• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.799-821
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• 1996

The ultimate goal of periodontal treatment has been to facilitate regeneration of diseased periodontal tissues, destroyed by inflammatory periodontal disease. For regeneration of the periodontium to occur, all of component tissues must be restored to their original position and architecture. Growth factors which were known to promote the cellular processes, ie, proliferation, migration and matrix synthesis, have been in the spotlight of current periodontics. Platelet-derived growth factor(PDGF) stimulates collagen and non collagen protein synthesis, migration and proliferation of periodontal ligament cells. Insulin-like growth factor(IGF) has potentials to induce collagen and bone matrix synthesis so that it regulates normal bone remodeling. Application of the combination have been known to facilitate formation of bone and cementum, and to synergistically interact to promote coronal migration and proliferation of periodontal ligament cells. These two growth factors have been reported to exhibit positive effect in the periodontally diseased teeth or class m furcation defects. The aim of the present study was to test the hypothesis that PDGF-BB alone or the combination of PDGF-BB and IGF-I can predictably enhance regeneration of the periodontium in the dehiscence defect. Following the resection of premolars, roots were embedded. After 12 weeks of healing period, standardized experimental $4{\times}4mm$ dehiscence defects were created on the mid-facial of the premolar roots in each of 4 young adult dogs. In control group, only methylcellulose gel was inserted in the defects. In experimental group I and II, gel with $2{\mu}g$ of PDGF-BB or $2{\mu}g$ of PDGF-BB and $1{\mu}g$ of IGF-I was inserted in the defects, respectively. At 8 weeks postsurgery, the dogs were sacrificed. The results were observed histologically and analyzed histomorphometrically.The results of this study were as follws. 1. The new cementum formation was $1.26{\pm}0.69mm$ in the control group, $1.80{\pm}0.84mm$ in the experimental group I, $1.93{\pm}0.51mm$ in the experimental group II. The experimental group III, the experimental group I, the control group were in the order of cementum formation without statistically significant differences between control and all experimental groups. 2. The new bone formation was $1.00{\pm}0.53mm$ in the control group, $1.53{\pm}0.63mm$ in the experimental group I, $l.33{\pm}0.45mm$ in the experimental group II. The experimental group I, the experimental group II, the control group were in the order of bone formation without statistically significant differences between control and all experimental groups. 3. The root resorption was $1.12{\pm}0.64mm$ in the control group, $1.34{\pm}0.73mm$ in the experimental group I, $0.79{\pm}0.59mm$ in the experimental group II without statistically significant differences between control and all experimental groups. These results suggested that the use of PDGF-BB alone or PDGF-BB and IGF-I in the dehiscence defects might facilitate periodontal regeneration in some degree, but has not shown statistically significant results.

• Journal of Periodontal and Implant Science
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• v.38 no.sup2
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• pp.373-384
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• 2008

Purpose: The aim of this study is to compare the healing response of various Hydroxyapatite(HA) coated dental implants by Ion-Beam Assisted Deposition(IBAD) placed in the surgically created circumferential gap in dogs. Materials and methods: In four mongrel dogs, all mandibular premolars and the first molar were extracted. After an 8 weeks healing period, six submerged type implants were placed and the circumferential cylindrical 2mm coronal defects around the implants were made surgically with customized step drills. Groups were divided into six groups : anodized surface, anodized surface with 150nm HA and heat treatment, anodized surface with 300nm HA and heat treatment, anodized surface with 150nm HA and no heat treatment, and anodized surface with 150nm HA, heat treatment and bone graft, anodized surface with bone graft. The dogs were sacrificed following 12 weeks healing period. Specimens were analyzed histologically and histomorphometrically. Results: During the healing period, healing was uneventful and implants were well maintained. Anodized surface with HA coating and $430^{\circ}C$ heat treatment showed an improved regenerative characteristics. Most of the gaps were filled with newly regenerated bone. The implant surface was covered with bone layer as base for intensive bone formation and remodeling. In case that graft the alloplastic material to the gaps, most of the coronal gaps were filled with newly formed bone and remaining graft particles. The bone-implant contact and bone density parameters showed similar results with the histological findings. The bone graft group presented the best bone-implant contact value which had statistical significance. Conclusion: Within the scope of this study, nano-scale HA coated dental implants appeared to have significant effect on the development of new bone formation. And additional bone graft is an effective method in overcoming the gaps around the implants.

• Journal of Periodontal and Implant Science
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• v.49 no.1
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• pp.25-38
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• 2019

Purpose: This study evaluated differences in bone healing and remodeling among 3 implants with different surfaces: sandblasting and large-grit acid etching (SLA; IS-III $Active^{(R)}$), SLA with hydroxyapatite nanocoating (IS-III $Bioactive^{(R)}$), and SLA stored in sodium chloride solution ($SLActive^{(R)}$). Methods: The mandibular second, third, and fourth premolars of 9 dogs were extracted. After 4 weeks, 9 dogs with edentulous alveolar ridges underwent surgical placement of 3 implants bilaterally and were allowed to heal for 2, 4, or 12 weeks. Histologic and histomorphometric analyses were performed on 54 stained slides based on the following parameters: vertical marginal bone loss at the buccal and lingual aspects of the implant (b-MBL and l-MBL, respectively), mineralized bone-to-implant contact (mBIC), osteoid-to-implant contact (OIC), total bone-to-implant contact (tBIC), mineralized bone area fraction occupied (mBAFO), osteoid area fraction occupied (OAFO), and total bone area fraction occupied (tBAFO) in the threads of the region of interest. Two-way analysis of variance (3 types of implant $surface{\times}3$ healing time periods) and additional analyses for simple effects were performed. Results: Statistically significant differences were observed across the implant surfaces for OIC, mBIC, tBIC, OAFO, and tBAFO. Statistically significant differences were observed over time for l-MBL, mBIC, tBIC, mBAFO, and tBAFO. In addition, an interaction effect between the implant surface and the healing time period was observed for mBIC, tBIC, and mBAFO. Conclusions: Our results suggest that implant surface wettability facilitates bone healing dynamics, which could be attributed to the improvement of early osseointegration. In addition, osteoblasts might become more activated with the use of HA-coated surface implants than with hydrophobic surface implants in the remodeling phase.

• The korean journal of orthodontics
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• v.54 no.1
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• pp.26-47
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• 2024

Objective: This systematic review aimed to evaluate the correlation between vitamin D levels and the rate of tooth movement, external apical root resorption, bone biomarker expression, and bone remodeling. Methods: Three databases (PubMed, Scopus, and Web of Science) were systematically searched from inception until 14th March 2023 to identify studies investigating the correlation between orthodontic tooth movement and vitamin D in animals and humans. The quality assessment was made in accordance with the Joanna Briggs Institute Critical Appraisal Checklist. Results: Overall, 519 records were identified, and 19 were selected for the qualitative synthesis. Eleven studies investigated the effect of local administration (injections in the periodontal ligament, to the gingiva distal to the teeth, or submucosae palatal area) and systemic administration (oral supplementation) of vitamin D on tooth movement, external apical root movement, pro-inflammatory cytokines, and bone remodeling factors. The remaining eight studies investigated the correlation between serum vitamin D levels and salivary vitamin D levels on bone turnover markers and tooth movement. Conclusions: The findings of this systematic review support that vitamin D3 local injections might increase the rate of tooth movement via the receptor activator of the nuclear factor-kB/osteoprotegerin axis. However, the non-uniform study designs and the different protocols and outcome methods make it challenging to draw reliable conclusions.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.506-513
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• 2004

Osteoclast action is necessary for alveolar bone remodeling in orthodontic tooth movement. The nervous system has also been reported to be associated with bone remodeling. This study was aimed to investigate the changes of osteoclasts in the periodontal ligament (PDL) space after surgical resection of the inferior alveolar nerve (IAN). Experimental rats were divided into young and adult groups. A surgical resection procedure of the IAN was carried out in the left side of the mandible and a sham operation in the right side of the mandible. The number of osteoclasts on the bundle bone surface and the resorption activity of the osteoclasts were histomorphometrically measured. The changes in distribution of substance P (SP) immunoreactive (IR) nerve fiber were evaluated in the PDL and pulp. SP-IR nerve fiber was depleted in both the PDL and pulp of the IAN resection side in both groups, which confirmed the resection of IAN to be successfully conducted. The number of osteoclasts in the IAN resection side was significantly reduced in both the young and adult groups (p<0.01 and p<0.05), whereas the resorption activity of osteoclasts did not show any significant difference between the IAN resection side and the sham operation side in both groups (p>0.05 and p<0.05). The adult group showed that the number of osteoclasts reduced significantly (p<0.01) and the resorption activity didn't change in comparison with the young group (p>0.05). These results suggest that surgical resection of the IAN and aging reduce the population of the recruited osteoclasts within the PDL, but don't affect on the osteoclastic resorption activity.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.23-26
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• 2010

The vascular changes in periodontal tissues cause local hypoxia which seems to affect the periodontal tissue cells. Abrupt changes in oxygen availability within the periodontium have been suggested to have a regulatory role in alveolar bone remodeling during tooth movement, bone growth or fracture healing. The purpose of this study was to study the effects of hypoxia on formation of osteoclast responsible for bone resorption, in vitro. Primary mouse bone marrow cells were cultured in normoxic (20% $O_2$) and hypoxic (1% $O_2$) conditions and assayed for cellular proliferation. The results obtained were as follows : 1. Reducing oxygen tension increased the formation of multinucleated osteoclasts. 2. Hypoxic stimulus increased the size of mature osteoclasts.

• BMB Reports
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• v.43 no.8
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• pp.513-523
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• 2010

Cytokines that bind to and signal through the gp130 co-receptor subunit include interleukin (IL)-6, IL-11, oncostatin M (OSM), leukemia inhibitory factor (LIF), cardiotrophin-1 (CT-1), and ciliary neutrophic factor (CNTF). Apart from contributing to inflammation, gp130 signalling cytokines also function in the maintenance of bone homeostasis. Expression of each of these cytokines and their ligand-specific receptors is observed in bone and joint cells, and bone-active hormones and inflammatory cytokines regulate their expression. gp130 signalling cytokines have been shown to regulate the differentiation and activity of osteoblasts, osteoclasts and chondrocytes. Furthermore, cytokine and receptor specific gene-knockout mouse models have identified distinct roles for each of these cytokines in regulating bone resorption, bone formation and bone growth. This review will discuss the current models of paracrine and endocrine actions of gp130-signalling cytokines in bone remodelling and growth, as well as their impact in pathologic bone remodelling evident in periodontal disease, rheumatoid arthritis, spondylarthropathies and osteoarthritis.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.581-590
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• 1996

Bone resorptiion was predominate in compression site, bone formation in tension site of periodontal ligament during tooth movement. The biologic response at compressiion site was different from tension site. Thus the CGHP immuno-positive nerve fiber will respond differently to mechanical force according to the area( compression or tension site). The purpose of this study was to investigate this response of CGRP immune-positive nerve fiber in the periodontal ligament according to the duration of applied force and the area (compression or tension site) during experimental tooth movement. The experimental animals were 7 week old male rat (approximately 200 gm). The orthodontic force was applied mesially to the right maxillary molar using the Ni-Ti coil spring during 12hours, 1, 3, 7, and 120days. Immunohistochemical staining using antibody against CGRP was performed after sacrifice. The results were as follows. The CGRP immune-positive nerve bundle showed reduced immunoreactivity and nerve fibers reduced in density after application of orthodontic force for 12 hours and 1day. The CGRP immune-positive nerve fibers showed many thin branches at the apical periodontal ligament after application of force for 3 days as compared with normal. The tension site in the apical periodontal ligament showed more branches than the compression site. In 7 day group, the CGRP immune-positive nerve fibers increased in terms of the number and had many thin branches in the apical periodontal ligament. The tension site had more branches than the compression site. In 12 day group, the CGRP immune-positive nerve fibers showed similar distribution to normal control at compression site of apical periodontal ligament, but the fibers at the tension site increased in number. The CGRP immuno-positive nerve fibers showed more increased at tension site than compression site after application of orthodontic force. Therefore it seems to have some relation to the bone remodeling besides the local inflammatory process.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.166-175
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• 2016

There is no genetic activity information with the functions of dental pulp and periodontal ligament in human. The purpose of this study was to identify the gene-expression profiles of, and the molecular biological differences between periodontal ligament and dental pulp obtained from human permanent teeth. cDNA microarray analysis identified 347 genes with a fourfold or greater difference in expression level between the two tissue types 83 and 264, of which were more plentiful in periodontal ligament and dental pulp, respectively. Periodontal ligament exhibited strong expression of genes related to collagen synthesis (FAP), collagen degradation (MMP3, MMP9, and MMP13), and bone development and remodeling (SSP1, BMP3, ACP5, CTSK, and PTHLH). Pulp exhibited strong expression of genes associated with calcium ions (CALB1, SCIN, and CDH12) and the mineralization and formation of enamel and dentin (SPARC/SPOCK3, PHEX, AMBN, and DSPP). Among these genes, SPP1, SPARC/SPOCK3, AMBN, and DSPP were well known in dental research. However, the other genes are the newly found and it may help to find a good source of regenerative therapy if further study is performed.

• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.26-36
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• 2011

Objectives: In the present study, three kinds of tissues cells (pulp, gingiva, and periodontal ligament) were investigated if those cells express MMP and TIMP when they were stimulated with neuropeptides (substance P, CGRP) or proinflammatory cytokine, TNF-$\alpha$. Materials and Methods: The cells cultured from human dental pulp (PF), gingiva (GF) and periodontal ligament were (PDLF) stimulated with Mock, SP, TNF-$\alpha$, and CGRP for 24 hrs and 48 hrs. for an RNase protection assay and Enzyme Linked Immunosorbent Assay. Cells (PF, GF and PDLF) seeded in 100 mm culture dish were stimulated with SP ($10^{-5}$, $10^{-8}\;M$) or only with medium (Mock stimulation) for 4hrs and for 24 hrs for RNase Protection Assay, and they were stimulated with CGRP ($10^{-5}\;M$) and TNF-$\alpha$(2 ng/mL) for 24 hrs and with various concentraion of TNF-$\alpha$(2, 10, and 100 ng/mL) for Rnase Protection Assay with a human MMP-1 probe set including MMP 1, 2, 8, 7, 8, 9, 12, and TIMP 2, 3. In addition, cells (PF, GF and PDLF) were stimulated with Mock and various concentraion of TNF-$\alpha$(2, 10, and 100 ng/mL) for 24 hrs and with TNF-$\alpha$(10 ng/mL) for 48 hrs, and the supernatents from the cells were collected for Enzyme Linked Immunosorbent Assay (ELISA) for MMP-1 and MMP-13. Results: The expression of MMPs in PF, GF, PDLF after stimulation with SP and CGRP were not changed compared with Mock stimulation for 4 hrs and 24 hrs. The expression of MMP-1, -12, -13 24 hrs after stimulation with TNF-$\alpha$ were upregulated, however the expression of TIMP-3 in PF, GF, PDLF after stimulation with TNF-$\alpha$ were downregulated. TNF-$\alpha$(2 ng/mL, 10 ng/mL, 100 ng/mL) increased MMP-1 and MMP-12 expression in PF dose dependently for 24 hrs. Conclusions: TNF-$\alpha$ in the area of inflammation may play an important role in regulating the remodeling of dentin, cementum, and alveolar bone.