Publications (13)23.77 Total impact
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Article: (-)-Epigallocatechin gallate induces apoptosis, via caspase activation, in osteoclasts differentiated from RAW 264.7 cells.
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ABSTRACT: Alveolar bone resorption is a characteristic feature of periodontal diseases and involves removal of both the mineral and the organic constituents of the bone matrix, a process mainly carried out by multinucleated osteoclast cells. (-)-Epigallocatechin gallate, the main constituent of green tea polyphenols, has been reported to induce the apoptotic cell death of osteoclasts and to modulate caspase activation in various tumor cells. In the present study, we investigated the inhibitory effect of (-)-epigallocatechin gallate on osteoclast survival and examined if (-)-epigallocatechin gallate mediates osteoclast apoptosis via caspase activation. The effect of (-)-epigallocatechin gallate on osteoclast survival was examined by tartrate-resistant acid phosphatase (TRAP) staining in osteoclasts differentiated from RAW 264.7 cells. In addition, we evaluated the apoptosis of osteoclasts by (-)-epigallocatechin gallate using a DNA-fragmentation assay. Involvement of caspase in (-)-epigallocatechin gallate-mediated osteoclast apoptosis was evaluated by treatment with a general caspase inhibitor, Z-VAD-FMK. Moreover, the effect of (-)-epigallocatechin gallate on the activation of caspase-3 was assessed by a colorimetric activity assay and western blotting. (-)-Epigallocatechin gallate significantly inhibited, in a dose-dependent manner, the survival of osteoclasts differentiated from RAW 264.7 cells and induced the apoptosis of osteoclasts. Treatment with (-)-epigallocatechin gallate resulted in DNA fragmentation and induced the activation of caspase-3 in RAW 264.7 cell-derived osteoclasts. Additional treatment with Z-VAD-FMK suppressed these effects of (-)-epigallocatechin gallate. From these findings, we could suggest that (-)-epigallocatechin gallate might prevent alveolar bone resorption by inhibiting osteoclast survival through the caspase-mediated apoptosis.Journal of Periodontal Research 07/2007; 42(3):212-8. · 1.69 Impact Factor -
Article: Activation of matrix metalloproteinase-2 by a novel oral spirochetal species Treponema lecithinolyticum.
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ABSTRACT: Periodontal tissue destruction is a characteristic of periodontitis. This can be caused by either bacterial enzymes or host cell-derived matrix metalloproteinases (MMPs). In order to elucidate the etiologic role of oral spirochetes, we investigated the effects of Treponema lecithinolyticum, a novel saccharolytic species, on MMP-2 activation. Gingival fibroblasts (GFs) and periodontal ligament (PDL) cells obtained from healthy human subjects were cultured to confluence in alpha-minimal essential medium (alpha-MEM) supplemented with 10% fetal bovine serum. After serum starvation for a day, the cultures were treated with whole cell sonicates, heat-denatured whole cell sonicates, outer membrane fraction (OMF) or formaldehyde-fixed cells of T. lecithinolyticum. Culture supernatants were collected after incubation for 24 to 48 hours and analyzed for MMP-2 activation by gelatin zymography. Collagenolytic activity was quantitatively measured using human [3H] type IV collagen as a substrate. Treatment of GFs and PDL cells with whole cell sonicates, formaldehyde-fixed whole cells, or the OMF of T. lecithinolyticum resulted in the production of MMP-2 partly in the fully active form with a molecular mass of 62 kDa, whereas non-treated control cultures and cultures treated with a heat-denatured fraction did not show the active form. Cultures exposed to T. lecithinolyticum had higher collagenolytic activity than non-treated cultures. Our results demonstrate that T. lecithinolyticum, possibly mediated by proteinaceous cell surface-associated components, may participate in extracellular matrix degradation by activation of MMP-2 during periodontal inflammation.Journal of Periodontology 12/2001; 72(11):1594-600. · 2.60 Impact Factor -
Article: Effects of pretreatment clinical parameters on bioactive glass implantation in intrabony periodontal defects.
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ABSTRACT: The various methods for regeneration of periodontal tissue that have been developed can be classified into guided tissue regeneration and bone implantation. Since the implantation materials have shown both deficiencies and merits, dentists have begun exploring the bioactive glass first used in plastic surgery. This paper examines the effectiveness of this new material on periodontal intrabony defects. Clinical effects of bioactive glass implantation in intrabony periodontal defects were evaluated 6 months after surgery in 38 intrabony defects from 38 patients with chronic periodontitis. Twenty-one experimental defects received bioactive glass implantation (test group), while 17 control defects were treated with a flap procedure only (control group). The criteria for comparative observation were preoperative and postoperative probing depth (PD), clinical attachment level (CAL), bone probing depth (BPD), and gingival recession. Reductions in PD were observed in both groups (P<0.01). The reduction in PD was significantly greater in the test group when preoperative PD exceeded 7 mm (P<0.01). Improvements in CAL were also observed in both groups (P<0.01), with the test group showing significantly greater gains (P<0.05). In those cases where preoperative CAL was less than 7 mm, there was no statistically significant difference between the two groups. Reduction in BPD was observed in both groups, with the test group showing significantly greater reduction (P <0.01). There was no significant difference in BPD change, however, when preoperative BPD was < or =7 mm. Significantly greater reduction of BPD in the test group was observed when intrabony defect depth was >4 mm (P <0.05). Significant improvements in PD, CAL, and BPD were noted in the test group when the crestal involvement exceeded 100 degrees. Correlation test between various clinical parameters indicated that greater changes in PD and CAL in the test group were observed when preoperative CAL was large (P<0.001), and greater changes in PD (P<0.05), CAL (P<0.01), and BPD (P<0.05) were noted when preoperative BPD was large. Correlation between crestal involvement and CAL change was noted only in the control group (P<0.01). High correlations were observed between PD changes and CAL changes and between CAL changes and BPD changes in both groups. Use of a bone substitute in a flap operation resulted in significantly greater improvements in CAL and BPD over flap operation alone and seemed to have positive effects in postoperative PD, CAL, and BPD in those cases with more severe preoperative CAL and BPD.Journal of Periodontology 07/2001; 72(6):730-40. · 2.60 Impact Factor -
Article: Detection of major putative periodontopathogens in Korean advanced adult periodontitis patients using a nucleic acid-based approach.
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ABSTRACT: Although extensive microbial analyses have been performed from subgingival plaque samples of periodontitis patients, systematic analysis of subgingival microbiota has not been carried out in a Korean population so far. The purpose of this study was to describe the prevalence of major putative periodontopathogens in Korean patients by culture-independent methods. A total of 244 subgingival plaque samples (5 sites in each participant) were taken from 29 advanced adult periodontitis (AP) patients and 20 periodontally healthy subjects. AP samples were obtained from the 4 deepest periodontal pockets (> or =6 mm probing depth [PD]) and 1 healthy site (< or =3 mm PD) in each patient. Polymerase chain reaction (PCR) of 16S ribosomal DNA (rDNA) of subgingival plaque bacteria was performed with eubacterial primers. Aliquots of PCR products were then applied on nylon membranes and hybridized with specific oligonucleotide probes labeled with digoxigenin. All diseased sites harbored Fusobacterium sp., while Porphyromonas gingivalis, Treponema sp., and Bacteroides forsythus were detected in more than 96% of 116 diseased sites. Peptostreptococcus micros, Actinobacillus actinomycetemcomitans, and Prevotella intermedia were present in 82%, 74%, and 71% of diseased sites, respectively. In sites of periodontally healthy subjects, Fusobacterium sp. was present in the highest proportion (58%). Treponema sp., P. gingivalis, and B. forsythus were detected in 22%, 18%, and 18% of healthy sites, respectively. P. micros, P. intermedia, and A. actinomycetemcomitans were found in 8%, 2%, and 1% of healthy sites, respectively. The prevalence of the periodontopathogens, with the exceptions of Fusobacterium sp. and B. forsythus, was significantly higher in the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects (P <0.05). Using highly sensitive methods relying on 16S ribosomal RNA-based oligonucleotide probes, we confirmed the strong association of 7 putative periodontopathogens with AP patients in a Korean population. With the exceptions of Fusobacterium sp. and B. forsythus, all the periodontopathogens were significantly more associated with the healthy sites of periodontitis subjects than in the healthy sites of periodontally healthy subjects.Journal of Periodontology 10/2000; 71(9):1387-94. · 2.60 Impact Factor -
Article: Alveolar bone formation at dental implant dehiscence defects following guided bone regeneration and xenogeneic freeze-dried demineralized bone matrix.
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ABSTRACT: The present study evaluated rate and extent of alveolar bone formation in dental implant dehiscence defects following guided bone regeneration (GBR) and implantation of xenogeneic freeze-dried demineralized bone matrix (xDBM). A total of 16 titanium plasma-sprayed (TPS) and 16 hydroxyapatite-coated (HA) titanium cylinder implants were inserted in 4 mongrel dogs following extraction of the mandibular premolar teeth. Four implant sites per jaw quadrant (2 TPS and 2 HA implant sites) were prepared into extraction sockets in each dog. Buccal alveolar bone was removed to create 3 x 5 mm dehiscence defects. Two jaw quadrants in separate animals received GBR, GBR + xDBM, xDBM (control), or gingival flap surgery alone (GFS; control). Thus, four conditions were available for each implant type (TPS or HA): GBR, GBR + xDBM; xDBM and GFS. The animals received fluorescent bone labels to allow observations of rate and extent of bone formation. Animals were sacrificed at 12 weeks postsurgery and block sections were harvested for histologic analysis. There were no apparent histologic differences between TPS and HA implant defects. GBR and GBR + xDBM resulted in almost complete bone closure of the dental implant dehiscence defect. Rate of bone formation appeared higher following GBR alone. Extent of bone formation appeared somewhat greater following GBR + xDBM; however, delayed. xDBM alone did not adequately resolve the bony defect. In conclusion, GBR results in rapid, clinically relevant bone closure of dental implant dehiscence defects. Adjunctive implantation of xDBM does not appear to significantly improve the healing response in the model used.Clinical Oral Implants Research 01/1999; 9(6):419-28. · 2.51 Impact Factor -
Article: Periodontal repair in intrabony defects treated with a calcium sulfate implant and calcium sulfate barrier.
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ABSTRACT: THIS RANDOMIZED, CONTROLLED, CLINICAL STUDY was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried, demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in intrabony periodontal defects. Twenty-six patients contributing 26 deep intrabony defects completed the study. Thirteen patients received the DBM+CS implant. Thirteen patients received gingival flap surgery alone (GFS; control). Clinical outcome was assessed at 6 and 12 months postsurgery. At 12 months postsurgery, probing depth (PD) reduction (mean +/-SD) for the DBM+CS and GFS group was to 4.3+/-0.5 and 3.0+/-1.3 mm; clinical attachment gain was to 2.9+/-0.8 and 1.7+/-1.5 mm; and probing bone level gain was to 2.9+/-1.4 and 1.2+/-1.2 mm, respectively. There were no apparent differences between evaluations at 6 and 12 months postsurgery. Clinical improvements were significantly different from presurgery for both groups at both observation intervals (P < 0.01). There were no significant differences between groups in PD reduction and clinical attachment gain. Probing bone level gain was significantly greater in the DBM+CS group compared to controls (P < 0.05). In summary, surgical implantation of DBM+CS with a CS barrier resulted in reduced PD and improved attachment levels comparable to that achieved by gingival flap surgery alone. However, gain in probing bone levels in deep intrabony periodontal pockets assessed by clinical parameters was greater than that observed by gingival flap surgery alone. These changes were noted at both 6 and 12 months after surgery. This regenerative technique needs further biologic evaluation before being generally accepted.Journal of Periodontology 01/1999; 69(12):1317-24. · 2.60 Impact Factor -
Article: Effect of a calcium sulfate implant with calcium sulfate barrier on periodontal healing in 3-wall intrabony defects in dogs.
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ABSTRACT: This controlled, split-mouth, preclinical study was designed to evaluate outcome following surgical implantation of an allogeneic, freeze-dried demineralized bone matrix-calcium sulfate (DBM+CS) composite with a CS barrier in 3-wall intrabony periodontal defects in 4 dogs. Control conditions included surgical implantation of DBM or CS and gingival flap surgery (GFS) alone. Three-wall intrabony defects (4x4x4 mm) were surgically created at the mesial and distal aspect of the maxillary and mandibular first and third premolars, respectively. Maxillary and mandibular defects each received 1 of the 4 experimental conditions. Experimental conditions were rotated between defect sites in subsequent animals. Block sections of the defects were collected at sacrifice 8 weeks postsurgery and processed for histometric analysis. Histometric defect height (means +/- SD) for the DBM+CS, DBM, CS, and GFS groups amounted to 4.2 +/- 0.5, 4.3 +/- 0.7, 4.0 +/- 0.2, and 4.1 +/- 0.2 mm, respectively. Connective tissue adhesion (connective tissue contact to the root without apparent cementum formation) amounted to 0.4 +/- 0.3, 0.4 +/- 0.3, 0.5 +/- 0.2, and 1.6 +/- 0.5 mm for the DBM+CS, DBM, CS, and GFS groups, respectively; the DBM+CS, DBM, and CS groups being significantly different from the GFS group (P < 0.05). Cementum regeneration amounted to 3.0 +/- 0.3, 3.1 +/- 0.4, 2.5 +/- 0.4, and 1.6 +/- 0.3 mm for the DBM+CS, DBM, CS, and GFS groups, respectively; the DBM+CS, DBM, and CS groups being significantly different from the GFS group (P < 0.05). Alveolar bone regeneration amounted to 2.7 +/- 0.4, 2.7 +/- 0.3, 1.8 +/- 0.5, and 0.7 +/- 0.1 mm for the DBM+CS, DBM, CS, and GFS groups, respectively; the DBM+CS, DBM, and CS groups being different from the GFS group (P < 0.05), and the DBM+CS and DBM groups being different from the CS group (P < 0.05). None of the DBM-containing implants provided evidence of bone metabolic activity. In summary, surgical implantation of DBM and CS, alone or in combination, may result in significantly improved regeneration of alveolar bone and cementum in this preclinical model. Observed regeneration is likely unrelated to a biologic activity inherent in DBM. Rather it appears that space-providing properties of the implants supported observed regeneration.Journal of Periodontology 09/1998; 69(9):982-8. · 2.60 Impact Factor -
Article: Effect of calcium sulphate on the healing of periodontal intrabony defects.
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ABSTRACT: The purpose of this series of three studies was to evaluate the regenerative potential of calcium sulphate in the treatment of periodontal intrabony defects.International Dental Journal 07/1998; 48(3 Suppl 1):330-7. · 0.96 Impact Factor -
Article: Periodontal repair in intrabony defects treated with a calcium carbonate implant and guided tissue regeneration.
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ABSTRACT: Clinical outcome following the concurrent use of a porous resorbable calcium carbonate (CC) implant and guided tissue regeneration (GTR) in intrabony periodontal defects was evaluated in a randomized four-treatment parallel arm study. Eighty (80) patients, each contributing one interproximal intrabony defect, were assigned to the four treatments (20 patients per treatment) including the CC implant and GTR (CC + GTR), GTR alone (GTR control), CC implant alone (CC control), and gingival flap surgery alone (GFS control). Fourteen patients treated with CC + GTR, 19 patients treated with the GTR control, 13 patients treated with the CC control, and 18 patients treated with the GFS control completed the study. Clinical healing was evaluated 6 months postsurgery and included changes in probing depth, clinical attachment level, probing bone level, and gingival recession. Postsurgery probing depth reduction was 4.5 +/- 1.7 mm (CC + GTR; P < 0.01), 4.8 +/- 1.8 mm (GTR; P < 0.01), 3.7 +/- 2.2 mm (CC; P < 0.01), and 3.3 +/- 1.6 mm (GFS; P < 0.01). Clinical attachment gain amounted to 3.3 +/- 1.4 mm (CC + GTR; P < 0.01), 4.0 +/- 2.1 mm (GTR; P < 0.01), 3.0 +/- 2.4 mm (CC; P < 0.01), and 2.0 +/- 1.7 mm (GFS; P < 0.01). The CC + GTR and GTR treatments exhibited significantly greater improvements compared to GFS (P < 0.05). Postsurgery probing bone level gain amounted to 4.0 +/- 1.7 mm (CC + GTR; P < 0.01), 4.1 +/- 1.5 mm (GTR; P < 0.01), 4.0 +/- 2.2 mm (CC; P < 0.01), and 0.5 +/- 2.0 mm (GFS; P > 0.05). The CC + GTR, GTR, and CC treatments exhibited significantly greater improvements compared to GFS (P < 0.05). Gingival recession increased significantly compared to presurgery for GTR, CC, and GFS treatments (-0.9 +/- 1.2, -0.7 +/- 0.7, and -1.2 +/- 1.4 mm, respectively; P < 0.01). The results suggest that the concurrent use of a porous resorbable CC implant and GTR has limited adjunctive effect in the treatment of intrabony periodontal defects.Journal of Periodontology 01/1997; 67(12):1301-6. · 2.60 Impact Factor -
Article: Effects of polyglactin mesh combined with resorbable calcium carbonate or replamineform hydroxyapatite on periodontal repair in dogs.
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ABSTRACT: This study evaluates periodontal repair and biomaterial reaction following implantation of a polyglactin mesh with or without porous resorbable calcium carbonate (RCC) or porous replamineform hydroxyapatite (RHA) in conjunction with reconstructive surgery. Ligature- and surgically-induced interproximal periodontal defects of left and right mandibular premolar teeth in 7 dogs were used. Bilaterally, mesial defects of the 2nd, 3rd and 4th premolar teeth were treated with polyglactin mesh, polyglactin mesh and RHA, or polyglactin mesh and RCC, respectively. The polyglactin mesh, shaped according to the contour of the defect, was adapted to the experimental teeth; its coronal margin positioned immediately apical to the cemento-enamel junction. Gingival flap margins were adapted and sutured to cover the polyglactin mesh completely. Clinical healing was generally uneventful. The dogs were sacrificed to provide block sections for histologic evaluation at 1, 3, 6, 12, 26, 32 and 56 weeks following wound closure. Generally, cementum regeneration was observed beginning at week 6 in all groups. Bone regeneration was observed from week 3 in polyglactin mesh-treated groups, and from week 6 in polyglactin mesh+RCC or polyglactin mesh+RHA treated groups. Bone regeneration appeared enhanced in polyglactin mesh+RCC or polyglactin mesh+RHA treated defects at week 12 and 26, with little difference between the three experimental conditions at week 56. Polyglactin mesh degradation was observed at week 3 and appeared complete at week 12. The RHA did not appear to resorb, while the RCC was gradually replaced by bone from week 3. Within limitations of the study conditions, periodontal regeneration was observed following implantation of a polyglactin mesh with or without RCC or RHA in conjunction with reconstructive surgery. As a conclusion, there seems to be no significant difference in periodontal regeneration after 12 months of healing between the group treated with the membrane only, and the group treated with the membrane and the bone substitution material. Changes in connective fiber orientation over the 1st 12 weeks of healing may suggest that "fibrous encapsulation" observed in earlier studies may only represent a transient stage in periodontal regeneration.Journal Of Clinical Periodontology 11/1996; 23(10):945-51. · 3.00 Impact Factor -
Article: [Scanning electron microscopic study of the white rat periodontium].
Taehan Ch'ikkwa Uisa Hyŏphoe chi 04/1988; 26(3):251-8. -
Article: [Electron microscopic study of the periodontal tissues in progressive periodontal disease. I. Alteration of junctional epithelium].
Taehan Ch'ikkwa Uisa Hyŏphoe chi 12/1987; 25(11):1043-54. -
Article: [An electron microscopy study of the effect of excessive occlusal force on the periodontium of dogs].
Taehan Ch'ikkwa Uisa Hyŏphoe chi 06/1984; 22(5):439-46.
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1996–2001
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Yonsei University
- • College of Dentistry
- • Department of Oral Biology
Seoul, Seoul, South Korea
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