<P> Dental anatomy is a field of anatomy dedicated to the study of tooth structure . The development, appearance, and classification of teeth fall within its field of study, though dental occlusion, or contact between teeth, does not . Dental anatomy is also a taxonomic science as it is concerned with the naming of teeth and their structures . This information serves a practical purpose for dentists, enabling them to easily identify teeth and structures during treatment . </P> <P> The anatomic crown of a tooth is the area covered in enamel above the cementoenamel junction (CEJ) or "neck" of the tooth . Most of the crown is composed of dentin (dentine in British English) with the pulp chamber inside . The crown is within bone before eruption . After eruption, it is almost always visible . The anatomic root is found below the CEJ and is covered with cementum . As with the crown, dentin composes most of the root, which normally has pulp canals . A tooth may have multiple roots or just one root (single - rooted teeth). Canines and most premolars, except for maxillary first premolars, usually have one root . Maxillary first premolars and mandibular molars usually have two roots . Maxillary molars usually have three roots . Additional roots are referred to as supernumerary roots . </P> <P> Humans usually have 20 primary (deciduous, "baby" or "milk") teeth and 32 permanent (adult) teeth . Teeth are classified as incisors, canines, premolars (also called bicuspids), and molars . Incisors are primarily used for biting pieces from foods such as raw carrots or apples and peeled but uncut bananas, while molars are used primarily for grinding foods after they are already in bite size pieces inside the mouth . </P> <P> Most teeth have identifiable features that distinguish them from others . There are several different notation systems to refer to a specific tooth . The three most common systems are the FDI World Dental Federation notation, the universal numbering system, and Palmer notation method . The FDI system is used worldwide, and the universal is used widely in the United States . </P>

How many teeth does the human body have