical method and this technique is useful method for maxillary furcation involvement but it is thought that periodic maintenance should be needed

• Journal of Periodontal and Implant Science
• /
• v.48 no.5
• /
• pp.317-325
• /
• 2018

Purpose: We investigated correlations between the findings of oral examinations and panoramic radiography in order to determine the efficacy of using panoramic radiographs in screening examinations. Methods: This study included patients who visited dental clinics at National Health Insurance Service (NHIS) Ilsan Hospital for checkups during 2009-2015 and underwent panoramic radiographic examinations within 1 year prior to the oral examinations. Among the 48,006 patients who received checkups, 1,091 were included in this study. The data were evaluated using the Cohen kappa and interrater agreement coefficients. Accuracy, sensitivity, and specificity were calculated using data from the panoramic radiographs as true positive diagnoses. Results: The interrater agreement coefficient for occlusal caries was 28.8%, and the Cohen kappa coefficient was 0.043 between the oral and panoramic radiographic examinations. Root caries and subgingival calculus were only found on the radiographs, while gingival inflammation was found only by the oral examinations. The oral examinations had a specificity for detecting occlusal dental caries of 100%, while their sensitivity for proximal dental caries and supragingival calculus was extremely low (14.0% and 18.3%, respectively) compared to the panoramic radiographic examinations. The oral examinations showed a relatively low sensitivity of 66.2% and a specificity of 43.7% in detecting tooth loss compared with panoramic radiography. Conclusions: Panoramic radiography can provide information that is difficult to obtain in oral examinations, such as root caries, furcation involvement, and subgingival calculus, which are factors that can directly affect the survival rate of teeth. It therefore seems reasonable and necessary to add panoramic radiography to large-scale health checkup programs such as that provided by the NHIS.

• Journal of Periodontal and Implant Science
• /
• v.32 no.3
• /
• pp.631-642
• /
• 2002

The present study evaluated of regeneration effect of platelet rich plasma on the treatment of classII furcation involvement, with allograft in humans. The control was treated without bioabsorbable membrane, and the test was treated with bioabsorbable membrane. Pocket depth, clinical attachment level, and gingival recession were measured at baseline, postoperative 3, 6months. Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. The change of pocket depth and clinical attachment level in both groups was decreased significantly at 3, 6months.(p<0.05) 2. The change of gingival recession in both groups was increased significantly at 3, 6months than at baseline.(p (0.05) 3. The change of pocket depth and clinical attachment level in both groups was increased significantly at 3, 6months, but there were no statistically or clinically significant differences with both groups. 4. The change of gingival recession in both groups was increased significantly at 3, 6months, but there were no statistically or clinically significant differences with both groups. 5. The significant reduction of the pocket depth and clinical attachment level exhibited marked changes at 3 months in both groups. In conclusion, the results of this study suggest that there are no statistically or clinically significant differences between with and without bioabsorbable membrane on treatment of classII furcations using allograft and PRP

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.23 no.2
• /
• pp.265-275
• /
• 1993

The purpose of this study was to compare the interpretation results of the panoramic radiographs with those of intraoral radiographs in evaluation of alveolar bone loss. All radiographs were obtained from 100 patients who had visited the Dental Infirmary of Kyungpook National University Hospital for periodontal state evaluation. The results were as follows: The percentages of interpretable sites were 95.9%(94.6% in maxilla, 97.4% in mandible) on the intraoral radiographs, and 90.7%(84.0% in maxilla, 97.3% in mandible) on the panoramic radiographs. The concordance of interpretation scores of marginal bone loss between intraoral and panoramic radiographs was 66.3%(65.6% in maxilla, 66.8% in mandible). And according to the site, the highest concordance was in the distal surface of the mandibular 2nd premolar at 82.0%, and the distal surface of the mandibular 1st premolar(76.8%), the distal surface of the maxillary central incisor(75.8%), the mesial surface of the 2nd premolar (75.0%) in descending order of frequency. According to the interpretation scores of the marginal bone loss, the percentages of concordance between intraoral and panoramic radiographs were the highest on the score 10 at 76.4%, and the lowest on the score 8, 9. And the percentages of concordance were inverse proportional rate from the score 5 to the score 9. Number of the observed sites of the furcation involvement in bitewing and panoramic radiographs were 268 sites, and the percentage of interpretable sites was 92.9% in bitewing radiographs and 86.6% in panoramic radiographs. And the concordance rate of interpretation was 79.5%.

• Journal of Periodontal and Implant Science
• /
• v.30 no.4
• /
• pp.793-803
• /
• 2000

Procedures for treatment of molar furcation invasion defects range from open flap debridement, apically repositioned flap surgery, hemisection, tunneling or extraction, to regenerative therapies using bone grafting or guided tissue regenerative therapy, or a combination of both. Several clinical evaluations using regenerative techniques have reported the potential for osseous repair of treated furcation invasions. Regenerative treatment of maxillary molars are more difficult due to the multiple root anatomy and multiple furcation entrances therefore, purpose of this study was to evaluated histologically self-curing glass-ionomer cement and light-curing glass-ionomer cement as a barrier in the treatment of a bi-furcated maxillary premolar. Five adult beagle dogs were used in this experiment. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree II furcation defect was made on maxillary third(P3), forth(P4) and fifth(P5) premolar. 2 month later experimental group were self-curing glassionomer cement and light-curing glassionomer cement. After 4, 8 weeks, the animals were sacrificed by vascular perfusion. Tissue block was excised including the tooth and prepared for light microscope with Gomori's trichrome staining. Results were as follows. 1. In all experiment group, there were not epithelial down growth and glass ionomer cement were encapsulated connective tissue. 2. In 4 weeks experiment I group slighly infiltrated inflammatory cells but not disturb the new bone or new cementum formation. 3. In 8 weeks, experiment groups I, II were encapsulated fine connective tissue. 4. Therefore glass-ionomer cement filling to the grade III maxillary furcations with multiple root anatomy and multiple furcation entrances were possible clinical methods and this technique is useful method for Maxillary furcation involvement.