The human teeth function to mechanically break down items of food by cutting and crushing them in preparation for swallowing and digesting. Humans have four types of teeth: incisors, canines, premolars, and molars, which each have a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food. The roots of teeth are embedded in the maxilla or the mandible and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, cementum, and dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface.
The term bioarchaeology was first coined by British archaeologist Grahame Clark in 1972 as a reference to zooarchaeology, or the study of animal bones from archaeological sites. Redefined in 1977 by Jane Buikstra, bioarchaeology in the US now refers to the scientific study of human remains from archaeological sites, a discipline known in other countries as osteoarchaeology or palaeo-osteology. In England and other European countries, the term 'bioarchaeology' is borrowed to cover all biological remains from sites.
The enamel organ, also known as the dental organ, is a cellular aggregation seen in a developing tooth and it lies above the dental papilla. The enamel organ is responsible for the formation of enamel, initiation of dentine formation, establishment of the shape of a tooth's crown, and establishment of the dentoenamel junction.
Dental fluorosis is a common disorder, characterized by hypomineralization of tooth enamel caused by ingestion of excessive fluoride during enamel formation.
Tooth development or odontogenesis is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. For human teeth to have a healthy oral environment, all parts of the tooth must develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth week of prenatal development, and permanent teeth begin to form in the twentieth week. If teeth do not start to develop at or near these times, they will not develop at all, resulting in hypodontia or anodontia.
Early childhood caries (ECC), formerly known as nursing bottle caries, baby bottle tooth decay, night bottle mouth and night bottle caries, is a disease that affects teeth in children aged between birth and 71 months. ECC is characterized by the presence of 1 or more decayed, missing, or filled tooth surfaces in any primary tooth. ECC has been shown to be a very common, transmissible bacterial infection, usually passed from the primary caregiver to the child. The main bacteria responsible for dental caries are Streptococcus mutans and Lactobacillus. There is also evidence that supports that those who are in lower socioeconomic populations are at greater risk of developing ECC.
Dilaceration is a developmental disturbance in shape of teeth. It refers to an angulation, or a sharp bend or curve, in the root or crown of a formed tooth.
Neanderthal anatomy differed from modern humans in that they had a more robust build and distinctive morphological features, especially on the cranium, which gradually accumulated more derived aspects, particularly in certain isolated geographic regions.
Mulberry molars are a dental condition usually associated with congenital syphilis, characterized by multiple rounded rudimentary enamel cusps on the permanent first molars. Mulberry molars are physically defective permanent molars. The deformity is caused by congenital syphilis. This type of abnormality is characterized by dwarfed molars with cusps covered with globular enamel growths. These teeth are functional but can be cosmetically fixed with crowns, bridges, or implants.
Enamel hypocalcification is a defect of tooth enamel in which normal amounts of enamel are produced but are hypomineralized. In this defect the enamel is softer than normal. Some areas in enamel are hypocalcified: enamel spindles, enamel tufts, and enamel lamellae.
Tooth wear refers to loss of tooth substance by means other than dental caries. Tooth wear is a very common condition that occurs in approximately 97% of the population. This is a normal physiological process occurring throughout life, but accelerated tooth wear can become a problem. Tooth wear varies substantially between people and groups, with extreme attrition and enamel fractures common in archaeological samples, and erosion more common today.
Tooth pathology is any condition of the teeth that can be congenital or acquired. Sometimes a congenital tooth diseases are called tooth abnormalities. These are among the most common diseases in humans The prevention, diagnosis, treatment and rehabilitation of these diseases are the base to the dentistry profession, in which are dentists and dental hygienists, and its sub-specialties, such as oral medicine, oral and maxillofacial surgery, and endodontics. Tooth pathology is usually separated from other types of dental issues, including enamel hypoplasia and tooth wear.
Tooth discoloration is abnormal tooth color, hue or translucency. External discoloration is accumulation of stains on the tooth surface. Internal discoloration is due to absorption of pigment particles into tooth structure. Sometimes there are several different co-existent factors responsible for discoloration.
Medieval bioarchaeology is the study of human remains recovered from medieval archaeological sites. Bioarchaeology aims to understand populations through the analysis of human skeletal remains and this application of bioarchaeology specifically aims to understand medieval populations.
Linear enamel hypoplasia is a failure of the tooth enamel to develop correctly during growth, leaving bands of reduced enamel on a tooth surface. It is the most common type of enamel hypoplasia reported in clinical and archaeological samples, with other types including plane-form enamel hypoplasia and pitting enamel hypoplasia.
An enamel fracture, or chip, is a complete fracture of the tooth enamel without the involvement of the dentine and pulp. A fracture occurs when a tooth contacts a hard object with enough force to break a section of enamel. Chips form with minimal plastic deformation since enamel is strong but brittle. A fracture typically occurs as an irregular break on the occlusal edge of the enamel, and is therefore different to other forms of tooth wear that leave smooth surfaces. Pulp sensibility testing is recommended to confirm pulpal health. Treatment depends on the size of the fractures. If a tooth fragment is still available, it can be bonded to the tooth. For small or minor fractures, it can be smoothed to remove rough margins and edges. For a larger or major fractures, dental composite resin can be used to mask the defective enamel for aesthetic purpose. In archaeological samples enamel fractures can give insight into the diet and behaviour of past populations.
Enamel hypoplasia can take a variety of forms, but all types are associated with a reduction of enamel formation due to disruption in ameloblast production. One of the most common types, Pitting Enamel Hypoplasia (PEH), ranges from small circular pinpricks to larger irregular depressions. Pits also vary in how they are occur on a tooth surface, some forming rows and others more randomly scattered. PEH can be associated with other types of hypoplasia, but it is often the only defect observed. Causes of PEH can range from genetic conditions to environmental factors, and the frequency of occurrence varies substantially between populations and species, likely due to environmental, genetic and health differences. The most striking example of this is in Paranthropus robustus, with half of all primary molars, and a quarter of permanent molars, displaying PEH defects, thought to be caused by a specific genetic condition, amelogenesis imperfecta.
