Matrix and Mineral Changes in Developing Enamel

1979 ◽  
Vol 58 (2_suppl) ◽  
pp. 871-882 ◽  
Author(s):  
C. Robinson ◽  
H.D. Briggs ◽  
P.J. Atkinson ◽  
J.A. Weatherell
Keyword(s):  
Mineral Content ◽  
Inorganic Ions ◽  
Organic Matrix ◽  
Small Samples ◽  
Enamel Organ ◽  
Enamel Matrix ◽  
Subsequent Loss ◽  
Matrix Components ◽  
Significant Concentration ◽  
Mineral Changes

An investigation of the changes taking place in the enamel and the enamel organ during enamel development has been carried out by analyzing small samples of tissue dissected from developing incisors of rat and bovine incisors. Observations showed that the synthesis of the enamel matrix and its subsequent loss were associated chiefly with a change in the major matrix components. This consisted of a selective loss of amelogenin components prior to secondary mineralization. Before this loss, some increase in the proportion of smaller molecular weight components suggested the possibility of limited breakdown. Even at the earliest stages examined, significant concentration of mineral ions was present. This increased steeply after most of the organic matrix had been removed. The Ca/P ratio of this mineral was constant throughout development. The concentration of minor inorganic ions (F, Mg and CO3) decreased as the tissue developed and a tendency was observed for certain ions (F, 32PO4) to penetrate and concentrate in the enamel, apparently as a consequence of the lost matrix being replaced by water, just prior to the steep increase in mineral content of the tissue.

scholarly journals Proteinases in Developing Dental Enamel

1999 ◽  
Vol 10 (4) ◽  
pp. 425-441 ◽  
Author(s):  
J.D. Bartlett ◽  
J.P. Simmer
Keyword(s):  
Proteinase Inhibitors ◽  
Dental Enamel ◽  
Serine Proteinase ◽  
Organic Matrix ◽  
Enamel Organ ◽  
Maturation Stage ◽  
Enamel Matrix ◽  
Enamel Matrix Proteins ◽  
Early Maturation

For almost three decades, proteinases have been known to reside within developing dental enamel. However, identification and characterization of these proteinases have been slow and difficult, because they are present in very small quantities and they are difficult to purify directly from the mineralizing enamel. Enamel matrix proteins such as amelogenin, ameloblastin, and enamelin are cleaved by proteinases soon after they are secreted, and their cleavage products accumulate in the deeper, more mature enamel layers, while the full-length proteins are observed only at the surface. These results suggest that proteinases are necessary for "activating" enamel proteins so the parent proteins and their cleavage products may perform different functions. A novel matrix metalloproteinase named enamelysin (MMP-20) was recently cloned from tooth tissues and was later shown to localize primarily within the most recently formed enamel. Furthermore, recombinant porcine enamelysin was demonstrated to cleave recombinant porcine amelogenin at virtually all of the sites that have previously been described in vivo. Therefore, enamelysin is at least one enzyme that may be important during early enamel development. As enamel development progresses to the later stages, a profound decrease in the enamel protein content is observed. Proteinases have traditionally been assumed to degrade the organic matrix prior to its removal from the enamel. Recently, a novel serine proteinase named enamel matrix serine proteinase-1 (EMSP1) was cloned from enamel organ epithelia. EMSP1 localizes primarily to the early maturation stage enamel and may, therefore, be involved in the degradation of proteins prior to their removal from the maturing enamel. Other, as yet unidentified, proteinases and proteinase inhibitors are almost certainly present within the forming enamel and await discovery.

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.

Patterns of Enamel Maturation

1979 ◽  
Vol 58 (2_suppl) ◽  
pp. 883-895 ◽  
Author(s):  
P.L. Glick
Keyword(s):  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Organic Matrix ◽  
Enamel Matrix ◽  
Concentration Gradients ◽  
Mineralization Process ◽  
Quantitative Electron Microscopy ◽  
Mineral Concentration ◽  
Process Pattern ◽  
Enamel Mineralization

Investigations of the maturation pattern of rat incisor enamel by quantitative electron microscopy and electron-probe microanalysis indicate that mineralization of rat enamel can be regarded, as in humans, as a regular and progressive process pattern of enamel matrix formation. The species variations that have been proposed in the pattern of enamel mineralization can be related to differences in both the rate of formation of the enamel matrix and in the total thickness of the enamel produced. Neither the microradiographic appearance of developing enamel, nor the solubility and staining characteristics of the organic matrix accurately reflects the mineral concentration gradients established during the mineralization process as indicated from electron microprobe analysis.

Matrix-Mineral Relationships-A. Morphologist's Viewpoint

1979 ◽  
Vol 58 (2_suppl) ◽  
pp. 922-929 ◽  
Author(s):  
M.U. Nylen
Keyword(s):  
Organic Material ◽  
Crucial Role ◽  
Crystal Surface ◽  
Organic Matrix ◽  
The Other ◽  
Enamel Matrix ◽  
Initial Cell ◽  
Cell Product ◽  
Ultrastructural Morphology ◽  
The Matrix

The literature on the ultrastructural morphology of the enamel matrix and its relationship to the crystals is reviewed. Two morphological entities of the matrix are discussed: One is the so-called stippled material which may be the initial cell product; the other, variously described as fibrillar, lamellar, tubular or helical, is thought by many to play a crucial role in nucleation and orientation of the crystals. A number of observations, however, suggest that the latter structures form secondarily to the crystals and that in reality they represent organic material adsorbed to the crystal surface and maintained as independent structures upon removal of the mineral. The need for additional studies is stressed including systematic studies of interactions between constituents of the organic matrix and the apatite crystals.

Study of the Architecture of Inorganic-Organic Matrix in the Ventral Segmental Concretion of Porcellius Chilensis Nicolet, 1849 (Crustacea, Isopoda)

2007 ◽  
Vol 1007 ◽  
Author(s):  
Ranjith Krishna Pai ◽  
Andrónico Neira-Carrillo ◽  
Maria Soledad Fernandez ◽  
José Luis Arias
Keyword(s):  
Structural Organization ◽  
Inorganic Material ◽  
Organic Matrix ◽  
Ultrastructural Changes ◽  
Amorphous Calcium Carbonate ◽  
Terrestrial Isopods ◽  
Matrix Components ◽  
Natural Composite ◽  
First Time

ABSTRACTMineralized biological concretions have attracted increasing interest because of their outstanding properties. The mineralized concretion of terrestrial isopods is an excellent model for acellular natural composite material. Before the molt terrestrial isopods resorb calcium from the posterior cuticle and store it in concretion within the cranial (head) and caudal (tail) ventral segments. This paper present for the first time an analysis of ultrastructural changes occurring in the caudal ventral segmental (CaVS) concretion of a terrestrial isopod Porcellius chilensis during their formation and degradation. The CaVS concretion of the woodlice Porcellius chilensis was analyzed with respect to their content of inorganic material. It was found that the concretion consists of amorphous calcium carbonate (ACC), and amorphous calcium phosphate (ACP), besides small amounts of water and an organic matrix. The CaVS concretion consists of structurally distinct stratum due to inhomogeneous solubility of ACC within the organic matrix that consists of calcareous knob with reticules elements. The organic matrix plays a role in the structural organization of the concretion and in the stabilization of ACC, which is unstable in vitro. We present an analysis of the distribution of minerals, elements, and organic matrix with in the CaVS concretion by using SEM, XRD, IR and EDS. The decalcification experiments exactly imitated the natural demineralization of the CaVS concretion of the Porcellius chilensis and it is thought that an inhomogeneous solubility of ACC and ACP within the CaVS concretion probably caused by variations in the stabilizing properties of matrix components.

scholarly journals IDENTIFIKASI PERUBAHAN MINERAL SELAMA PROSES PEMANASAN PELET KOMPOSIT NIKEL DENGAN ANALISIS DIFRAKSI SINAR X ( IDENTIFICATION OF MINERAL CHANGES DURING HEATING OF NICKEL COMPOSITE USING X-RAY DIFFRACTION ANALYSIS )

2018 ◽  
Vol 12 (1) ◽  
pp. 9-16
Author(s):  
Nur Vita Permatasari ◽  
Adji Kawigraha ◽  
Abdul Hapid ◽  
Nurhadi Wibowo
Keyword(s):  
Low Temperature ◽  
Diffraction Analysis ◽  
Mineral Content ◽  
Reduction Process ◽  
X Ray Diffraction ◽  
Composite Pellet ◽  
X Ray ◽  
Color Changes ◽  
Ore Processing ◽  
Mineral Changes

Logam nikel didapat dari proses pengolahan bijih nikel yang salah satunya adalah saprolit. Pada penelitian ini proses reduksi pelet komposit yang merupakan masa campuran bijih nikel serta batubara kadar rendah dan bahan tambahan dilakukan dalam tungku tabung. Proses reduksi dilakukan pada temperatur 450 °C, 700 °C serta 1100 °C selama 0 jam. Proses reduksi juga dilakukan pada temperatur yang lebih tinggi yaitu 1300 °C namun dengan pemanasan terlebih dahulu pada temperatur 700 °C dan ditahan pada 1 jam dan 2 jam. Produk pelet komposit dianalisis dengan metode difraksi sinar X untuk mengetahui kandungan mineralnya. Hasil menunjukkan bahwa pemanasan pelet komposit menyebabkan terjadinya perubahan warna dari warna coklat menjadi abu-abu. Pemanasan juga menyebabkan terjadinya perubahan komposisi mineral dari masing-masing pelet. Mineral-mineral yang terdapat dalam pelet komposit dan produknya adalah antigorit, klinoklor, kuarsa, enstatit, forsterit,gutit, hematit, magnetit, nikel dan besi. Pemanasan pelet pada temperatur rendah yang lebih lama akan menghasilkan jumlah logam besi yang lebih rendah. Nickel is obtained from saprolite through nickel ore processing. In this study, reduction of composite pellet has been done in a tube furnace. The pellet comsist of nickel ore, coal and additive. The reduction process carried out at 450˚C, 700˚C and 1100˚C for 0 hour. Moreover the reduction is also carried out at 700 °C during 1 and 2 hours followed by heating at 1300˚C for 2 and 1 hours. Reduction product was analyzed by X-Ray diffraction to determine the mineral content. The results indicate that the heating causing color changes from red brown to gray. Heating changes the mineral composition of the pellet. The minerals are antigorite, clinoclore, quartz, enstatite, forsterite, goethite, hematite, magnetite, nickel and iron. Heating the pellets at low temperature longer will produce lower iron.

Na-K-ATPase in the Enamel Organ: Localization and Possible Roles in Enamel Formation

1987 ◽  
Vol 1 (2) ◽  
pp. 267-275 ◽  
Author(s):  
P.R. Garant ◽  
T. Sasaki ◽  
P.E. Colflesh
Keyword(s):  
Plasma Membranes ◽  
Organic Matrix ◽  
Enamel Organ ◽  
Maturation Stage ◽  
Enamel Formation ◽  
Morphological Alterations ◽  
Maturation Stages ◽  
Delayed Maturation ◽  
The One

Ouabain-sensitive, K-dependent p-nitrophenyl phosphatase (p-NPPase) activity was localized ultra-Ocytochemically in the lateral plasma membranes of secretory ameloblasts and the stratum intermedium and principally in the papillary layer cells of aldehyde-fixed rat incisor enamel organs by the one-step lead method. Daily intraperitoneal injection of ouabain (250 μg, 500 μg, and 1 mg/100 g body weight) for two weeks reduced p-NPPase activity in the enamel organ cells. However, the degree to which this activity was reduced appeared to vary among the experimental animals. Addition of ouabain to the cytochemical incubation medium completely inhibited p-NPPase activity in the tissues. Although long-term ouabain injection did not result in any morphological alterations of the enamel organ cells, it caused, in part, an appearance of electron-dense, homogeneous matrix-like substances (MS) in the extracellular spaces of the ameloblast layers at both the secretion and maturation stages. In addition, long-term ouabain injection appeared to have resulted in delayed maturation of enamel as measured by energy-dispersive x-ray analysis of Ca and P in surface enamel. These results suggest that Na-K-ATPase of enamel organ cells may participate in the net flow (removal) of organic matrix components and water from the enamel during the maturation stage of enamel formation. It is suggested that this flow is maintained by local osmotic gradients generated by Na-K-ATPase within the papillary layer.

Osteoporosis: prevention and treatment

1989 ◽  
Vol 27 (1) ◽  
pp. 1-4
Keyword(s):  
Vertebral Body ◽  
Hip Fractures ◽  
Mineral Content ◽  
Community Care ◽  
Organic Matrix ◽  
Economic Consequences ◽  
Osteoporosis Prevention ◽  
Serious Illness ◽  
Prevention And Treatment ◽  
The Cost

Osteoporosis is a reduction in both the mineral content and the organic matrix of bone. This predisposes to fractures, most commonly of the upper femur, wrist, humeral neck or a vertebral body. Osteoporosis causes much serious illness, with major economic consequences: in England and Wales about 37,500 hip fractures annually cost £165 million, assuming each patient requires 40 days in hospital at a cost of £110 a day, and this does not include the cost of community care after leaving hospital.1

In Vitro Study of Cellular Influence on 45Ca Uptake in Developing Rat Enamel

1977 ◽  
Vol 56 (3) ◽  
pp. 313-319 ◽  
Author(s):  
James W. Bawden ◽  
Alf Wennberg
Keyword(s):  
In Vitro Study ◽  
Enamel Organ ◽  
Cellular Activity ◽  
Enamel Matrix ◽  
Apparent Effect ◽  
In Vitro Method ◽  
45Ca Uptake ◽  
Developing Rat ◽  
Rat Molars

An in vitro method was used to study the influence of enamel organ cellular activity on the uptake of 45Ca in the developing enamel of rat molars. Heat killing, inhibition with DNP, or stripping of the enamel organ from the tooth had no apparent effect on 45Ca uptake patterns in maturing enamel. However, uptake in newly secreted enamel matrix was increased.

Sign in / Sign up

Export Citation Format

Share Document