• Journal of Periodontal and Implant Science
• /
• v.27 no.4
• /
• pp.949-961
• /
• 1997

To date, various clinical procedures have been used to restore periodontal apparatus destroyed by periodontal disease. And then, many experimental approaches have been proceeded to develop treatment methods to promote periodontal regeneration. Mechanical, chemical treatments to enhance the attachment of periodontal tissue cells as changing the physical properties of root surfaces, bone graft procedure, and treatments for guided tissue regeneration have been used for periodontal regeneration. However, recent studies have revealed that biologic factors such as growth factors promote biologic mechanism associated with periodontal regeneration. This study was done to enucleate how ELF stimulus affect the periodontal regeneration. We can have following conclusions from this experimental results. The influence of low frequency(ELF) electric stimulus (30Hz at $lO{\mu}A$) known to promote bone formation in vivo, was evaluated for its ability to affect bone cell function in vitro. After 12 hour exposure of ELF stimulus at most appropriate densities ($5{\times}10^4\;cells/cm^2$) to increase osteoblastic cells normally, rat calvarial cells were incubated for 60 hours were used in this study. We have found ELF stimulus suppress calvarial cell proliferation and the ability of protein synthesis, enhance the alkaline phosphatase activity significantly.

• 대한치주과학회:학술대회논문집
• /
• 2001.12a
• /
• pp.86-86
• /
• 2001

• The Journal of the Korean dental association
• /
• v.54 no.7
• /
• pp.501-512
• /
• 2016

We evaluated a self-inflatable osmotic tissue expander for its utility in creating sufficient soft tissue elongation for primary closure after bone grafting. Six patients with alveolar defects who required vertical augmentation of >6 mm before implant placement were enrolled. All had more than three prior surgeries, and flap advancement for primary coverage was restricted by severely fibrosed scars. Expanders were inserted beneath the flap and fixed with a screw. After 4 weeks, expander removal and bone grafting were performed simultaneously. A vertical block autograft and guided bone regeneration and distraction osteogenesis were performed. Expansion was sufficient to cover the grafted area without additional periosteal incision. Complications included mucosal perforation and displacement of the expander. All augmentation procedures healed uneventfully and the osseous implants were successfully placed. The tissue expander may facilitate primary closure by increasing soft tissue volume. In our experience, this device is effective, rapid, and minimally invasive, especially in fibrous scar tissue.

• Journal of Life Science
• /
• v.22 no.4
• /
• pp.447-455
• /
• 2012

Akt plays an important role in a variety of cellular physiologies such as growth, proliferation, and differentiation. In skeletal muscle, Akt has been implicated in regulating regeneration, hypertrophy, and atrophy. In this study, the role of Akt has been examined during skeletal muscle differentiation. Culturing C2C12 myoblasts under low serum (1% horse serum) and high density converted cell morphology from a round shape to an elongated and multi-nucleated shape. Morphological changes were initiated from day 2 of differentiation. In addition, the expression of both myogenin G and myogenin D was elevated from day 2 of differentiation. Skeletal muscle differentiation was abolished by silencing Akt1 or Akt2, but was significantly enhanced by the over-expression of either Akt1 or Akt2. The activation of Akt was observed from day 2 of differentiation and disappeared after day 7. The expression of kruppel-like factor 4 was observed from day 6 of differentiation. Moreover, this expression was blocked in cells silencing either Akt1 or Akt2. In addition, the promoter activity of kruppel-like factor 4 was significantly reduced in cells silencing Akt1 or Akt2. These results suggest that Akt regulates skeletal muscle differentiation through the regulation of kruppel-like factor 4 expression.

• Journal of Periodontal and Implant Science
• /
• v.33 no.4
• /
• pp.673-691
• /
• 2003

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, and the administration of growth factors as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exists, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and a bone xenograft used in conjunction with a non-resorbable guided-tissue membrane, e-PTFE, compared to a control group with regards to bone regeneration at the implant fixture site. Implant fixtures were inserted and graft materials placed into the left femur of in the experimental group, while the control group received only implant fixtures. In the first experimental group, platelet-rich plasma and BBP xenograft were placed at the implant fixture site, and the second experimental group had platelet-rich plasma, BBP xenograft, and the e-PTFE membrane placed at the fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2 , 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the first experimental group compared to the control group. 2. The histopathological findings of the second experimental group showed rapid resorption of BBP with subsequent new bone formation replacing the resorbed BBP. 3. The second experimental group showed new bone formation in the area adjacent to the fixture threads beginning two weeks after fixture implantation, with continued bone remodeling in the areas mesial and distal to the fixture. 4. Significant new bone formation and bone remodeling was observed in both experimental groups near the implant fixture sites. 5. The rate of osseointegration at the fixture threads was greater in the second experimental group compared to the first group, and the formation of new bone and trabeculae around the fixture site occurred after the fourth week in the second experimental group. The results of the experiment suggest that a greater degree of new bone formation and osseointegration can occur at the implant fixture site by utilizing platelet-rich plasma and bone xenografts, and that these effects can be accelerated and enhanced by concurrent use of a non-resorbable guided tissue membrane.

• Journal of Periodontal and Implant Science
• /
• v.23 no.3
• /
• pp.359-373
• /
• 1993

The ultimate objective of periodontal therapy is not only stopping the progression of periodontal disease, but also promoting the regeneration of lost periodontal tissue. Guided Tissue Regeneration, which is based on the principle that the goal of periodontal regeneration can be achieved by preventing apical migration of gingival epithelium and blocking cells originating from connective tissue, has been developed and used as a clinical procedure, and although it has shown excellent results in connective tissue healing, there have not been many studies showing its effect on the regeneration of alveolar bone loss due to periodontal disease. The objectives of this study are to investigate the result of 12 months-long treatment following guided tissue regeneration using expanded polytetrafluoroehylene membrane, and to observe the presence of regenerated alveolar bone. Forty-one teeth from 28 patients with clinical diagnosis of periodontitis has been selected. In fifteen of those interproximal intrabony defects, only flap operation had been carried out, and designated as the control group. Twenty-six intrabony defects received e-PTFE membrane following flap operation, and designated as the experimental group. Eleven teeth whose membrane had been exposed were excluded from the experiment. Various measurements including probing depth, loss of attachment, probing bone level and gingival recession have been recorded at 6th month and 12th month, and the significance of the changes has been analyzed. The results are as follows: 1. Probing depth at 6th and 12th month has shown a significant decrease in both groups (p<0.01), but significantly higher decrease was found in the experimental group compared to the control at the month(p<0.05). 2. Loss of attachment at 6th and 12th month has shown a significant decrease in both groups, but significantly higher decrease was found in the experimental group compared to the control (p<0.05). 3. Probing bone level at 6th and 12th month has shown a insignificant decrease in the control group and significant decrease in the experimental group (p<0.01). Significantly higher decrease in probing bone level was found in the experimental group (p<0.05). 4. Gingival recession at 6th and 12th month has shown a statistically significant increase (p<0.05), and the control group showed higher increase compared to the experimental group although no statistical significance was found. As these results have shown, the use of e-PTFE membrane in intrabony pockets results in marked decrease in the loss of attachment and probing bone level. This seems to indicate that e-PTFE membrane may play a role in alveolar bone regeneration in intrabony defects.

• Journal of the Korean Society of Radiology
• /
• v.17 no.6
• /
• pp.993-999
• /
• 2023

Bio materials of fibrinogen and collagen are widely used in tissue regeneration engineering. In this study, I aim to create a new dual-structure support using these two materials. Strategically, tissue regeneration takes priority over blood vessel regeneration, so by forming a fibrinogen support that helps blood vessel formation on the outside of the double support and placing collagen, which is more effective in tissue regeneration, in the center, a synergistic effect in new tissue regeneration is expected. Although these two materials have been used interchangeably in previous studies, there has been no report yet on making a support through the formation of a support structure for the core system. Therefore, the core of this study, the double scaffold, is to propose a method for manufacturing a core structure with a collagen scaffold on the inside and fibrinogen on the outside. The experimental results showed that the fibrinogen located on the outside of the scaffold resulted in rapid biodegradation and drug release due to strategic biodegradation of the dual structure scaffold. On the other hand, collagen scaffolds were found to be able to maintain drug release time relatively longer than fibrinogen scaffolds. In conclusion, it is believed that applying the method of creating a double scaffold will have a synergistic effect on defective tissue regeneration.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.21 no.3
• /
• pp.257-265
• /
• 1999

To investigate the sequential changes in microvascular architecture and osseous regeneration during the bony healing after an application of the guided tissue regeneration method, we made artificial defects measuring $0.7cm{\times}0.3cm$ in size on femoral bones of rats measuring about 200gm and applied non-absorbable TEFE membrane at experimental sites but not at control sites. Then we observed the sequential changes and correlations between new vacuolation and bony regeneration using microvascular corrosion cast method and routine light microscopic observation at 1, 2 and 3 weeks after operation, respectively. The results showed that there were close relationships between regeneration of microvasculature and bone. In early phase, the invasion of granulation tissue at control sites delayed bony regeneration, however, in later phase, there was no remarkable differences in bony regeneration between control and experimental sites. The placement of barrier also affected in revascularization of regenerating bony defects. This is, the experimental sites showed parallel arranged nutritional vessels along long axis with well developed retiform plexus whereas the control revealed vertical invasion of microvasculature from outside of marrow space through bony defects which was also rearrange with time into parallel pattern with a vertical plexus but lesser organized than that of experimental sites. These findings suggest that the reconstruction of regenerating vasculature within the marrow cavity only may be sufficient and/or more be efficient in regeneration of bony defects.

• Journal of Periodontal and Implant Science
• /
• v.31 no.2
• /
• pp.345-356
• /
• 2001

The purpose of the present study was to evaluate the clinical efficacy of guided tissue regeneration(GTR) using resorbable polylactic/polyglycolic copolymer(PLA/PGA) membrane in mandibular class II furcation involvement and to compare it to the clinical efficacy of only flap operation. Both procedures were conducted in 5 patients with class II furcation involvements. After 6 months of follow up, the probing pocket depth, clincial attachment level, bone probing depth, and radiographic changes were compared, and the following results were obtained: 1. GTR using PLA/PGA demonstrated a statistically significant reduction in probing pocket depth and bone probing depth, and the control group demonstrated a statistically significant reduction in bone probing depth. 2. The comparison between the experimental and control group failed to demonstrate statistically significant difference in clinical improvement, but more reduction in probing pocket depth and bone probing depth were observed in the experimental group. The probing pocket depth and the bone probing depth were $2.2{\pm}1.6mm$ and $2.4{\pm}1.1mm$ respectively in the control group, while they were $2.4{\pm}1.3mm$ and $3.0{\pm}1.2mm$ respectively in the experimental group. 3. Radiographic change was not detectable for the both groups during the 6 months of follow up. 4. Sites with deeper probing pocket depth at baseline examination showed greater amount of clinical improvement in both groups. Other clinical factors didn't have any significant effect on the treatment results. It is concluded that though there are some limitations, PLA/PGA membrane is effective for the treatment of mandibular class II furcation involvement.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.6
• /
• pp.869-878
• /
• 2014

In this study, we performed two-dimensional electrophoresis with protein extracts from lizard tails, and analyzed the protein expression profiles during the tissue regeneration to identify the dedifferentiation factor. As a result, we identified 18 protein spots among total of 292 spots, of which proteins were specifically expressed during blastema formation. We selected lactoferrin as a candidate because it is the mammalian homolog of leech-derived tryptase inhibitor, which showed the highest frequency among the 18 proteins. Lactoferrin was specifically expressed in various stem cell lines, and enhanced the efficiency of iPSC generation upto approximately 7-fold relative to the control. Furthermore, lactoferrin increased the efficiency by 2-fold without enforced expression of Klf4. These results suggest that lactoferrin may induce dedifferentiation, at least partly by increasing the expression of Klf4.