Estimating Adult Age from the Dentition

Once a permanent tooth erupts, it begins to wear. Rate and patterns of wear are governed by tooth developmental sequences, tooth morphology, tooth size, internal crown structure, tooth angulation, non dietary tooth use the biomechanics of chewing, and diet. If the rate of wear within the population is fairy homogeneous, it follows that the extent of wear is function of age. This fact can be used in assigning dental ages to adult specimens.
The first step id assessing age by dentition is the application of the seriation of all dentations based on development and wear.
Miles was the first to establish a scale of attrition based and development. The basics of technique are as utilized like this: A first molar accumulates about 6 years of wear before the second molar of the same individual erupts (assuming eruption at 6 and 12 years, respectively). When a similar amount of wear (6 year's worth) is found on a third molar of another individual (a molar assumed to have erupted at the age of 18), the age of that individual can be estimated as 18+6=24.

Estimating Subadult Age from the Dentition

Eruption and wear of teeth have been used extensively in aging the human skeleton. Tooth development is more closely associated with chronological age than is development of more other skeletal parts, and it seems to be under tighter genetic control. Sex-based variation on development and eruption of teeth is most apparent at the canine position, and this tooth sould be afforded less attention when aging eruption dentitions. When aging the subadult is based on dentition, we must note all aspects of development, including the completeness of all crowns and roots (it means Formation) and the place of each tooth relative to alveolar margin ( Eruption). be sur to make different between eruption through the alveolar margin ( bonny part) or through the gum (soft tissue).
in addition dental develpoment is differnt to sex and population.

our teeth

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Anatomoy of the Tooth

Crown: part of the tooth covered by enamel.
Root: part of the tooth that anchors the tooth in the alveolus of the mandiable or maxilla.
Neck (Cervix): constricted part of th tooth at the junction of the crown and root.
Enamel: the specialized hard tissue that covers the crown,os both avascular and acellular. It is about 97% mineralized, essentially foosilized once it is formed.
Cervicoenamel line (Junction, CEJ): the line that encircling the crown which is the most rotward extent to enamel.
Dentinonamel junction (DEJ): the boundary between the enamel cap and the underlying dentin.
Dentin: the tissue that forms the core of the tooth.this tissue has no vascular supply but is supported by the vascular system in the pulp and is lined in the inner surface ( the walls of the pulp cavity) by odontoblasts, dentin-producing cells. Dentin undelies the enamel of the crown and encapsulates the pulp cavity, the central soft tissue space within a tooth. Occlusal wear may expose dentin, and beacuse dentin is softer than enamel th resulting expostures are usually occlusally oncave.
Pulp chamber: the expanded part of the pulp cavity at the crown end of the tooth.
Root canal: narrow end of the pulp cavity at the root end of the tooth.
Cementum: bonelike tissue that covers the external surface of tppth roots.
Calculus: calcified desposit commonly found on the sides of the tooth crowns.the origin of the calculus lie with plaque,colonies of microrganism that establish themselves on the teeth.
Pulp: the soft tissue within the pulp chamber. the include nerves and blood vessels.
Apical foramen: the oppening at each root Apex, or tip,through wich nerve fibres and vessels pass from the aveolar region to the pulp cavity.
Cusp: an occluslal projection of the crown. Major cusps of homonid molars are individually named: Protocone,Hypocone,Paracone,Metacone,Protoconid
,Hypoconid,Metaconid,Etoconid,Hypoconulid.
knowledge of these cusps,their reltive sizes and wear, is often valuable in identifying isolated teeth. Cups of the upper jaw end with the suffix -cone whereas the lower jaw end with the suffix -conid. the tips of the cusp is the apex. Ridges that descend from cusp Apices are Crests.
Fissure: a cleft on the occlusal surface between cusps. Fissures divide the cusps into patterns.the most widley aknowledged of these is the Y-5 Pattern, in pattern in which the five lower molar cusps are arranged in a Y Pattern.
*** The primitive mammalian cusp pattern was a triangle of cusps in both upper and lower molars. From this pattern a remarkable variety of forms has arisen through the evolution, ranging from the tall columnar molars of warthogs to the bladelike molars of some carnivors.
In humans, as in most other primates, the mesial (anterior) part of the molar is the Trigon (trigonid in lower molars). The distal (posterior) part of the primate molar, added to the modified original triangle of cusps, is the Talon ( or the Talonid in lower molars).

Dental Terminology

Mammals have teeth of different sizes and shapes, a condition known as heterodonty, allowing different teeth to be specialized for different tasks. These specialized teeth include: Incisors (I) Canine teeth (C) Premolars (P) Molars (M)

the position of all teeth are indicated by numbers ,referring to the position that the tooth holds in tooth row ,thus incisiors can be 1s or 2s (central or lateral). Human canins are all 1s.Premolars can be 3s or 4s (or 1s or 2s for the non-paleontoligically inclined), and molars can be 1s,2s,3s.

When we want to describe a tooth ,we should write like this,for example

"Ldi2" :left deciduous second mandibular incisor

or

"RM1":right permanent first maxillary molar.

Dental formulae are used to indicate the number of each type of tooth for a given species. Because the jaw is bilaterally symetrical, only one half of the jaw is described. The incisors are indicated first, followed by the canine, promolars and molars. The maxillary arcade or upper jaw is listed over the mandibular arcade or lower jaw. this is the dental formula of human:

Deciduous : (upper jaw)2 1 0 2 / (lower jaw)2 1 0 2 = 10
Permanent : (upper jaw)2 1 2 3 / (lower jaw) 2 1 2 3 = 16

when we read a book -specially old ones- we may see some uncommon name of teeth like eye tooth. In human dental anatomy the canine teeth are refered to as the "eyeteeth" and the premolars as the "bicuspids".The third molars of humans are also known as "wisdom teeth".