• Journal of Periodontal and Implant Science
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• v.52 no.1
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• pp.3-27
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• 2022

Purpose: This study was conducted to evaluate and compare the effects of different graft materials used in alveolar ridge preservation on dimensional hard tissue changes of the alveolar ridge, assessed using cone-beam computed tomography (CBCT) scans. Methods: A systematic electronic search of MEDLINE and the Cochrane Central Register of Controlled Trials and a manual search were conducted from November 2019 until January 2020. Randomized controlled trials were included if they assessed at least 1 variable related to vertical or horizontal hard tissue changes measured using CBCT scans. After a qualitative analysis of the included studies, subgroups were formed according to the graft material used, and a quantitative analysis was performed for 5 outcome variables: changes in vertical alveolar bone height at 2 points (midbuccal and midpalatal/midlingual) and changes in horizontal (buccolingual) alveolar bone width at 3 different levels from the initial crest height (1, 3, and 5 mm). Results: The search resulted in 1,582 studies, and after an independent 3-stage screening, 16 studies were selected for qualitative analysis and 9 for quantitative analysis. The metaanalysis showed a significantly (P<0.05) lower reduction of alveolar ridge dimensions for the xenogenic subgroup than in the allogenic subgroup, both vertically at the midbuccal aspect (weighted mean difference [WMD]=-0.20; standard error [SE]=0.26 vs. WMD=-0.90; SE=0.22) as well as horizontally at 1 mm (WMD=-1.32; SE=0.07 vs. WMD=-2.99; SE=0.96) and 3 mm (WMD=-0.78; SE=0.11 vs. WMD=-1.63; SE=0.40) from the initial crest height. No statistical analysis could be performed for the autogenic subgroup because it was not reported in sufficient numbers. Conclusions: Less vertical and horizontal bone reduction was observed when xenogenic graft materials were used than when allogenic graft materials were used; however, the loss of alveolar ridge dimensions could not be completely prevented by any graft material.

• Journal of Oral Medicine and Pain
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• v.38 no.2
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• pp.103-108
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• 2013

Pachyonychia congenita is a very rare group of an autosomal dominant genodermatosis caused by heterozygous mutations in the keratin genes. The clinical findings affect nail and toenails, soles, and oral mucosa, etc. The main symptoms include nail and toenail dystrophy, hyperkeratosis of hands and feet, follicular hyperkeratosis, oral leukokeratosis. Many therapeutic modalities have been used to treat skin lesion, including surgical and mechanical procedures, chemical agents, medications. Oral lesions but not usually require treatment, if the patient's discomfort occurs, symptomatic therapy is performed. In the patients accompanied by oral and skin lesions, clinician have to observe specific manifestations with dystrophy of the fingernails and toenails, plantar hyperkeratosis, oral leukokeratosis and tissue biopsy is required for diagnosis confirmed.

• Imaging Science in Dentistry
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• v.34 no.2
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• pp.81-89
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• 2004

Purpose: To investigate the histopathological changes in the temporomandibular joint in streptozotocin-induced diabetic rat following irradiation. Materials and Methods : Sprague-Dawley rats weighing about 250 gm were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control group were injected with citrate buffer only. After 5 days, the head and neck region of the rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy. The rats were killed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimen including the temporomandibular joint were sectioned and observed using a histopathological method. Results : In the diabetic group, severe bone resorption in the mandibular condyle was observed throughout the period of experiment. Necrosis of bone marrow and trabeculae was observed at 28 days after diabetic state. Atrophy and fibrosis in the retrodisca] tissue was gradually progressed during the time of the experiment. In the diabetic-irradiated group, severe bone resorption in the mandibular condyle was observed during the early experimental phases, but regeneration of bone marrow was initiated at ]4 days after diabetic state and irradiation. A]so, calcification of abnormal trabeculae was observed at 28 days after diabetic state and irradiation. The retrodisca] tissue was degenerated in the early experimental phases, but it had been gradually regenerated during the experimental time. Conclusion: This experiment suggests that bone resorption and degeneration in the mandibular condyle are caused by the induction of diabetes, and abnormal bone formation is induced after irradiation in diabetic state.

• Journal of Biosystems Engineering
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• v.38 no.2
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• pp.113-120
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• 2013

Purpose: Stem cells provide new opportunities in the regenerative medicine for human or animal tissue regeneration. In this study, we report an efficient method for the modulating behaviors of electro-active stem cells by micro-electric current stimulation (mES) without using chemical agents, such as serum or induction chemicals. Methods: Dental pulp stem cells (DPSCs) were cultured on the tissue culture dish in the mES system. To find a suitable mES condition to promote the DPSC functions, the response surface analysis was used. Results: We found that a working micro-current of 38 ${\mu}A$ showed higher DPSC proliferation compared with other working conditions. The mES altered the expressions of intracellular and extracellular proteins compared to those in unstimulated cells. The mES with 38 ${\mu}A$ significantly increased osteogenesis of DPSCs compared with ones without mES. Conclusions: Our findings indicate that mES may induce DPSC proliferation and differentiation, resulting in applying to DPSCs-based human or animal tissue regeneration.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.27.1-27.9
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• 2016

Background: The objective of this study was to place bone graft materials in cranial defects in a rabbit model and compare their bone regenerating ability according to the size and density of demineralized dentin matrix (DDM). Methods: We selected nine healthy male rabbits that were raised under the same conditions and that weighed about 3 kg. Two circular defects 8 mm in diameter were created in each side of the cranium. The defects were grafted with DDM using four different particle sizes and densities: 0.1 mL of 0.25- to 1.0-mm particles (group 1); 0. 2 mL of 0.25- to 1.0-mm particles (group 2); 0.1 mL of 1.0- to 2.0-mm particles (group 3); and 0.2 mL of 1.0- to 2. 0-mm particles (group 4). After 2, 4, and 8 weeks, the rabbits were sacrificed, and bone samples were evaluated by means of histologic, histomorphometric, and quantitative RT-PCR analysis. Results: In group 1, osteoblast activity and bone formation were greater than in the other three groups on histological examination. In groups 2, 3, and 4, dense connective tissue was seen around original bone even after 8 weeks. Histomorphometric analysis of representative sections in group 1 showed a higher rate of new bone formation, but the difference from the other groups was not statistically significant. RT-PCR analysis indicated a correlation between bone formation and protein (osteonectin and osteopontin) expression. Conclusions: DDM with a space between particles of $200{\mu}m$ was effective in bone formation, suggesting that materials with a small particle size could reasonably be used for bone grafting.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.133-141
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• 2000

Purpose : The purpose of this study is to estabilish clinical guidance of microvascular anastomosis in diabetic patients. This study was performed with experimental microvascular anastomosis in streptozotocin induced diabetic rats and observed histopathologic change and endohelial healing process. Materials and Methods : 70 Sprague-Dawley rats, weighting 200 to 250grams, were used for the experiment. 35 induced diabetic rats with streptozotocin and 35 control group were selected. After end-to-end carotid artery microvascular anastomosis was done, the experimental rats were sacrificed at different time interval (1st day, 3rd day, 1st week, 2nd, 4th, 6th and 8th week) for histologic examination. Light microscope observation was used in this study. Results : 1. Histopathologic changes are nearly the same healing process in two groups. But period of tissue reaction was faster in the control than diabetic group. 2. In endotheliall healing, control group started at 1 week after and completed at 4 weeks after, but diabetic group was observed partially at 4 weeks after and complete healing was not observed still at 8 weeks after. 3. In subintimal hyperplasia, control group was observed at 6 weeks after but diabetic group was observed at 6 weeks after and partially at 8 weeks after. 4. All groups showed severe inflammatory response in the early period. This respond is decreased at 2 weeks after in control group but still remained at 8 weeks after in the diabetic group. 5. In media, inflammatory response and degeneration were observed in early period. Regeneration of smooth muscle cell was observed at 1 week after in control group but 4 weeks after in the diabetic group. Conclusions : As the results of study, it could be thought that vascular regeneration process was not failured but delayed in the diabetes. It was considered that diabetes mellitus was not absolute contraindication of microvascular anastomosis.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.4
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• pp.364-370
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• 2015

Fixed restoration using implants for patients with posterior partial edentulism is generalized technique. As patient demands increase, the functional and esthetic implant restoration to achieve similar results to lost natural teeth is becoming an important issue. It is inevitable to use customized CAD/CAM abutments rather than ready-made abutments for the creation of implant prosthesis which closely resembles natural teeth. Using CAD/CAM abutment made it possible to obtain natural emergency profiles for posterior implant prostheses, ensuring more comfortable, efficient management of oral hygiene. However, keratinized gingiva with sufficient width and height for a natural emergence profile is required to use a large diameter CAD/CAM abutment which ensures stability and esthetics of hard/soft tissue around the implants. In this case, for esthetical and functional implant zirconia prosthesis, soft tissue graft was performed and customized CAD/CAM abutments were used following ridge augmentation, sinus graft and implantation. Satisfactory results were obtained functionally and esthetically through periodic clinical evaluation, and I hereby report this case.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.939-948
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• 2005

The role of the periosteum on osteointegration of $Bio-Oss^{(R)}$(Geistlich, Wolhusen/Switzerland) was studied in rabbit calvarial defect. 12 New Zealand white male rabbits between 2.8 and 4 kg were included in this randomized, blinded, prospective study. Each rabbit was anesthetized with Ketamine HCl(5 mg/kg) and Xylazine HCl(1.5 ml/kg). An incision was made to the bony cranium and the periosteum was reflected. Using a 6-mm trephine bur(3i. USA), four 8-mm defects were created with copious irrigation. The defects were classified into barrier membrane($Tefgen^{(R)}$, Lifecore Biomedical. Inc, U.S.A.) only group as a control, $Bio-Oss^{(R)}$ with barrier membrane group, $Bio-Oss^{(R)}$ with periosteum covering group, and $Bio-Oss^{(R)}$ without periosteum covering group. There were 2 rabbits in each group. The wound was closed with resorbable suture materials. Rabbits were sacrificed using phentobarbital(100 mg/kg) intravenously at 1, 2, and 4 weeks after surgery. The samples were fixed in 4% paraformaldehyde, and decalcified in hydrochloric acid decalcifying solution(Fisher Scientific, Tustin, CA) at $4^{\circ}C$ for 2-4 weeks. It was embedded in paraffin and cut into 6 ${\mu}m$ thickness. The sections were stained with H & E and observed by optical microscope. The results were as follows; 1. The periosteum played an important role in osteointegration of $Bio-Oss^{(R)}$ in bone defects. 2. When the periosteum remained intact and $Bio-Oss^{(R)}$ was placed on the defect, $Bio-Oss^{(R)}$ with periosteum covering has been incorporated into the newly formed bone from 2-week postoperatively. 3. When the periosteum was removed at the surgical procedure, invasion of connective tissue took place among the granules, and new bone formation was delayed compared to periosteum covering group. Therefore, when the bone grafting was performed with periosteal incision procedure to achieve tension-free suture, the integrity of the overlying periosteum should be maintained to avoid fibrous tissue ingrowth.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.385-396
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• 2006

For the regeneration of periodontal tissues, the microenvironment for new attachment of connective tissue fibers should be provided, At this point of view, cementum formation in root surface plays a key role for this new attachment. This study was performed to figure out which factor promotes differentiation of cementoblast Considering anatomical structure of tooth, we selected the cells which may affect the differentiation of cementoblast - Ameloblast, OD11&MDPC23 for odontoblasts, NIH3T3 for fibroblsts and MG63 for osteoblasts. And OCCM30 was selected for cementoblast cell line. Then, the cell lines were cultured respectively and transferred the conditioned media to OCCM30. To evaluate the result, Alizarin red S stain was proceeded for evaluation of mineralization. The subjected mRNA genes are bone sialoprotein(BSP), alkaline phosphate(ALP) , osteocalcin(OC), type I collagen(Col I), osteonectin(SPARC ; secreted protein acidic and rich in cysteine). Expression of the gene were analysed by RT-PCR, The results were as follows: 1. For alizarin red S staining, control OCCM30 didn't show any mineralized red nodules until 14 days. But red nodules started to appear from about 4 days in MDPC-OCCM30 & OD11-OCCM30. 2. For results of RT-PCR, ESP mRNAs of control-OCCM30 and others were expressed from 14 days, but in MDPC23-OCCM30 & OD11-OCCM30 from 4 days. Like this, the gene expression of MDPC23-OCCM30 & OD11-OCCM30 were detected much earlier than others. 3. For confirmation of odontoblast effect on cementoblast, conditioned media of osteoblasts(MG63) which is mineralized by producing matrix vesicles didn't affect on the mineralized nodule formation of cementoblasts(OCCM30). This suggest the possibility that cementoblast mineralization is regulated by specific factor in dentin matrix protein rather than matrix vesicles. Therefore, we proved that the dentin/odontoblast promotes differentiation/mineralization of cementoblasts. This new approach might hole promise as diverse possibilities for the regeneration of tissues after periodontal disease.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.366-374
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• 2010

Introduction: This study evaluated the capability of silk fibroin (SF) and recombinant human bone morphogenetic protein-2 loaded SF (SF-BMP) as a bone defect replacement matrix when grafted in a calvarial bone defect of rats in vivo. Materials and Methods: A total 70 calvarial critical size defects (5.0 mm in diameter) made on 35 adult female Sprague-Dawley rats were used in this study. The defects were transplanted with (1) rhBMP-2 loaded silk fibroin graft (SF-BMP: 0.8+$10\;{\mu}g$), (2) Silk fibroin (SF: $10\;{\mu}g$), and (3) no graft material (Raw). The samples were evaluated with soft x-rays, alkaline phosphatase activity, calcium/phosphate quantification, histological and histomorphometric analysis at postoperative 4 and 8 weeks. Results: The SF-BMP group ($48.86{\pm}14.92%$) had a significantly higher mean percentage bone area than the SF group ($24.96{\pm}11.01%$) at postoperative 4 weeks.(P<0.05) In addition, the SF-BMP group ($40.01{\pm}12.43%$) had a higher % bone area at postoperative 8 weeks than the SF group ($33.26{\pm}5.15%$). The mean ratio of gray scale levels to the host bone showed that the SF-BMP group ($0.67{\pm}0.08$) had a higher mean ratio level than the SF group ($0.61{\pm}0.09$) at postoperative 8 weeks. These differences were not statistically significant.(P=0.168 and P=0.243, respectively) The ratio of the calcium and phosphate contents of the SF-BMP ($0.93{\pm}0.22$) group was lower than that of the SF ($1.90{\pm}1.42$) group at postoperative 4 weeks. However, the SF-BMP group ($0.75{\pm}0.31$) had a higher Ca/$PO_4$ ratio than the SF ($0.68{\pm}0.04$) at postoperative 8 weeks. These differences were not statistically significant.(P=0.126 and P=0.627, respectively) For the bone-specific alkaline phosphatase (ALP) activity, which is recognized as a reliable indicator of the osteoblast function, the SF-BMP ($23.71{\pm}8.60\;U/L$) groups had a significantly higher value than the SF group ($12.65{\pm}6.47\;U/L$) at postoperative 4 weeks.(P<0.05) At postoperative 8 weeks, the SF-BMP ($21.65{\pm}10.02\;U/L$) group had a lower bone-specific ALP activity than the SF group ($16.72{\pm}7.35\;U/L$). This difference was not statistically significant.(P=0.263) For the histological evaluation, the SF-BMP group revealed less inflammation, lower foreign body reactions and higher bone healing than the SF group at postoperative 4 and 8 weeks. The SF group revealed more foreign body reactions at postoperative 4 weeks. However, this immunogenic reaction decreased and the remnant of grafted material was observed at postoperative 8 weeks. For histomorphometric analysis, the SF-BMP group had a significantly longer bone length to total length ratio than those of the SF group at postoperative 4 and 8 weeks.(P<0.05) Conclusion: The rhBMP-2 loaded silk fibroin graft revealed fewer immunoreactions and inflammation as well as more new bone formation than the pure silk fibroin graft. Therefore, silk fibroin may be a candidate scaffold for tissue engineered bone regeneration.