Age estimation of adults and non-adults Flashcards
What are the methods of age estimation in adults?
Focussing on:
- Dental wear
- Changes to the morphology of the pubic synthesis joint surface of the pelvis
- Late fusing epiphyses (if <30 years old)
- Degeneration changes (however, this is influenced by many factors eg. occupation and disease)
What are the methods of age estimation in non-adults?
Focussing on the different growth standards/stages
1) Dental development
2) Diaphyseal length (long bone)
3) Appearance and fusion of the ossification centres
Is it more accurate to determine the age of an adult or a non-adult?
Non-adult
Why do we want to determine the age of an individual at death?
- Determine if adult/non-adult (different methods used to assess each)
- Important for identification
- Important when understanding the demographic of an assemble (helps to determine a particular context of death)
When do the deciduous teeth erupt?
1 year - 6 years after birth
When do the permanent teeth erupt?
6 years - 12 years after birth
How can you recognise immature bones? (4)
1) Size and proportion (adult bones but smaller)
2) Texture and density (porous, wobbly surface)
3) Shape and form
4) Epiphyses and metaphyses
How to determine the dental development stage determine the age of a non-adult?
1) The eruption of the the DECIDOUS and PERMANENT teeth
2) Measurements of the length of the long bone
How can the appearance and fusion of the ossification centres age a non-adult?
Stages of ossification:
- Bones develop in several pieces
- Appearance of these pieces and fusion of these centres is AGE DEPENDANT
How many teeth do non-adults have?
What are these?
20
Per quadrant:
- Central incisor
- Lateral incisor
- Canine
- 2 x molars
How many teeth do adults have?
What are these?
32
Per quadrant:
- Central incisor
- Lateral incisor
- Canine
- 2 x premolars
- 3 x molars
What is the order of the eruption of the deciduous teeth? (on the mandible)
1) Central incisor
2) Lateral incisor
3) Molar 1
4) Canine
5) Molar 2
What is the order of the eruption of the permanent teeth? (on the mandible)
1) Molar 1
2) Central incisor
3) Lateral incisor
4) Canine
5) Premolar 1
6) Premolar 2
7) Molar 2
8) Molar 3
At what ages should have NO deciduous teeth?
By 12.5 years
Describe the eruption of M1 and P1/P2
M1 erupts behind dm2 (so can look like a 3rd molar)
P1 erupts in the space of dm1
P2 erupts in the space of dm2
When is the start of mixed dentition in the mandible?
5.5 years old
When is the 6 teeth in the mandible quadrant?
When M1 erupts (5.5 years)
When is the 7 teeth in the mandible quadrant?
When M2 erupts (12.5-13.5 years)
When does the deciduous central incisor begin to erupt?
When is fully erupted?
4.5-7.5 months
FE - 10.5 months
When does the deciduous lateral incisor begin to erupt?
When is fully erupted?
7.5-10.5 months
FE - 1.5 year
When does the deciduous molar 1 begin to erupt?
When is fully erupted?
10.5months
FE - 1.5 year
When does the deciduous canine begin to erupt?
When is fully erupted?
10.5 months-1.5year
FE - 2.5 year
When does the deciduous molar 2 begin to erupt?
When is fully erupted?
1.5year
FE - 2.5 year
When does the permanent molar 1 begin to erupt?
When is fully erupted?
5.5 years
FE - 5.5 years
When does the permanent central incisor begin to erupt?
When is fully erupted?
6.5 years
FE - 7.5 years
When does the permanent lateral incisor begin to erupt?
When is fully erupted?
7.5 years
FE - 7.5 years
When does the permanent canine begin to erupt?
When is fully erupted?
10.5 years
FE - 10.5 years
When does the permanent premolar 1 begin to erupt?
When is fully erupted?
11.5 years
FE - 11.5 years
When does the permanent premolar 2 begin to erupt?
When is fully erupted?
12.5 years
FE - 12.5 years
When does the permanent molar 2 begin to erupt?
When is fully erupted?
10.5-11.5 years
FE - 12.5 years
When does the permanent molar 3 begin to erupt?
When is fully erupted?
16.5-23.5 years
FE - 23.5 years
What is the most reliable indicator or chronological age?
The formation and eruption of the deciduous and permanent teeth
What does a newly formed crown in the gum look like?
No roots
Sharp
Darker in colour
What does root reabsorption of the deciduous teeth look like?
Tapered ends of the roots (like icelolly)
Why do the deciduous teeth fall out?
Roots are reabsorbed to such extent that the crowns fall out
Why are wisdom teeth not a good indicator of age?
Some don’t erupt at all or are removed
What are the main differences between deciduous and permanent teeth?
Deciduous:
- 5 tooth types (no premolars)
- 20 (rather than 32)
- Smaller
- Prominent bulge to crown above the cervical margin
- Lower quality enamel (thinner)
- NARROW roots of the anterior teeth
- FLARED roots of the molars
- Roots are longer
- Roots are reabsorbed prior to exfoliation of the crowns
- LIGHTER in colour
Why are the deciduous teeth more likely to decay?
Enamel is lower quality
Why do the molars of the deciduous teeth have flared roots?
To accommodate the permanent molars underneath
What is the difference between maxillary and mandibular molars
Mandibular have 2 roots
Maxillary have 3 roots
What is the difference between maxillary and mandibular anterior teeth
Mandibular:
Smaller teeth
Smaller roots
What is the difference between canines and premolars?
Canines - single cusp and longer (longest tooth). Pointy
Premolars - bicuspid
What is the difference between the central and lateral insicors?
Central is larger
How many roots do premolars have?
1
What is often used to chart tooth development in non-adults?
Why are these not very reliable?
How is this overcome?
Pictorial charts
Not very reliable as individuals vary in sequence and timing of tooth development
Overcome by using age ranges
Why can non-adults appear to have 3 molars?
There is a stage (before the premolars have replaced the deciduous molars) where 2 molars are deciduous and the 3rd is permanent
What is a more reliable method: tooth eruption or crown development?
Crown development (tooth eruption can be very varible)
At birth, what crowns are already developed?
The central and lateral incisors
When do the remaining deciduous crowns in non-adults develop?
4.5 months
When does the crown of the permanent molar 1 develop?
2.5-3.5 years
When does the crown of the permanent incisor 1 develop?
10.5 months - 1.5 years
When does the crown of the permanent canine develop?
2.5-3.5 years
When does the crown of the permanent premolar 1 develop?
4.5-5.5 years
When does the crown of the permanent premolar 2 develop?
5.5-6.5 years
When does the crown of the permanent molar 2 develop?
5.5-6.5 years
When does the crown of the permanent molar 3 develop?
11.5 years
What bones are used in non-adults when measuring the diaphyseal lengths?
Humerus
Femur
Tibia
What ages are diaphyseal length measurements used as an age estimation methog?
Infants to 12-15 years old
What must be done after the measurement of diaphyseal length in order to get an age estimate of a non-adult?
Must be compared to reference data to infer age
Why might diaphyseal length not correlate with other developmental stages (eg. dental development and epiphyseal fusion)?
- Growth may be delayed by periods of malnutrition and illness
- Sex differences in growth
What is more reliable, dentition or diaphyseal length when estimating the age of non-adults?
Dentition
How many bones do perinates/infants have?
How many do adults have?
How many do juveniles have?
300
206
Between 300-206
What are the early fusing epiphyses?
- Frontal bones
- Mandible
- Vertebral bodies
- Neural arches
When does epiphyseal fusion of the primary and secondary ossification centres in the long bones occur?
During adolescence
What does epiphyseal fusion provide a marker for?
Marker of maturity that can be used to assess age and stage of development
Where does epiphyseal fusion occur?
Both ends of the:
- Humerus
- Femur
- Tibia
- Ulna
- Radius
- Clavicle
What are the late fusing epiphyses?
Fusion that occurs later in adult life:
- Medial clavicle
- Sacrum
- Annular rings on the vertebrae
- Flakes on the pelvis
- Development and eruption of the M3
What are the annular rings of the vertebrae?
- The tough circular exterior of the intervertebral disc surrounding the soft inner core
- Connect the spinal vertebrae above and below the disc (is seen in between the vertebrae)
Describe the late fusion of the medial clavicle
- Epiphyses flake partially fuse: 16-21 years old
- Epiphyses covering most of the surface: 24-29 years old
- Complete fusion unlikely before 22 years –> attained by 30 years
Describe the late fusion of the sacrum
Complete union of the S1 and S2 occurs between 25 and 30 years of age
When does M3 usually erupt?
Can this be an indicator of immaturity?
18-25 years old
NO, absence cannot be an indicator of immaturity
How is age estimated over 30 years old?
What is this influenced by?
DEGENERATION
Influenced by, environmental variables including:
- Diet
- Physical activity
- Trauma
- Disease
What does the uncertainty of age estimation increase with?
Increases with AGE
What methods are used to estimate the ages of adults?
- Dental wear
- Cranial suture closure
- Degeneration of the joints in the pelvis (auricular surface and the pubic synthesis)
- Bone mineral density
- Histological analysis
When does cranial suture closure tend to occur?
On average between the ages of 30-40
What happens to mineral bone density with age?
Thinning of the cortical and trabecular bones with age
Where is trabecular bone found?
In the long bones
How can histological analysis determine age?
Accumulation of Haversian systems in cortical bone throughout adult life
–> counts of osteons can be used to estimate age at death
What causes dental wear?
Attrition - by tooth-tooth contact
Abrasion - from hard particulates
Erosion - from acidic fluids in the oral cavity
Describe the pattern of dental wear on teeh
- Happens on the occlusal surface (look at the molars)
- Teeth go from white (enamel) to dark (dentine revealed)
- First forms small circles (as the cusps are worn down)
- Then, see larger patches of dentine
Is dental wear a good estimation of the age of an adult?
Why/
NO
Although it is cumulative and age progressive,
Dental wear can be influenced by:
- Diet
- Dental disease
- Non-dietary usage of the teeth
Why is there differences in the dental wear rates of the molars?
Due to the differences in the timings of eruption (exposed to dental wear for a longer time)
- M1 (5.5 years)
- M2 (12.5 years)
- M3 (23.5-25 years)
What is the Brothwell scheme of looking at dental wear?
Groups typical molar wear patterns into 4 different age categories in adults
In the mandibular molars
How does the loss of teeth antemortemly impact dental wear?
Rate of wear on the remaining teeth is accelerated
How can you tell if a tooth is lost antemortem?
Recognised by:
- Remodelling and eventual obliteration of the tooth socket
- Movement of the remaining tooth crowns to replace the lost tooth
What is the best way of determining the age of an adult?
Why?
Using the pubic synthesis
As it is an immobile joint - less likely to be influenced by movement and activity
Describe the basic ageing of the pubic synthesis
Young adults:
- Horizontal grooves and ridges (billowing)
With increasing age:
- The grooves are infilled and the margins are thickened –> RIM around the joint surface
In OLD age:
- Surface is pitted
- Porous, irregular margin
What needs to be dome before determining the age of the adult using the pubic synthesis?
Why?
Determine the SEX of the individual
Different rates of metamorphosis
Who developed the six sequential stages of development of the pubic synthese?
Suchey and Brooks
Why must there be other methods of determining the edge from the deterioration of joint surfaces?
What other methods are used?(2)
As the pubic synthesis is very delicate and often lost during excavation
Other methods:
- Auricular surface of the ilium
- Changes in the sternal ends of the ribs 4-6
- Closure of the cranial sutures
How does the auricular surface of the ilium change with ageing?
Becomes pitted
How do the sternal ends of the ribs 4-6 change with ageing?
Smooth and straight walled –> deeper surface with wider scalloping of the walls/bony projections on the margins begin to develop
What happens to the cranial sutures with ageing?
Most fuse between 30-50
What must be done when reporting age?
- Give a range for age at death
- Use as many methods as possible to determine the overall age-at-death (from the overlap)
- Be clear with the methods that have been used to form the estimation
What must NOT be done when reporting age?
- DON’T give an average age from the age range
- DON’T assume all methods are equally accurate
