Clinical relevance of chronologic, dental, and skeletal age

1. CLINICAL RELEVANCE OF
CHRONOLOGIC, DENTAL AND
SKELETAL AGE
DETERMINATION
By:
Elton Arunga
Mahin Muradali

2. • Chronological age refers to the actual amount of time a person has been
alive. In other words, the number of days, months or years a person has
been alive does not change, regardless of how healthy a lifestyle they are
living
• Skeletal age/Bone age is the degree of maturation of a child's bones. As
a person grows from fetal life through childhood, puberty, and finishes
growth as a young adult, the bones of the skeleton change in size and
shape. These changes can be seen by x-ray
• Dental age of an individual, obtained from the stages
of dental development present in the individual, is taken as the estimate of
chronological age. The availability of X-rays has facilitated visualization of
identifiable development stages of dental maturity for each tooth

3. • Growth prediction is done using
• Chronologic age
• Skeletal development
• Dental development
• Growth charts
• Secondary sexual characteristics
• Chronologic age is not always sufficient to assess the development age and
somatic maturity of an individual
• Chronologic age and dental age are often synchronous
• A child +/- 2 years from the average value is a late or early developer

4. • Skeletal age assessment is done through
• Hand wrist radiograph
• Cervical vertebra
• Frontal sinus
• Mid-palatine suture
• Hand wrist radiograph is the standard assessment
• Non dominant hand (left hand), full hand, spread fingers
• Used to show the predictable and scheduled pattern of appearance,
ossification and union
• Capitate bone ossifies first while the sesamoid bones ossify last

7. • Bone age is an interpretation of skeletal maturity, typically based on
radiographs of the left hand and wrist or knee
• A child’s bone age may or may not approximate his or her chronologic age
• Many factors influence the progression of skeletal development, including
nutrition, genetics, hormones, and disease states

8. METHODS OF ASSESSING SKELETAL
MATURITY
• Based on changes in ossification centers over time
• Long bones eg ulna, radius, phalanges, grow until epiphyses fuse with
metaphyses at the growth plates (epiphyseal growth plates)
• The fusion occurs at different times in a child’s body
• Children older than 3 years have different ossification centers seen on the
hand with progression of age radiographically
• Children younger than 3 years have changes in the knee better appreciated
than on the hand ( fetal hypothyroidism)

9. An example of
skeletal
maturation
during
childhood at
various ages.
A, 5 years
B, 7 years
C, 9 years
D, 11 years
E, 13 years
F, 15 years

10. • Two most commonly used methods of scoring skeletal maturity include:
• Tanner-Whitehouse (TW)
• Greulich-Pyle (GP)
• TW method calculates a radius, ulna and short bone score(20 sites), with
each major bone in the hand contributing to the total score
• GP method compares the overall visual appearance of the hand with age
standards the GP Atlas –simpler and quicker
• Practically, clinical assessment is given in estimation of age ranges by
studying radiographs

11. INFANCY TODDLER PREPUBERTY
EARLY/MID PUBERTY
LATE
PUBERTY
FUSION
NO OF
CARPAL
BONES
CAPITATE
AND HAMATE
APPEAR
3-4 MONTHS
APPEARAN
CE AND NO
OF
EPIPHYSE
S
PROXIMAL
APPEAR
SIZE OF EPIPHYSES
COMPARED TO METAPHYSES
EPI<MET 2-7 YRS
EPI=MET 10-12 YRS
EPI>MET 12-14 YRS
FUSION 14 YEARS
FUSION AT
DISTAL
PHALANGE
S
LONG BONE
FUSION

12. DELAYED BONE AGE
• Bone age is traditionally used to assess a child’s growth and future height
potential
• Constitutional delay is one of the most common causes of delayed bone age
and short stature
• Constitutional delay is a bone age at least 2 years less than chronologic
age. Associated with short stature, delayed puberty or reaching final adult
height later than peers
• Familial shortness however shows normal bone age and therefore normal
shortness

13. • Children with
• chronic diseases e.g cancer or cardiac, liver or kidney diseases,
• diseases causing nutrient malabsorption such as inflammatory bowel disease
• Processes involving inflammation or infection such as immunodeficiency
• Psychiatric disease such as anorexia and depression
• Poor nutrition
• Genetic disorders such as trisomy 21
have a delayed bone age because of the disease process

14. • Prematurely bone children have long-standing skeletal maturation delays
• Endocrine problems causing short stature are commonly associated with
delayed bone age - hypothyroidism
• Growth hormone deficiency also leads to delayed skeletal maturation –
pituitary malformations, tumors and infiltrative diseases, secondary
hypothyroidism, hypogonadism
• Certain medications alter bone development- exogenous corticosteroids
may lead to delayed skeletal maturation in select sensitive children –
amphetamines and dextroamphetamines used in ADHD

15. ADVANCED BONE AGE
• Constitutional advancement is also occurs especially in families with
history of early onset of puberty.
• Other causes include sex steroid exposure or obesity
• Pathologic causes of precocious puberty such as ovarian, Leydig or
germ cell tumors can lead to rapid skeletal changes
• Brain tumors and malformations, adrenal tumors and adrenal
diseases, and hyperthyroidism are associated with advanced bone
age

16. OTHER BONE AGE APPLICATIONS
• Athletics and athletic performance in selection of elite athletes
• Legal and policy matters- forensic cases, international immigration

17. LIMITATION IN BONE AGE DETERMINATION
• TW and GP methods developed standards based on a largely white
population
• not necessarily generalizable to children of other ethnicities, particularly
African and certain Asian backgrounds

18. FUTURE TRENDS
• Automation of bone age reading and determination of bone age from
other imaging modalities
• BoneXpert
• Dual energy radiograph absorptiometry(DXA), ultrasonography and
MRIs

19. • Knowing a child’s skeletal maturation may be a time-effective and cost-effective
way to direct further diagnostic testing, provide a diagnosis, and even predict a
prognosis
• There is a greater degree of association between dental age and chronological
age than between dental and skeletal age
• Tooth development shows less variability than other developmental features and
also low variability in relation to chronological age.
• Mechanisms controlling dental development are independent of somatic and
sexual maturity
• Ref: Creo AL and Schwenk WF. Bone Age: A Handy Tool for Pediatric Providers.
Pediatrics.2017;140(6):e20171486

20. DENTAL AGE
• Chronological age (CA) and dental age(CA) are synchronous in a normal
patient.
• Dental age can be correlated to skeletal and chronologic age but there is
some controversy as eruption timetable can be altered due to general and
local factors.
• A child is labeled as an early or late developer if there is a difference of +/-
2 years from the average value.
• Dental age can be determined by two common methods :
• Stage of tooth eruption
• Stage of tooth mineralization

21. THE CONCEPT OF ‘AGE’
• The physiological age of a person is determined by the degree of
maturation of the different tissue systems.
• DA is usually based on the maturation of teeth. The different biological
ages can be used as a single entity or combined to assess the
maturation of a growing child. DA and CA are two indicators of
biological maturity which collectively have the least variability.
• Determination of age is of importance in forensic medicine, paediatric
endocrinology, and treatment planning in orthodontics and paediatric
dentistry.

22. METHODS FOR AGE DETERMINATION FROM
DENTITION
A. According to the state of development of the dentition:
• Methods applied to the forming dentition
• Methods for the adult fully formed dentition.
B. According to the technique of investigation:
• Clinical or visual – Visual observation of the stage of eruption of the teeth and
evidence of changes due to function such as attrition can give an approximate
estimate of age
• Radiographic - provide the gross stage of dental development
• Histological- usually appropriate for postmortem situations. It is also significant
for estimation of age of early development of dentition.
• Physical and chemical analysis. – The physical and chemical analysis of dental
hard tissues to determine alterations in ion levels with age have been proposed.
Provides more accurate indications during the first 18-20 years of life.

25. RADIOGRAPHIC METHODS
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

26. • Eruption of crown into the oral cavity
• Degree of root completion of erupted or un-erupted teeth
• Degree of resorption of deciduous teeth
• Measurement of open apices in teeth
• Volume of pulp chamber and root canals/ formation of physiological
secondary dentine
• Tooth to pulp ratio
• Third molar development and topography

27. PRENATAL, NEONATAL AND POSTNATAL
AGE ESTIMATION
• Radiographically, the mineralization of deciduous incisors starts at the
16th week of intrauterine life. Before the mineralization of tooth germs
starts, the tooth germs may be visible as radiolucent areas on the
radiograph; 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.

28. 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

29. AGE ESTIMATION METHODS IN CHILDREN
AND ADOLESCENTS
1. Schour and Masseler method (1941)
In 1941, 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.

30. 2.Nolla’s method (1960) / Scoring 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.

32. 3.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

33. 4. DEMIRIJIAN’S METHOD(1973)
• Demirjian et al. proposed an age estimation method that makes use of
10 developmental stages (numbered 0–9) for the eight mandibular
permanent teeth on the left side. Based on the developmental stage of
each tooth, a sex-specific “maturity score” is assigned to them. The
maturity score allocated to the teeth are added and a total maturity
score obtained. This total is then substituted in a formula.

35. OPEN APEX METHOD (CAMERIERE
METHOD)
• The open apex method is also an age estimation method for children and
juveniles. Here, seven left mandibular teeth (excluding the 3rd molars)
from the left side are used.
• The number of teeth with root development completed with apical ends
completely closed was calculated (N0). For the teeth with incomplete root
development, that is, with open apices, the distance between inner sides
of the open apex was measured (A).

36. • For the teeth with two roots, the sum of the distances between inner
sides of two open apices was evaluated. To nullify the magnification,
the measurement of open apex or apices (if multirooted) was divided
by the tooth length (L) for each tooth and these normalized
measurements of seven teeth were used for age estimation. The
dental maturity was calculated as the sum of normalized open apices
(s) and the numbers of teeth with root development complete (N0).
• The values are substituted in the following regression formula for age
estimation:
Age = 8.971 + 0.375 g + 1.631 × 5 + 0.674 N0 − 1.034 s − 0.176 s N0.
Where g is a variable equal to 1 for boys and 0 for girls.

37. THIRD MOLARS IN AGE ESTIMATION
• Although the third molar is a valuable indicator of age in the age group 16–23 years
when all other teeth have completely developed, its accuracy in age estimation is
questionable.
• Estimation of age by studying tooth emergence, although convenient clinically, has the
following limitations:
1. Emergence has varying clinical interpretations
• Piercing of the gingiva and exposure of the crown
• Bony emergence through the alveolar bone
• Attainment of occlusion by the teeth.
2. Exact timing of emergence is often missed
3. They are under the influence of infection, arch space, and premature tooth loss.

38. DEVELOPMENT OF THIRD MOLAR AS A
GUIDE
• 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)

39. MORPHOLOGICAL METHODS
Gustafson’s Method (1950)
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)

40. Gustafson suggested the last two changes. 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

42. REASONS FOR ACCELERATED DENTITION
• Congenital syphilis
• Eosinophil tumours
• Macrosomia preacox
• Hyperpituitarism

43. REASONS FOR DELAYED DENTITION
• Rickets
• Mongolism
• Cretinism
• Achondroplasia
• Vit A, D deficiency
• Calcium deficiency

44. REFERENCES
• Puranik, Manjunath & Priyadarshini, C & Uma, Shankarachari Rajgopalachari. (2015). Dental
Age Estimation Methods: A Review. International Journal of Advanced Health Sciences. 1. 19-
25.
• Seth, Jyotsna & Agarwal, Anubha & Aeran, Himanshu & Krishnan, Yogeshwari. (2018). Dental
age estimation in children and adolescents. Indian Journal of Dental Sciences. 10. 248.
10.4103/IJDS.IJDS_69_18.
• Uzuner, Fatma & Kaygisiz, Emine & Darendeliler, Nilüfer. (2018). Defining Dental Age for
Chronological Age Determination. 10.5772/intechopen.71699.
• https://www.youtube.com/watch?v=C5jk9qBzfDw&t=51s Determination for Age and Dental
Eruption
• https://www.dentalage.co.uk/wp-
content/uploads/2014/09/peiris_ts_roberts_gj_prabhu_n_2009_DAA_UK_v_Australian_Populati
on.pdf
• https://www.slideshare.net/indiandentalacademy/growth-prediction-and-age-estimation1-fixed-