-
[show abstract]
[hide abstract]
ABSTRACT: It has been demonstrated that genetic variation accounts for approximately half of the variance in periodontitis. The reported association of polymorphisms in the osteoprotegerin (OPG) gene with osteoporosis suggests that the OPG gene may also influence the genetic risk for periodontitis.
We investigated the distribution of OPG gene polymorphisms in 49 patients with aggressive (n = 14) or chronic (n = 35) periodontitis and 49 control subjects without periodontitis, using polymerase chain reaction (PCR)-restriction fragment length polymorphism and PCR-single strand conformation polymorphism followed by direct sequencing.
A total of seven known polymorphisms and one new mutation, G373A, were identified. The T950 and G1181 alleles were more common in patients with periodontitis (P = 0.028 and P = 0.047, respectively) than in control subjects. Especially, G1181 allele was associated with patients with aggressive periodontitis.
The TG haplotype of T950C and G1181C polymorphisms in the OPG gene may be useful genetic markers for the prediction of periodontitis. Further studies in a larger population are required to determine whether these alleles directly contribute to periodontitis susceptibility.
Oral Diseases 08/2008; 14(5):440-4. · 2.49 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study was to develop platelet-derived growth factor (PDGF-BB) loaded moldable porous poly (L-lactide) (PLLA)-tricalcium phosphate (TCP) membranes for guided bone regeneration (GBR) therapy. The membranes were designed to fit various types of bone defect sites. PDGF-BB-dissolved PLLA-TCP in methylene chloride-ethyl acetate solution was cast on a dome shaped metallic mold to fabricate a model membrane. The release rate of PDGF-BB, the osteoblast attachment test, and guided bone regeneration potential were evaluated with PDGF-BB-loaded PLLA-TCP membranes. Regular pores were generated throughout the membrane mainly due to phase inversion of PLLA-methylene chloride-ethyl acetate solution. A therapeutic amount of PDGF-BB was released from the membrane. The release rate could be controlled by varying the initial loading content of PDGF-BB. A significant amount of cells attached onto the PDGF-BB-loaded membrane rather than onto the unloaded membrane. Dome shaped bone formation was achieved in rabbit calvaria at 4 weeks. This indicated that restoration of bone defects to the bone's original shape can be made possible by using molded membranes, which guide bone regeneration along with providing sufficient spaces. Bone forming efficiency was increased remarkably due to PDGF-BB release from PLLA-TCP membranes. These results suggested that the PDGF-BB releasing molded PLLA-TCP membrane may potentially improve GBR efficiency in various types of bone defects.
Journal of Biomedical Materials Research 07/2001; 55(3):295-303.
-
Y M Lee,
Y J Seol,
Y T Lim,
S Kim,
S B Han,
I C Rhyu,
S H Baek,
S J Heo,
J Y Choi,
P R Klokkevold, C P Chung
[show abstract]
[hide abstract]
ABSTRACT: In this study we investigated not only osteoblastic cell proliferation and differentiation on the surface of calcium metaphosphate (CMP) matrices in vitro but also bone formation by ectopic implantation of these cell-matrix constructs in athymic mice in vivo. Interconnected porous CMP matrices with pores 200 microm in size were prepared to use as scaffolds for rat-marrow stromal-cell attachment. Cell-matrix constructs were cultured in vitro, and cell proliferation and ALPase activities were monitored for 56 days. In addition to their being cultured in vitro, cell-matrix constructs were implanted into subcutaneous sites of athymic mice. In vitro these porous CMP matrices supported the proliferation of osteoblastic cells as well as their differentiation, as indicated by high ALPase activity. In vivo the transplanted marrow cells gave rise to bone tissues in the pores of the CMP matrices. A small amount of woven bone formation was detected first at 4 weeks; osteogenesis progressed vigorously with time, and thick lamellar bones that had been remodeled were observed at 12 weeks. These findings demonstrate the potential for using a porous CMP matrix as a biodegradable scaffold ex vivo along with attached marrow-derived mesenchymal cells for transplantation into a site for bone regeneration in vivo.
Journal of Biomedical Materials Research 03/2001; 54(2):216-23.
-
[show abstract]
[hide abstract]
ABSTRACT: With the aim of providing effective periodontal therapeutic modality, drug-releasing membranes for guided tissue regeneration (GTR) were developed. As GTR membranes, biodegradable barrier membranes composed of porous poly(L-lactide) (PLLA) films cast on poly(glycolide) (PGA) meshes were fabricated using an in-air drying phase inversion technique. PLLA was dissolved in methylene chloride-ethylacetate mixtures, cast on knitted PGA mesh, and then air-dried. Tetracycline, which is used in periodontal therapy because of its antibacterial activity and tissue regenerating effects, including osteoblast chemotactic effect and anti-collagenolytic activity, was incorporated into the membranes by adding it to PLLA solutions. The guided bone regenerating potential of tetracycline-loaded membranes was evaluated using release kinetics both in vitro and in vivo, biodegradation tests, and cell attachment tests. Homogeneous pores were generated both at the surface and in a sublayer of the membranes. The release kinetics of tetracycline depended mainly upon the hydrophilicity of tetracycline and the porosity of the membrane. The release rate further could be controlled by loaded drug contents. The release of tetracycline was appropriate for maintaining anti-microbial activity and for its tissue-regenerating potential. The membranes retained a proper degradation property, maintaining their mechanical integrity for the barrier function for 4 weeks. Tetracycline-loaded membranes induced increased cell attachment levels compared with those of unloaded membranes. Tetracycline-loaded membranes markedly increased new bone formation in rat calvarial defects and induced bony reunion after 2 weeks of implantation. These results suggest that tetracycline-loaded PLLA membranes potentially enhance guided tissue regenerative efficacy.
Journal of Biomedical Materials Research 10/2000; 51(3):391-7.
-
[show abstract]
[hide abstract]
ABSTRACT: Platelet-derived growth factor-BB (PDGF-BB) releasing porous chondroitin-4-sulfate (CS)-chitosan sponge was designed with an aim of controlling growth factor delivery in order to improve bone formation. Porous CS-chitosan sponge was fabricated by freeze drying and crosslinking aqueous CS-chitosan solution. PDGF-BB was incorporated into the CS-chitosan sponge by soaking CS-chitosan sponge into the PDGF-BB solution. CS-chitosan sponge retained a porous structure with a 150-200-microm pore diameter that was suitable for cellular migration and osteoid ingrowth. Release rate of PDGF-BB could be controlled by varying the composition of CS in the sponge or initial loading content of PDGF-BB. CS-chitosan sponge induced increased osteoblast migration and proliferation as compared with chitosan sponge alone. Furthermore, the release of PDGF-BB from CS-chitosan sponge significantly enhanced osteoblast proliferation. These results suggest that PDGF-BB-releasing CS-chitosan sponge may be beneficial to enhance bone cell adaptation and regenerative potential when applied in wound sites.
Journal of Controlled Release 08/2000; 67(2-3):385-94. · 5.73 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Chitosan is a biodegradable natural polymer that has been shown to improve wound healing. This study aimed to develop chitosan/tricalcium phosphate (TCP) sponges as tissue engineering scaffolds for bone formation by three-dimensional osteoblast culture.
The sponges were prepared by freeze-drying and cross-linking a mixture of chitosan solution with TCP. Fetal rat calvarial osteoblastic cells were isolated, cultured, and seeded into the sponges. The cell-sponge constructs were cultured for 56 days. Cell proliferation, alkaline phosphatase (ALPase) activity, and calcium deposition in the cell-sponge constructs were measured at 1, 7, 14, 28, and 56 days. Histologic examination was performed with light microscopy and scanning electron microscopy.
Chitosan/TCP sponges supported the proliferation of osteoblastic cells as well as their differentiation as indicated by high ALPase activities and deposition of mineralized matrices by the cells. Light and scanning electron microscopic examination indicated that seeded osteoblastic cells were well attached to sponge matrices and proliferated in a multi-layer fashion. Small bone-like spicules were observed on the sponge matrix at 14 days. Seeded cells appeared to be embedded in the newly formed tissue matrix, which is characteristic of the osteoblast differentiation and their progression into osteocytic cells. The amount of mineralized tissue formed in the sponge at 56 days was significant.
These results suggest that the chitosan/TCP sponge is a feasible tool as a scaffolding material to grow osteoblast in a three-dimensional structure for transplantation into a site for bone regeneration.
Journal of Periodontology 04/2000; 71(3):410-7. · 2.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In order to achieve optimal effects, growth factors including platelet-derived growth factor (PDGF) should be delivered with a biodegradable carrier that will release therapeutic concentrations over a sufficient length of time. The purpose of this study was to evaluate the bone regenerative effect of PDGF-BB delivered with a chitosan/tricalcium phosphate (TCP) sponge carrier in a rat calvarial defect model.
The PDGF-BB-loaded chitosan/TCP sponge carrier was fabricated by freeze-drying a mixture of chitosan solution and TCP powder and soaking in a PDGF-BB solution. The release kinetics of PDGF-BB loaded onto the sponge were measured in vitro with 125I-labeled PDGF-BB. Chitosan/TCP sponges with and without PDGF-BB were implanted into 8 mm calvarial defects in rats. Rats were sacrificed at 2 and 4 weeks following implantation, and histologic and histomorphometrical examinations were performed.
In vitro evaluation demonstrated that an effective therapeutic concentration of PDGF-BB following a high initial burst release was maintained throughout the examination period. In the histologic examination, the chitosan/TCP sponge carrier promoted osseous healing of the rat calvarial defects as compared to controls. The addition of PDGF-BB to the carrier further enhanced bone regeneration. Evidence of the degraded sponge matrix was observed mingled within the newly formed bone without connective tissue encapsulation.
The results of this study support the use of chitosan/TCP sponges as a delivery system for growth factors and demonstrate that PDGF-BB loaded onto chitosan/TCP sponge carriers has an osteogenic effect on bone regeneration in vivo.
Journal of Periodontology 04/2000; 71(3):418-24. · 2.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: With an aim of improving bone regeneration, chitosan sponge containing platelet-derived growth factor-BB (PDGF-BB) were developed. For fabrication of chitosan sponge, chitosan solution was freeze-dried, crosslinked and freeze-dried again. PDGF-BB was incorporated into the chitosan sponge by soaking chitosan sponge into the PDGF-BB solution. Release kinetics of PDGF-BB, cell attachment, proliferation capacity and bony regenerative potentials of PDGF-BB-loaded chitosan sponge were investigated. Prepared chitosan sponge retained porous structure with 100 microm pore diameter that was suitable for cellular migration and growth. Release rate of PDGF-BB could be controlled by varying initial loading content of PDGF-BB to obtain optimal therapeutic efficacy. PDGF-BB-loaded chitosan sponge induced significantly high cell attachment and proliferation level, which indicated good cellular adaptability. PDGF-BB-loaded chitosan sponge demonstrated marked increase in new bone formation and rapid calcification. Degradation of the chitosan sponge was proceeded at defect site and subsequently replaced with new bone. Histomorphometric analysis confirmed that PDGF-BB-loaded chitosan sponge significantly induced new bone formation. These results suggested that chitosan sponge and PDGF-BB-loaded chitosan sponge may be beneficial to enhance periodontal bone regeneration.
Biomaterials 02/2000; 21(2):153-9. · 7.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The purpose of this study was to investigate the pathogenicity of Staphylococcus lugdunensis in acute oral infection.
S. lugdunensis was isolated from patients with acute oral infections and from healthy control subjects. Antibiotic susceptibility, in vitro cellular toxicity, in vivo virulence, and hemolytic activity testing and dot blot analysis were performed. The statistical significance of in vitro cellular toxicity was determined by means of analysis of variance.
Isolated from the infected patients, S. lugdunensis showed resistance to penicillin, ampicillin, methicillin, cephalothin, and clindamycin, exhibited virulence in vivo, and showed delta-like hemolysin activity. Four of the 6 strains of S. lugdunensis gave synergistic hemolysis. In dot blot analysis, S. lugdunensis showed a positive reaction to the probe of the delta-hemolysin gene in S. aureus.
The results suggest that S. lugdunensis may be a potential pathogen in acute oral infection.
Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics 10/1999; 88(3):297-302. · 1.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Platelet-derived growth factor-BB (PDGF-BB) was incorporated into porous poly (L-lactide) (PLLA) membranes with an aim of improving early bone healing in guided tissue regeneration (GTR) therapy. Porous PDGF-BB loaded membranes were fabricated by coating PDGF-BB-dissolved PLLA methylene chloride-ethyl acetate solutions on polyglycolic acid (PGA) meshes. Release kinetics of PDGF-BB, biologic activity, degradability and guided tissue regenerative potentials of the membranes were investigated. Release of PDGF-BB could be controlled by adding bovine serum albumin that may provide porous diffusion channels for PDGF-BB release and by varying initial loading content of PDGF-BB. Biologic activity of PDGF-BB in the membranes was ascertained by fibroblast chemotaxis. PDGF-BB loaded membranes maintained proper degradation property for periodontal application. PDGF-BB loaded membrane markedly increased new bone formation in rat calvarial defects, and completed bony reunion after 2 weeks of implantation period. These results suggested that PDGF-BB loaded PLLA membrane might potentially enhance guided tissue regenerative efficacy.
Journal of Controlled Release 03/1998; 51(2-3):201-11. · 5.73 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Clinical and microbiological effects of subgingival delivery of 10% minocycline-loaded (MC), bioabsorbable microcapsules were examined in 15 adult periodontitis patients. Patients received oral hygiene instruction 2 weeks prior to the study. At baseline (day 0) all teeth received supragingival scaling (SC); 2 quadrants received no further treatment and 1 quadrant received subgingival scaling and root planning (SRP). In the fourth quadrant, the tooth with the deepest probing sites (at least 1 site > or = 5 mm) was treated with minocycline microcapsules. The sites were evaluated at baseline and weeks 1, 2, 4, and 6. Clinical indices included bleeding on probing (BOP), probing depths (PD), and attachment loss (AL). Microbiological evaluations included percent morphotypes by phase-contrast microscopy; cultivable anaerobic, aerobic, and black-pigmented Bacteroides (BPB); and percent Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, and Actinomyces viscosus by indirect immunofluorescence. In the SC + MC group, BOP, PD, and AL were significantly reduced from baseline for weeks 1 to 6. BOP in the SC + MC group was significantly reduced compared to the SRP group from weeks 2 to 6. In the SC + MC group the percent of spirochetes and motile rods decreased and the percent of cocci increased after 1 week. The increased cocci and decreased motile rods were statistically greater at weeks 4 and 6 in the SC + MC group compared to the SRP group. This study demonstrates that local subgingival delivery of 10% minocycline-loaded microcapsules as an adjunct to scaling results in reduction in the percent sites bleeding on probing greater than scaling and root planning alone and induces a microbial response more favorable for periodontal health than scaling and root planing.
Journal of Periodontology 11/1997; 68(11):1102-9. · 2.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The biological effects of drug-loaded biodegradable novel membrane for guided bone regeneration (GBR) was evaluated. The membranes were polyglycolic acid mesh coated with poly-L-lactic acid containing flurbiprofen, tetracycline or PDGF-BB. Porous structure was generated in the membranes by using a phase inversion method. The membrane was less toxic, nicely biodegradable and biocompatible for 8 wk after implantation in the dorsal skin of the rat. The drugs released from the membranes were shown to be effective for new bone formation. Tetracycline, flurbiprofen or PDGF-BB loaded membrane was markedly effective for osteoid tissue and new bone formation in the bony defect prepared in rat calvaria to compare with that by unloaded membrane. These results suggested that drug-loaded biodegradable barrier membrane might be a potential tool for GBR in periodontal therapy.
Journal of Periodontal Research 02/1997; 32(1 Pt 2):172-5. · 1.69 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Refractory periodontitis manifests as a rapid, unrelenting, progressive loss of attachment despite the type and frequency of therapy. This study examined possible relationships between cytokine levels in gingival crevicular fluid (GCF), occurrence of specific periodontopathic microflora, and disease activity in patients with refractory periodontitis. Refractory periodontitis patients (7 male and 3 female) were selected on the basis of history and longitudinal clinical observations. In each patient, 2 teeth with pocket depths greater than 6 mm were selected and individual acrylic stents were fabricated with reference grooves for each site. The sites were examined at both baseline and 3 months later. The pattern and amount of alveolar bone resorption were assayed by quantitative digital subtraction radiography. Pocket depth and attachment loss were measured with a Florida Probe. The gingival index was measured at 4 sites around each sample tooth. Sites were divided into active sites (> or = 2.1 mm loss of attachment in 3 months) or inactive sites (< or = 2.0 mm loss of attachment in 3 months). The distribution and prevalence of the predominant microflora in active and inactive sites were compared using anaerobic culture and indirect immunofluorescence. Interleukin-1 beta, 2, 4, 6 and tumor necrosis factor-alpha (TNF-alpha) levels in gingival crevicular fluid (GCF) were quantified by ELISA. Prevotella intermedia and Eikenella corrodens significantly decreased in inactive sites but remained the same in active sites after 3 months. The active sites revealed significantly higher GCF levels of IL-2 and IL-6 than inactive sites at both baseline and at 3 months. IL-1 beta was also significantly greater in active sites than in inactive sites at 3 months. Alveolar bone loss in active sites correlated with increased GCF levels of IL-1 beta and IL-2. These results suggest that GCF levels of IL-1 beta, IL-2 and IL-6 and P. intermedia and E. corrodens in subgingival plaque may serve as possible indicators of disease activity in refractory periodontitis.
Journal Of Clinical Periodontology 12/1995; 22(11):885-90. · 3.00 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The methanolic extract from the root of Scutellaria baicalensis Georgi and its flavonoids, wogonin, baicalein, and baicalin were evaluated for anti-inflammatory action and the activatory effect on gingival fibroblasts. In LPS-induced production of IL-1 beta, three flavonoids at 1 microgram/ml expressed a significant (> 50%) inhibitory effect, similar to that of prednisolone. Moreover, the flavonoids inhibited IL-1 beta-induced synthesis of PGE2 and LTB4 considerably, although the effect of wogonin on LTB4 synthesis was marginal. In addition, three flavonoids exerted a moderate inhibition (33-36%) of collagenolytic activity, comparable to 40% inhibition by tetracycline. Meanwhile, the cellular activity of fibroblasts was augmented remarkably (40%) by baicalein (2) and slightly by baicalin (3) or wogonin (1). Consistent with the cellular activation, flavonoids enhanced the synthesis of both collagen and total protein in fibroblasts, in contrast to growth factors which increased only the synthesis of total protein. Although the effects of the methanolic extract resembled those of the flavonoids, the extract expressed a preferential effect on the synthesis of collagen and total protein.
Planta Medica 05/1995; 61(2):150-3. · 2.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The present study was performed to investigate the factors associated with disease progression in localized juvenile periodontitis (LJP) patients by longitudinal monitoring of microbiological changes. Following a 9-month period, 9 LJP patients were divided into 2 groups based upon attachment loss, progressing and non-progressing. Both groups received scaling, root planing, and modified Widman flaps. Clinical and microbiological data were obtained at baseline, following the observation period, and at 6 and 12 months post-treatment. At 6 and 12 months post-treatment significantly more cocci were persistent in the non-progressing group than in the progressing group. Actinobacillus actinomycetemcomitans was also more frequently isolated in the progressing group than in the non-progressing group initially and following the 9-month observation period. Also after treatment, A. actinomycetemcomitans recolonized earlier in the progressing group than in the non-progressing group. These studies suggest that A. actinomycetemcomitans may play a role in disease progression in LJP; however, they do not eliminate the possibility that other organisms may also play a role, since A. actinomycetemcomitans was not detected in all of the patients in whom disease progressed.
Journal of Periodontology 11/1992; 63(10):806-11. · 2.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Actinobacillus actinomycetemcomitans is though to play an important role in the pathogenesis of localized juvenile periodontitis (LJP). Preliminary data suggested that the serotype distribution of A. actinomycetemcomitans in Korea and the United States differ. This study evaluated A. actinomycetemcomitans prevalence, serotype distribution, and leukotoxicity in Korean LJP patients by culture, enzyme-linked immunosorbent assay, indirect immunofluorescence, and lactate dehydrogenase release from polymorphonuclear leukocytes exposed to A. actinomycetemcomitans. A. actinomycetemcomitans occurred in 75% of LJP lesions and 6% of normal sites with approximately equal distribution of serotype a, b, and c. Single serotypes were isolated from nine patients while three patients harbored two serotypes either in the same or different disease sites. A. actinomycetemcomitans leukotoxicity occurred in 22% isolates with a 69% prevalence. Individual sites harbored both leukotoxic and non-leukotoxic strains with no serotype association. The distribution of serotypes and leukotoxic strains of A. actinomycetemcomitans in Korean LJP patients differed from those reported in the United States. This suggests that serotype b may not be more important in the pathogenesis of LJP.
Journal of Periodontology 10/1989; 60(9):506-11. · 2.60 Impact Factor
-
Taehan Ch'ikkwa Uisa Hyŏphoe chi 12/1986; 24(11):961-8.
-
[show abstract]
[hide abstract]
ABSTRACT: Previous studies demonstrated that serum antibodies to Actinobacillus actinomycetemcomitans strain Y4 are significantly elevated in sera from localized juvenile periodontitis (LJP) and postlocalized juvenile periodontitis (P-LJP) patients compared to normal controls in United States populations. This study examined the age of subjects in relation to the antibody levels to A. actinomycetemcomitans in a Korean population. Seven groups were investigated including sera from newborns, infants, children, periodontally normal puberty and adult groups and LJP and P-LJP groups. Antibody levels were determined by an enzyme-linked immunosorbent assay (ELISA) to A. actinomycetemcomitans strain SNUDC 10-1 (serotype C) isolated from a Korean LJP patient. In the healthy non-LJP and non-P-LJP subjects, IgG levels decreased from the newborn group to the 5-month-old group and then gradually increased through the adult group. The IgM levels in these groups continuously increased from birth until a plateau was reached in the 2- to 6-year group. Serum IgA levels to strain SNUDC 10-1 were too low to be measured by this assay.
Journal of Periodontology 09/1986; 57(8):510-5. · 2.60 Impact Factor
-
Taehan Ch'ikkwa Uisa Hyŏphoe chi 02/1986; 24(1):73-9.
-
Taehan Ch'ikkwa Uisa Hyŏphoe chi 11/1984; 22(10):865-8.
