Minerals: Native, inorganic or fossilized organic substances having a definite chemical composition and formed by inorganic reactions. They may occur as individual crystals or may be disseminated in some other mineral or rock. (Grant & Hackh's Chemical Dictionary, 5th ed; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Mineral Waters: Water naturally or artificially infused with mineral salts or gases.Mineral Oil: A mixture of liquid hydrocarbons obtained from petroleum. It is used as laxative, lubricant, ointment base, and emollient.Osteoporosis: Reduction of bone mass without alteration in the composition of bone, leading to fractures. Primary osteoporosis can be of two major types: postmenopausal osteoporosis (OSTEOPOROSIS, POSTMENOPAUSAL) and age-related or senile osteoporosis.Bone and Bones: A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.Mineral Fibers: Long, pliable, cohesive natural or manufactured filaments of various lengths. They form the structure of some minerals. The medical significance lies in their potential ability to cause various types of PNEUMOCONIOSIS (e.g., ASBESTOSIS) after occupational or environmental exposure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p708)Bone Diseases, MetabolicCalcification, Physiologic: Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.Silicates: The generic term for salts derived from silica or the silicic acids. They contain silicon, oxygen, and one or more metals, and may contain hydrogen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th Ed)Calcium Compounds: Inorganic compounds that contain calcium as an integral part of the molecule.Trace Elements: A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Phosphorus: A non-metal element that has the atomic symbol P, atomic number 15, and atomic weight 31. It is an essential element that takes part in a broad variety of biochemical reactions.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Radius: The outer shorter of the two bones of the FOREARM, lying parallel to the ULNA and partially revolving around it.Fractures, Bone: Breaks in bones.Bone Remodeling: The continuous turnover of BONE MATRIX and mineral that involves first an increase in BONE RESORPTION (osteoclastic activity) and later, reactive BONE FORMATION (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium HOMEOSTASIS. An imbalance in the regulation of bone remodeling's two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as OSTEOPOROSIS.Calcium, Dietary: Calcium compounds used as food supplements or in food to supply the body with calcium. Dietary calcium is needed during growth for bone development and for maintenance of skeletal integrity later in life to prevent osteoporosis.Aluminum Silicates: Any of the numerous types of clay which contain varying proportions of Al2O3 and SiO2. They are made synthetically by heating aluminum fluoride at 1000-2000 degrees C with silica and water vapor. (From Hawley's Condensed Chemical Dictionary, 11th ed)Spine: The spinal or vertebral column.Parathyroid Hormone: A polypeptide hormone (84 amino acid residues) secreted by the PARATHYROID GLANDS which performs the essential role of maintaining intracellular CALCIUM levels in the body. Parathyroid hormone increases intracellular calcium by promoting the release of CALCIUM from BONE, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.Hip: The projecting part on each side of the body, formed by the side of the pelvis and the top portion of the femur.Osteocalcin: Vitamin K-dependent calcium-binding protein synthesized by OSTEOBLASTS and found primarily in BONES. Serum osteocalcin measurements provide a noninvasive specific marker of bone metabolism. The protein contains three residues of the amino acid gamma-carboxyglutamic acid (Gla), which, in the presence of CALCIUM, promotes binding to HYDROXYAPATITE and subsequent accumulation in BONE MATRIX.Vitamins: Organic substances that are required in small amounts for maintenance and growth, but which cannot be manufactured by the human body.Bone Density Conservation Agents: Agents that inhibit BONE RESORPTION and/or favor BONE MINERALIZATION and BONE REGENERATION. They are used to heal BONE FRACTURES and to treat METABOLIC BONE DISEASES such as OSTEOPOROSIS.Bone Development: The growth and development of bones from fetus to adult. It includes two principal mechanisms of bone growth: growth in length of long bones at the epiphyseal cartilages and growth in thickness by depositing new bone (OSTEOGENESIS) with the actions of OSTEOBLASTS and OSTEOCLASTS.Calcium Carbonate: Carbonic acid calcium salt (CaCO3). An odorless, tasteless powder or crystal that occurs in nature. It is used therapeutically as a phosphate buffer in hemodialysis patients and as a calcium supplement.Bone Resorption: Bone loss due to osteoclastic activity.Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Apatites: A group of phosphate minerals that includes ten mineral species and has the general formula X5(YO4)3Z, where X is usually calcium or lead, Y is phosphorus or arsenic, and Z is chlorine, fluorine, or OH-. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Calcium Phosphates: Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.Tibia: The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Aluminum Compounds: Inorganic compounds that contain aluminum as an integral part of the molecule.Bone Demineralization, Pathologic: Decrease, loss, or removal of the mineral constituents of bones. Temporary loss of bone mineral content is especially associated with space flight, weightlessness, and extended immobilization. OSTEOPOROSIS is permanent, includes reduction of total bone mass, and is associated with increased rate of fractures. CALCIFICATION, PHYSIOLOGIC is the process of bone remineralizing. (From Dorland, 27th ed; Stedman, 25th ed; Nicogossian, Space Physiology and Medicine, 2d ed, pp327-33)Carbonates: Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)Alendronate: A nonhormonal medication for the treatment of postmenopausal osteoporosis in women. This drug builds healthy bone, restoring some of the bone loss as a result of osteoporosis.Dietary Supplements: Products in capsule, tablet or liquid form that provide dietary ingredients, and that are intended to be taken by mouth to increase the intake of nutrients. Dietary supplements can include macronutrients, such as proteins, carbohydrates, and fats; and/or MICRONUTRIENTS, such as VITAMINS; MINERALS; and PHYTOCHEMICALS.Alkaline Phosphatase: An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.1.Vitamin D: A vitamin that includes both CHOLECALCIFEROLS and ERGOCALCIFEROLS, which have the common effect of preventing or curing RICKETS in animals. It can also be viewed as a hormone since it can be formed in SKIN by action of ULTRAVIOLET RAYS upon the precursors, 7-dehydrocholesterol and ERGOSTEROL, and acts on VITAMIN D RECEPTORS to regulate CALCIUM in opposition to PARATHYROID HORMONE.Diet: Regular course of eating and drinking adopted by a person or animal.X-Ray Microtomography: X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.Durapatite: The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.Zeolites: Zeolites. A group of crystalline, hydrated alkali-aluminum silicates. They occur naturally in sedimentary and volcanic rocks, altered basalts, ores, and clay deposits. Some 40 known zeolite minerals and a great number of synthetic zeolites are available commercially. (From Merck Index, 11th ed)Phosphates: Inorganic salts of phosphoric acid.Copper: A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.Asbestos: Asbestos. Fibrous incombustible mineral composed of magnesium and calcium silicates with or without other elements. It is relatively inert chemically and used in thermal insulation and fireproofing. Inhalation of dust causes asbestosis and later lung and gastrointestinal neoplasms.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Oxides: Binary compounds of oxygen containing the anion O(2-). The anion combines with metals to form alkaline oxides and non-metals to form acidic oxides.Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Bone Matrix: Extracellular substance of bone tissue consisting of COLLAGEN fibers, ground substance, and inorganic crystalline minerals and salts.Body Composition: The relative amounts of various components in the body, such as percentage of body fat.Tooth Calcification: The process whereby calcium salts are deposited in the dental enamel. The process is normal in the development of bones and teeth. (Boucher's Clinical Dental Terminology, 4th ed, p43)Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.Osteogenesis: The process of bone formation. Histogenesis of bone including ossification.Silicic Acid: A hydrated form of silicon dioxide. It is commonly used in the manufacture of TOOTHPASTES and as a stationary phase for CHROMATOGRAPHY.Animal Feed: Foodstuff used especially for domestic and laboratory animals, or livestock.Microradiography: Production of a radiographic image of a small or very thin object on fine-grained photographic film under conditions which permit subsequent microscopic examination or enlargement of the radiograph at linear magnifications of up to several hundred and with a resolution approaching the resolving power of the photographic emulsion (about 1000 lines per millimeter).Postmenopause: The physiological period following the MENOPAUSE, the permanent cessation of the menstrual life.Osteoporotic Fractures: Breaks in bones resulting from low bone mass and microarchitectural deterioration characteristic of OSTEOPOROSIS.Tooth Demineralization: A tooth's loss of minerals, such as calcium in hydroxyapatite from the tooth matrix, caused by acidic exposure. An example of the occurrence of demineralization is in the formation of dental caries.Quartz: Quartz (SiO2). A glassy or crystalline form of silicon dioxide. Many colored varieties are semiprecious stones. (From Grant & Hackh's Chemical Dictionary, 5th ed)Osteoblasts: Bone-forming cells which secrete an EXTRACELLULAR MATRIX. HYDROXYAPATITE crystals are then deposited into the matrix to form bone.Dental Enamel: A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)Magnesium Compounds: Inorganic compounds that contain magnesium as an integral part of the molecule.Diphosphonates: Organic compounds which contain P-C-P bonds, where P stands for phosphonates or phosphonic acids. These compounds affect calcium metabolism. They inhibit ectopic calcification and slow down bone resorption and bone turnover. Technetium complexes of diphosphonates have been used successfully as bone scanning agents.Phosphorus, Dietary: Phosphorus used in foods or obtained from food. This element is a major intracellular component which plays an important role in many biochemical pathways relating to normal physiological functions. High concentrations of dietary phosphorus can cause nephrocalcinosis which is associated with impaired kidney function. Low concentrations of dietary phosphorus cause an increase in calcitriol in the blood and osteoporosis.Asbestos, Serpentine: A type of asbestos that occurs in nature as the dihydrate of magnesium silicate. It exists in two forms: antigorite, a plated variety, and chrysotile, a fibrous variety. The latter makes up 95% of all asbestos products. (From Merck Index, 11th ed, p.893)Geology: The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Tooth Remineralization: Therapeutic technique for replacement of minerals in partially decalcified teeth.Collagen Type I: The most common form of fibrillar collagen. It is a major constituent of bone (BONE AND BONES) and SKIN and consists of a heterotrimer of two alpha1(I) and one alpha2(I) chains.Etidronic Acid: A diphosphonate which affects calcium metabolism. It inhibits ectopic calcification and slows down bone resorption and bone turnover.Soil: The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.Root Canal Filling Materials: Materials placed inside a root canal for the purpose of obturating or sealing it. The materials may be gutta-percha, silver cones, paste mixtures, or other substances. (Dorland, 28th ed, p631 & Boucher's Clinical Dental Terminology, 4th ed, p187)Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Retrograde Obturation: Procedure that involves the removal of infectious products from a root canal space through use of special instruments and fillings. This procedure is performed when root canal treatment fails.Bone Diseases: Diseases of BONES.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Animal Nutritional Physiological Phenomena: Nutritional physiology of animals.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Dust: Earth or other matter in fine, dry particles. (Random House Unabridged Dictionary, 2d ed)Nutritional Requirements: The amounts of various substances in food needed by an organism to sustain healthy life.Spectrometry, X-Ray Emission: The spectrometric analysis of fluorescent X-RAYS, i.e. X-rays emitted after bombarding matter with high energy particles such as PROTONS; ELECTRONS; or higher energy X-rays. Identification of ELEMENTS by this technique is based on the specific type of X-rays that are emitted which are characteristic of the specific elements in the material being analyzed. The characteristic X-rays are distinguished and/or quantified by either wavelength dispersive or energy dispersive methods.Asbestos, Crocidolite: A lavender, acid-resistant asbestos.Electron Probe Microanalysis: Identification and measurement of ELEMENTS and their location based on the fact that X-RAYS emitted by an element excited by an electron beam have a wavelength characteristic of that element and an intensity related to its concentration. It is performed with an electron microscope fitted with an x-ray spectrometer, in scanning or transmission mode.Densitometry: The measurement of the density of a material by measuring the amount of light or radiation passing through (or absorbed by) the material.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Geological Phenomena: The inanimate matter of Earth, the structures and properties of this matter, and the processes that affect it.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Iron Compounds: Organic and inorganic compounds that contain iron as an integral part of the molecule.Premenopause: The period before MENOPAUSE. In premenopausal women, the climacteric transition from full sexual maturity to cessation of ovarian cycle takes place between the age of late thirty and early fifty.Dentin: The hard portion of the tooth surrounding the pulp, covered by enamel on the crown and cementum on the root, which is harder and denser than bone but softer than enamel, and is thus readily abraded when left unprotected. (From Jablonski, Dictionary of Dentistry, 1992)Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Hip Joint: The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.Nutritive Value: An indication of the contribution of a food to the nutrient content of the diet. This value depends on the quantity of a food which is digested and absorbed and the amounts of the essential nutrients (protein, fat, carbohydrate, minerals, vitamins) which it contains. This value can be affected by soil and growing conditions, handling and storage, and processing.Weight-Bearing: The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.Teriparatide: A polypeptide that consists of the 1-34 amino-acid fragment of human PARATHYROID HORMONE, the biologically active N-terminal region. The acetate form is given by intravenous infusion in the differential diagnosis of HYPOPARATHYROIDISM and PSEUDOHYPOPARATHYROIDISM. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1995)Renal Osteodystrophy: Decalcification of bone or abnormal bone development due to chronic KIDNEY DISEASES, in which 1,25-DIHYDROXYVITAMIN D3 synthesis by the kidneys is impaired, leading to reduced negative feedback on PARATHYROID HORMONE. The resulting SECONDARY HYPERPARATHYROIDISM eventually leads to bone disorders.Nutritional Status: State of the body in relation to the consumption and utilization of nutrients.Pelvic Bones: Bones that constitute each half of the pelvic girdle in VERTEBRATES, formed by fusion of the ILIUM; ISCHIUM; and PUBIC BONE.Body Height: The distance from the sole to the crown of the head with body standing on a flat surface and fully extended.Metacarpus: The region of the HAND between the WRIST and the FINGERS.Ovariectomy: The surgical removal of one or both ovaries.Calcinosis: Pathologic deposition of calcium salts in tissues.Asbestos, Amphibole: A class of asbestos that includes silicates of magnesium, iron, calcium, and sodium. The fibers are generally brittle and cannot be spun, but are more resistant to chemicals and heat than ASBESTOS, SERPENTINE. (From Hawley's Condensed Chemical Dictionary, 11th ed)Osteomalacia: Disorder caused by an interruption of the mineralization of organic bone matrix leading to bone softening, bone pain, and weakness. It is the adult form of rickets resulting from disruption of VITAMIN D; PHOSPHORUS; or CALCIUM homeostasis.Silicon Dioxide: Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.Food, Fortified: Any food that has been supplemented with essential nutrients either in quantities that are greater than those present normally, or which are not present in the food normally. Fortified food includes also food to which various nutrients have been added to compensate for those removed by refinement or processing. (From Segen, Dictionary of Modern Medicine, 1992)Fertilizers: Substances or mixtures that are added to the soil to supply nutrients or to make available nutrients already present in the soil, in order to increase plant growth and productivity.Hip Fractures: Fractures of the FEMUR HEAD; the FEMUR NECK; (FEMORAL NECK FRACTURES); the trochanters; or the inter- or subtrochanteric region. Excludes fractures of the acetabulum and fractures of the femoral shaft below the subtrochanteric region (FEMORAL FRACTURES).Amelogenesis: The elaboration of dental enamel by ameloblasts, beginning with its participation in the formation of the dentino-enamel junction to the production of the matrix for the enamel prisms and interprismatic substance. (Jablonski, Dictionary of Dentistry, 1992).Random Allocation: A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.Carbon Sequestration: Any of several processes for the permanent or long-term artificial or natural capture or removal and storage of carbon dioxide and other forms of carbon, through biological, chemical or physical processes, in a manner that prevents it from being released into the atmosphere.Micronutrients: Essential dietary elements or organic compounds that are required in only small quantities for normal physiologic processes to occur.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Vitamin D Deficiency: A nutritional condition produced by a deficiency of VITAMIN D in the diet, insufficient production of vitamin D in the skin, inadequate absorption of vitamin D from the diet, or abnormal conversion of vitamin D to its bioactive metabolites. It is manifested clinically as RICKETS in children and OSTEOMALACIA in adults. (From Cecil Textbook of Medicine, 19th ed, p1406)Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Construction Materials: Supplies used in building.Ulna: The inner and longer bone of the FOREARM.Anthropometry: The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.Osteoprotegerin: A secreted member of the TNF receptor superfamily that negatively regulates osteoclastogenesis. It is a soluble decoy receptor of RANK LIGAND that inhibits both CELL DIFFERENTIATION and function of OSTEOCLASTS by inhibiting the interaction between RANK LIGAND and RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B.Tomography, X-Ray: Tomography using x-ray transmission.Magnesium Oxide: Magnesium oxide (MgO). An inorganic compound that occurs in nature as the mineral periclase. In aqueous media combines quickly with water to form magnesium hydroxide. It is used as an antacid and mild laxative and has many nonmedicinal uses.Magnesium Deficiency: A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. (Harrison's Principles of Internal Medicine, 12th ed, p1936)Spectroscopy, Fourier Transform Infrared: A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.Ferric Compounds: Inorganic or organic compounds containing trivalent iron.Phytic Acid: Complexing agent for removal of traces of heavy metal ions. It acts also as a hypocalcemic agent.6-Phytase: An enzyme that catalyzes the conversion of myo-inositol hexakisphosphate and water to 1L-myo-inositol 1,2,3,4,5-pentakisphosphate and orthophosphate. EC 3.1.3.26.Glass: Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.Osteocytes: Mature osteoblasts that have become embedded in the BONE MATRIX. They occupy a small cavity, called lacuna, in the matrix and are connected to adjacent osteocytes via protoplasmic projections called canaliculi.Elements: Substances that comprise all matter. Each element is made up of atoms that are identical in number of electrons and protons and in nuclear charge, but may differ in mass or number of neutrons.Meteoroids: Any solid objects moving in interplanetary space that are smaller than a planet or asteroid but larger than a molecule. Meteorites are any meteoroid that has fallen to a planetary surface. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Asbestos, Amosite: Asbestos, grunerite. A monoclinic amphibole form of asbestos having long fibers and a high iron content. It is used in insulation. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Amenorrhea: Absence of menstruation.Biological Availability: The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.X-Ray Diffraction: The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Osteoclasts: A large multinuclear cell associated with the BONE RESORPTION. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in CEMENTUM resorption.Kaolin: The most common mineral of a group of hydrated aluminum silicates, approximately H2Al2Si2O8-H2O. It is prepared for pharmaceutical and medicinal purposes by levigating with water to remove sand, etc. (From Merck Index, 11th ed) The name is derived from Kao-ling (Chinese: "high ridge"), the original site. (From Grant & Hackh's Chemical Dictionary, 5th ed)Amelogenin: A major dental enamel-forming protein found in mammals. In humans the protein is encoded by GENES found on both the X CHROMOSOME and the Y CHROMOSOME.Mars: The fourth planet in order from the sun. Its two natural satellites are Deimos and Phobos. It is one of the four inner or terrestrial planets of the solar system.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Selenium: An element with the atomic symbol Se, atomic number 34, and atomic weight 78.96. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE.Compressive Strength: The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)Americium: Americium. A completely man-made radioactive actinide with atomic symbol Am, atomic number 95, and atomic weight 243. Its valence can range from +3 to +6. Because of its nonmagnetic ground state, it is an excellent superconductor. It is also used in bone mineral analysis and as a radiation source for radiotherapy.Milk: The white liquid secreted by the mammary glands. It contains proteins, sugar, lipids, vitamins, and minerals.Ilium: The largest of three bones that make up each half of the pelvic girdle.Cholecalciferol: Derivative of 7-dehydroxycholesterol formed by ULTRAVIOLET RAYS breaking of the C9-C10 bond. It differs from ERGOCALCIFEROL in having a single bond between C22 and C23 and lacking a methyl group at C24.Pneumoconiosis: A diffuse parenchymal lung disease caused by inhalation of dust and by tissue reaction to their presence. These inorganic, organic, particulate, or vaporized matters usually are inhaled by workers in their occupational environment, leading to the various forms (ASBESTOSIS; BYSSINOSIS; and others). Similar air pollution can also have deleterious effects on the general population.Lactation: The processes of milk secretion by the maternal MAMMARY GLANDS after PARTURITION. The proliferation of the mammary glandular tissue, milk synthesis, and milk expulsion or let down are regulated by the interactions of several hormones including ESTRADIOL; PROGESTERONE; PROLACTIN; and OXYTOCIN.Hyperparathyroidism, Secondary: Abnormally elevated PARATHYROID HORMONE secretion as a response to HYPOCALCEMIA. It is caused by chronic KIDNEY FAILURE or other abnormalities in the controls of bone and mineral metabolism, leading to various BONE DISEASES, such as RENAL OSTEODYSTROPHY.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Puberty: A period in the human life in which the development of the hypothalamic-pituitary-gonadal system takes place and reaches full maturity. The onset of synchronized endocrine events in puberty lead to the capacity for reproduction (FERTILITY), development of secondary SEX CHARACTERISTICS, and other changes seen in ADOLESCENT DEVELOPMENT.Apexification: Endodontic procedure performed to induce TOOTH APEX barrier development. ROOT CANAL FILLING MATERIALS are used to repair open apex or DENTAL PULP NECROSIS in an immature tooth. CALCIUM HYDROXIDE and mineral trioxide aggregate are commonly used as the filling materials.Soil Microbiology: The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Dietary Proteins: Proteins obtained from foods. They are the main source of the ESSENTIAL AMINO ACIDS.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Digestion: The process of breakdown of food for metabolism and use by the body.Bones of Upper Extremity: The bones of the upper and lower ARM. They include the CLAVICLE and SCAPULA.Diaphyses: The shaft of long bones.Menopause: The last menstrual period. Permanent cessation of menses (MENSTRUATION) is usually defined after 6 to 12 months of AMENORRHEA in a woman over 45 years of age. In the United States, menopause generally occurs in women between 48 and 55 years of age.Mandible: The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth.Avitaminosis: A condition due to a deficiency of one or more essential vitamins. (Dorland, 27th ed)Manganese: A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)Metacarpal Bones: The five cylindrical bones of the METACARPUS, articulating with the CARPAL BONES proximally and the PHALANGES OF FINGERS distally.Hydroxycholecalciferols: Hydroxy analogs of vitamin D 3; (CHOLECALCIFEROL); including CALCIFEDIOL; CALCITRIOL; and 24,25-DIHYDROXYVITAMIN D 3.Calcitriol: The physiologically active form of vitamin D. It is formed primarily in the kidney by enzymatic hydroxylation of 25-hydroxycholecalciferol (CALCIFEDIOL). Its production is stimulated by low blood calcium levels and parathyroid hormone. Calcitriol increases intestinal absorption of calcium and phosphorus, and in concert with parathyroid hormone increases bone resorption.