Overview

Abstract

Bone and teeth comprise the mineralized hard tissues of the human body. They have evolved from a hard external skeleton in early vertebrates that led eventually to bony plates, teeth, and scales as well as to the internal skeleton that characterizes modern jawed vertebrates [1]. Bone andteeth form in organic extracellular matrix. The mineral component essentially consists of hydroxyapatite (i.e., a special calcium phosphate, Ca10(PO4)6(OH)2) with various potential substitutes, such as fluoride, replacing hydroxide (see chapter “Dental caries”). The organic constituents vary in different tissues [1]. Bone consists of ∼65 % (w/w) minerals, 25 % organic matrix (∼95 % of which are collagen fibrils), and water. The tooth consists of a bulk of dentin covered with enameon the crown (Fig. 1a). Dentin is similar to bonein proportion of mineral (∼70 % w/w) and collagen fibrils, but includes different non-collagenous proteins. Unlike bone and dentin, enamel is a highlymineralized (∼97 % w/w), virtually inorganic tissue; its initial organic matrix is removed through specific maturation processes [2]. In addition to these three principal hard tissues, the roots of the teeth are covered by cementum, a bone-like tissue (Fig. 1a).