Article by Dr. Moses Jok Kuol Aluong, BDS (Mak)
Editing & Illustrations by Dr. Syeda Batul Fatima, BDS (Mak)
Did you know that your teeth hold the secrets to your age, even long after you’re gone? Actually, it is not just about the age only. A research by Amit K. Nayar and colleagues concluded that age, sex, and blood group can be reliably determined in freshly extracted teeth of individuals, which can significantly help in identification even after a period of 6 weeks post-extraction. By the way, at first glance, dental age estimation might seem like a magical trick from a fantasy novel—how could anyone determine someone’s age just by examining their teeth? Well, this fascinating process is firmly rooted in science, blending biology of tooth development, chemistry, visual examination and technology into a toolkit that helps unravel mysteries across various disciplines.
From the ancient remains unearthed by archaeologists to solving modern-day forensic puzzles, the power of dental age estimation is unmatched. But it’s not just for the dead or mysterious—it also plays a vital role in pediatric dentistry and orthodontics, helping to diagnose developmental delays and plan appropriate interventions.
Why dental age matters anyway?
1. Forensic & Criminal Investigations
Teeth are remarkably resilient, often surviving extreme conditions that obliterate other tissues. In tragic events like fires or explosions, dental features can help identify victims and provide closure to grieving families.
2. Pediatric & Orthodontic care
Understanding dental age helps detect delays in tooth eruption, enabling timely interventions that can improve a child’s oral and overall health.
So, how does it work? Let’s sink our teeth into the science!
Methods
Dentists and forensic odontologists rely on a variety of methods, each offering unique insights into the timeline of dental development. These methods include:
Visual Observation
By examining the sequence of tooth eruption and changes in color or wear, practitioners can estimate age. It’s a straightforward method but highly dependent on the experience of the examiner.
Radiographic Imaging
X-rays, mainly the panoramic radiographs (OPG), reveal the stages of dental development, from the earliest signs of mineralization to the full maturation of the root. This method provides detailed insights without going invasive.
Biochemical Analysis
Advanced techniques like analyzing amino acid racemization or radioactive carbon in dental enamel offer precise age estimations, albeit with ethical and logistical challenges when sampling living patients.
Histological Examination
Using microscopic techniques, dental tissues are studied in detail, revealing minute changes that correlate with aging.
Dental Age Estimation In Utero
In prenatal stage, up to 6 months, the dentin and the enamel images are not radiopaque enough to be visualized on radiographs.
In that period, the usage of Gravimetric Method and Alizarin Staining of fetal tooth germs are recommended in the age assessment.
0-5 weeks intrauterine
Teeth formation and development start during embryonic stage (3rd to 8th weeks) of intrauterine life, particularly during the 6th week. This follows the fact that by the third week the trilaminar disc – made of the three germs layers: endoderm, mesoderm and ectoderm; from which all the body tissues and organs are derived – has been formed.
Therefore before the development of teeth, non-dental methods of age estimation can be used as below:
WEEK 1
| 0 hour | Fertilisation: Zygote formation |
| 30 hours | 2 cell stage |
| 40 hours | 4 cell stage |
| 3 days | 12 to 16 cell stage |
WEEK 2
This is the week of 2’s
1. Trophoblast differentiates into cytotrophoblast and syncytiotrophoblast
2. Embryoblast differentiates into epiblast and hypoblast
3. Extraembryonic mesoderm differentiates into somatic layer and splanchnic layer
4. Two cavities are formed: Amniotic cavity and yolk sac cavity
WEEK 3
This is the week of 3’s :)
Formation of the trilaminar disc comprised of the three germ layers including endoderm, mesoderm and ectoderm. These later differentiate to cells that give rise to a number of specific tissues and organ.
3RD TO 5TH WEEK
Number of somites is correlated to approximate age in days
| APPROX. AGE IN DAYS | NO. OF SOMITES |
| 20 | 1-4 |
| 21 | 4-7 |
| 22 | 7-10 |
| 23 | 10-13 |
| 24 | 13-17 |
| 25 | 17-20 |
| 26 | 20-23 |
| 27 | 23-26 |
| 28 | 26-29 |
| 30 | 34-35 |
Development of teeth
All parts of the body are derived from only three germ layers.
Teeth themselves arise from an epithelial–mesenchymal interaction between overlying oral epithelium and underlying mesenchyme derived from neural crest cells.
6 weeks (1 1/2 months) In Utero: Dental Lamina
The Dental Lamina: C-shaped structure formed by the basal layer of the epithelial lining of the oral cavity along the length of the upper and lower jaws.
8 weeks (1 1/2 months) In Utero: Bud Stage
The lamina subsequently gives rise to a number of dental buds, 10 in each jaw, which form the primordia of the ectodermal components of the teeth.
10 Weeks In Utero: Cap Stage
Soon, the deep surface of the buds invaginates, resulting in the cap stage of tooth development. Such a cap consists of an outer layer, the outer dental epithelium, an inner layer, the inner dental epithelium, and a central core of loosely woven tissue, the stellate reticulum. The mesenchyme, which originates in the neural crest in the indentation, forms the dental papilla.
12 Weeks (3months) in Utero: Bell Stage
As the dental cap grows and the indentation deepens, the tooth takes on the appearance of a bell (bell stage).
14 Weeks to 19 Weeks in Utero: Calcification of 1° dentition
During this period, the dental age is estimated using the amount of calcification of the developing primary dentition
| DENTAL AGE | BEGINNING OF CALCIFICATION OF 1o TEETH |
| 14 weeks | Mandibular & Maxillary Central Incisors |
| 15 weeks | Mandibular & Maxillary First Molars |
| 16 weeks | Mandibular & Maxillary Lateral Incisors |
| 17 weeks | Mandibular & Maxillary Canines |
| 18 weeks | Mandibular Second Molars |
| 19 weeks | Maxillary Second Molars |
6 Months in Utero
Mesenchyme cells of the papilla adjacent to the inner dental layer differentiate into odontoblasts, which later produce dentin. In the meantime, epithelial cells of the inner dental epithelium differentiate into ameloblasts (enamel formers). These cells produce long enamel prisms that are deposited over the dentin. Furthermore, a cluster of these cells in the inner dental epithelium forms the enamel knot that regulates early tooth development.
8 Months in Utero
The calcification begins for first permanent maxillary and mandibular molars.
AFTER BIRTH
Methods: Visual and Radiographic methods
Radiographic evaluation is used to stage the degree of morphologic development of the primary and/or secondary dentition as well as resorption of the primary dentition. Infant/Child techniques should consider sex, ancestry, and population specificity.
The dates of eruption are relatively variable; ±6 months.
Preterm infants typically have some delay, and there is some variance among ethnic groups.
The eruption sequence, however, is usually preserved.
One can expect that the mandibular central incisors will erupt first, closely followed by the other incisors. After 3- to 4-months, first molars erupt, followed in another 3 or 4 months by the maxillary and mandibular canines. At 24 to 30 months, the mandibular then the maxillary second molars erupt.
Infant/ Early Childhood Dental Age Estimation
0 Month
At birth, neither the maxillary nor the mandibular alveolar process is well developed. Occasionally a “natal tooth” is present.
Within the first 1 year after birth
1 month
Crown completion of Maxillary Central Incisors – this happens at 1 1/2 months after birth.
2 months
At 2 1/2 months, there is crown completion of: 1o mandibular central incisors & 1o maxillary lateral incisors.
3 months
- Beginning of calcification of: 2o Mandibular Central Incisors, 2o Maxillary Central Incisors & 2o Mandibular Lateral Incisors.
- Crown completion of 1o mandibular lateral incisor.
4 months
Beginning of calcification of: 2o Mandibular Canines & 2o Maxillary Canines
5 months
Crown completion of 1o mandibular first molar – this happens at 5 ½ months.
6 months
Crown completion of the 1o Maxillary First Molar
7 months
No changes known to occur.
8 months
Eruption of 1o Mandibular Central Incisor
9 months
Crown completion of: 1o mandibular canines & 1o maxillary canines.
10 months
Crown completion of 1o mandibular first molars & eruption of maxillary lateral incisors begins.
11 months
Crown completion of 1o maxillary first molars & calcification of 2o maxillary lateral incisors begins.
After 1 Year
13 months
Eruption of 1o mandibular lateral incisors.
16 months
Eruption of 1o mandibular first molars & 1o maxillary first molars.
18 months (1 1/2 years)
Root completion of: 1o mandibular central incisors, 1o maxillary central incisors & 1o mandibular lateral incisors.
19 months
Eruption of 1o maxillary canines
20 months
Eruption of 1o mandibular canines & calcification of maxillary first premolar
22 months
Calcification of mandibular first premolar
After 2 Years
24 months
Root completion of 1o maxillary lateral incisors.
27 months
- Calcification of 2o maxillary second premolar, 2o mandibular second molar & 2o maxillary second molar.
- Root completion of 1o mandibular first molar.
- Eruption of 1o mandibular second molars.
28 months
Calcification of mandibular second premolar.
29 months
Eruption of maxillary second molars.
30 months
Root completion of 1o maxillary second molar.
3 years
3 years/36 months
Root completion of: 1o maxillary second molar & 1o mandibular second molar.
3 1/4 years
Root completion of 1o maxillary canines & 1o mandibular second canines.
3 1/2 years
Crown completion of 2o mandibular central incisor.
3 3/4 years
Crown completion of 2o mandibular first molars.
4 years
At 4 years
Crown completion of 2o mandibular lateral incisor.
4 1/4 years
Crown completion of 2o maxillary first molar.
4 1/2 years
Crown completion of 2o maxillary central incisors.
5 years
5 1/2 years
Crown completion of 2o maxillary lateral incisors
5 3/4 years
Crown completion of 2o mandibular canines.
Late Childhood Dental Age Assessment
This is typically the period of mixed dentition from 6 years to 12 years. It utilizes both the visual and radiographic methods.
Dental age 6
6 years:
- Crown completion of 2maxillary canines.
- Eruption of the 2mandibular first molars.
6 ¼ years:
- Eruption of the 2 mandibular central incisors.
- Eruption of the 2maxillary first molars.
Dental age 6 characterized by eruption of first permanent molars and lower central incisors.
Dental age 7
7 years:
Crown completion of maxillary first premolar
7 ¼ years:
Eruption of the 2 maxillary central incisors
7 ½ Years:
Eruption of the 2 mandibular lateral incisors.
Completion of crowns of:
- • Mandibular second premolar
- • 2o mandibular second molar
7 ¾ years:
Completion of crowns of:
- • Maxillary second premolar
- • 2o maxillary second molar
-About half of the roots of the upper lateral incisors are completed.
-Canines and premolars will only have their crown completed or will be at the beginning of root formation.
Dental age 8
8 years:
Beginning of calcification of maxillary third molars
8 ¼ years:
Eruption of the 2o maxillary lateral incisors.
*There will be a delay of 2 to 3 years before the eruption of other permanent teeth.
Dental Age 8, all permanent incisors erupted.
Dental age 9
9 years:
Beginning of calcification of mandibular third molars
9 ½ years:
Completion of root formation of the 2o mandibular central incisors.
Other changes:
- One third of the roots of the lower canines and first premolars will be completed.
- Root development of the lower second premolar barely starts.
- Root development of the upper first premolar has started and the crown of the canines and the upper second premolars is completed.
Dental age 9
Dental age 10
10 years:
Completion of root formation of 2 mandibular lateral incisors
10 ¼ years:
Eruption of maxillary first premolars
10 ½ years:
Root completion of 2 maxillary central incisors
Eruption of:
- • 2o Mandibular Canines
- • Mandibular premolars
- • Development of half of the root of the canines and lower first premolars.
- • Development of almost half of the root of the upper first premolars.
- • Significant development of the roots of the upper canines, lower second premolars and upper second premolars.
- • Roots of the lower incisors are completely formed (closed apex).
Dental age 11
11 years:
- Eruption of second maxillary premolars
- Root completion of maxillary lateral incisors
11 ¼ years:
Eruption of mandibular second premolar
11 ½ years:
Eruption of 2o maxillary canines
Other Changes by the end of 11 years:
Roots of all incisors and first molars are completed.
Dental age 11
Dental age 12
12 years:
Eruption of 2o second mandibular molars
12 ½ years:
Eruption of 2o second maxillary molars
12 ¾ years:
Root completion of 2o mandibular canines
Dental Age 12, all succedaneous permanent teeth and second permanent molars erupted.
Dental age 13
13 ½ years:
Completion of root development of:
- • Maxillary canines
- • Mandibular first premolars
- • Maxillary first premolars
Dental age 13
Dental age 14
14 years:
Crown completion of both mandibular and maxillary third molars.
14 ½ years:
Root Completion of maxillary second premolars.
Dental age 15
15 years:
Root completion of mandibular second premolar.
15 ¾ years:
Root completion of maxillary second molars.
Dental Age 15
Dental age 16
Root completion of 2o mandibular second molars.
Dental age 20
Eruption of both mandibular and maxillary third molars.
Dental Age 22
Root completion of both maxillary and mandibular third molars.
Conclusion
1. A child who has an early dental development could have a dental age of 12 for a chronological age of 10 and inversely for a child having a slower development, a dental age of 12 for a chronological age of 14.
Dental age 11 for chronological age 8 evident by eruption of all premolars and permanent canines.
2. It is more important to recognize an anomaly in dental development than a delay or acceleration. For instance, an upper canine that has not erupted at 14 years of age can be considered normal if the second premolar has not yet erupted.
It is more important to recognize an anomaly in dental development than a delay or acceleration.
3. However, if the second premolars have erupted at 12 years of age and the canines are not yet there, maybe there is something wrong.
4. A few deviations from what is normal having a significant clinical importance should be known or recognized:
• The eruption of the lower second molar before the lower second premolar decreases space for the second premolar.
• The eruption of the upper canine before the upper second premolar – the canine will erupt more labially, in ectopia.
• Asymmetry of eruption between the left and right sides.
5. Dental maturation of children at similar ages in different ethnic groups may differ due to different gene pools, living conditions, climate, socioeconomic status, nutrition and secular changes, which may affect the accuracy of the dental age estimation. To overcome this limitation, population-specific standards based on dental maturity curves can be used.
6. Once dental development is complete, the invasive morphological and histological methods are preferred. Gustafson morphological method is the most accurate around 40–50 years and with increasing inaccuracy in younger and especially in older age groups. Biochemical age determination procedures based on aspartic acid racemization in dentin is more reliable; however, an influence of iatrogenic and carious lesions on the composition of the surrounding dentin and thus on aspartic acid racemization cannot be excluded.