
Acanthodii
Class of primitive, fossil fish that had a true bony skeleton, a heterocercal tail fin, a persistent notochord, ganoid scales, and stout spines in front of the fins. The acanthodians lived from the ...

acid–base homeostasis
All living things depend on water. Life consists of a highly complex series of chemical reactions occurring in aqueous media. Among the most important factors in the composition of these ...

Actinopterygii
; class Osteichthyes)A subclass of ray-finned fish, that includes the majority of living bony fish of sea and fresh water. The fins are composed of a membranous web of skin supported by a varying ...

alignment
The location of the tooth relative to the supporting alveolar bone and adjacent and opposing teeth.

alveolar crest
The most coronal part of the alveolar bone. In the healthy periodontium, the distance between the alveolar crest and the cement–enamel junction is 1–2mm, as measured on a radiograph.

analgesia
(an-ăl-jeez-iă)reduced sensibility to pain, without loss of consciousness and without the sense of touch necessarily being affected.

Andreas Vesalius
(1514–64)Belgian physician and anatomist, who was a professor at Padua for six years before becoming a physician to the Habsburg court. He is remembered for producing in 1538–43 definitive text and ...

blood
(blud)a fluid that circulates throughout the body, via the arteries and veins, providing a vehicle by which an immense variety of different substances are transported between the various organs and ...

bone sounding
The process of probing anaesthetized tissue with a periodontal probe to establish the level of the underlying alveolar bone.

calcium
(kal-siŭm)a metallic element that is an important constituent of bones, teeth, and blood. It is also essential for many metabolic processes, including nerve function, muscle contraction, and blood ...

cancellous
adj. lattice-like: applied to the porous spongy network of flattened sheets of bone, interconnected like a honeycomb, that forms the interior of bones and has a lower density than the surrounding ...

caries
n. decay and crumbling of the substance of a tooth (see dental caries) or a bone. —carious adj.

cartilage
A skeletal connective tissue formed by groups of cells that secrete into the intercellular space a ground substance containing a protein, collagen (q.v.), and a polysaccharide, chondroitin sulfuric ...

cartilage bone
Bone that is formed by replacing the cartilage of an embryo skeleton. The process, called endochondral ossification, is brought about by the cells (osteoblasts) that secrete bone. Compare membrane ...

cartilaginous fish
Fish in which the skeleton, including the skull and jaws, consists entirely of cartilage and never, even in the adult stage, comprises bony tissue. Sharks and rays (Chondrichthyes) have a ...

cementum
(si-men-tŭm)a thin layer of hard tissue on the surface of the root of a tooth. It anchors the fibres of the periodontal membrane to the tooth.

chondroitin
A polysaccharide of galactosamine and glucuronic acid, a mucopolysaccharide. Chondroitin sulphate is a component of cartilage and the organic matrix of bone, and has been used in treatment of ...

chondroitin sulphate
A mucopolysaccharide that forms an important constituent of cartilage, bone, and other connective tissues. It is composed of glucuronic acid and N-acetyl-D-galactosamine units.

cod liver oil
(kod)a pale yellow oil, extracted from the livers of cod and related fish, that is rich in vitamins A and D and used in the treatment and prevention of deficiencies of these vitamins (e.g. rickets).

collagen
n. a protein that is the principal constituent of white fibrous connective tissue (as occurs in tendons). Collagen is also found in skin, bone, cartilage, and ligaments. It is relatively inelastic ...