Dentition is a term which refers to the arrangement of the teeth in the mouth. Different animals can have very different dentition depending on their primary diets; in humans, there are 32 teeth shared between the upper and lower jaws. The teeth can provide a great deal of information about a person or animal and how it lives or lived; biologists, archaeologists, and dentists all study dentition as part of their work.
Many animals are born with what is known as primary, milk, baby, or deciduous dentition. Teeth start to form in the jaw in utero and erupt after birth. These primary teeth remain in place in childhood and are gradually replaced by the adult or secondary dentition. Typically the deciduous dentition features fewer teeth which are also smaller, and these teeth can be retained for varying amounts of time. Some animals may have more than two sets of teeth, allowing three or four sets of teeth to grow in sequentially.
Depending on what an organism eats, its teeth can be quite varied. Animals like humans have what is known as heterodont dentition, meaning that their dentition is made up of a mixture of tooth types. This allows humans to eat a varied diet because they have teeth equipped for grinding, cutting, and tearing. By contrast, animals like armadillos are homodonts, with only one type of tooth, because this suffices for their dietary need.
Dentists study dentition so that they can care more effectively for their patients. In dental school, doctors learn about how the teeth develop, what they are comprised of, and what kind of problems can emerge in the mouth. Humans can experience problems ranging from impacted teeth to cavities. Using tools like dental molds, x-ray images, and visual examinations, dentists can learn about the arrangement of teeth in a specific patient and develop appropriate treatment plans.
People like archaeologists are interested in the teeth of historic humans and non-human animals because they provide interesting information about the process of evolution as well as how animals lived at various periods in history. Likewise, forensic anthropologists can use teeth to identify victims of crimes or to collect information which can assist with identification, including making impressions of toothmarks to find people associated with a crime scene. For example, if a criminal eats an apple and tosses it aside, the marks in the apple can be studied and compared against casts taken from the mouths of suspects to see if there is a match.
