3. Age Estimation Flashcards
What 2 principles is estimation of age based on?
- Growth and development in immature skeletons
- Degenerative changes in adult skeletons
What environmental variables may potentially influence skeletal age changes?
- Diet
- Physical activity
- Disease
- Trauma
How does the uncertainty of age estimation change with increasing age?
Uncertainty (error) increases with increasing age
What are the different ageing methods for adults?
- Dental occlusal wear
- Pubic symphysis metamorphosis
- Auricular surface metamorphosis
- Cranial suture closure
- Rib sternal-end metamorphosis
- Changes in trabecular bone density (in proximal ends of humerus and femur)
What is dental wear caused by?
- Attrition from inter-tooth contact (between upper and lower teeth)
- Abrasion from hard particulates
- Erosion from acidic fluids in oral cavity
What does wear rates of teeth depend on?
- Diet
- Dental disease
- Non-dietary usage of teeth
Break down of enamel by occlusal wear exposes what?
Dentine (dark) and pulp cavity
What can ante-mortem tooth loss be recognised by?
- Remodelling and eventual obliteration of tooth socket
- Movement of tooth crowns adjacent to lost tooth
- Hyper-eruption of corresponding tooth on opposite jaw
When do the following teeth erupt?
- M1
- M2
- M3
- M1 = 6 years
- M2 = 12-14 years
- M3 = 18-21 years
How does the pubic symphysis change with age?
- In young adults, the symphyseal surface consists of horizontal grooves and ridges (billowing)
- With increasing age, the grooves are infilled and margins are thickened to develop a rim around joint surface
- In old age, the surface is pitted and porous with an irregular margin
What are the auricular surface of ileum stages characterised by?
- Transverse organisation
- Granularity
- Porosity
- Margins of joint surface
How does the sternal ends of ribs 4-6 change with age?
- In young adults, joint surface is smooth straight-walled and slightly indented
- With increasing age, surface becomes deeper and wider with scalloping of the walls
What are the age-related changes in the head of the Humerus and Femur?
- Thinning and cavitation of the trabeculae
- Increased height of the apex of the medullary cavity
- Thinning of the cortex of the diaphysis
How does root dentine transparency change with age?
Microscopic tubules in dentine are progressively infilled, starting at the root apex
How does cementum growth change with age?
Cementum accumulates in thin layers on the surface of tooth roots - can count layers and add to age of tooth eruption to estimate age
What are the growth standards based on for estimation of age at death in immatures?
- Increase with age in linear bone dimensions
- Appearance and fusion of centres of ossification
- Calcification, eruption and subsequent loss of deciduous teeth and their replacement by permanent teeth
How can immature bones be recognised?
- Texture and density of metaphyseal surfaces
- Size and proportion of bones
When does midline fusion occur?
Early in postnatal life
When does epiphyseal fusion occur?
Adolescence
What are late-fusing centres and when are they completed?
- Medial clavicle and sacral bodies
- Early adult life
What best described foetal and neonatal stages of development?
Early development of occipital bone
What are the features of deciduous teeth?
- Smaller
- Cemento-enamel junction is less sinuous
- Roots of anterior teeth narrow
- Roots of posterior teeth flared to accommodate premolar crowns
- Pulp chambers are large with thinner primary dentine
What happens during exfoliation of primary teeth?
Root of primary tooth resorbs as the permanent tooth erupts from beneath until primary crown is lost
How many roots do primary maxillary and mandibular roots have?
- Maxillary have 3 roots
- Mandibular have 2 roots
When do the first primary teeth erupt?
When do most children have all primary teeth?
- 6 months
- 2.5 years
What stages of dental development are growth standards available for?
- Calcification and emergence of primary teeth
- Root resorption and exfoliation of primary teeth
- Calcification and emergence of permanent teeth
Why are pictorial charts of dental development not sufficiently accurate for age estimation?
Individuals vary in sequence and timing of dental development
