Bone Demineralization Technique: Removal of mineral constituents or salts from bone or bone tissue. Demineralization is used as a method of studying bone strength and bone chemistry.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)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.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)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.Tooth Remineralization: Therapeutic technique for replacement of minerals in partially decalcified teeth.Hardness Tests: A test to determine the relative hardness of a metal, mineral, or other material according to one of several scales, such as Brinell, Mohs, Rockwell, Vickers, or Shore. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Cariostatic Agents: Substances that inhibit or arrest DENTAL CARIES formation. (Boucher's Clinical Dental Terminology, 4th ed)Dental Caries Activity Tests: Diagnostic tests conducted in order to measure the increment of active DENTAL CARIES over a period of time.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).Fluorides, Topical: Fluorides, usually in pastes or gels, used for topical application to reduce the incidence of DENTAL CARIES.Root Caries: Dental caries involving the tooth root, cementum, or cervical area of the tooth.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)Dental Caries: Localized destruction of the tooth surface initiated by decalcification of the enamel followed by enzymatic lysis of organic structures and leading to cavity formation. If left unchecked, the cavity may penetrate the enamel and dentin and reach the pulp.Bone Transplantation: The grafting of bone from a donor site to a recipient site.Bone Banks: Centers for acquiring, characterizing, and storing bones or bone tissue for future use.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Bone Substitutes: Synthetic or natural materials for the replacement of bones or bone tissue. They include hard tissue replacement polymers, natural coral, hydroxyapatite, beta-tricalcium phosphate, and various other biomaterials. The bone substitutes as inert materials can be incorporated into surrounding tissue or gradually replaced by original tissue.Biopolymers: Polymers synthesized by living organisms. They play a role in the formation of macromolecular structures and are synthesized via the covalent linkage of biological molecules, especially AMINO ACIDS; NUCLEOTIDES; and CARBOHYDRATES.Defibrillators, Implantable: Implantable devices which continuously monitor the electrical activity of the heart and automatically detect and terminate ventricular tachycardia (TACHYCARDIA, VENTRICULAR) and VENTRICULAR FIBRILLATION. They consist of an impulse generator, batteries, and electrodes.Bone Density: The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.Calcification, Physiologic: Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.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.Bone Matrix: Extracellular substance of bone tissue consisting of COLLAGEN fibers, ground substance, and inorganic crystalline minerals and salts.Spine: The spinal or vertebral column.Osteogenesis: The process of bone formation. Histogenesis of bone including ossification.Bone Regeneration: Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.Arthritis, Infectious: Arthritis caused by BACTERIA; RICKETTSIA; MYCOPLASMA; VIRUSES; FUNGI; or PARASITES.Dental Articulators: Mechanical devices that simulate the temporomandibular joints and jaws to which maxillary and mandibular casts are attached. The entire assembly attempts to reproduce the movements of the mandible and the various tooth-to-tooth relationships that accompany those movements.Joint Capsule: The sac enclosing a joint. It is composed of an outer fibrous articular capsule and an inner SYNOVIAL MEMBRANE.Osteotomy, Le Fort: Transverse sectioning and repositioning of the maxilla. There are three types: Le Fort I osteotomy for maxillary advancement or the treatment of maxillary fractures; Le Fort II osteotomy for the treatment of maxillary fractures; Le Fort III osteotomy for the treatment of maxillary fractures with fracture of one or more facial bones. Le Fort III is often used also to correct craniofacial dysostosis and related facial abnormalities. (From Dorland, 28th ed, p1203 & p662)ArthritisSynovial Membrane: The inner membrane of a joint capsule surrounding a freely movable joint. It is loosely attached to the external fibrous capsule and secretes SYNOVIAL FLUID.Arthritis, Rheumatoid: A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.Chemistry, Analytic: The branch of chemistry dealing with detection (qualitative) and determination (quantitative) of substances. (Grant & Hackh's Chemical Dictionary, 5th ed)GeorgiaChemistry Techniques, Analytical: Methodologies used for the isolation, identification, detection, and quantitation of chemical substances.MarylandRussia (Pre-1917)Professional Staff Committees: Committees of professional personnel who have responsibility for determining policies, procedures, and controls related to professional matters in health facilities.Georgia (Republic)Goats: Any of numerous agile, hollow-horned RUMINANTS of the genus Capra, in the family Bovidae, closely related to the SHEEP.Milk: The white liquid secreted by the mammary glands. It contains proteins, sugar, lipids, vitamins, and minerals.Goat Diseases: Diseases of the domestic or wild goat of the genus Capra.Milk, HumanPhosphorus: 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.Mythology: A body of stories, the origins of which may be unknown or forgotten, that serve to explain practices, beliefs, institutions or natural phenomena. Mythology includes legends and folk tales. It may refer to classical mythology or to a body of modern thought and modern life. (From Webster's 1st ed)Absorptiometry, Photon: A noninvasive method for assessing BODY COMPOSITION. It is based on the differential absorption of X-RAYS (or GAMMA RAYS) by different tissues such as bone, fat and other soft tissues. The source of (X-ray or gamma-ray) photon beam is generated either from radioisotopes such as GADOLINIUM 153, IODINE 125, or Americanium 241 which emit GAMMA RAYS in the appropriate range; or from an X-ray tube which produces X-RAYS in the desired range. It is primarily used for quantitating BONE MINERAL CONTENT, especially for the diagnosis of OSTEOPOROSIS, and also in measuring BONE MINERALIZATION.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.Osteoporosis, Postmenopausal: Metabolic disorder associated with fractures of the femoral neck, vertebrae, and distal forearm. It occurs commonly in women within 15-20 years after menopause, and is caused by factors associated with menopause including estrogen deficiency.Body Composition: The relative amounts of various components in the body, such as percentage of body fat.Femur Neck: The constricted portion of the thigh bone between the femur head and the trochanters.