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Purpose: A number of techniques and materials have been used for periodontal regeneration and bone graft procedures with guided tissue regeneration(GTR) have been suggested as alternatives to osseous surgery in the management of local infra-bony defects. However, the long-term stability and treatment outcome following bone graft procedure of infra-bony defects is poorly documented. The purpose of this study was to assess radiographic change in infra-bony defects over 2 years after bone graft procedures with various graft materials. Material and Methods: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients showed clinical and radiographic evidence of infra-bony defect(s). 44 sites of 34 patients aged 31 to 69 (mean age 48.3) were treated by bone graft procedure with a bone graft material. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. Result: We observed 1.15±1.95 mm of bone fill, 0.40±1.19 mm of crestal resorption, 1.55±1.77 mm of defect resolution, and 40±44% of percentage of defect resolution. Deeper initial defect depth, narrower initial defect angle showed significantly greater bone fill, defect resolution, and % of defect resolution. But no significant difference was observed in graft sites and graft materials. Conclusion: If good oral hygiene maintenance and periodic recall check of patients is assured, bone graft procedure using various graft materials is one of the appropriate treatment modality for regenerative therapy of infra-bony defects. (J Korean Acad Periodontol 2008;38:437-444)

Purpose: The purposes of this study were to compare and quantify the expression of Stromelysin-1 and MT-MMP-1 in the gingival tissues of patients with type 2 diabetes mellitus(DM) and healthy adults with chronic periodontitis. Materials and Methods: Gingival tissue samples were obtained during periodontal surgery or tooth extraction. According to the patient's systemic condition & clinical criteria of gingiva, each gingival sample was devided into three groups. Group 1 (n=8) is clinically healthy gingiva without bleeding and no evidence of bone resorption or periodontal pockets, obtained from systemically healthy 8 patients. Group 2 (n=8) is inflammed gingiva from patients with chronic periodontitis. Group 3 (n=8) is inflammed gingiva from patients with chronic periodontitis associated with type 2 DM. Tissue samples were prepared and analyzed by Western blotting. The quantification of Stromelysin-1 and MT-MMP-1 were performed using a densitometer and statistically analyzed by one-way ANOVA followed by Tukey test. Results: In the analysis of expression levels, Stromelysin-1 and MT-MMP-1 expressions were similar in group 1 and 2. Stromelysin-1 and MT-MMP-1 expressions was more increased in group 3 than group 1, 2. The difference between group 3 and group 1, 2 was statistically significant. Also, in the interrelationship of Stromelysin-1 and MT-MMP-1 expressions, expressions of Stromelysin-1 and MT-MMP-1 showed increasing tendency in chronic periodontitis associated with type 2 DM and it seems that the MT-MMP-1 expressions were increasing in proportion to Stromelysin-1 expressions. Conclusion: It is suggested that Stromelysin-1 and MT-MMP-1 may be partly involved in the progression of periodontal inflammation associated with type 2 DM, as related to a metabolism of other factors, such as AGE, plasmin and other inflammatory mediators. Therefore, the expression levels of Stromelysin-1 and MT-MMP-1 can be inflammatory markers of periodontal inflammed tissue with type 2 DM. (J Korean Acad Periodontol 2008;38:629-638)

Purpose: This study investigated the osteoconductivity of natural calcium carbonate-derived bone substitutes, hen eggshell (ES), and compared with those of commercial bone substitutes. Materials and Methods: Osseous defects created in the rat calvaria were filled with particulated ES(ES-1), ES with calcium-deficient hydroxyapatite surface layer (ES-2), Biocoral(Inoteb, France), and Bio-Oss(Geistlich Pharma, Wolhusen, Switzerland). After 4 and 8 weeks of healing, histomorphometic analysis was performed to evaluate the amount of newly formed mineralized bone area (NB%). Results: Histologic and histomorphometric analysis showed new bone formation and direct bony contact with the grafted materials in all groups. At 4 weeks, Biocoral group showed greater NB% compared to Bio-Oss and ES-1 groups (P

Purpose: Tunneling is a periodontal surgical procedure that creates access for patient cleansing and maintenance within the furcal area of a molar tooth with severe furcation involvement. Up to date, there are few studies about a long term clinical and radiographic stability of tunneling. The purpose of this retrospective study is to evaluate the long term prognosis after tunnel preparation of molars with through and through furcation. Material and Methods: 25 teeth of 23 patients aged 36 to 70 (mean age 51.7) were treated surgically with tunnel preparation. These cases were followed for 2 to 13 years (mean 6.5years) after surgery. Patients were recalled for an evaluation which was based on a questionnaire, a clinical examination, and radiographic analysis. Clinical assessment included plaque index, caries registration, probing pocket depth, bleeding on probing, tooth mobility. Baseline and over 2-year follow-up radiographs were collected and evaluated for this study. Result: 3 teeth(12%) had been extracted and 1 tooth(4%) hemisected. Root caries was detected in 3 teeth(12%). Thus 72% of the teeth were still caries free and in function. Clinical parameters including PI, PD, BOP, mobility showed somewhat favourable results. Radiographic furcal bone loss showed no statistically significant difference compared to interproximal crestal bone loss (3.59±1.69% vs 3.42±2.95%) when root length was used as reference. There was no correlation between root trunk length and furcal bone loss. Conclusion: Over 2 years after tunneling procedure, teeth showed a clinically and radiographically stable condition, despite of slight root caries and alveolar bone loss within clinically acceptable range. The tunnel procedure may be considered as a viable periodontal treatment option for molar teeth with severe furcation involvement in individuals following a regular maintenance program. (J Korean Acad Periodontol 2008;38:521-528)

Purpose: The goal of periodontal regenerative therapy is to replace bone, cementum, and periodontal ligament on a previously diseased root surface, which has suffered the loss of these supporting structures. To accomplish the regeneration, a number of surgical procedures have been advocated throughout the years. There seems to be a potential for some spontaneous periodontal tissue regeneration in the bottom of periodontal defect following open flap debridement alone. The aim of this study was to analyse the radiographic bone changes over 2-year after flap operation. Material and Methods: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients had clinical and radiographic evidence of infrabony defect(s). forty two sites of 33 patients aged 26 to 65 (mean age 45.5) were treated by flap operation with or without osseous surgery. Baseline and over 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, gender, defect depth, defect angle) using the paired t-test were examined. Result: We observed 0.74 mm of bone fill, 0.66 mm of crestal resorption, 1.40 mm of defect resolution, and 27% of percentage of defect resolution. Mandible, women, deeper initial defect depth, narrower initial defect angle showed greater bone fill, defect resolution, and % of defect resolution. Conclusion: The results of this study suggest that the use of flap operation did enhance the outcome in terms of radiographically detectable bone fill. Both treatment resulted in some loss of crestal bone height. (J Korean Acad Periodontol 2008;38:429-436)

Purpose: The purpose of this study was to histomorphometrically evaluate the osteoconductivity of a new biphasic calcium phosphate ceramics with fully interconnected microporous structure. Material and Methods: Osseous defects created in the rabbit calvaria were filled with four different bone graft substitutes. Experimental sites were filled with a new fully interconnected microporous biphasic calcium phosphate with(BCP-2) or without(BCP-1) internal macropore of 400 in diameter. MBCP(Biomatlante, France) and Bio-Oss(Geistlich Pharma, ㎛ Switzerland) were used as controls in this study. Histomorphometric evaluation was performed at 4 and 8 weeks after surgery. Result: In histologic evaluation, new bone formation and direct bony contact with the graft particles were observed in all four groups. At 4 weeks, BCP-1(15.5%) and BCP-2(15.5%) groups showed greater amount of newly formed mineralized bone area(NB%) compared to BO(11.4%) and MBCP(10.3%) groups. The amounts of NB% at 8 weeks were greater than those of 4 weeks in all four groups, but there was no statistically significant differences in NB% between the groups. Conclusion: These results indicate that new bone substitutes, BCP with interconnected microporous structure and with or without internal macroporous structures, have the osteoconductivity comparable to those of commercially available bone substitutes, MBCP and Bio-Oss. (J Korean Acad Periodontol 2008;38:117-124)

대한치주과학회지 : Vol. 37, No. 2(Suppl.), 2007 Identification of Matrix Mineralization-Related Genes in Human Periodontal Ligament Cells Using cDNA Microarray Jae-Hee Shin1, Jin-Woo Park1, Shin-Il Yeo1, Woo-Chang Noh1, Moon-Kyu Kim2, Jung-Chul Kim2, Jo-Young Suh1* 1. Department of Periodontology, College of dentistry, Kyungpook National University 2. Department of Immunology, School of Medicine, Kyungpook National University

The innate immune system is comprised of the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner. It is mainly directed to recognition of invariant molecules of infectious agents. Most of them are essential for pathogen survival, and are conserved and shared by groups of pathogens, such as lipopolysaccharide (LPS) present in gram-negative bacteria. It is also essential for the activation of the adaptive immune response, capable of coping with a high mutation rate and an antigen (Ag) heterogeneity of infectious agents, and of generating a longlasting immune memory. It is generally thought that the B cell compartment is a representative of the adaptive branch of immune defense. However, because of their anatomical location, B-1 and marginal zone (MZ) B cells are the first cell populations to encounter Ags. These two B cell subsets have evolved to provide a first line of defense against pathogens. With their additional properties to produce factors that can directly mediate microbial destruction and to express Toll-like receptors, B cells provide an important link between the innate and adaptive branches of the immune system.1) B-1 cells represent a specialized subset of B cells that are distinct from the majority of recirculating conventional B cells (termed B-2) in an individual. They are distinguished by tissue dis

Titanium is one of the most commonly used implant materials, particularly for dental and orthopedic applications and its uses are continuously increasing. This extensive use is based on the properties of material, including a combination of corrosion resistance and biocompatibility with satisfactory mechanical performance. This high degree of biocompatibility is thought to be the result, in part, from the protective and stable oxide layer, typically 4 nm thick film of amorphous or poorly crystallized and nonstoichiometric titanium oxide that presumably aids in the bonding of the extracellular matrix at the implant-tissue interface. The characteristic composition and structure of the oxide layer often differ depending on the technique used to prepare the surface of the metal. It has been shown that methods of implant surface preparation can significantly affect the resultant properties of the surface and subsequently the biological responses that occur at the surface. Successful long-term stability of the biomaterial in bone tissue relies on several factors; among them is the important connection between the implant and bone tissue. 1) However, titanium is generally considered to be bio-inert and not likely to form direct bonding with bone, and it must be fixed clinically to bone by mechanical interlocking. However, mechanically fixed implants can

【Periodontal surgery as part of the treatment of periodontal disease is mainly performed 1) to gain access to diseased areas for adequate cleaning; 2) to achieve pocket reduction or elimination; and 3) to restore the periodontal tissues lost through the disease; i.e., a new attachment formation of periodontal regeneration. To accomplish the latter, often referred to as the ultimate goal of periodontal therapy, a number of surgical procedures have been advocated throughout the years. Clinical studies have demonstrated that considerable gain of clinical attachment and bone can be achieved following guided tissue regeneration (GTR) therapy of intrabony defects. The aim of this study was to analyse the radiographic bone changes 2-year after GTR using a bone graft material and nonresorbable membrane. Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients had clinical and radiographic evidence of intrabony defect(s), 33 sites of 30 patients aged 32 to 56 (mean age 45.6) were treated by GTR with a bone graft material and nonresorbable membrane. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. We observed $2.86{\pm}1,87mm$ of bone fill, $065{\pm}0.79mm$ of crestal resorption, $3.49{\pm}2.11mm$ of defect resolution, and $44.42{\pm}19.51%$ of percentage of defect resolution. Mandible, deeper initial defect depth, narrower initial defect angle showed greater bone fill, defect resolution, and % of defect resolution. But no difference was observed between xenograft and allograft. Outcome of GTR as a therapy of intrabony defect was better than other therapy, but herein, good oral hygiene maintenance as a anti-infective treatment and periodic recall check of patients are essential.】

Chronic periodontitis is a chronic inflammatory disease that results in the destruction of the supporting connective and osseous tissues of the teeth 1) . A group of enzymes thought to be important in this degenerative process is the matrix metalloproteinase familly (MMPs) 2,3) . Gingival fibroblasts, keratinocytes, resident macrophages and polymorphonuclear leukocytes (PMNLs) are capable of expressing MMP-1, MMP-2, MMP-3, MMP-8 and MMP-9 2) . Collagen is the major extracellular matrix component of gingiva and thus is implicated in pathological states such as periodontitis. It is now recognized that during active periodontitis, degradation of gingival tissue (mainly collagen) is due in part to matrix metalloproteinases (MMPs) expressed in situ by inflammatory cells (monocyes, macrophages, lymphocytes, PMNLs) and resident cells (fibroblasts, epithelial cells, and endothelial cells) 3) .1) Matrix metalloproteinases (MMPs) are a family of metal dependent proteolytic enzymes that mediate the degeneration of extracellular matrix and basement membranes 4,5) . MMPs are composed of at least 23 related zinc or calcium dependent endopeptidases that are able to degrade extracellular matrix proteins at a pH close to neutral 6) . MMPs are secreted as inactive form (proenzyme) and are activated in the extracellular compartment or in the vicinity of the cell membranes by other MMPs or serine proteinases through peptide cleavage. Three major types of MMPs have been identified: the collagenases degrade interstital collagen types I, II and III; the gelatinases (also called type IV collagenases) degrade type IV collagen and denatured interstitial collagens; and the stro

Diabetes mellitus(DM) in itself does not cause periodontitis. However, there are epidemiologic evidences that diabetes predisposes and accelerates the irreversible periodontal destruction. Severe periodontitis has been associated with an increased risk of poor glycemic control and, in turn, untreated advanced periodontal disease can deteriorate the metabolic control of diabetes 1-4) . Accumulation of plaque is not related directly to the early onset and rapid progression of periodontal tissue destruction in diabetes. Various pathogenic factors have been suggested to explain the increased prevalence and severity of periodontitis in diabetes. An exaggerated inflammatory response to potential periodontopathogenic bacterial virulence factors, such as lipopolysaccharide(LPS), may influence the periodontitis in diabetes. Moreover, an impaired recruitment and cellular function of polymorphonuclear leukocytes(PMNLs) has been linked to extensive periodontal tissue destruction 1-3) .1) Structual studies on diabetic patients have revealed vascular changes in gingiva and other tissues, a thickening of subendotherial basement membrane and, paradoxically, an increased permeability of basement membrane to virulent pathogenic microflora and to its potential vilurent factors 5-7) . Futhermore, a prolonged exposure to hyperglycemia can be primary factor responsible for the formation of non-enzymatic advanced glycosylation end-products(AGEs), demonstrated recently in periodontal tissues of diabetic patients. AGEs are further responsible for

Cigarette smoking has been shown to alter an individual’s response to various forms of periodontal therapy. In vitro and in vivo studies have indicated that smoking and the use of smokeless tobacco products may significantly contribute to the development and progression of inflammatory periodontal disease. The enhanced periodontal destruction observed in smokers may be caused by an alteration of the host response such as the reduced function of oral and peripheral neutrophils, and the decreased levels of salivary and serum antibodies. Similar effects have been observed at higher concentrations of various tobacco components such as nicotine, acroleine, and cyanide. Another hypothesis regarding the contribution of tobacco, and especially nicotine, to the etiology of periodontitis is that the reparative and regenerative potential of periodontal cells may be affected. It has been documented that nicotine can suppress the growth of osteoblast-like cells in vitro. Additionally, nicotine may be stored in and then released from periodontal fibroblasts. However, most of this cytotoxic substance remains within the fibroblasts, resulting in alterations of the cellular metabolism or various functions. Nicotine is a potent component of tobacco smoke. Nicotinic receptors are widespread and are heterogeneous groups comprised of multiple sub-units. The exact importance of individual receptor sub-units is currently not fully understood. However, this may explain in part the wide variety of physio

The biological principles of guided bone regeneration have been successfully applied for regeneration of bone both in experimental animal studies1-3) and in clinical studies4,5). Also, various procedures such as improving the barriers mechanical properties6) and peripheral sealing7) and using grafting materials8) have been tested to enhance, both qualitatively and quantitatively, bone repair in membrane-protected defects. This concept implies that a membrane barrier is placed to prevent non-desirable soft tissue cells from entering the wound area, thereby giving preference to bone-forming cells to repopulate the defect. Factors which stimulate bone repair are subjects for research in osseous regenerative therapy. Effects of cytokines, or growth factors, on bone repair9) are examples of such subjects. Another subject is electrical stimulation which naturally occurs in bone, as such bone may be particularly susceptible to electrical therapy10). Fukada and Yasuda11), on the piezoelectric effect of bone, gave impetus for research in medicine and implied that application of external forces in bone results in electric signals. Yasuda12) implanted electrodes into rabbit femurs and observed new bone in the vicinity of the cathods. Bassett et al.13) described in vivo osteogenesis in response to electric currents, and Friedenberg et al.14) reported on the clinical use of electricity to heal nonunions. Thus, these studies demonstrated that if endogenous stress-generated potentials effected bone remodeling, perhaps electric signals applied externally without the simultaneous application of stress could lead to a response resulting in bone formation12-14). The exact action mechanism of these electrical stimulation for osteogenesis are currently unclear, but investigators have reported various possible modes, such as decreased pO2 and increased pH in the vicinity of the cathode15); accumulation of positive charges16); differentiation of mesenchymal cells into osteoblast and osteocytes17); increased alkaline phosphatase activity18); elevation of cyclic

Bisphosphonates는 파골세포에 의한 골흡수를 방지하는 물질로 알려져 있으며 임상에서 널리 쓰이고 있다. 그 중 Alendronate는 Aminobisphosphonates의 한 종류로 non-aminobisphosphonates인 etidronate보다 100-1000배 더 강한 효과를 보이는 것으로 알려져 있다. 본 실험의 목적은 백서두개골 결손부의 골재생을 실험모델로 하여 alendronate의 국소투여 효과를 알아보는 것으로 액체의 흡수성과 골전도성이 우수한 것으로 알려진 collagen membrane을 사용하여 결손부 양측에 alendronate와 physiologic saline을 각각 적용하여 1주, 2주, 4주의 조직학적 치유양상, 파골세포활성도, 경도를 평가하였다. 조직학적 치유양상은 1주째 collagen membrane에 의한 염증성 침윤이 나타났으며 2주째부터 골성회복이 관찰되었고 4주째 완전한 골성회복을 보여 각주별 실험군, 대조군 공히 유사한 양상을 보였고 실험에 사용한 $200{\mu}g$ 의 용량은 조직학적으로 관찰할만한 골재생의 향상을 위해서는 부족한 용량으로 사료되는 바이다. TRAP(+) cell은 1주째 대조군에 비해 실험군에서 유의하게 적은 수를 보였으며(p 【The present study aimed to examine the effects of topical application of alendronate with a collagen membrane on the healing of the calvarial defect in rats, which has a good experimental design for the healing of tissue destruction, To study the effect of alendronate on bone healing, the collagen membrane containing $200{\mu}g$ alendronate was inserted in the defects of the right side and collagen membrane treated with physiologic saline was inserted in the defects of the left side. After 1, 2 and 4 weeks, observation of histologic feature after H&E staining, cell counting after TRAP staining, and hardness measurement(Knoop) were performed. In histologic finding, similar features were shown for both test and control groups each week. In cell counting only the 1 week test groups showed significant reduction of TRAP(+)cells than control groups(p】