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1
Brahmanta, Arya, Sutjipto Sutjipto e Ida Bagus Narmada. "Histological changes during orthodontic tooth movement due to hyperbaric oxygen therapy". Dental Journal (Majalah Kedokteran Gigi) 49, n. 2 (14 febbraio 2017): 63. http://dx.doi.org/10.20473/j.djmkg.v49.i2.p63-66.
Testo completoAbstract (sommario):
Background: Mechanical force of orthodontics causes changes in periodontal ligament vascularization and blood flow, resulting in biochemical and cellular changes as well as changes in the contour of the alveolar bone and in the thickness of the periodontal ligaments. Hyperbaric oxygen (HBO) therapy is one of many solutions stimulating the growth of new blood vessels and increasing tissue oxygenation. Thus, HBO plays a role in recovery of periodontal ligament and osteoblasts. Purpose: This study aimed to determine the effects of HBO therapy for seven days on periodontal ligament size and osteoblast number in the tension site during bone remodeling in tooth movement. Method: The study was true experimental laboratories with completely randomized control group post test only design. Twenty-four males guinea pigs were randomly divided into three groups. K0 was the control group without any treatment, K1 was the group given a mechanical orthodontic pressure, and K2 was the group treated with the addition of hyperbaric oxygen therapy. The maxillary incisors were moved distally by elastic separator. After HBO therapy on day 7, all of the groups were sacrificed, and then periodontal ligament size and osteoblast number were analyzed by one-way Anova and LSD statistical tests. Result: The results showed significant differences in the size of the periodontal ligament and the number of osteoblasts in the tension site among the groups (p<0.05). Conclusion: HBO therapy at 2.4 ATA for 7 days is effective in recovery of periodontal ligament and increased osteoblast number during bone remodeling in tension area of orthodontic tooth movement.
2
Pinheiro, Gabriela Veloso Vieira da Silva, Robinson Sabino-Silva, Melissa Rodrigues de Araujo, Shaiene Patrícia Gomes, Stephanie Wutke Oliveira, Emília Maria Gomes Aguiar, Léia Cardoso-Sousa, Carla Castiglia Gonzaga e Marcela Claudino. "Experimental Acute Sepsis Reduced Number of Osteocalcin Immunolabeled Cells in Periodontal Ligament". Brazilian Dental Journal 31, n. 2 (aprile 2020): 143–51. http://dx.doi.org/10.1590/0103-6440202003024.
Testo completoAbstract (sommario):
Abstract The aim of this study was to evaluate the effect of acute sepsis in the periodontal ligament, alveolar and furcation bone in absence of periodontitis induction through histological and immunohistochemical analyses. A septic rat model was established by cecal ligation and puncture (CLP). Twelve rats were randomly divided into CLP (n=6) and Sham (n=6) groups. The animals were euthanized at 24 h and hemimandibles were submitted to histomorfometric (bone matrix, collagenous fibers, fibroblasts, osteocytes, inflammatory cells, and blood vessels) and immunohistochemical (BMP-2/4, RANKL and osteocalcin) evaluation in alveolar bone, furcation bone and periodontal ligament. Our results demonstrated that histomorphometric parameters were similar in alveolar bone, furcation bone and periodontal ligament of Sham and CLP rats. Regarding to immunohistochemical analyses, the number of BMP-2/4 and RANKL immunolabeled cells was also similar in both groups. Furthermore, it was detected a reduction in the osteocalcin immunolabeled cells in periodontal ligaments of CLP compared to Sham rats (p=0.0014). In conclusion, the acute sepsis induction resulted in reduced number of osteocalcin labelled cells in periodontal ligament region. Moreover, no significant histological differences were observed in the periodontium of rats under acute sepsis. Considering the role of osteocalcin in bone remodeling, the study contributes to revealing the importance of careful periodontal evaluation in the presence of sepsis.
3
Khertek, M. V., e S. V. Logvinov. "Morfoquantitative and ultrastructural analysis of blood and lymph vessels in the first molars and premolars periodontal ligament". Bulletin of Siberian Medicine 10, n. 6 (28 dicembre 2011): 57–60. http://dx.doi.org/10.20538/1682-0363-2011-6-57-60.
Testo completoAbstract (sommario):
Morfoquantitative and ultrastructural analysis of the specific volumes of blood and lymph vessels in the periodontal first molars and premolars with different surfaces (medial, distal, buccal, and palatal) and at different levels of the roots are studied. It was noted that at physiological pressure on the molars and premolars, the specific volume of the investigated values are different. Throughout the root of the observed two zones of compression and expansion of periodontal. Depending on these areas of blood and lymphatic vessels was significantly different.
4
Hasegawa, Tomoka, Yukina Miyamoto-Takasaki, Miki Abe, Zixuan Qiu, Tomomaya Yamamoto, Yimin, Taiji Yoshida et al. "Histochemical examination on principal collagen fibers in periodontal ligaments of ascorbic acid-deficient ODS-od/od rats". Microscopy 68, n. 5 (3 luglio 2019): 349–58. http://dx.doi.org/10.1093/jmicro/dfz021.
Testo completoAbstract (sommario):
Abstract In this study, we aimed to clarify the role of ascorbic acid in collagen synthesis in periodontal ligaments using osteogenic disorder Shionogi (ODS)/ShiJcl-od/od rats lacking L-gulonolactone oxidase. These rats cannot synthesize ascorbic acid in vivo. Eight-week-old ODS/ShiJcl-od/od male rats were administered ascorbic acid solution at a concentration of 200 mg/dL (control group, n = 6) or ascorbic acid solution at concentration of 0.3 mg/dL (insufficient group, n = 12). Six rats of the insufficient group were then given with ascorbic acid solution at concentration of 200 mg/dL for additional 3 weeks (rescued group, n = 6), and then, their mandibles were histochemically examined. Consequently, the insufficient group specimens were seen to possess fewer collagen fibers, and silver impregnation revealed numerous fine, reticular fiber-like fibrils branching off from collagen in the periodontal ligaments. In control group, faint immunoreactivities for matrix metalloproteinase (MMP)2 and cathepsin H were seen in the periphery of blood vessels and throughout the ligament, respectively. In contrast, in the insufficient group, intense MMP2-immunoreactivity was observed to be associated with collagen fibrils in the periodontal ligaments, and cathepsin H-immunopositivity was seen in ligamentous cells. The rescued group showed abundant collagen fibers filling the periodontal ligament space. Under transmission electron microscopy, ligamentous fibroblasts incorporated collagen fibrils into tubular endosomes/lysosomes while simultaneously synthesizing collagen fibril bundles. Thus, ascorbic acid insufficiency affected the immunolocalization of cathepsin H and MMP2; however, ligamentous fibroblasts appear to possess the potential to synthesize collagen fibers when supplied with ascorbic acid.
5
Al-Maula, Bushra Habeeb, Zena Jehad Wally, Mohanad Jameel Najm Al-Magsoosi, Rasha Hatem Dosh, Ruba M. Mustafa, Suhad Jabbar Hamed Al-Nasrawi, Abdullatif Alfutimie e Julfikar Haider. "Studying Effects of Calcium Oxide Nanoparticles on Dentinogenesis in Male Wistar Rats". International Journal of Dentistry 2021 (24 luglio 2021): 1–9. http://dx.doi.org/10.1155/2021/9983538.
Testo completoAbstract (sommario):
This study aimed to evaluate potential impacts of calcium oxide nanoparticles (CaO-NPs) at different dosages on predentin thickness, number of blood vessels, periodontal ligament thickness, and blood glucose level of Wistar rats. Twelve rats were randomly gathered into four groups, untreated (control) and CaO-NP-treated groups at three concentrations (25, 50, and 100 mg/kg of the body weight) over a period of 60 days. Histological investigation was performed on twenty-four lower incisor teeth extracted from all the tested groups under a light microscope, and an automatic Fujifilm was used to measure the blood glucose level. The results showed that regular nanoparticle treatment significantly increased predentin and periodontal ligament thicknesses, a gradual decrease in vascularization in the pulp tissue, and an increase in the blood glucose level as the dosages of nanoparticles administered to the rats increased. Administration of the CaO-NPs at low dosage (25 mg/kg) could be beneficial for the growth and integrity of teeth and dentinal tissues in rats.
6
Karakida, Lilian Mary, Cristiano Miranda de Araujo, Aline Cristina Batista Rodrigues Johann, Elisa Souza Camargo, Orlando Motohiro Tanaka e Odilon Guariza Guariza Filho. "Interaction of Anabolic Androgenic Steroids and Induced Tooth Movement in Rats". Brazilian Dental Journal 28, n. 4 (agosto 2017): 504–10. http://dx.doi.org/10.1590/0103-6440201601119.
Testo completoAbstract (sommario):
Abstract This study evaluated the interaction between tooth movement and two anabolic androgenic steroids (AAS), Deposteron® and Nebido®. One hundred Wistar rats were divided into 3 groups: control (C) n=30, Nebido experimental (N) n=35 and Deposteron experimental (D) n=35. The control group was subdivided into 6 subgroups: 1, 2, 3, 5, 7 and 14. The experimental groups were subdivided into 7 subgroups: 0, 1, 2, 3, 5, 7 and 14, which corresponded to the day of animal’s euthanasia after applying orthodontic force. Orthodontic devices were used to induce tooth movement using 50 cN of reciprocal force between the maxillary right first molar and the maxillary incisors. After euthanasia, the tissues were processed and stained with hematoxylin and eosin (HE) and tartrate-resistant acid phosphatase (TRAP). Osteoclasts, Howship’s lacunae and blood vessels were quantified. Groups N and D showed acceleration in the reorganization of the periodontal ligament compared to group C. The peak of the histological events occurred in group C on day 5 and in groups N and D on day 3 after installation of the orthodontic device. There was a statistically significant difference in the number of osteoclasts (p<0.05) between groups N3 and C3, and between groups N3 and D3. Supra-physiological doses of the AAS Nebido® and Deposteron® altered the number of osteoclasts, Howship’s lacunae and blood vessels, accelerating the reorganization of the periodontal ligament, resulting in accelerated biological effects from the induced tooth movement in rats.
7
Zanoni, Jacqueline N., Nathalia M. Lucas, Aline R. Trevizan e Ivan D. S. Souza. "Histological evaluation of the periodontal ligament from aged wistar rats supplemented with ascorbic acid". Anais da Academia Brasileira de Ciências 85, n. 1 (1 marzo 2013): 327–35. http://dx.doi.org/10.1590/s0001-37652013005000003.
Testo completoAbstract (sommario):
Ascorbic acid (AA) is able to neutralize reactive oxygen species and is essential for collagen synthesis. In aging process oxidative stress is elevated. This study aims to investigate the effects of AA supplementation on the periodontal ligament (PL) of rats during aging. Twenty five rats were used and divided into groups: J90 (90-day-old control), E345 (345-day-old control), E428 (428-day-old control), EA345 (345-day-old supplemented with AA from 90-day-old on) and EA428 (428-day-old supplemented with AA from 90-day-old on). We analyzed the thickness, density of fibroblasts and blood vessels and collagen fibers types in the PL. In group J90 there was predominantly type III collagen fibers (87.64%). In animals supplemented with AA, the area filled by type I fibers (group EA345: 65.67%, group EA428: 52.23%) was higher than type III fibers. PL in group EA428 was thicker than the one observed in group E428 (P < 0.05). During natural aging process, AA promoted the maturation of collagen fibers and enhanced angiogenesis in periodontal ligament. One can conclude that the supplementation with AA represented a beneficial factor for the development of PL in aged rats.
8
Imber, Jean-Claude, Andrea Roccuzzo, Alexandra Stähli, Nikola Saulacic, James Deschner, Anton Sculean e Dieter Daniel Bosshardt. "Immunohistochemical Evaluation of Periodontal Regeneration Using a Porous Collagen Scaffold". International Journal of Molecular Sciences 22, n. 20 (9 ottobre 2021): 10915. http://dx.doi.org/10.3390/ijms222010915.
Testo completoAbstract (sommario):
(1) Aim: To immunohistochemically evaluate the effect of a volume-stable collagen scaffold (VCMX) on periodontal regeneration. (2) Methods: In eight beagle dogs, acute two-wall intrabony defects were treated with open flap debridement either with VCMX (test) or without (control). After 12 weeks, eight defects out of four animals were processed for paraffin histology and immunohistochemistry. (3) Results: All defects (four test + four control) revealed periodontal regeneration with cementum and bone formation. VCMX remnants were integrated in bone, periodontal ligament (PDL), and cementum. No differences in immunohistochemical labeling patterns were observed between test and control sites. New bone and cementum were labeled for bone sialoprotein, while the regenerated PDL was labeled for periostin and collagen type 1. Cytokeratin-positive epithelial cell rests of Malassez were detected in 50% of the defects. The regenerated PDL demonstrated a larger blood vessel area at the test (14.48% ± 3.52%) than at control sites (8.04% ± 1.85%, p = 0.0007). The number of blood vessels was higher in the regenerated PDL (test + control) compared to the pristine one (p = 0.012). The cell proliferative index was not statistically significantly different in pristine and regenerated PDL. (4) Conclusions: The data suggest a positive effect of VCMX on angiogenesis and an equally high cell turnover in the regenerated and pristine PDL. This VCMX supported periodontal regeneration in intrabony defects.
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Imamura, Kentaro, Yusuke Hamada, Wataru Yoshida, Tasuku Murakami, Saki Nakane-Koyachi, Kouki Yoshikawa e Atsushi Saito. "Investigating the Effects of Dehydrated Human Amnion-Chorion Membrane on Periodontal Healing". Biomolecules 12, n. 6 (20 giugno 2022): 857. http://dx.doi.org/10.3390/biom12060857.
Testo completoAbstract (sommario):
Each growth factor (GF) has different effects and targets, and plays a critical role in periodontal healing. Dehydrated human amnion-chorion membrane (dHACM) contains various GFs and has been used to enhance wound healing. The purpose of this study was to evaluate the effects of dHACM on periodontal healing, using in vitro and in vivo experimental approaches. Standardized periodontal defects were created in rats. The defects were randomly divided into three groups: Unfilled, filled with hydroxypropyl cellulose (HPC), and dHACM+HPC. At 2 and 4 weeks postoperatively, periodontal healing was analyzed by microcomputed tomography (micro-CT), and histological and immunohistochemical analyses. In vitro, periodontal ligament-derived cells (PDLCs) isolated from rat incisors were incubated with dHACM extract. Cell proliferation and migration were evaluated by WST-1 and wound healing assay. In vivo, micro-CT examination at 2 weeks revealed enhanced formation of new bone in the dHACM+HPC group. At 4 weeks, the proportions of vascular endothelial growth factor (VEGF)-positive cells and α-smooth muscle actin (α-SMA)-positive blood vessels in the dHACM+HPC group were significantly greater than those in the Unfilled group. In vitro, dHACM extracts at 100 µg/mL significantly increased cell proliferation and migration compared with control. These findings suggest that GFs contained in dHACM promote proliferation and migration of PDLCs and angiogenesis, which lead to enhanced periodontal healing.
10
Parlange, L. M., e M. R. Sims. "A T.E.M. stereological analysis of blood vessels and nerves in marmoset periodontal ligament following endodontics and magnetic incisor extrusion". European Journal of Orthodontics 15, n. 1 (1 febbraio 1993): 33–44. http://dx.doi.org/10.1093/ejo/15.1.33.
Testo completo
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Freezer, S. R., e M. R. Sims. "A transmission electron-microscope stereological study of the blood vessels, oxytalan fibres and nerves of mouse-molar periodontal ligament". Archives of Oral Biology 32, n. 6 (1987): 407–12. http://dx.doi.org/10.1016/0003-9969(87)90075-6.
Testo completo
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Schröder, Agnes, Leonie Barschkies, Jonathan Jantsch, Peter Proff, Lina Gölz, James Deschner e Christian Kirschneck. "Role of Oxygen Supply in Macrophages in a Model of Simulated Orthodontic Tooth Movement". Mediators of Inflammation 2020 (29 luglio 2020): 1–11. http://dx.doi.org/10.1155/2020/5802435.
Testo completoAbstract (sommario):
Apart from periodontal ligament fibroblasts, immune cells like macrophages also play an important mediating role in orthodontic tooth movement (OTM). Upon orthodontic force application to malpositioned teeth, macrophages in the periodontal ligament get exposed to both mechanical strain and hypoxic conditions (via a compression of blood vessels). In this study, we assessed the relative impact of orthodontically induced mechanical strain and hypoxic conditions on macrophages for the mediation and regulation of OTM. Macrophages were stimulated with physiological orthodontic compressive forces of 2 g/cm2 for 4 h and 24 h on gas-impermeable or gas-permeable cell culture plates under normoxic or hypoxic cell culture conditions. We quantified expression of genes involved in inflammation (Tnf, Il-6, and Cox-2), extracellular remodelling (Mmp-9), and angiogenesis (Vegf) by RT-qPCR. Furthermore, we analysed HIF-1α, prostaglandin-E2, and VEGF protein expression via immunoblotting or ELISA. Mechanical strain and oxygen supply both differentially affected expression of genes and proteins involved in inflammation and angiogenesis. In this context, we found that HIF-1α protein levels were elevated by combined mechanical strain and hypoxic conditions, whereas gas-permeable plates providing sufficient oxygen supply prevented HIF-1α stabilization at the protein level after pressure application on macrophages. Our results thus indicate that macrophages involved in the mediation of OTM are affected by and respond differently to hypoxic conditions and mechanical compressive strain, which occur concomitantly during OTM, than periodontal ligament fibroblasts (PDLF), thus indicating different roles of these cells in the regulation of OTM at the cellular-molecular level. We further observed that contrary to PDLF HIF-1α stabilization in macrophages is rather induced via the decreased oxygen supply associated with OTM than via mechanotransduction by mechanical strain.
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Niklas, A., P. Proff, M. Gosau e P. Römer. "The Role of Hypoxia in Orthodontic Tooth Movement". International Journal of Dentistry 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/841840.
Testo completoAbstract (sommario):
Orthodontic forces are known to have various effects on the alveolar process, such as cell deformation, inflammation, and circulatory disturbances. Each of these conditions affecting cell differentiation, cell repair, and cell migration, is driven by numerous molecular and inflammatory mediators. As a result, bone remodeling is induced, facilitating orthodontic tooth movement. However, orthodontic forces not only have cellular effects but also induce vascular changes. Orthodontic forces are known to occlude periodontal ligament vessels on the pressure side of the dental root, decreasing the blood perfusion of the tissue. This condition is accompanied by hypoxia, which is known to either affect cell proliferation or induce apoptosis, depending on the oxygen gradient. Because upregulated tissue proliferation rates are often accompanied by angiogenesis, hypoxia may be assumed to fundamentally contribute to bone remodeling processes during orthodontic treatment.
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Butera, Andrea, Carolina Maiorani, Annalaura Morandini, Manuela Simonini, Arianna Colnaghi, Stefania Morittu, Stefania Barbieri et al. "Assessment of Oral Microbiome Changes in Healthy and COVID-19-Affected Pregnant Women: A Narrative Review". Microorganisms 9, n. 11 (19 novembre 2021): 2385. http://dx.doi.org/10.3390/microorganisms9112385.
Testo completoAbstract (sommario):
During pregnancy, there are several metabolic changes and an alteration in the composition of microorganisms that inhabit the oral cavity, with an increase in pathogenic bacteria that promote the onset of gingival diseases. This review is based on research in reference to the PICO model (Problem/Intervention/Comparison/Outcome), related to changes in the oral microbiome of pregnant women and possible oral consequences in patients with COVID-19. The results showed a growth of some pathogenic bacteria in pregnant women, including Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum, and the selective growth of the Prevotella intermedia, Porphyromonas gingivalis and Tannerella species, probably due to the fact that these bacteria use progesterone as a source of nutrition. These same bacteria are implicated in the development of periodontal disease. Periodontal pockets have bidirectional interactions between the oral cavity and the systemic circulatory system through the peripheral gingival blood vessels. The affinity of the SARS-CoV-2 virus to specific membrane receptors is now clear, and could involve the internal and external epithelial lining or the fibroblasts of the periodontal ligament. According to the results of the present review, the control of oral microbiome changes during pregnancy would be welcomed. The use of probiotics could help clinicians manage pregnant patients, reducing inflammatory indexes. Future studies should focus not only on changes in the level of the oral microbiome in pregnancy or the correlation between periodontal disease and COVID-19, but also on oral changes induced by both clinical situations.
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Balic, Anamaria. "Biology Explaining Tooth Repair and Regeneration: A Mini-Review". Gerontology 64, n. 4 (2018): 382–88. http://dx.doi.org/10.1159/000486592.
Testo completoAbstract (sommario):
The tooth is an intricate composition of precisely patterned, mineralized matrices and soft tissues. Mineralized tissues include enamel (produced by the epithelial cells called ameloblasts), dentin and cementum (produced by mesenchymal cells called odontoblasts and cementoblasts, respectively), and soft tissues, which include the dental pulp and the periodontal ligament along with the invading nerves and blood vessels. It was perceived for a very long time that teeth primarily serve an esthetical function. In recent years, however, the role of healthy teeth, as well as the impact of oral health on general well-being, became more evident. Tooth loss, caused by tooth decay, congenital malformations (tooth agenesis), trauma, periodontal diseases, or age-related changes, is usually replaced by artificial materials which lack many of the important biological characteristics of the natural tooth. Human teeth have very low to almost absent regeneration potential, due to early loss of cell populations with regenerative capacity, namely stem cells. Significant effort has been made in recent decades to identify and characterize tooth stem cells, and to unravel the developmental programs which these cells follow in order to generate a tooth.
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Blaushild, N., Y. Michaeli e S. Steigman. "Histomorphometric Study of the Periodontal Vasculature of the Rat Incisor". Journal of Dental Research 71, n. 12 (dicembre 1992): 1908–12. http://dx.doi.org/10.1177/00220345920710121001.
Testo completoAbstract (sommario):
This study assessed quantitatively the vascular system in the cementum-related periodontal ligament (PDL) along the rat incisor. The lower left incisors of six rats (± 200 g) were subjected to routine histological procedures and cross-sectioned serially (2 μm), and the distance between each section and the apex was computed. The PDL of five sections at different levels along the tooth was divided into mesial, lingual, and lateral parts. The number and area of small and terminal arterioles, capillaries (C), sinusoids (S), post-capillary venules (PCV), and connecting venules, as well as the area of the PDL, were established. Blood vessels (BV) occupied 47 ± 2% of the PDL area in the apical half and 4 ± 2% at the incisal end. Of the total BV area, 41%, 32%, and 27% were located on the lingual, mesial, and lateral tooth sides, respectively. The majority of BV belonged to the venous system (98.5 ± 0.6% and 82.5 ± 3.0% in the apical and incisal parts, respectively). The apical venous system comprised 95.4 ± 1.6% S and 3.2 ± 1.0% PCV, reversing to 27.2 ± 14.2% S and 55.2 ± 11.3% PCV in the incisal half. The number of arterial profiles increased gradually from 6.8 ± 1.5 at the apex to 25.3±2.4 in the incisal part and that of C from 9.0 ± 1.18 to 25.0 ± 4.3. The extensive vascularization in the apical half of the PDL is consistent with the high metabolic demands and with the need for protective cushioning of the constantly growing dental and periodontal tissues. The paucity of blood supply and the presence of numerous small BVs in the incisal end equate with the metabolic needs of the highly organized supporting tissue in this region.
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Usumi-Fujita, Risa, Jun Hosomichi, Noriaki Ono, Naoki Shibutani, Sawa Kaneko, Yasuhiro Shimizu e Takashi Ono. "Occlusal hypofunction causes periodontal atrophy and VEGF/VEGFR inhibition in tooth movement". Angle Orthodontist 83, n. 1 (18 giugno 2012): 48–56. http://dx.doi.org/10.2319/011712-45.1.
Testo completoAbstract (sommario):
Abstract Objective: To examine changes in microvasculature and the expression of vascular endothelial growth factor A (VEGF-A) and VEGF receptor 2 (VEGFR-2) in rat hypofunctional periodontal ligament (PDL) during experimental tooth movement. Materials and Methods: Twelve-week-old male Sprague-Dawley rats were divided into normal occlusion and occlusal hypofunction groups. After a 2-week bite-raising period, rat first molar was moved mesially using a 10-gf titanium-nickel alloy closed coil spring in both groups. On days 0, 1, 2, 3, and 7 after tooth movement, histologic changes were examined by micro–computed tomography and immunohistochemistry using CD31, VEGF-A, VEGFR-2, and the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method. Results: Hypofunctional molars inclined more than normal molars and did not move notably after day 1 of tooth movement. Blood vessels increased on the tension side of the PDL in normal teeth. Immunoreactivities for VEGF-A and VEGFR-2 in normal teeth were greater than those in hypofunctional teeth during tooth movement. Compressive force rapidly caused apoptosis of the PDL and vascular endothelial cells in hypofunctional teeth, but not in normal teeth. Conclusions: Occlusal hypofunction induces vascular constriction through a decrease in the expression of VEGF-A and VEGFR-2, and apoptosis of the PDL and vascular cells occurs during tooth movement.
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Nayak, Bob N., William A. Wiltshire, Ben Ganss, Howard Tenenbaum, Christopher A. G. McCulloch e Charles Lekic. "Healing of Periodontal Tissues Following Transplantation of Cells in a Rat Orthodontic Tooth Movement Model". Angle Orthodontist 78, n. 5 (1 settembre 2008): 826–31. http://dx.doi.org/10.2319/082807-396.1.
Testo completoAbstract (sommario):
Abstract Objective: To determine the fate and differentiation of transplanted periodontal ligament (PL) precursor cells and mouse embryonic stem (ES) cells and their relative capacity to regenerate wounded periodontium. Materials and Methods: Orthodontic tooth movement was introduced 24 hours before transplantation of PL or ES cells, and rats were euthanized either 24 hours or 72 hours after cell transplantation. The control rats received either no tooth movement and no cell transplantation or tooth movement and no cell transplantation. Differentiation of transplanted cells was assessed from mandibular periodontal histological tissue sections by immunohistochemical methods using monoclonal antibodies against PL cell differentiation markers. Data were analyzed using Student's t-test at a significance level of P = .05. Results: Transplantation of PL and ES cells resulted in a higher number of osteopontin, bone sialoprotein, and α-smooth muscle actin labeled transplanted cells, predominantly around the blood vessels of the periodontium in study rats compared with control rats (cell transplantation but no orthodontic tooth movement, P = .05). Combined treatments of tooth movement and cell transplantation resulted in enhanced regeneration of the periodontium as a result of tooth movement. Transplantation of PL cells induced a higher number of differentiating cells in the PL and alveolar bone than did transplantation of ES cells. Conclusions: Orthodontic tooth movement promotes the differentiation of transplanted cells, and the differentiation occurs predominantly in the paravascular areas of the periodontium. In terms of regeneration of wounded periodontium, transplantation of PL cells produced a higher level of regeneration than ES cells, possibly because of PL cell plasticity and the capacity to undergo effective differentiation in the periodontal cellular microenvironment.
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Ribeiro, Jucienne Salgado, José Vinicius Bolognesi Maciel, Luégya Amorin Henriques Knop, Maria Ângela Naval Machado, Ana Maria Trindade Grégio e Elisa Souza Camargo. "Effect of Growth Hormone in Experimental Tooth Movement". Brazilian Dental Journal 24, n. 5 (ottobre 2013): 503–7. http://dx.doi.org/10.1590/0103-6440201302286.
Testo completoAbstract (sommario):
The aim of this study was to evaluate, by histological analysis, the effect of growth hormone (GH) on periodontal ligament and alveolar bone during experimental tooth movement in rats. Eighty male Wistar rats divided into control (C) and experimental (E) groups were examined after 3, 7, 14 and 21 days under controlled climate conditions. Orthodontic force (30 cN) was applied on the maxillary first molar by an orthodontic appliance. Group E received 0.1 IU/kg/day of GH and Group C received 0.5 mL/kg/day of saline. The samples were processed and evaluated under optical microscopy and polarized light microscopy. The Kruskal Wallis test was applied to compare the intergroup variables at 5% significance level. Group E presented a larger number of osteoclasts on the 3rd and 7th days and Howship lacunae on the 3 rd day, a smaller number of blood vessels and greater amount of mature collagen on the 3 rd and 7 th days than Group C (p<0.05). It was concluded that GH accelerated and intensified bone resorption and produced delay in immature collagen formation during experimental tooth movement.
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Sasaki, T., T. Shimizu, C. Watanabe e Y. Hiyoshi. "Cellular Roles in Physiological Root Resorption of Deciduous Teeth in the Cat". Journal of Dental Research 69, n. 1 (gennaio 1990): 67–74. http://dx.doi.org/10.1177/00220345900690011101.
Testo completoAbstract (sommario):
This study has attempted to assess the importance of mesenchymal cells, fibroblasts, cementoblasts, and mononuclear phagocytes (i.e., macrophages) in physiological root resorption of feline deciduous teeth. Deciduous incisors of three- to six-month-old kittens undergoing root resorption were investigated by means of electron microscopy. In an early phase of root resorption, the resorption organ consisted of many fibroblasts and relatively few macrophages and odontoclasts, the last with a wide, clear zone and narrow, immature, ruffled border. In the active phase of root resorption, the resorption organ contained many odontoclasts with a well-developed ruffled border and a reduced clear zone, cementoblasts, fibroblasts, macrophages, neutrophils, and many blood vessels. Cementoblasts were present usually on the resorbing dentin surface adjacent to odontoclasts and, in many cases, these cells communicated with each other via gap junctions. Cementoblasts frequently extended broad cell processes with secretion granules and with phagosomes containing collagen fibrils into the dentinal tubules exposed to resorption lacunae. Some macrophages exhibiting a clear zone-like structure also appeared on resorbing dentin surfaces. In the resting phase of root resorption, the dentin surface was covered mostly with cementoblasts resembling bone lining cells. There was an occasional macrophage, but no odontoclasts were observed during this phase. During removal of the periodontal ligament concomitant with root resorption, many fibroblasts phagocytosed mature collagen fibrils, as well as amorphous fluffy material. These results suggest that these mesenchymal cells, as well as odontoclasts, are essential for the cellular removal of dental hard and soft tissues during shedding of feline deciduous teeth.
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Tirez, Elisabeth, e Mariano S. Pedano. "Regeneration of the Pulp Tissue: Cell Homing versus Cell Transplantation Approach: A Systematic Review". Materials 15, n. 23 (2 dicembre 2022): 8603. http://dx.doi.org/10.3390/ma15238603.
Testo completoAbstract (sommario):
Background: The main objective of this systematic review was to compare the apical healing, root maturation and histological characteristics of teeth treated with cell-based versus cell-free techniques. Methods: The methodology of this review was based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A literature search strategy was carried out on PubMed, EMBASE and the Web of Science databases. The last search was done on 1 August 2021. Articles written in languages other than English were excluded. Two researchers independently selected the studies and extracted the data. As no randomized clinical trials were available, animal studies were included. Results: In total, 26 studies were included in the systematic review: 22 articles only researched the cell-free technique, 3 articles compared the cell-based to the cell-free technique, and 1 article compared the cell-based technique to apexification. In terms of apical healing, qualitative analysis of the data suggested that there seems to be no significant difference between cell-free and cell-based techniques. The results regarding tooth maturation are contradictory. The main difference between the cell-free and the cell-based techniques seems to be the histology of the treated tooth. The cell-free technique seems to result in cementum-like, bone-like or periodontal ligament-like tissue. One study, on the other hand, found that the cell-based technique resulted in regeneration of the whole pulp with an odontoblast layer, connective tissue, blood vessels and neuronal tissue. Conclusions: Currently, the number of randomized clinical trials on this topic are very scarce. This is probably due to the limited infrastructure and lack of resources to apply the cell-based technique. Even though both techniques seem to be promising for clinical application, long-term data need to be provided regarding the healing and reparative patterns.
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Utreja, Achint, e Carla A. Evans. "Marfan Syndrome—An Orthodontic Perspective". Angle Orthodontist 79, n. 2 (1 marzo 2009): 394–400. http://dx.doi.org/10.2319/112707-558.1.
Testo completoAbstract (sommario):
Abstract Marfan syndrome is a heritable disorder of connective tissue that can affect the heart, blood vessels, lungs, eyes, bones, and ligaments. It is characterized by tall stature, elongated extremities, scoliosis, and a protruded or caved-in breastbone. Patients typically have a long, narrow face. A high-arched palate produced by a narrow maxilla and skeletal Class II malocclusion due to mandibular retrognathia are other common features. For a patient with no family history of the disorder, at least three body systems must be affected before a diagnosis can be made. Individuals affected by the syndrome routinely seek orthodontic treatment to correct the orofacial manifestations. In this report, the authors present the records of three patients with Marfan syndrome who were treated at a dental school. Two patients had severe periodontal disease in the absence of significant contributing local factors. The presentation of systemic symptoms and typical physical characteristics varied. The syndrome thus went unnoticed in one patient for many years. We discuss here the observed intraoral findings and the progress of orthodontic treatment to provide a brief overview of the challenges involved in treating such patients.
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Shintcovsk, Ricardo Lima, Luégya Knop, Orlando Motohiro Tanaka e Hiroshi Maruo. "Nicotine effect on bone remodeling during orthodontic tooth movement: Histological study in rats". Dental Press Journal of Orthodontics 19, n. 2 (aprile 2014): 96–107. http://dx.doi.org/10.1590/2176-9451.19.2.096-107.oar.
Testo completoAbstract (sommario):
Introduction: Nicotine is harmful to angiogenesis, osteogenesis and synthesis of collagen. Objective: The aim of this study was to investigate the effect of nicotine on bone remodeling during orthodontic movement in rats. Methods: Eighty male Wistar rats were randomly divided into three groups: Group C (control), group CM (with orthodontic movement) and group NM (nicotine with orthodontic movement) groups. The animals comprising groups C and CM received 0.9% saline solution while group NM received nicotine solution (2 mg/kg). A nickel-titanium closed-coil spring was used to induce tooth movement. The animals were euthanized and tissue specimens were processed histologically. We quantified blood vessels, Howship's lacunae and osteoclast-like cells present in the tension and compression areas of periodontal ligaments. The extent of bone formation was evaluated under polarized light to determine the percentage of immature/mature collagen. Results: We observed lower blood vessel densities in the NM group in comparison to the CM group, three (p < 0.001) and seven (p < 0.05) days after force application. Osteoclast-like cells and Howship's lacunae in the NM group presented lower levels of expression in comparison to the CM group, with significant differences on day 7 (p < 0.05 for both variables) and day 14 (p < 0.05 for osteoclast-like cells and p < 0.01 for Howship's lacunae). The percentage of immature collagen increased in the NM group in comparison to the CM group with a statistically significant difference on day 3 (p < 0.05), day 7 (p < 0.001), day 14 (p < 0.001) and day 21 (p < 0.001). Conclusions: Nicotine affects bone remodeling during orthodontic movement, reducing angiogenesis, osteoclast-like cells and Howship's lacunae, thereby delaying the collagen maturation process in developed bone matrix.
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Rahardjo, Pambudi, Maria Lisdiana Tandjung e Dandy Bayu Angkasa. "PENGARUH KOMBINASI TERAPI OKSIGEN HIPERBARIK DAN PROPOLIS TERHADAP DIAMETER PEMBULUH DARAH DI DAERAH TARIKAN LIGAMEN PERIODONTAL SELAMA PERGERAKAN GIGI UNTUK MENCEGAH RELAPS". DENTA 13, n. 1 (1 febbraio 2019). http://dx.doi.org/10.30649/denta.v13i1.183.
Testo completoAbstract (sommario):
<strong><em>Background</em></strong><em>: The mechanical force of orthodontic device causes occurrence of a tension and a pressure area in the periodontal ligament. In the tension area, an inflammatory response characterized by vasodilation of blood vessels will occur. The function of blood vessel is to flow blood and other nutrients to accelerate the periodontal ligament remodeling process, so that relapse can be prevented. <strong>Objective:</strong> To determine the effect of combination of propolis 3%, 5% for 14 days and HBOT 2,4 ATA 3x30 minutes with 5 minutes interval for 7 days in the tension area of the periodontal ligament as an effort to prevent relapse. <strong>Materials and Methods</strong>: A randomized post-test only control group design was used in this study. 42 male guinea pigs (cavia cobaya) are divided into 7 groups K- (without treatment), K + (using separator), P1 (using separator and propolis extract 3%), P2 (using separator and propolis extract 5%), P3 (using separator and hyperbaric oxygen therapy), P4 (using separator and combination of hyperbaric oxygen therapy and 3% propolis extract), and P5 (using separator and combination of hyperbaric oxygen therapy and 5% propolis extract) . <strong>Results</strong>: Data shows that mean of diameter of blood vessels increased from the smallest K- (41,8417±0,84511), K+(61,77±1,254482), P1(72,5983±0,68869), P2(73,2333±1,24481), P3(74,2583± 0,62030), P4(91,47±0,76585), to the largest in P5(91,5483±0,96178). One-way Anova and LSD test showed significant differences in blood vessels diameter (p <0.05). <strong>Conclusion</strong>: The combination of propolis 3% and 5% and HBOT have significant effect in increasing blood vessels diameter in the tension area of the periodontal ligament</em>
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Chang, Pi En, Shujin Li, Hyun-Yi Kim, Dong-Joon Lee, Yoon Jeong Choi e Han-Sung Jung. "BBS7–SHH Signaling Activity Regulates Primary Cilia for Periodontal Homeostasis". Frontiers in Cell and Developmental Biology 9 (7 dicembre 2021). http://dx.doi.org/10.3389/fcell.2021.796274.
Testo completoAbstract (sommario):
Objectives: Mechanical stimuli are essential for the maintenance of periodontal ligament (PDL) homeostasis. Although there are several studies on atrophic changes in PDL due to occlusal hypofunction, the underlying mechanism is still unknown. Here, we aimed to explore the changes of gene expression in occlusal hypofunctional PDL and elucidate the related role in maintaining the PDL homeostasis.Methods: To investigate the transcriptomic difference between control and hypofunctional PDL tissue from patients, RNA sequencing was performed on 34 human teeth. The atrophic changes in PDL were evaluated by histological analysis. The effect of the Bardet-Biedl syndrome 7 (BBS7) knockdown was evaluated by the RT-qPCR, Western blot, wound healing, and tubule formation assay.Results: We detected that the expression of BBS7 was downregulated in occlusal hypofunctional PDL through RNA sequencing. Dynamic changes, including the number of periodontal ligament cells, alignment of collagen fibers, diameter of blood vessels, appearance of primary cilia, and torturous oxytalan fibers, were observed following occlusal hypofunction. Furthermore, Sonic hedgehog signaling (Shh) activity was closely associated with BBS7 expression in PDL cells. In addition, the cell migration and angiogenesis were also suppressed by BBS7 knockdown in vitro.Conclusion: We suggest that BBS7 plays an essential role in maintaining Shh signaling activity for PDL homeostasis.
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Faccini, Melissa, Felipe Agostini, Tassio Drieu, Francisco Ubiratan Ferreira de Campos, Aguinaldo Garcez, Glauber Fabre Carinhena, Samira Salmeron, Ana Regina Casaroto, Fabricio Pinelli Valarelli e Karina Maria Salvatore Freitas. "Preliminary Histological Evaluation of the Application of Ozone in the First Days of Orthodontic Force Induction in Animal Model". European Journal of Dentistry, 24 agosto 2021. http://dx.doi.org/10.1055/s-0041-1731886.
Testo completoAbstract (sommario):
Abstract Objectives The aim of the study is to histologically evaluate the effect of ozone therapy on orthodontic force induction in an animal model. Materials and Methods Twenty-four Wistar rats were divided into three groups (n = 8). A NiTi coil spring was installed from the maxillary first molar to the maxillary central incisor. G1 was control and G2/G3 received 1 mL of ozonated gas at concentrations of 10 and 60 µg/mL, in the buccal mucosa above the first molar roots. The animals were euthanized 3 and 5 days after the procedure. Histological sections were obtained, longitudinally of the first molar’ long axis, in the mesiodistal direction. The number of osteoclasts, osteoblasts, blood vessels, polymorphonuclear and mononuclear cells, formation of osteoid tissue and hyaline areas, and root resorption were evaluated with light microscope, in tension and pressure sides. Intergroup comparisons were performed with Kruskal–Wallis, Dunn, and Chi-square tests. Results At 3-days pressure side, a greater number of osteoclasts was observed in ozone groups and greater number of blood vessels and polymorphonuclear cells were observed in G2. On the tension side, there was a significantly greater number of blood vessels, osteoblasts, and mononuclear cells in G2. At 5-days pressure side, there was a significantly greater number of osteoclasts in G2, blood vessels and osteoblasts in the ozone groups, and lesser number of polymorphonuclear cells in G3. Conclusion Ozone therapy increased the number of osteoclasts on the pressure side and osteoblasts on tension side, in 10 µg/mL concentration, demonstrating histological parameters favorable to bone remodeling. The 60 µg/mL ozone concentration accelerated the periodontal ligament reorganization process.
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"Effects of simulated weightlessness on the migration of osteoblast precursor cells relative to blood vessels in rat periodontal ligament utilizing 3H-thymidine label". American Journal of Orthodontics and Dentofacial Orthopedics 100, n. 1 (luglio 1991): 96. http://dx.doi.org/10.1016/s0889-5406(08)80028-5.
Testo completo
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Ullrich, Niklas, Agnes Schröder, Jonathan Jantsch, Gerrit Spanier, Peter Proff e Christian Kirschneck. "The role of mechanotransduction versus hypoxia during simulated orthodontic compressive strain—an in vitro study of human periodontal ligament fibroblasts". International Journal of Oral Science 11, n. 4 (5 novembre 2019). http://dx.doi.org/10.1038/s41368-019-0066-x.
Testo completoAbstract (sommario):
Abstract During orthodontic tooth movement (OTM) mechanical forces trigger pseudo-inflammatory, osteoclastogenic and remodelling processes in the periodontal ligament (PDL) that are mediated by PDL fibroblasts via the expression of various signalling molecules. Thus far, it is unknown whether these processes are mainly induced by mechanical cellular deformation (mechanotransduction) or by concomitant hypoxic conditions via the compression of periodontal blood vessels. Human primary PDL fibroblasts were randomly seeded in conventional six-well cell culture plates with O2-impermeable polystyrene membranes and in special plates with gas-permeable membranes (Lumox®, Sarstedt), enabling the experimental separation of mechanotransducive and hypoxic effects that occur concomitantly during OTM. To simulate physiological orthodontic compressive forces, PDL fibroblasts were stimulated mechanically at 2 g·cm−2 for 48 h after 24 h of pre-incubation. We quantified the cell viability by MTT assay, gene expression by quantitative real-time polymerase chain reaction (RT-qPCR) and protein expression by western blot/enzyme-linked immunosorbent assays (ELISA). In addition, PDL-fibroblast-mediated osteoclastogenesis (TRAP+ cells) was measured in a 72-h coculture with RAW264.7 cells. The expression of HIF-1α, COX-2, PGE2, VEGF, COL1A2, collagen and ALPL, and the RANKL/OPG ratios at the mRNA/protein levels during PDL-fibroblast-mediated osteoclastogenesis were significantly elevated by mechanical loading irrespective of the oxygen supply, whereas hypoxic conditions had no significant additional effects. The cellular–molecular mediation of OTM by PDL fibroblasts via the expression of various signalling molecules is expected to be predominantly controlled by the application of force (mechanotransduction), whereas hypoxic effects seem to play only a minor role. In the context of OTM, the hypoxic marker HIF-1α does not appear to be primarily stabilized by a reduced O2 supply but is rather stabilised mechanically.
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Shalehin, N., Y. Seki, H. Takebe, S. Fujii, T. Mizoguchi, H. Nakamura, N. Yoshiba et al. "Gli1+-PDL Cells Contribute to Alveolar Bone Homeostasis and Regeneration". Journal of Dental Research, 4 luglio 2022, 002203452211069. http://dx.doi.org/10.1177/00220345221106921.
Testo completoAbstract (sommario):
The periodontal ligament (PDL) contains mesenchymal stem cells (MSCs) that can differentiate into osteoblasts, cementoblasts, and fibroblasts. Nevertheless, the distribution and characteristics of these cells remain uncertain. Gli1, an essential hedgehog signaling transcription factor, functions in undifferentiated cells during embryogenesis. Therefore, in the present study, the differentiation ability of Gli1+ cells was examined using Gli1-CreERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice. In 4-wk-old iGli1/Tomato mice, Gli1/Tomato+ cells were only slightly detected in the PDL, around endomucin-expressing blood vessels. These cells had proliferated over time, localizing in the PDL as well as on the bone and cementum surfaces at day 28. However, in 8-wk-old iGli1/Tomato mice, Gli1/Tomato+ cells were quiescent, as most cells were not immunoreactive for Ki-67. These cells in 8-wk-old mice exhibited high colony-forming unit fibroblast activity and were capable of osteogenic, chondrogenic, and adipogenic differentiation in vitro. In addition, after transplantation of teeth of iGli1/Tomato mice into the hypodermis of wild-type mice, Tomato fluorescence indicating the progeny of Gli1+ cells was detected in the osteoblasts and osteocytes of the regenerated bone. These results demonstrate that Gli1+ cells in the PDL were MSCs and could contribute to the alveolar bone regeneration.