scholarly journals Application of cryopreservation to tooth germ transplantation for root development and tooth eruption

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xinghan Li ◽  
Megumi Nakamura ◽  
Weidong Tian ◽  
Yasuyuki Sasano
Keyword(s):  
Periodontal Ligament ◽  
Root Elongation ◽  
Tooth Germ ◽  
Tooth Eruption ◽  
Enamel Organ ◽  
Micro Computed Tomography ◽  
Significant Difference ◽  
Old Donor ◽  
Tooth Germs ◽  
Tomography Analysis

AbstractWe cryopreserved mouse tooth germs with widely open cervical margins of the enamel organ to overcome difficulties in cryoprotectant permeation and tested their efficacy by transplanting them into recipient mice. The upper right first molar germs of 8-day-old donor mice were extracted and categorized into the following four groups according to cryopreservation time: no cryopreservation, 1 week, 1 month, and 3 months. The donor tooth germs were transplanted into the upper right first molar germ sockets of the 8-day-old recipient mice. The upper left first molars of the recipient mice were used as controls. The outcome of the transplantation was assessed at 1, 2, and 3 weeks after transplantation. Stereomicroscopic evaluation revealed that most of the transplanted teeth erupted by 3 weeks after transplantation. Micro-computed tomography analysis revealed root elongation in the transplanted groups as well as in the controls. There was no significant difference between the cryopreserved and non-cryopreserved transplanted teeth, but the roots of the cryopreserved teeth were significantly shorter than those of the control teeth. Histological examination revealed root and periodontal ligament formations in all the transplanted groups. These results suggest that the transplantation of cryopreserved tooth germs facilitates subsequent root elongation and tooth eruption.

scholarly journals Statin Effects on Vascular Calcification

2021 ◽  
Author(s):  
Joshua Zhaojun Xian ◽  
Mimi Lu ◽  
Felicia Fong ◽  
Rong Qiao ◽  
Nikhil Rajesh Patel ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Surface Area ◽  
Vascular Calcification ◽  
Emission Tomography ◽  
Micro Computed Tomography ◽  
Positron Emission ◽  
Significant Difference ◽  
Calcium Deposits ◽  
Tomography Analysis

Objective: Statins lower cardiovascular event risk, yet, they paradoxically increase coronary artery calcification, a marker consistently associated with increased cardiovascular risks. As calcium deposits influence rupture risk due to stress from compliance mismatch at their surfaces, we hypothesized that statins may lower cardiovascular risk by altering the microarchitecture of calcium deposits. Thus, using mice with preexisting vascular calcification, we tested whether pravastatin reduces the mineral surface area of calcium deposits. Approach and Results: Aged Apoe − /− mice were treated with pravastatin or vehicle for 20 weeks. Aortic calcification was assessed by in vivo sodium fluoride labeled with fluoride 18 isotope-micro-positron emission tomography/micro-computed tomography imaging at weeks 0, 10, and 20 and by histomorphometry at euthanasia. Micro-computed tomography analysis showed that, in both groups, the amount of vascular calcification increased significantly over the 20-week period, but pravastatin treatment did not augment over the controls. In contrast, the micro-positron emission tomography analysis showed that, at week 10, the pravastatin group had less 18 F uptake, suggesting reduced surface area of actively mineralizing deposits, but this decrease was not sustained at week 20. However, a significant difference in the mineral deposit size was found by histomorphometry. The pravastatin group had significantly more aortic microcalcium deposits (<50 µm in diameter) than the controls. The pravastatin group also had more vascular cells positive for alkaline phosphatase activity than the controls. The amount of collagen and osteopontin, additional osteoblastic markers, were not significantly different between the 2 groups. Conclusions: These results suggest that pravastatin treatment alters the microarchitecture of aortic calcium deposits with potential effects on plaque stability.

Uptake of Radioactive Calcium by Hard Tissue Cells

1979 ◽  
Vol 58 (2_suppl) ◽  
pp. 1021-1022
Author(s):  
F.S. Sayegh ◽  
K. Porter ◽  
G. Sun
Keyword(s):  
Germ Cells ◽  
Calcium Uptake ◽  
Soluble Fraction ◽  
Specific Radioactivity ◽  
Tooth Germ ◽  
Enamel Organ ◽  
Hard Tissue ◽  
Subcellular Organelles ◽  
Tissue Cells ◽  
Tooth Germs

45Ca was injected into prenatal mice to study the calcium uptake by tooth germ cells. Both dental papillae, containing the odontoblasts, and the enamel organs were found to actively metabolize the labeled calcium. The maximum specific radioactivity occurred at 15 minutes after injection. The subcellular organelles (e.g. mitochondria) of the papillae were more active in metabolizing the labeled calcium whereas a large portion of the radioactivity of the enamel organ was found in a fraction containing the pre-calcified material. In fetal tooth germs, the rate of incorporation of labeled calcium into the pre-calcified material was slower than in the postnatal tooth germs since a large portion of the radioactivity remained in the soluble fraction.

Autoradiography of Incorporated Leucine-H3 in the Enamel Matrix and Enamel Organ of the Upper Incisor of the Rat

1964 ◽  
Vol 04 (02) ◽  
pp. 186-192
Author(s):  
Leonel Costacurta
Keyword(s):  
Amino Acid ◽  
Blood Vessels ◽  
Tooth Germ ◽  
Longitudinal Section ◽  
Equal Length ◽  
Enamel Organ ◽  
Enamel Matrix ◽  
Distal Extremity ◽  
Old Rats ◽  
Thin Band

SummaryDental germs of the upper incisors of six-days old rats were studied for the uptake of leucine-H3 by different layers of the enamel organ in correlation to the various stages of the development of enamel.The longitudinal section of the tooth germ was divided into 15 zones of about equal length in order to facilitate the description and interpretation of results. Autoradiographic images of the histologic preparations from rats sacrificed 30 minutes, 1 hour, 1 day and 3 days after the injection were made. The strongest reactions were observed in dental germs of rats sacrificed 1 hour, and particularly one day, after the leucine-H3 injection.The uptake of this compound by the enamel matrix increases progressively up to the young enamel and then decreases to the distal extremity; the greatest quantity of this labeled amino-acid was observed in the primary and young enamel. The reactions were present in the transitional enamel only along a thin band close to the dentine-enamel junction.In the enamel organ leucine-H3 incorporation was greatest in the three layers, the zones corresponding to primary and young enamel. In zones corresponding to transitional enamel, the inner epithelium showed a small quantity, and the stellate reticulum a blackening only in its superficial part, were the blood vessels reach the enamel organ.

scholarly journals Micro Computed Tomography Analysis of Four-Way Conversion Catalysts using Artificial Intelligence-Enabled Image Processing

2021 ◽  
Vol 27 (S1) ◽  
pp. 1028-1029
Author(s):  
Robert Palomino ◽  
Ke-Bin Low ◽  
Chunxin Ji ◽  
Ivan Petrovic ◽  
Florian Waltz ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Computed Tomography ◽  
Image Processing ◽  
Micro Computed Tomography ◽  
Tomography Analysis

scholarly journals Role of Innate Inflammation in the Regulation of Tissue Remodeling during Tooth Eruption

2021 ◽  
Vol 9 (1) ◽  
pp. 7
Author(s):  
Yusuke Makino ◽  
Kaoru Fujikawa ◽  
Miwako Matsuki-Fukushima ◽  
Satoshi Inoue ◽  
Masanori Nakamura
Keyword(s):  
Bacterial Infections ◽  
Tooth Movement ◽  
Tooth Eruption ◽  
Intercellular Adhesion Molecule ◽  
Enamel Organ ◽  
Pcr Analysis ◽  
Maturation Stage ◽  
Oral Epithelium ◽  
Rt Pcr ◽  
Inflammatory Reactions

Tooth eruption is characterized by a coordinated complex cascade of cellular and molecular events that promote tooth movement through the eruptive pathway. During tooth eruption, the stratum intermedium structurally changes to the papillary layer with tooth organ development. We previously reported intercellular adhesion molecule-1 (ICAM-1) expression on the papillary layer, which is the origin of the ICAM-1-positive junctional epithelium. ICAM-1 expression is induced by proinflammatory cytokines, including interleukin-1 and tumor necrosis factor. Inflammatory reactions induce tissue degradation. Therefore, this study aimed to examine whether inflammatory reactions are involved in tooth eruption. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed sequential expression of hypoxia-induced factor-1α, interleukin-1β, and chemotactic factors, including keratinocyte-derived chemokine (KC) and macrophage inflammatory protein-2 (MIP-2), during tooth eruption. Consistent with the RT-PCR results, immunohistochemical analysis revealed KC and MIP-2 expression in the papillary layer cells of the enamel organ from the ameloblast maturation stage. Moreover, there was massive macrophage and neutrophil infiltration in the connective tissue between the tooth organ and oral epithelium during tooth eruption. These findings suggest that inflammatory reactions might be involved in the degradation of tissue overlying the tooth organ. Further, these reactions might be induced by hypoxia in the tissue overlying the tooth organ, which results from decreased capillaries in the tissue. Our findings indicate that bacterial infections are not associated with the eruption process. Therefore, tooth eruption might be regulated by innate inflammatory mechanisms.

scholarly journals Root canal preparation using micro-computed tomography analysis: a literature review

2018 ◽  
Vol 32 (suppl 1) ◽  
Author(s):  
Manoel Damião de Sousa-Neto ◽  
Yara Correa Silva-Sousa ◽  
Jardel Francisco Mazzi-Chaves ◽  
Kleber Kildare Teodoro Carvalho ◽  
Ana Flávia Simões Barbosa ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Literature Review ◽  
Root Canal ◽  
Micro Computed Tomography ◽  
Root Canal Preparation ◽  
Tomography Analysis

scholarly journals Expression of α-smooth muscle actin in the periodontal ligament during post-emergent tooth eruption

2018 ◽  
Vol 46 (6) ◽  
pp. 2423-2435
Author(s):  
Domna Dorotheou ◽  
Marie-Luce Bochaton-Piallat ◽  
Catherine Giannopoulou ◽  
Stavros Kiliaridis
Keyword(s):  
Smooth Muscle ◽  
Periodontal Ligament ◽  
Smooth Muscle Actin ◽  
Root Apex ◽  
Tooth Eruption ◽  
Muscle Actin ◽  
Adult Rats ◽  
Time Points ◽  
Male Wistar Rats ◽  
The Right

Objective This study was performed to explore the expression of α-smooth muscle actin (α-SMA) in the periodontal ligament (PDL) of young and adult rats during post-emergent tooth eruption in opposed and unopposed teeth at two time points: 3 and 15 days after antagonist loss. Methods Four-week-old (n = 20) and 22-week-old (n = 20) male Wistar rats were used. The right maxillary molar crowns were cut down. PDL samples were isolated from the first mandibular molars at two time points: 3 and 15 days after cut-down of the right maxillary molars. Quantitative reverse-transcription polymerase chain reaction and immunohistochemical staining were performed to detect differences in α-SMA expression in the PDL tissues of unopposed versus opposed molars. Results α-SMA was upregulated in the PDL of the unopposed molars in the 3-day group of young rats. The region around the root apex of the unopposed molars in this group exhibited strong immunostaining for α-SMA. The expression level and immunoreactivity of α-SMA did not differ in both time points in young controls and among all the adult groups. Conclusion α-SMA-positive myofibroblasts are implicated in post-emergent tooth eruption of unopposed molars of young animals.

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