• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.51-63
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• 1994

There has been many attempts to develop a method that can regenerate periodontal tissues that were lost due to periodontal diseasd, but none of them was completely successful. This study was designed to investigate the healing and regeneration of periodontal tissue when bone substitutes such as porous replamineform hydroxyapatite and porous resorbable calcium carbonate were used in combination with oxidized cellulose membrane and collagen absorbable hemostat, compared to a control where only oxidized cellulose membrane or collagen absorbable hemostat were used. Chronic periodontitis was induced on mandibular premolars of and adult dog by placing orthodontic elastic ligatures for 10 weeks. After flap operation, the control group were received oxidized cellulose membrane (control- I )or collagen absorbable hemostat (control- II) only, while one experimental group was given either porous replamineform hydroxyapatite or porous resorbable calcium carbonate in addition to oxidized cellulose membrane (Experimental I-A, I-B), and another experimental group was treated by using either porous replamineform hydroxyapatite or porous resorbable calcium carbonate in addition to collagen absorbable hemostat. (Experimental II-A, II-B) After 56 weeks, healing was histologically analyzed with the following results. 1. Apical migration of junctional epithelium was observed only in areas coronal to the notch for both control and experimental group. 2. Inflammatory cell infiltration was not observed in any groups. 3. Oxidized cellulose membrane and collagen absorbable hemostat were completely resorbed. 4. Newly-formed cementum was observed up to the level where junctional epithelium was located, for both control and experimental groups. 5. Bone formation was limited of the middle portion of the notch in the control group, where as experimental groups showed bone formation up to the level of implant materials coronal to the notch. 6. Minute resorption of apically located portions of implanted materials was observed in experimental group I-B and II-B only.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.555-561
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• 1998

Hypophosphatasia is a rare metabolic disorder which manifests characteristics such as abnormal mineralization of bone and dental tissues, diminished serum and tissue alkaline phosphatase, and increased urinary secretion of PEA. It inherited as an autosomal recessive or dominant trait and occurs in all races. In general, hypophosphatasia can be classified in 4 subtypes which are the perinatal, infantile, childhood, adult type depending upon the age at presentation and severity. In young children with Hypophosphatasia the long bones show irregular defects, and the skull showes poor calcification. In older children with premature closure of the skull sutures there may be multiple lucent area called gyral or convolutional markings, described as resembling beaten copper, presumably resulting from increased intracranial pressure. Examination of the jaws reveals a generalized lucency of the maxilla and mandible. the cortical bone and lamina dura are thin, and the alveolar bone may be deficient. Clinical features of Hypophosphatasia include premature loss of deciduous teeth, especially incisors, hypoplasia or aplasia of root cementum, enamel hypoplasia, irregular calcification of dentin, large pulp chamber, and resorption of marginal alveolar bone and roots. Our report involves a patient with a chief complaint of early loss of both Mx. and Mn. deciduous incisors. After conducting a through clinical and radiographic examination this patient was referred to pediatrics under the suspicion of hypophosphatasia, the diagnosis proved to be correct and successful results were accomplished through a denture made to improve esthetics and function.

• Journal of Periodontal and Implant Science
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• v.27 no.3
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• pp.633-645
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• 1997

The recent trend of research and development on guided tissue regeneration focuses on the biodegradable membranes, which eliminate the need for subsequent surgical removal. They have demonstrated significant and equivalent clinical improvements to the ePTFE membranes. This study evaluate guided tissue regeneration wound healing in surgically induced intrabony periodontal defects following surgical treatment with a synthetic biodegradable membranes, made from a copolymer of glycolide and lactide, in 8 beagle dogs. After full thickeness flap reflection, exposed buccal bone of maxillary and mandibular canine and premolar was removed surgically mesiodistally and occlusoapically at $6mm{\times}6mm$ in size for preparation of periodontal defects. In experimental sites a customized barrier was formed and fitted to cover the defect. Flap was replaced slightly coronal to CEJ and sutured. Plaque control program was initiated and maintained until completion of the study. In 4, 8, 16 and 24 weeks after surgery, the animals were sacrificed and then undecalcified specimens were prepared for histologic evaluation. Histologic examination indicated significant periodontal regeneration characterized by new connective tissue attachment, cementum formation and bone formation. These membranes showed good biocompatibility throughout experiodontal period. The barriers had been completely resorbed with no apparent adverse effect on periodontal wound healing at 24 weeks. These results implicated that present synthetic biodegradable membrane facilitated guided tissue regeneration in periodontal defect.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.429-436
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• 2008

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.

• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.317-332
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• 2001

The purpose of this study was to investigate effects of the natural coral(NC) and the hydroxyapatite/calcium sulfate hemihydrate(HA/CS) on an early stages of wound healing in the rat periodontal fenestration defects. In this experiment, twelve male rats(Mean : 520g in BW) aged 8 to 9 months were used. Experimental periodontal fenestration defects were surgically created with tapered fissure bur at the buccal surface of the left mandibular 1st, 2nd molars. The buccal aspects of molar roots were carefully denuded of their periodontal ligament through a bony window created in the left mandibles of rats under general anesthesia. Each experimental periodontal fenestration defect was grafted with natural coral and HA/CS, randomly. An area without bone graft was assigned for negative control group. At 10,35 days, rats were serially sacrificed via intracardiac perfusion with 2.5% glutaraldehyde and specimens were processed with Hematoxylin-Eosin stain for light microscopic evaluation. The results of this study were as follows : 1. The defect areas were filled with dense connective tissues at 10 days in control group. But in the test(NC, HA/CS)groups, the connective tissues around graft materials were formed more loosely and the response of inflammation by graft materials itself was not found. 2. The defect areas were filled with new osteoid tissues and new cementum was not formed on the cut root surface at 35 days in the control group. 3. New osteoid tissue formation was more prominent at 35 days in control than test groups. 4. The NC and HA/CS particles were encapsulated by loose connective tissues at 10 days and by dense connective tissues at 35 days, respectively. 5. In the test groups, resorption of graft particles was not found through the experimental time. From the above results, natural coral and hydroxyapatite/calcium sulfate hemihydrate may be biocompatible and osteoconductive and have a weak adverse reaction to the periodontal tissues.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.605-624
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• 1996

Various bonegraft materials and the technique of guided tissue regeneration have been used to regenerate lost periodontal tissue. Calcium sulfate has been known as a bone graft material because of good biocompatibility, rapid resorption and effective osteoinduction. It has been known that calcium sulfate works as a binder to stabilize the defect when it is used with synthetic graft materials. The effects on the regeneration of pericxiontal tissue were studied in dogs after grafting 3-wall intrabony defects with calcium carbonate and calcium sulfate and covering with calcium sulfate barrier. The 3-wall intrabony defectstdmm width, 4mm depth, 4mm length) were created in anterior area and treated with flap operation alone(contol group), with porous resorbable calcium carbonate graft alonetexperirnental group 1), with calcium sulfate graft alonetexperimental group 2) and with composite graft of 80% calcium carbonate and 20% calcium sulfate with calcium sulfate barriertexperimental group 3). Healing responses were histologically observed after 8 weeks and the results were as follows: 1. The alveolar bone formation was $0.59{\pm}0.19mm$ in the control group, $1.80{\pm}0.25mm$ in experimental group 1, $1.61{\pm}0.21mm$ in experimental group 2 and $1.94{\pm}0.11mm$ in experimental group 3 with statistically significant differences between control group and all experimental groups(P<0.05). There were statistically significant differences between experimental group 1 and group 2 (P<0.05). 2. The new cementum formation was $0.48{\pm}0.19mm$ in the control group. $1.72{\pm}0.26mm$ in experimental group 1, $1.43{\pm}0.17mm$ in experimental group 2, $1.89{\pm}0.15mm$ in experimental group 3 with statiscally significant differences between control group and all experimental groups (p<0.05). There were statistically significant differences between experimental group 1 and group 2, and between experimental group 2 and group 3(P<0.05). 3. The length of junctional epithelium was $1.61{\pm}0.20mm$ in the contol group, $0.95{\pm}0.06mm$ in experimental group 1, $1.34{\pm}0.16mm$ in experimental group 2, $1.08{\pm}0.11mm$ in experimental group 3 with statiscally significant differences between control group and experimental group 1. and btween control group and experimental group 3(p<0.05). There were statistically significant differences between experimental group 1 ,and group 2, and between experimental group 2 and group 3(P<0.05). 4. The connective tissue adhesion was $1.67{\pm}O.20mm$ in the control group, $1.33{\pm}0.24mm$ in experimental group 1. $1.23{\pm}0.16mm$ in experimental group 2, $1.08{\pm}0.14mm$ in experimental group 3 with statistically significant differences between control group and all experimental groups(p<0.05). There were nostatistically significant differences between all experimental groups. As a result, epithelial migration was not prevented when calcium sulfate was used alone, but new bone and cementum formation were enhanced. Epithelial migration was prevented and new bone and cementum formation were also enhanced when calcium carbonate was used alone and when both calcium carbonate and calcium sulfate were used.

• The korean journal of orthodontics
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• v.30 no.3 s.80
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• pp.317-333
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• 2000

The purpose of this study was to determine the proliferative activity of the osteoblasts and fibroblasts in the midpalatal area and to investigate the adjacent periodontal tissues of individual tooth following rapid expansion of the palate. Ten young adult dogs, aged approximately ten months, were used in the experiment. The experimental design was consisted of 1 week expansion group(Group E1, 3 dogs), 2 week expansion group(Group E2, 3 dogs), 2 week expansion and 2 week retention group(Group E3, 3 dogs), and control group(Group C, 1 dog). For each group, expansion screw was activated one time per day(1/4 turn;$90^{\circ}$) following Hyrax-screw application. The experimental animals in each group were sacrificed at 1, 2 and 4 weeks following palatal expansion. Maxillary tissue blocks were obtained and prepared ior the histomorphologic and immunohistochemical studies. Light mcroscope, polarizing microscope, and soft X-ray apparatus were used in this study, and following results were obtained. 1. In polarizing microscopic study, the expansion groups(E1 & E2) showed blue color representing bone resorption and new bone formation in midpalatal suture area. E3 groups skewed less blue color compared to the E1 and E2 group. But yellow color increased by calcification in the E3 groups. 2. Immunohistochemical study revealed that positive responses of the osteoblasts to PCNA and undifferentiated fibroblasts to EGF in E1 group were somewhat increased. Positive response to PCNA and EGF were increased in fibroblasts and the osteoblasts forming new bone in E2 group. In E3 group, the positive response cell concentrated the periphery of edge of palatal process in both PCNA and EGF. 3. Throughout the expansion period(E1 & E2), light microscopic study showed the edges of the extensive resorption and new palatal processes, indicating bone remodeling within the suture. E3 group exhibited less remodeling of midpalatal suture area. E2 group and E3 group showed cementum formation and resorption at the apex of 3rd premolar and 1st molar E3 group exhibited extensive hyalinized zone on the cervical portion of buccal side of 1st molar. 4. Soft X-ray analysis of E1 group showed hypomineralized defect and microfractures in various parts of the suture areas when compared with control animals. There was no significant difference in the degree of mineralization in the midpalatal suture region between the C and E3 groups. Tooth axis showed tipping of 3rd premolar and 1st molar in the E2 group and E3 group. Based upon these experimental results, it is concluded that the undifferentiated mesenchymal cells always presented in midpalatal suture area following RPE. Differentiated osteoblasts and fibroblasts possess proliferating cellular activity until the 2 week retention period. The posterior teeth are tend to tip buccally as RPE force applied. Retention group exhibited irreversible response with severe hyalinized zone on the buccal surface of the first molar.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.297-310
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• 1998

The purpose of this study was to investigate the initial tissue change, to repair on the teeth & surrounding tissue under the intrusive orthodontic forces by use of elastic chain, through the microscopic findings. For this study, three young adult mongrel dogs were used, and were divied into three group : the control group was deliveried only casting crown and the experimental group 1 was equipped with energy chain during 1 week and experimental 2 group was deliveried using energy chain during 1 week and 3 weeks observation. All experimental groups and control groups were sacrificed to make the samples for microscopic findings on premolar teeth. All samples were examed and compared the histologic changes through the microscopic with H-E stain. The obtained results were as follows. 1. In hematoxylin-eosin stain of the control group, the periodontal ligament was constant width from apical third to cervical third of the root, and the periodontal fiber arrangement was horizontal or oblique in cervical third, oblique in middle and apical third of the root. 2. In Masson Trichrome stain of the control group, osteoblast and osteoclast appeared in cervical third of root, and bone resorption and new bone formation was observed in middle and apical third of the root. 3. In experimental 1, osteoclasts were increased highly, and hyperemia of blood vessels and new bone formation and bone resorption by reversal line in apical third of the root were seen. PDL width was increased apprarently from crest to apex of the root and more in apical third. 4. In experimental 2, osteoclasts and hyperemia of blood vessels were more increased than control material in apical third of the root. PDL width was increased more than control group in root apex, and was seen less than experimental 1. PDL arrangement was similar to experimental 1 and was mixed only in root apex. Therefore, in premolar intrusion of the young adult dog, there were increased osteoclast, hyperemia and dilation of blood vessel, resorption of alveolar bone and cementum and different arrangement of PDL in initial tissue change. There was not observed complete repair after remove intrusive force.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.223-234
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• 1992

The purpose of this study was to investigate the changes of periodontal tissues in the irradiated mandibular bone in rats which were fed normal diet and low calcium diet In order to carry out this experiment, 64 seven-week old Sprague-Dawley strain rats weighing about 150gms were selected and equally divided into one experimental group of 32 rats and one control group with the remainder. The experimental group and the control group were then subdivided into two groups when the rats reached the age of 10 weeks, 16 rats were allotted for each subdivided group was composed of 16 rats and exposed to irradiation. The two groups were irradiated a single dose of 20Gy on the only jaw area and irradiated with a cobalt-60 teletherapy unit The rats in the control and experimental groups were serially dissected by fours on the 3rd, the 7th, the 14th, and the 21st day after irradiation. After each dissection, both sides of the dead rat mandibular bodies were removed and fixed with 10% neutral formalin. The specimens sectioned and observed in histopathological. histochemical. and immunocellular chemical methods. The obtained results were as follows: 1. In the mandibles of rats with low calcium diet the increased number of fibroblasts of periodontal ligaments. many small capillaries and irregular arrangement of loose collagen fibers were detected and the partial resorption of dentin and cementum could be found by the microscopic studies. 2. In the group of irradiated rats, degenerated periodontal tissues led to the condition of irregular arrangement of collagen fibers and the decreased number of fibroblasts. But this condition was somewhat restored after 21 days of experiment. 3. Periodontal tissues of the irradiated rat group with low calcium diet were destroyed earlier than those of the irradiated rat group with normal diet. Soon this condition was restored and then high cellularity and dense collagen fibers were observed. 4. Many periodontal cells bearing tumor necrosis factor could be clearly observed in the nonirradiated group of rats with normal diet, whereas could not be observed on the 7th day and reappeared on 14th day in the irradiated group of rats with normal diet. A few of them could be observed in the group of rats with low calcium diet, but they could be clearly observed in the both groups after 21 days of experiment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.29-37
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• 2012

Introduction: Fibrous-osseous lesions of the jaws are difficult to diagnose precisely until excised biopsy results are found, so they might be confused with malignant lesions. This clinical study focused on the diagnostic aids of lesions that demonstrate different clinical, radiologic, and histological findings. Materials and Methods: A total of 16 patients with benign fibrous-osseous lesions on the jaws (6 fibrous dysplasias, 6 ossifying fibromas, 3 cemental dysplasias, and one osteoblastoma) were reviewed. Nine patients with malignant fibrous-osseous lesions (8 osteosarcomas and one Ewing's sarcoma) were also retrospectively reviewed. Results: Osteosarcoma patients complained of facial swelling and tooth mobility. The radiographic findings showed the irregular resorption of cortical bone and periosteal reactions. Histological features included cellular pleomorphism and atypical mitosis. An Ewing's sarcoma patient complained of tooth mobility and facial swelling. Onion-skin appearance and irregular expansile marginal bony radiolucency were seen in the radiography. Fibrous dysplasia patients complained of facial swelling and asymmetry. The radiographic features were mostly ground-glass radiopacity. Histological findings showed a bony trabeculae pattern surrounded by fibrous ground substances. Ossifying fibroma patients complained of buccal swelling and jaw pains, showing expanded cortical radiolucent lesions with a radiopaque margin. Histological findings were revealed as cellular fibrous stroma with immature woven bones. In cemental dysplasia, most of their lesions were found in a routine dental exam. Well-circumscribed radiopaque lesions were observed in the radiography, and cementum-like ossicles with fibrous stroma were seen in the microscopy. An osteoblastoma patient complained of jaw pain and facial swelling. Radiographic findings were mottled, dense radiopacity with osteolytic margin. Trabeculae of the osteoid with a vascular network and numerous osteoblasts with woven bone were predominantly found in the microscopy. Conclusion: Our study showed similar results as other studies. We suggest the clinical parameters of diagnosis and treatment for malignant and benign fibrous-osseous lesions of the jaws.