Dental age assessment

DENTAL AGE ASSESSMENT

CONTENTSINTRODUCTION

BASIC PRINCIPLES OF DENTAL AGE ESTIMATION

GROWTH SPURTS

METHODS OF AGE ESTIMATION

-MORPHOLOGICAL METHODS-BIOCHEMICAL METHODS-RADIOGRAPHIC METHODS

STUDIES

USE OF DENTAL AGE ASSESSMENT IN FORENSIC ODONTOLOGY

CONCLUSION REFERENCES

HISTORYThe first known attempts that used teeth as an indicator of age originated from England.

In the early 19th century ,because of economic depression due to the industrial revolution , juvenile work and criminality were serious social problems.

Edwin saunders , a dentist , was the first to publish information regarding dental implications in age assessment by presenting a pamphlet entitled :

“Teeth A Test of AGE” to the England parliament in 1837.

INTRODUCTIONTeeth are the strongest parts in the human body and are therefore very resistant to external influences , such as extreme temperatures , explosions and other extreme conditions ,which make them available for extensive post mortem periods.

In addition, teeth are good indicators of people`s age . These two facts allow us to use human teeth for age estimation in forensic work.

Therefore, recommendations for age estimation in living persons include a dental status and a panoramic radiograph and an x ray examination of hand.

Dental development is more reliable as an indicator of biological maturity in children

Age is estimated on the basis of;

Chronological age: It is the most commonly and easily determined developmental age parameter simply figured out from the child`s date of birth.

Dental age: Dental age is the state of dental maturation, and is determined up to the ag of 18. Dental age has been based on two different methods :

1. Tooth eruption stage2. Tooth mineralization stage.

Mental age: It is defined as the age at which an individual performs on an intelligence test.

Bone age: It is the degree of maturation of a child`s bones

Chronological age estimation: Chronological age was calculated by subtracting the date of birth from the date on which radiograph was taken.

Dental age estimation: Dental age was calculated using Demirjian’s method where seven permanent teeth in the third quadrant were included incisors, canine, premolars, and molars (first and second) ‑were traced in the cephalometric tracing sheet .

Based on the apex closure, the teeth were rated accordingly from Stage A to H.

All the scores were summed up and the final score was calculated from which the dental age was obtained using the Demirjian’s table.

Skeletal age estimation : Skeletal age assessment was done using hand wrist radiographs using Fishman’s SMI where four stages of bone ‑maturation found in six anatomical sites: thumb, third finger, fifth finger, ‑and the radius were considered.

The radiographs were assessed based on the skeletal maturity index and scores were given accordingly.

Basic principles of dental age estimationDental age can be estimated according to developmental traits such as1. mineralization 2. Gingival emergence3. Quantification of cementum layers4. Decreasing pulpal space.

Degenerative changes such as

1.Dental attrition2.Periodontal recession3.Dentinal sclerosis 4.Density of dentine.

Dental age has been assessed on the basis of the number of teeth at each chronological age or on stages of the formation of crowns and roots of the teeth.

Dental age during mixed dention period may be assessed on the basis of which teeth have erupted,the amount of resorption of the roots of primary teeth, and the amount of development of the permanent teeth.

Growth spurts : Periods of sudden acceleration of growth. Due to physiological alteration in hormonal secretion male female1.Infantile/childhood growth spurt : 3 years 3 years

2.Mixed dention/juvenile growth spurt : 7-9 years 6-7 years

3.prepubertal/adolescent growth spurt: 14-15 years 11-12 years

Girls have earlier growth spurt than boys

GROWTH SPURTS

METHODS OF AGE ESTIMATION

Literature describes several techniques that address age estimation in adults. The various methods are divided into three categories:

1.Morphological methods

2.Biochemical methods 3. Radiological methods.

Morphological methods are based on assessment of teeth (ex-vivo). Hence, these methods require extracted teeth for microscopic preparation.

Morphological methods

Various morphological methods include :

1. Gustafson (1950)2. Dalitz (1962)3. Bang and Ramm (1970)4. Johanson (1971)5. Maples (1978)6. Solheim (1993) are few morphological methods

Gustafson (1950) and Thoma (1944) described the age changes occurring in the dental tissues and noted six changes related to age. They are:

a. Attrition of the incisal or occlusal surfaces due to mastication (A) b. Periodontitis (P) c. Secondary dentin (S) d. Cementum apposition (C) e. Root resorption (R) f. Transparency of the root (T)

Gustafson`s method

In the method proposed, each sign was ranked and allotted 0, 1, 2, 3 points.

The point values of each age-change are added according to the following formula:

An+ Pn + Sn + Cn + Rn + Tn = points.

The exact equation calculated was: y = 11.43 + 4.56x,

where, y = age and x = points according to the formula above.

The error of estimation as calculated by Gustafson (1950) was ±3.6 years

Disadvantage: Cannot be used in living person

Dalitz methodDalitz re-examined Gustafson’s method and suggested a 5-point system from 0-4, instead of the 4-point system that was previously used.

This change was proposed in order to give a slightly greater accuracy

The other criteria, attrition (A), periodontitis (P), secondary dentine (S) deposition, and transparency of the root (T) of the 12 anterior teeth are related appreciably to age and to a similar degree.

Dalitz suggested this formula.

E = 8.691 + 5.146A + 5.338P + 1.866S + 8.411T

Disadvantage: It does not take into account bicuspids and molar teeth

Bang and ramm method

They found that, transparency of the root dentin advances coronally from the tip of the root during the third decade.

A great advantage of the method is that good results are obtained by measuring intact roots only.

Johanson method

Johanson made a more detailed study on the root transparency.

and stated that it is more clear when the thickness of the ground section of the tooth was 0.25 mm.

Maples method

Suggested the use of only two criteria of the total six Gustafson recommended-(secondary dentine formation and root transparency).

In order to make the method more simple and accurate.

Solheim method

Solheim used five of the changes that Gustafson recommended (attrition, secondary dentin, periodontitis, cementum apposition, and root transparency)

and added another three new changes that showed a significant correlation in different types of teeth.

The three new age-related changes were surface roughness, color, and sex.

Biochemical methods

The biochemical methods are based on the racemization of amino acids. The racemization of amino acids is a reversible first-order reaction and is relatively rapid in living tissues in which metabolism are slow.

Aspartic acid has been reported to have the highest racemization rate of all amino acids and to be stored during aging.

In particular, L-aspartic acids are converted to D-aspartic acids and thus the levels of D-aspartic acid in human enamel, dentine, and cementum increase with age.

They are as follows:

1. Helfman and Bada method (1975, 1976)

2. Ritz et al. method (1995)

Helfman and bada method

The authors reported studies that focused on the racemization of amino acids

and obtained a significant correlation between age and ratio of D-/l-enantiomers in aspartic acid in enamel and coronal dentin.

Used the racemization method in dentinal biopsy specimens in order to estimate the age of living individuals.

This method emerged from the need to identify the age of living individuals without extracting teeth.

Ritz et al. method

Radiographic methodsRadiology plays an indispensable role in the human age determination.

Radiographic assessment of age is a simple, non-invasive and reproducible method that can be employed both on living and unknown dead.

Various radiographic images that can be used in age identification are intraoral periapical radiographs, lateral oblique radiographs, cephalometric radiographs, panoramic radiographs, digital imaging and advanced imaging technologies.

 Evaluation of radiographs to assess tooth calcification is a much better alternative, since:

1) Calcification can be observed from radiographs for a period of several years.

2) It is not altered by local factors

3) The study of tooth calcification also let us assess age at periods when no emergence takes place (2.5-6 years and > 12 yrs).

• Advantage-

a)simple,

b)easy to master

• Age estimation - accurate. • Dental calcification - better indicator of age in first two decades of life

The radiological age determination is based on assessment of various features as follows: • Jaw bones prenatally • Appearance of tooth germs • Earliest detectable trace of mineralization or beginning of mineralization • Early mineralization in various deciduous teeth during intrauterine life • Degree of crown completion

• Eruption of the crown into the oral cavity • Degree of root completion of erupted or unerupted teeth. • Degree of resorption of deciduous teeth • Measurement of open apices in teeth • Volume of pulp chamber and root canals/formation of physiological secondary dentin

• Tooth-to-pulp ratio • Third molar development and topography

Age estimation is grouped into three phases:

1. Pre-natal, neonatal and post-natal 2. Children and adolescents 3. Adults

The subsequent radiographs of the mandible will depict the deciduous teeth in various stages of mineralization as per the pre-natal age of the fetus. One of the methods employed is:

1.Pre-natal, Neonatal and Post-natal Age Estimation

Stages by Kraus and Jordan (1965)

They studied the early mineralization in various deciduous teeth as well as the permanent first molar.

The development is described in 10 stages, denoted by Roman numerals from I to X; the IXth stage includes three stages and the Xth stage includes five stages.

Age Estimation in Children and Adolescents

Dental age estimation in children and adolescents is based on the time of emergence of the tooth in the oral cavity and the tooth calcification.

The radiographic analysis of developing dentition, especially when there is no clinical evidence available (2.5-6 years) as well as the clinical tooth emergence in various phases will help in age determination.

Methods applied for age determination in children and adolescents:

1. Schour and Masseler method (1941)2. Nolla’s method (1960)3. Moorees, Fanning and Hunt method {1963}

Schour and Masseler method

Schour and Masseler studied the development of deciduous and permanent teeth, describing 21 chronological steps from 4 months to 21 years of age and

published the numerical development charts for them. These charts do not have separate surveys for males and females.

Nolla’s method

Nolla evaluated the mineralization of permanent dentition in 10 stages.

After every tooth is assigned a reading, a total is made of the maxillary and mandibular teeth and then the total is compared with the table given by Nolla.

The advantages of this method are that it can be applied to an individual with or without the third molar and that girls and boys are dealt with separately.

Nolla's developmental stagesThe Nolla's developmental stages are given below.

Moorees, Fanning and Hunt method (1963)

In this method, the dental development was studied in the 14 stages of mineralization for developing single and multirooted.

Permanent teeth and the mean age for the corresponding stage was determined.

Clinically, the development of permanent dentition completes with the eruption of the third molar at the age of 17-21 years, after which the radiographic age estimation becomes difficult.

Age Estimation in Adults

The two methods commonly followed are the assessment of the volume of teeth and the development of the third molar:

1. Volume assessment of teeth

a. Pulp-to-tooth ratio method by Kvaal b. Coronal pulp cavity index

2.Development of third molar a. Harris and Nortje method b. Van Heerden system

Volume assessment of teeth

The age estimation in adults can be achieved by radiological determination of the reduction in size of the pulp cavity resulting from a secondary dentine deposition, which is proportional to the age of the individual.

Pulp-to-tooth ratio method by Kvaal

In this method, pulp-tooth ratio is calculated for six mandibular and maxillary teeth

The Coronal Pulp Cavity Index

This method calculates the correlation between the reduction of the coronal pulp cavity and the chronological age.

Only mandibular premolars and molars were considered, as the mandibular teeth are more visible than the maxillary ones.

Only mandibular premolars and molars were considered, as the mandibular teeth are more visible than the maxillary ones.

Panoramic radiography is used to measure the length (mm) of the tooth crown (coronal length, [CL]) and the length (mm) of the coronal pulp cavity (coronal pulp cavity height or length [CPCH]).

The tooth-coronal index (TCI) is computed for each tooth and regressed on the real age of the sample using the formula.

TCI=CPCH*100/CL

Development of third molar

The radiographic age estimation becomes problematic after 17 years of age as eruption of permanent dentition completes by that age with the eruption of the third molar.

Later, the development of the third molar may be taken as a guide to determine the age of the individual.

Harris and Nortje method

They have given five stages of third molar root development with corresponding mean ages and mean length.

van Heerden system

The development of the mesial root of the third molar was assessed to determine the age using panoramic radiograph (in this system he considered five stages).

DEMIRJIAN, GOLDSTEIN, AND TANNER METHOD (1973)

In 1973, Demirjian introduced a method (DemI973) which estimated chronological age based on developments of seven teeth from the left side of the mandible.

This method was similar to that of Tanner, Whitehouse, and Healy, who estimated chronological age based on the maturity of hands and wrists.

Dental Formation Stages:

If there is no sign of calcification, the rating 0 is given .The crypt formation is not taken into consideration

There are 9 stages of tooth formation

A.In both uniradicular and multiradicular teeth, a beginning of calcification is seen at the superior level of the crypt in the form of an inverted cone or cones. There is no fusion of these calcified points.

B.Fusion of the calcified points forms one or several cusps which unite to give a regularly outlined occlusal surface.

Stage Description

C a. Enamel formation is complete at the occlusal surface. Its convergence toward the cervical region is seen.

b. The beginning of a dentinal deposit is seen

c. The outline of the pulp chamber has curved shape at the occlusal border

D. a. The crown formation is completed down to the cementoenamel junction.

b. The superior border of the pulp chamber in the uniradicular teeth has a definite curved form, being concave toward the cervical region. The projection of the pulp curved shape at the occlusal border horns if present, gives an outline shaped like an Umbrella top in molars the pulp chamber has a trapezoidal form. c. Beginning of root formation is seen in the form of a spicule.

E. Uniradicular teeth a. The walls of the pulp chamber now form straight lines, whose continuity is broken by the presence of the pulp horn, which is larger than in previous stage the crown height.

b. The root length is less than the crown height.

• Molars: a. Initial formation of the radicular bifurcation is seen in the form of either a calcified point or a semi-lunar shape. b. The root length is still less than crown height.

F. Uniradicular teeth a. The walls of the pulp chamber now form a more or less

isosceles triangle. The apex ends in a funnel shape.

b. The root length is equal to or greater than the crown height.

• Molars:

a. The Calcified region of the bifurcation has developed further down from its semi-lunar stage to give the roots a more definite and distinct outline with funnel shaped endings.

b. The root length is equal to or greater than the crown.

G. The walls of the root canal are now parallel and, its apical end is still partially open.

H. The apical end of the root canal is completely closed. a. The periodontal membrane has a uniform width around the root and the apex

Correlation between skeletal maturity and teeth calcification. Mittal S.K. et al(2011) investigated the relationship between skeletal maturity using CVM and teeth calcification. Conclusion was follows;

A. The second molar showed the highest correlation and the.

B. Stage F of tooth calcification corresponded to onset of peak height velocity (stage 2 of CVMI) . 

 C. Stage G of tooth calcification in canine; first premolar and second molar (except for second premolars in males) corresponded to peak of pubertal growth spurt (stage 3 of CVMI).

D. Root formation of the canine as well as the first premolar was completed in the majority of the subjects at stage 5 of CVMI.

For all the teeth except third molar root formation was completed at stage 6 of CVMI

Using the Scoring System

1. Each tooth will have a rating (A-H), assessed by the procedure described.

2. This is converted into a score using the table for boys or girls as appropriate.

3. The scores for all seven teeth are added together to give the maturity score

4. The maturity score may be plotted on the centile charts (boys or girls as appropriate) where the age of the child is known.

5. The maturity score may be converted directly into a dental age either by reading off on the horizontal scale the age at which the 50th centile attains the maturity score value, or

by using table which has been constructed by this means.

Advantages :

Demirjian and Goldstein’s method is simple, as it is an orthopantomogram based method and it enables more reliable standardization and has good reproducibility and intra-examiner/inter-examiner reliability

Limitations

1. Demirjian method use orthopantomograms which are difficult to obtain in young children, due to both technical reasons, as well as legal and ethical considerations.

2. Since simultaneous evaluation of seven left mandibular teeth are required, cannot apply it in children with lacking teeth inborn or acquired.

3. This method may not express, agenesis of teeth, distinctive retardation of dental development (excluding third molars), and systemic diseases and various developmental stages of the tooth

5. This method does not give maturity scores for stages 1-4 in case of 1st molar, central and lateral incisor; thus excluding the individuals below the age of 4-4.5 years.

4. The appreciation of developmental stage may become difficult as the choice of the tooth developmental stage is quite subjective

Dental age estimation using Willems method: A digital orthopantomographic studyRezwana Begum Mohammed, PV Krishnamraju, PS Prasanth, Praveen Sanghvi, M Asha Lata Reddy, S Jyotsna

Digital Orthopantomogram of 332 subjects (166 males, 166 females) who fit the study and the criteria were obtained.

Assessment of mandibular teeth (from central incisor to the second molar on left quadrant) development was undertaken and DA was assessed using Willems method.

Results

The present study showed a significant correlation between DA and CA in both males (r = 0.71 and females (r = 0.88). 

 The mean difference between DA and CA according to Willems method was 0.39 years and is statistically significant (P <0.05). 

Conclusion: This study showed significant relation between DA and CA. Thus, digital radiographic assessment of mandibular teeth development can be used to generate mean DA using Willems method and also the estimated age range for an individual of unknown CA.

Dental age assessment: The applicability of Demirjian's method in South Indian children Shobha tandon

The material was 184 South Indian children aged 5 to 15 years and an additional 34 children as the test sample.

It was found that Demirjian's method gave an overestimation of 3.04 and 2.82 years in males and females, respectively.

The skeletal age was found to differ from the dental and chronologic age. It may be concluded that the accuracy of age estimation based on Demirjian's method is not applicable for the South Indian children.

From this study, it can be inferred that the assessment of dental age is dependent on the ethnic group on which it is to be tested.

The Demirjian conversion of the maturity score to the dental age was not applicable in the South Indian children

conc

Dental age assessment using Demirjian's method on northern Turkish children emine sen et al

Panoramic radiographs of 900 healthy, northern Turkish children, 4–12 years of age were examined with Demirjian's method.

Panoramic radiographs were scored by one examiner. Dental age was compared to chronological age by using a paired t-test. The median age for individual teeth for each stage was calculated

The northern Turkish children were generally advanced in dental maturity compared with the children in Demirjian's sample.

The mean difference between dental and chronologic ages of boys and girls varied from 0.36 to 1.43 years and 0.50–1.44 years, respectively.

The standards of dental age described by Demirjian et al. in 1973 and 1976 may not be suitable for northern Turkish children.

Each population of children may need their own specific standard for an accurate estimation of chronological age.

conc

A total of 1175 orthopantomograms were assembled from patients of Caucasian origin between 16 and 22 years of age.

Each third molar present was scored by two observers according to a 10-stage developmental scale.

The k statistics measured the intra- and inter-observer reliability.

Dental age estimation and third molars: a preliminary study K. Mesottena , K. Gunsta , A. Carbonezb , G. Willems

The general statistical analysis was based on multiple regression analysis in order to obtain multiple regression formulas for dental age estimation based on the number of third molars present on the evaluated orthopantomogram

The statistical analysis revealed both for males and females high Pearson correlation coefficients between contralateral third molars and smaller coefficients between antimeres

This investigation revealed that the chronological age of a Caucasian individual may be estimated based on regression formulas with a S.D. of 1.52 or 1.56 years for males and females, respectively, when all four third molars are present

conc

A total of 991 dental panoramic radiographs of 5–15-year-old Malaysian children were included in the study.

The mean Demirjian and Willems estimated ages were compared to the mean chronological age.

Validity of Demirjian and Willems methods for dental age estimation for Malaysian children aged 5–15 years old

Kai ming kee , Noriah Hussain ,;peggy gan et al

Results

The mean chronological age of the sample was 10.1 ± 2.8 and 9.9 ± 3.0 years for males and females respectively.

Using the Demirjian method, the mean estimated dental age was 10.8 ± 2.9 years for males and 10.5 ± 2.9 years for females.

For Willems method, the mean estimated age was 10.3 ± 2.8 years males and 10.0 ± 3.0 years respectively.

Conclusions

Willems method was more applicable for estimating dental age for Malaysian children.

Overestimation in Demirjian method could be due to advanced development of second bicuspids and molars.

TESTING STANDARD METHODS OF DENTAL AGE ESTIMATION BY MOORREES, FANNING AND HUNT AND DEMIRJIAN, GOLDSTEIN AND TANNER ON THREE SOUTH AFRICAN CHILDREN SAMPLES

VM Phillips1 , TJ van Wyk Kotze2

The aim of this study was to test the accuracy of the dental age estimation methods of MFH and DGT on samples of children of different ethnic groups.

The data used for this study consisted of 914 pantomographic radiographs of children between the ages of three years to 16 years that had routine dental treatment at the Dental Faculty at Tygerberg.

The study showed that the MFH method consistently under-estimates the age and the method of Demirjian et al over-estimates the ages.

conc

These methods are not applicable to accurately estimate the ages of South African juveniles.

Dental age assessment in forensic odontology

Estimating chronological age of individuals with no or doubtful/incomplete age documentation is a principal discipline in Forensic Odontology.

Forensic age estimations in the living are requested in relation to age thresholds in criminal investigations, during immigration procedures and for civil purposes.

In addition, estimating age of unknown bodies facilitates a traced search for ante mortem data by narrowing the age interval of the search.

In forensic age estimations often dental age estimation methods are combined with methods based on non-dental variables.

Practical experience is learned by observing and registering age-related features on collected medical imaging material or on extracted and cut tooth specimen.

The obtained data are fitted to the matching age estimation method(s).

Accordingly, an estimated age and a corresponding measure of the uncertainty is obtained in a manual way or using specific software. Special attention is given to report correctly the obtained outcomes.

Dental age can be determined two methods:

- Stage of eruption- stage of tooth mineralization on radiograph 

Stage of Eruption : Determination of dental age from observation of eruption has been the only method available for a long time In certain cases however, the accuracy of the method is limited. During the quiescent period in eruption, this appoach is inadequate. 

Stage of tooth mineralization on radiograph (Demirjian et al 1973) When determining dental age radiographically according to the stages of germination, the degree of the development of individual teeth is compared to a fixed scale.

For age determination one does not rely on the last stage of tooth formation but on the entire process of dental mineralization. The procedure can be used for the entire deciduous and mixed dentition period, and is not influnced by early loss of deciduous teeth.

The calculation is made using a point evaluation system.

Each tooth is given a point value according to its state of development. The sum of individual points gives the development value, which can be transferred into the dental age with the aid of standard tables

The smaller the sum of points, the younger the dental age; the higher the sum, the older the dental age.

The procedure is not valid for patients with several congenitally absent teeth

Engstrom in 1983 conducted a study to analyze development of the lower 3rd molar and whether it could be correlated to skeletal maturity.

A probable reason for the great variability seen in previous studies regarding 3rd molar development might be because its development was related to chronological age rather than skeletal age.

Engstrom.C Engstrom.H, Sagne.s : Lower third molar development in relation to skeletal maturity and chronological age

Hand wrist x-rays were taken and their skeletal development classified as

PP2 : proximal phalanx of second finger, the epiphysis as wide as diaphysis.

MP3cap : Middle phalanx of third finger, the epiphysis cap its diaphysis.

DP3u: Distal phalanx of third finger, complete epiphyseal union.

Ru : Distal epiphysis of radius

Development of lower third molar appeared slightly earlier in boys than in girls. Strong correlation was found between chronological age and third molar development. A strong correlation was also found between third molar development and skeletal maturity.

At stage PP2- The 3rd molar showed signs of completed crown molar mineralization in most subjects.

At stage MP3cap- Lower third molar crown formation was complete in most subjects and root development has begun in some.At stage DP3u- Lower third molar crown was still incomplete in some subjects but full root length was attained in others.

At stage Ru- Only the crown was completed in 1/3rd of subjects. Half the root had developed in 1/3rd and full length was seen in another 1/3rd.

The results seem to show that lower third molar development on the whole seems to be correlated with skeletal maturation

variableMale Female

Correlationcoefficient

Correlation coefficient

Dental age

Skeletal age

P value P value

0.711 0.000

0.000

0.000

0.0000.863

0.821

0.788

Correlation of chronological age with dental age and skeletal age

Age estimation using maxillary central incisors: A radiographic studyNitin Agarwal, Parul Ahuja, Abhishek Sinha, Anil Singh

Aim: The purpose of the present study was to present a method for assessing the chronological age based on the relationship between age and morphological parameters of maxillary central incisors. 

Materials and Methods: Fifty subjects between 20-70 years of age were included in the study. Intraoral periapical radiographs were taken in relation to maxillary central incisors using paralleling technique.

The following measurements were recorded: lengths of tooth, pulp, root and width of root and pulp at three different points. Regression formulas were used to calculate the dental age. 

Results: The mean estimated age showed no statistically significant difference from the actual mean age (P > 0.05). Also, maximum difference was seen for root length variable (-1.035 ± 1.86 years).

This study was conducted on the dental images of 28 patients of known age (1–195 weeks) using the central teeth measurements that can be displayed on the two image axes.

The results show that virtual dental identification from computerised tomography images is a reliable method.

Age estimation from primary teeth through virtual dental identification Dagalp, kaglar et al

The best measurements for age estimation can be obtained from the longest vertical dimension in the sagittal plane, which is the tooth height (R2 =  96.4).

Additionally, the best age estimation formula was generated from the tooth height with labio-lingual measurement (R2 = 98.1), where the margin of error of the mean predicted value was equal to ± 1.07 weeks.

This age estimation formula can be applied up to two years of age, which is the completion of upper central primary tooth development.

In conclusion, virtual dental identification procedures can be applied in cases of forensic odontology investigations.

• Teeth can resist extreme condition.

• Pretty and Sweet state that teeth are an excellent source of DNA

• Applied technique → polymerase chain reaction- allows amplification of highly degraded DNA.

IDENTIFICATION FROM DENTAL DNA:

• This facilitates comparison with a known biological antemortem sample of the decedent such as hair from a comb, epithelial cells from a toothbrush or biopsy specimen. • Advantage: - DNA pattern can be compared to the parents or siblings, thus facilitating positive identification

Types of DNA: Pretty and Sweet pointed out 2 types of DNA: Genomic or Nuclear DNA: located in the nucleus of a cell and commonly used in nuclear studies.

Mitochondrial DNA: present in the mitochondria of cells.

• Tooth pulp is considered as the best source of dental DNA.

• Ajayprakash and co-workers isolated DNA from dental pulp and accurately determined personal identity using HLA-DQ amplification.

Extraction of Dental DNA:

Cytogenic grinding:

•Advocated by Sweet and Hildebrand. Technique:

cooling the whole tooth to extremely low temperatures using liquid nitrogen

mechanically grinding it to fine powder.

sufficient amount of DNA (intact, carious as well root-filled teeth).

Disadvantage: - tooth needs to be completely crushed.

subsequently flushing of the tissue debris. 

According to Trivedi and coworkers

less destruction method for DNA isolation.

opening of the root canals,

scraping the pulp area with a notched medical needle

Problems with dental identification

1) Absence of antemortem records.

2) Absence of acquired dental tracts for identification.

3) Limitations for storing dental records for certain period.

4) Poor quality dental records

5) In post mortem situation, all of the teeth may not be recovered as a result of post mortem trauma or loss of Pdl.

6) Fire can result in irreversible changes to restorations and teeth which can reduce the amount of information available for comparison.

Identification in mass disaster

• The term "mass disaster" evokes images of a chaotic event.

• The process of dental identification is same except the magnitude of event is far greater.

• Mass disasters can be classified in one of three ways:

I . Natural 2. Accidental 3. Criminal

Natural mass disasters include earthquakes, tornadoes, volcanic eruptions, fire storms and floods.

• Principal problem for the dental identification team → environmental infrastructure is often compromised.

Dental offices containing antemortem records may be destroyed

Accidental mass disasters are most often associated with transportation accidents, fires, industrial and mining accidents, and military accidents.

• Occur over short periods, closed populations

 According to clark, 50% of identification are from dental evidence. So odontology is a part of team.

• Clarke states- ‘dental examination is usually done after most other procedures such as photography, fingerprinting, and autopsy’.

• Postmortem unit is responsible for processing the radiograph and also need to arrange photography of teeth

Reconstructive post mortem (dental profiling)

• Dental profiling includes extracting a triad of information- race, gender, occupation & age.

• According to Sweet and pretty- “The information from this process will enable a more focused search for ante mortem records”.

IDENTIFYING ETHNIC ORIGIN FROM TEETH

• Traditionally, the human species has been categorized into three ‘races’ – Caucasoid, Mongoloid, Negroid.

• Many of the best traits of estimation of race are found in the mid facial skeleton, including the area of nose, mouth and cheek bones. .

• Landmarks – a)shape of the cranium,

b)lateral projection of zygomatic arches,

c)shape and contour of the orbits and

d)nasal aperture.

Age estimation from incremental lines of cementum

• Kagerer and Grupe– Acellular cementum incremental lines are used in estimation.

• Mineralized unstained cross sections of teeth, preferably mandibular central incisors and third molars are used.

• Author Claims accuracy to within 2-3 years of actual age.

• Hypomineralized bands in the incremental line — indicates pregnancy, skeletal trauma and renal disorders which can be related to persons life-history → facilitating identification

CONCLUSION

• The roles of any forensic scientist are to collect, preserve and interpret trace evidence, then to relay the results to the judicial authority in a form of a report.

• Forensic Odontology is the forensic science that is concerned with dental evidence.

• Dental records that are used to provide patients with optimal dental service could also be very beneficial to legal authorities during an identification process.

• Therefore, all forms of dental treatments should be recorded and kept properly.

Determination of dental age is done by reference to the ever-growing human deciduous and permanent dentitions. The importance of age estimation includes an assessment of minor/major status in individuals without legal documents, Demirjian method, the widely used method with appropriate modifications shall be a reliable method.

conclusion

References:

Wheelers dental anatomy

Dental Age Estimation Methods: A Review C Priyadarshini1 , Manjunath P Puranik2 , S R Uma3

Panchbhai AS. Dental radiographic indicators, a key to age estimation. Dentomaxillofac Radiol 2011;40:199-212

Demirjian A, Goldstein H, Tanner JM. A new system of dental age assessment. Hum Biol 1973;45:211-27

McKenna CJ, James H, Taylor JA, Townsend GC. Tooth development standards for South Australia. Aust Dent J 2002;47:223-7. 3. Al-Emran S. Dental age assessment of 8.5 to 17 Year-old Saudi children using Demirjian’s method. J Contemp Dent Pract 2008 1;9:64-71

Evidence based forensic dentistry by balwanth rai , jasdeep kaur

Fishman LS. Radiographic evaluation of skeletal maturation. A clinically oriented method based on hand wrist ‑films. Angle Orthodontics 1982;52:88 112.‑

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