Polypeptides structurally similar to insulin. The IGF family consists of two ligands (IGF‐I and IGF‐II), two cell surface receptors (IGF‐1R and IGF‐2R) and several IGF binding proteins. They control growth, differentiation, and the maintenance of differentiated function in numerous tissues. In oral tissues, IGFs are involved in tooth growth and development, in the biology of several periodontal structures, and in various aspects of salivary gland homeostasis.