• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.507-519
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• 1999

The ultimate objective of periodontal treatment is to stop disease progression and to regenerate destroyed periodontal tissues and thereby regain normal function. Growth factors are naturally found polypetides which stimulate many cellular activities pertaining to wound healing by acting as signal molecule in controlling cell movement, proliferation, and matrix production. Platelet derived growth factor (PDGF) is 28,000-35,000 Da molecular weight dimeric protein with 2 long positively charged polypeptide chains connected by sulfide bonds. The purpose of this study is to evaluate histologically the initial guided tissue regeneration in a periodontal defect f a beagle dog treated with a biodegradable membrane formed with polylactic acid (poly-L-lactic acid) and polyglycolic acid loaded with 200ng/$cm^2$ platelet derived growth factor. 2 beagle dogs were used in he experiment. $5mm{\times}6mm$ alveolar bone defect was formed in upper and lower canines and third premolars and a reference notch was placed. PDGF-BB non-containing membrane was used as control. Each defect was randomly assigned to the test roup or the control group. The dogs were sacrificed 3 weeks after membrane placement. Toluidine blue and multiple staining was done for histological analysis. In the 3 week specimen in the control group, no new one formation could be seen. Small amount f bone resorption below the notch could be seen. In the notch, loose connective tissue with infiltration of inflammatory cells could be seen. Also thin discontinuous new cementum could be seen and the membrane still retained its structure. Where PDGF-BB containing membrane was used, new bone formation could be seen in the notch at weeks and also continuous thin cementum could be seen. PDL cells were observed between new bone and new cementum and some were attached to bone and cementum. These results suggest that new bone and cementum formation seen when PDGF-BB loaded membrane was used was due to inhibition of downgrowth of epithelial cells and also due to continuous release of the growth factor. Further study on the resorption characteristics of the membrane nd the release characteristics of the PDGF-BB is necessary. Also, development of a membrane easier to use clinically is necessary.

• Journal of Periodontal and Implant Science
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• v.49 no.4
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• pp.215-227
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• 2019

Purpose: To histologically characterize periodontal healing at 8 weeks in surgically created dehiscence defects in beagle dogs that received a collagen matrix with periodontal ligament (PDL) progenitor cells. Methods: The bilateral maxillary premolars and first molars in 6 animals were used. Standardized experimental dehiscence defects were made on the buccal side of 3 premolars, and primary culturing of PDL progenitor cells was performed on the molars. Collagen matrix was used as a scaffold and a delivery system for PDL progenitor cells. The experimental sites were grafted with collagen matrix (COL), PDL progenitor cells with collagen matrix (COL/CELL), or left without any material (CTL). Histologic and histomorphometric analyses were performed after 8 weeks. Results: The defect height from the cementoenamel junction to the most apical point of cementum removal did not significantly differ across the CTL, COL, and COL/CELL groups, at $4.57{\pm}0.28$, $4.56{\pm}0.41$, and $4.64{\pm}0.27mm$ (mean ${\pm}$ standard deviation), respectively; the corresponding values for epithelial adhesion were $1.41{\pm}0.51$, $0.85{\pm}0.29$, and $0.30{\pm}0.41mm$ (P<0.05), the heights of new bone regeneration were $1.32{\pm}0.44$, $1.65{\pm}0.52$, and $1.93{\pm}0.61mm$ (P<0.05), and the cementum regeneration values were $1.15{\pm}0.42$, $1.81{\pm}0.46$, and $2.57{\pm}0.56mm$ (P<0.05). There was significantly more new bone formation in the COL/CELL group than in the CTL group, and new cementum length was also significantly higher in the COL/CELL group. However, there were no significant differences in the width of new cementum among the groups. Conclusions: PDL progenitor cells carried by a synthetic collagen matrix may enhance periodontal regeneration, including cementum and new bone formation.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.387-404
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• 1988

The purpose of this study was to investigate the root resorption and repair pattern of human teeth under intrusive orthodontic loadings of varying magnitude and duration. 50 gms, 100 gms, 200 gms of force applied to the 96 experimental teeth with duration of 2, 5, 7, 10 weeks, after removing the arch wire and retaining during 2 and 6 weeks, experimental teeth were extracted. Results were as follows: 1. The initial resorption site was visible in the apex within 2 weeks with 50 gms, 100 gms samples. 2. The sites of resorption increased markedly with duration of the force. 3. The 50 grams samples of the all duration reveal the shallow resorption and the 100 gms samples of the all duration except 2 weeks reveal the shallow and deep resorption sites. 4. After 7 weeks with 50 gms and 100 gms, cellular cementum repair accompanied the continuing resorption. 5. 2 and 6 weeks after removing the force with 200 gms, the same cellular cementum repair accompanied with 50 gms, 100 gms samples.

• The Journal of the Korean dental association
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• v.18 no.9 s.136
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• pp.739-745
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• 1980

The histologic responses of periapical tissues to root canal fillings with Grossman sealer were studied 10 dogs. Root canal fillings were performed on the 20 lower and upper teeth. The animals were sacrificed 1,2,3,4 and 5 weeks after the completion of operation. The following results were based on histopathologic studies; 1) After 1 week, the necrosis of dentin and cementum surrounding root apex was found in the root canal fillings. 2) After 2 weeks, the necrosis of cementum and surrounding alveolar bone were revealed. The resorption of dentin was appeared partially. 3) After 2 weeks, newly formed dentin was appeared surrounding necrotic dentin. 4) After 4-5 weeks, the osteoblastic activity was revealed abundantly surrounding the alveolar bone. 5) Fibrosis was prominantly appeared surrounding over-filled area, and fibrous encapsulation was performed.

• Imaging Science in Dentistry
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• v.37 no.1
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• pp.1-7
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• 2007

Fibro-osseous lesions are composed of connective tissue and varying amount of mineralized substances, which may be bony or cementum-like structures. It is necessary for oral radiologist to differentiate due to the tendency of these fibro-osseous lesions to show similar histopathologic appearances, while the management of each lesion is different. However we often encounter a little difficulty in judgement because there are some overlaps between concept of each lesions. So recently I suggest, we face a need to review basic concept and classification of several fibro-osseous jaw lesions. In this article, several fibre-osseous lesions, such as fibrous dysplasia, cemento-ossifying fibroma and cemento-osseous dysplasia, will be discussed basing on the review of literature. particular emphasis will be made on the nomenclature revision of WHO's classification in 1992.

• Oral Biology Research
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• v.42 no.4
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• pp.248-253
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• 2018

Cemental tears are uncommon form of root fracture that can lead to rapid localized periodontal attachment loss. Studies have described periodontal breakdown as being associated with the separation of the cementum from the underlying tooth structure. The aim of this case report is to assess the outcome of treatment of cemental tear with several surgical treatment regimens. Three patients with cemental tear were treated with different surgical method. In all three cases, the cemental tear occurred on maxillary right central incisors. In each case, the root fragment were removed, the localized defect was treated using different surgical methods including guided tissue regeneration and bone graft followed by scaling and root planting. In all three cases, symptoms subsided after the treatment and clinical attachment level was improved up to 2 mm at 3 month after surgery. Both conventional and regenerative periodontal surgery could achieve successful outcomes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.3
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• pp.124-124
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• 2015

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.13 no.2
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• pp.91-94
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• 2017

Hypercementosis is an excessive deposition of secondary cementum on the root of a tooth. It is mostly presented as a solitary lesion or in rare cases as a generalized type, but which is seldom recognized; typically it is discovered during regular dental X-ray. Increased thickness of cementum is not uncommon but generalized hypercementosis on impacted permanent teeth which may cause delayed eruption is rarely reported. This case report discusses a patient with cerebral palsy, epilepsy and mental retardation that presents multiple hypercementosis with delayed eruption. On intraoral examination, multiple retained primary molar teeth were found. As there was no any further symptoms, regular dental checkup had been done for several years. In 2015, a surgical opening was performed in the second molar area, but there was no specific change. Panoramic view showed multiple impacted permanent teeth with increased thickness of roots due to excessive deposition of cementum. Hypercementosis was also observed in the root of the erupted tooth. Several laboratory test results including hormone, urine, complete blood count test were reviewed. The patient was also diagnosed with subclinical hypothyroidism, impaired fasting glucose and had been taken valproic acid($Orfil^{(R)}$) for 10 years. However, none of them clearly explained generalized hypercementosis or delayed eruption. The patient is now 24 years old and regular dental checkups and radiographs are taken to confirm that there is no change in the lesion.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.153-171
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• 1999

The purpose of this study was to evaluate the effect of modified calcium sulfate paste on periodontal regeneration. l-wall intrabony defect(mesio-distal width: 4mm, depth: 4mm) was surgically created on the distal side of P2 and mesial side of p4 in four dogs. The control group(GFS) was treated with conventional flap operation alone, and the experimental group(CS) was treated with conventional flap operation with modified calcium sulfate paste application. Both control and experimental groups were sacrificed after 8weeks of healing period, The results of histological and histometric observations were as follows. 1. The length of the junctional epithelium was 0.41${\pm}$0.01mm in the control groups, 0.47${\pm}$0.01mm in the experimental group. 2. The connective tissue attachment was 0.28${\pm}$0.02mm(6.15${\pm}$0.28%) in the control group, 0.18${\pm}$0.01mm(3.41${\pm}$0.14%) in the experimental group. The control group showed more connective tissue attachment. 3. The new cementum formation was 3.80${\pm}$0.06mm(84.80${\pm}$0.33%) in the control group, 4.49${\pm}$0.06mm(87.57${\pm}$0.15%) in the experimental group. Both groups showed a lot of new cementum formation. 4. The new bone formation was 1.43${\pm}$0.03mm(32.37%) in the control group, 2.04${\pm}$O.09mm(40.94%) in the experimental group. 5. The inflamatory cells were observed partially around resorbed calcium sulfate in the connective tissue of the experimental group. 6. Partially resorbed calcium sulfate were found within the connective tissue, around alveolar bone, and in the newly formed alveolar bone, On the basis of these results, newly formed calcium sulfate paste enhanced new bone formation and new cementum formation. The resorption rate of calcium sulfate seems to be controlled by the add-in compounds. Thus research about biocompatibility and adequate resorptionrate is required to develop a improved material.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.621-628
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• 2008

Purpose: Osteopontin is one of the major non-collagenous protein of hard tissue. Use of peptide domain of biologically active protein has some advantages. The objective of this experimental study is evaluation of periodontal regenerative potency of synthetic peptide gel which containing collagen binding domain of osteopontin in the degree III periodontal defect of beagle dogs. Material and Methods: Experimental degree III furcation defect was made in the mandibular third and fourth premolar of beagles. Regenerative material was applied during flap operation. 8 weeks after regenerative surgery, all animals were sacrificed and histomorphometric measurement was performed to calculate the linear percentage of the new cementum formation and the volume percentage of new bone formation. Result: The linear percent of new cementum formation was 41.6% at control group and 67.1% at test group and there was statistically significant difference. The volume percent of new bone formation was 52.1% at control group and 58.9% at test group. Conclusion: As the results of present experiment, synthetic peptide gel containing collagen binding domain of osteopontin significantly increase new bone and cementum formation in the degree III furcation defect of canine mandible.