This document discusses dental anatomy and forensic dentistry. It begins by describing the basic anatomy of teeth, including the crown, gumline, neck, root, dentin, pulp, cementum, periodontal ligament, and alveolar bone. It then compares the features of primary and permanent teeth. The document outlines methods for estimating age based on teeth, including examining the development and eruption times of primary and secondary teeth. It discusses estimating age in the prenatal, neonatal, and postnatal periods based on tooth weight and formation. Methods for estimating age in children, adolescents, and adults are described, including the Atlas, Schour-Massler, Demirjian, and Gustafson techniques. Amino acid race
2. 1. Crown: covered by enamel
(hydroxyapatite). The shape of the
crown varies depending on the type
of tooth (incisor, canine, premolar, or
molar) and its function.
2. Gumline: Also known as the gingival
line
3. Neck: The neck of the tooth is the
area between the crown and the root
where the tooth narrows. It is also
referred to as the cervical region.
4. Root: Below the gumline, teeth have
one or more roots, which anchor the
tooth to the jawbone. The number of
roots varies with tooth type, with
molars typically having multiple roots
and incisors usually having just one.
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3.
4.
5. 1. Dentin: Beneath the enamel, a hard tissue
that forms the bulk of the tooth's structure.
2. Pulp: The pulp is the innermost part of the
tooth, located within the crown and root
canals. It contains blood vessels, nerves,
and connective tissues.
3. Cementum: Cementum covers the tooth's
roots and helps anchor it to the jawbone
through the periodontal ligament. It is not as
hard as enamel but is essential for tooth
stability.
4. Periodontal Ligament (PDL): The PDL is a
connective tissue that surrounds the tooth
roots and attaches them to the jawbone. It
also allows for slight mobility of teeth,
which is necessary for functions like
chewing.
5. Alveolar Bone: The alveolar bone is the bony
socket in the jawbone in which each tooth is
embedded..
6. ● Upper and lower second deciduous molars
resemble first permanent molars in the same
quadrant.
● Upper first deciduous molars vaguely
resemble upper premolars.
● Lower first deciduous molars are odd and
unique unto themselves
● Upper molars : 3 roots
● Lower molars : 2 roots
7. TEMPORARY TEETH PERMENENT TEETH
Small, narrow, light and
delicate
Big, broad, heavy and strong
Crowns china- white in color Crowns ivory – white in color
.Neck more constricted Neck less constricted
Edges serrated Edges are not serrated
Anterior teeth vertical Anterior teeth usually
inclined somewhat forward
Molars are usually larger.
Their crowns are flat, and
their roots are smaller and
more divergen
Premolars which replace the
temporary molars are usually
smaller; their crowns have
cusps which sharply
differentiate them. Their
roots are bigger and
relatively straight.
8. Growth Pattern
13 to 16 weeks IU : Calcification of primary teeth begins
in utero
18 to 20 weeks IU: primary teeth begin to calcify
Lower deciduous teeth erupt first thus initiating the
deciduous dentition
2 to 2 ½ years of age: deciduous second molars
completes the deciduous dentition
The root of a deciduous tooth is completely formed in
just about one year after eruption
The mixed dentition exists from approx. age 6 -12 years.
9. TEMPORARY
TEETH
ERUPTION TIME Complete Root
Calcification
Central Incisors
(lower)
6-8 Months 1 ½- 2 Years
Central Incisors
(Upper)
7-9 Months 1 ½ -2 Years
Lateral Incisor
(Upper)
7-9 Months 1 ½ -2 Years
Lateral Incisor
(lower)
10-12 Months 1 ½ -2 Years
First molars 12-14 Months 2 -2½ Years
Canines 17-18 Months 2 -2½ Years
Second Molar 20- 30 Months 3 Years
10. PERMANENT TEETH ERUPTION TIME Complete Root
Calcification
First molar 6-7 Years 9-10 Years
Central Incisors 6-8 Years 10 Years
Lateral Incisors 8-9 Years 11 Years
First Premolar 9-11 Years 12-13 Years
Second Premolar 10-12 Years 13-14 Years
Canines 11-12 Years 13-14 Years
Second Molar 12-14 Years 14-16 Years
Third Molar 17-21 Years 18-25 Years
11. Human dentition and age estimation
(1) the difference between the two
sets of teeth
(2) the time of their eruption
3) the period when their root
calcification is complete ( x-ray
examination)
4) Teeth Type : (1) temporary,
deciduous or milk teeth and (2)
permanent teet
For age estimation from
teeth, it is necessary to
know
12. Age estimation from dentition can be categories into three
prenatal,
neonatal and
postnatal periods
Estimation of age
in children and
adolescents
Age estimation in
adults
13. Age estimation during prenatal, neonatal and postnatal periods
Development Timeframe
primary tooth germ begins to form seventh week of the
intrauterine life (IU)
germ formation for the first molar begin 4 months IU
development of enamel of all temporary
teeth complete
first year
15. Neonatal lines
The trauma of childbirth induces
metabolic stress on the tooth-
forming cells. This cellular
disruption results in a thin band of
altered enamel and dentin called
the neonatal line.
neonatal could take up to three
weeks after birth to fully appear.
Therefore the absence of the
neonatal line does not indicate that
the child was ‘stillborn’. However,
the presence of neonatal line
positively indicates a live birth
16. Forensic experts need to estimate the age
from skeletal remains.
In such cases, radiography and histological
study is not effective.
Alternatively, measuring the weight of the
mineralized tooth cusps could help.
At six months of IU life a teeth weighs about
60 mg,
0.5 g in a new born baby
1.8 g at six months after the birth
17. Methods of age estimation
Dental age estimation in Children and adolescent
Atlas method (radiographic method)
Schour and Massler
Demirjan method
Dental age estimation in Adults
Gustafson’s method (Morphological techniques)
Radiographic method
Other methods : Visual method and Amino acid
racemization
21. Schour and Massler method
Schour and Massler in 1941 introduced a
chart explaining the development and
eruption of human dentition.
They studied the development of deciduous
and permanent teeth in seven stages, i.e.,
prenatal (4.5–5 months utero), neonatal (at
birth), infancy (birth to 6 months), childhood
(2–6 years), early grade school (6–10
years), prepubertal period (10–12 years),
and adulthood (12–21 years) using
histological and radiographical method.
22.
23. key aspects of the Schour and Massler method:
Developmental
Stages of Teeth
Radiographic
Evaluation
Staging Criteria
(degree of root
formation, crown
development, and
eruption status)
Age Estimation
(assessing the
stages of tooth
development and
comparing them
to the established
criteria)
Limitations:
variations in tooth development
among individuals and
populations
as potential differences in
radiographic interpretations
24. Demirjian method
It was developed by Mustafa Demirjian and colleagues and was first
introduced in 1973. This method involves evaluating the development of
seven left mandibular permanent teeth to estimate a person's dental age.
Selection of Teeth: mandibular left central incisor, lateral
incisor, canine, first and second premolars, and first and
second molars.
Developmental Stages: Each tooth is categorized into
eight developmental stages (A to H) based on panoramic
radiographs.
Assessment Criteria: formation and calcification of the
tooth crown and root.
25. Lewis, J. M., & Senn, D. R.
(2010). Dental age estimation
utilizing third molar
development: A review of
principles, methods, and
population studies used in the
United States. Forensic science
international, 201(1-3), 79-83.
26. Dental age estimation in Adults
(a)Gustafson method
Gustafson (1950) studied the changes
occurring in individual teeth The following 6
dental changes were studied for age
estimation.
(i) Attrition: The occlusal aspect of the
tooth is worn out gradually with age. enamel
is worn out first ,then dentin and lastly the
pulp is exposed
(ii)Periodontosis: recession occurs in the
gums and the surrounding periodontal
tissues with advancing age.
(iii)Secondary dentin: The secondary
dentin develops within the walls of the pulp
cavity and decreases the size of the pulp
cavity which could be due to ageing
27. Dental age estimation in Adults
(iv)Cementum apposition: The age
can be calculated by counting the
incremental lines of the cementum (
formed due to the deposition of
secondary cementum)
(v) Root resorption: It usually occurs
late in the age the cementum and
dentin show characteristically sharp
grooves.
(vi)Transparency of the root: With
age the dentinal tubules are filled
with minerals and turn opaque. This is
the most reliable criteria of the all
28.
29. The grade value of each of the age change is then added which gives a total
score (Y).
The error of estimation in this method was ±3.6 years as calculated by
Gustafson (1947).
An + Pn + Sn + Cn + Rn + Tn = total score (Y) (n = score of individual
criteria)
An increase in total score (Y) corresponded linearly with increase in age.
Age was estimated using the following equation:
Age = 11.43 + 4.56 × Y (total score)
30. (b) Amino Acid Racemization
dates of biological materials such as
bone, shell and teeth
At present, based on accuracy,
simplicity, and the time required, teeth
are the best organ for the estimating
age.
This method is exclusively used in the
age estimation of unidentified corpses.
The level of proteins are high in dentine
than enamel hence dentin is preferred
over enamel for age estimation. The
procedure is as follows:
31. Sample handling
(Fixatives such as
ethanol, formalin and
formaldehyde )
Bleach treatment
(sodium hypochlorite )
Washing solution
(acetone followed by 0.2
N HCl)
Pulverization (Proteins
are extracted by EDTA)
Demineralization (by
mineral acid (HCl or
EDTA) to isolate a
fraction of the total
dentine protein)
Hydrolysis (100-110°C
from 6-20 hrs)
High pressure gas
chromatography (HPGC)
and gas chromatography
(GC)
32. Where: D & l are integrated peak areas of the respective enantiomer
a: rate constant of racemization of asp in dentin
b: y-intercept
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