Dentition Deciduous teeth There are 20 primary teeth

Dentition – Deciduous teeth • There are 20 primary teeth (10 at every jaw): – 8 incisors, 4 canines and 8 primary molars. • By 4 months in utero: Teeth begin to form in bone • By Age 2: All deciduous or ‘baby’ teeth have erupted

Dentition – Permanent Teeth • There are 32 permanent teeth (16 at every jaw): – 8 incisors, 4 canines, 8 premolars, and 12 molars • By Age 6: Permanent teeth have started to erupt • By Age 12: Second set of molars have emerged • Age 17 -24: Wisdom teeth have erupted

Dentition • The number of teeth of each type of tooth is written as a dental formula for one side of the mouth. • The teeth are numbered in order: – Incisors, Canines, Premolars, Molars – I: C: P: M

• Juvenile skull less than 6 -7 years old. • Dentition: 2: 1: 2 – – 2 incisors 1 canine 2 premolars 0 molars

• Skull from a 12 year old male. • Dentition: 2: 1: 2: 2 – – 2 incisors 1 canine 2 premolars 2 molars – Wisdom tooth is under the surface of the gum

• Adult male skull • Dentition: 2: 1: 2: 3 – – 2 incisors 1 canine 2 premolars 3 molars

Human developmental phases and general characteristics used for aging • • Perinatal Neonate Infant/toddler Late childhood Adolescence Early adulthood Middle and late adulthood

Perinatals - before birth • The age of perinatals, individuals not yet born, can be determined by looking at bone size. • This is a fairly accurate estimate due to the fact malnourishment will not affect growth; the fetus will take necessary nutrients from the mother.

Neonates ~ 0 -6 or 7 months • Prove very difficult to accurately determine the age because of individual variation of development (genetics & nourishment). • Neonates have no teeth • Areas of the skeleton have not fused together (especially the cranium and pelvis).

Infants and toddlers 6 or 7 months ~ 2 years • All (20) deciduous teeth erupted by age 2. • Permanent teeth (under ‘baby’ teeth) start to form at birth, thus the formation of permanent teeth is a relatively good age determinant. • Some ossification has begun, this is highly variable at this age

Late childhood ~ 6 years -11 years • Late childhood is when the permanent teeth begin to come in. • More bones begin to ossify. • Second set of molars come in at about age 12.

Adolescence ~12 - 18 years • Adolescence shows increased long bone length and fusion of the ends (or cap) to the shaft. • This epiphyseal union/fusion is a particularly useful age technique. (see skeletal diagrams for age references).

Age range ~ 20 – 35 ish • Young adults and older adults have several methods of age determination: • closure of the cranial sutures; morphology of rib-ends, • pubic symphysial • microstructure of bone and teeth; wear on teeth, incremental layers of cementum

• Age of epiphyseal fusion. • First number is approximate age at which fusion first begins. • Second number is approximate age at which fusion is complete.

Diagram of human shoulder and arm • Practice Q’s • Region A has just begun to fuse • Region B, fusion is approximately 90% complete. • There is a complete epiphysial union at location C. • Fusion at distal end of radius and ulna is approximately 5060%. • What is the approximate age of this person?

Answer… Age 18 -20 Age range 18 -25 Age range 15 -19 Age range 13 -18 Age range 15 -23

Practice Q’s… • Description of partial skull and partial pelvis found in a remote wooded area: • Skull - coronal suture is approximately 60% fused, lamboidal suture is fused and semi smooth, frontal area (forehead) has a 40 0 angle. • The subpubic angle is approximately 50 0, and the pubic bone (pubic symphysis) is completely fused. • What is the sex and age of this individual?

Answer…. • Skull - coronal suture is approximately 60% fused, ( age range 30 -35) lamboidal suture is fused and semi smooth (age range closes at 30, get more snooth over time), frontal area (forehead) has a 40 0 angle (male less than 90 0). • The subpubic angle is approximately 50 0, (male 50 -800) and the pubic bone (pubic symphysis) is completely fused (age 20 -23).

Adult dentition and age range of tooth eruption

Frontal view of adult dentition, numbers for identification and tooth name.

Maxilla of female found in wooded area after a suicide. Did this woman have her wisdom teeth?

Maxilla of female found in wooded area after a suicide. Did this woman have her wisdom teeth? YES 2: 1: 2: 3