Permanent teeth Permanent teeth Permanent teeth or adult teeth are the second set of teeth formed in diphyodont mammals. In humans and old world simians, there are thirty-two permanent teeth, consisting of six maxillary and six mandibular molars, four maxillary and four mandibular premolars, two maxillary and two mandibular canines, four maxillary and four mandibular incisors. The first permanent tooth usually appears in the mouth at around six years of age, and the mouth will then be in a transition time with both primary (or deciduous dentition) teeth and permanent teeth during the mixed dentition period until the last primary tooth is
Hinge teeth teeth in a bivalve shell is often essential for identification and classification. A formal terminology is used to describe the different types of dentition. The hinge teeth, or the lack thereof, is an important feature in identifying bivalves because the teeth are generally similar within the major taxonomic groups. Historically the hinge teeth have provided a convenient means by which to construct classification schemes and attempt to indicate the phylogenetic relationships within the class Bivalvia. There are formal names for the various types of hinge tooth arrangements or "dentition". The "taxodont" hinge shows either one or two rows of similar