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Age Determination
  1. Age determination from bones:
    1. Age from Skull Sutures:
      1. Two halves of mandible unite at:         2 years.
      2. Metopic suture closes at:         3 years.
      3. Sutures on inner side close:         5-10 years earlier than outer side.
      4. Coronal, sagittal, lambdoid sutures start to close on inner side at:         25 years.
      5. On outer side, fusion occurs in the following order-
        • i. Posterior 1/3rd sagittal suture –          30-40 yrs.
        • ii. Anterior 1/3rd sagittal suture + lower ½ of coronal suture–         40-50 yrs.
        • iii. Middle 1/3 sagittal suture + upper ½ coronal suture–          50-60 yrs.
      6. For viewing X-rays, lateral view is preferable and the most successful estimation is done from sagittal sutureQ, next lambdoid and then coronal.
      7. Lapsed union occurs commonly in sagittal suture (failure of ectrocranial suture closure).
    2. Sternum:
      The four pieces of body of sternum fuse with one another from below upwards between 14 to 25 years
      At about 40 years xiphoid unites with body.
    3. Manubrium unites with body of sternum at 60 years.
    4. Ribs :- Ends of the ribs fuse at 21 years.
    5. Hyoid Bone:
      The greater cornua of the hyoid bone unites with the body between 40 to 60 years.


    6. Pelvis:
      1. Iliac crest appears at 14 years and fuses at 18-20 years
      2. Ischial tuberosity appears at 16 years and fuses at 21 years
      3. Triradiate cartilage appears at 13 years and fuses at 15 years
  2. Age determination from teeth
    1. TEMPORARY or DECIDUOUS TEETH: 20 in number.
      1. 4 incisors, 2 canines and 4 molars in each jaw.
      2. Dentition is delayed in RICKETS and ill-nourished children.
      3. Dentition appears early in SYPHILIS.
      4. Eruption of temporary teeth is complete by 2-2.5 years.
      5. The temporary teeth begins to fall at about 6-7 yrs after the first permanent tooth eruption i.e., permanent molar.
      6. Mixed dentition (temporary + permanent) remains from 6 to 12 yrs of age. The total no. of teeth remain 24 *.
    2. Feature of temporary of permanent teeth





Small, lighter, narrow

Heavier, stronger, broader


China white color

Ivory white color


More constricted

Less constricted



A ridge at the junction of crown with the fangs present.

No ridge.

  1. The sequence of eruption of temporary teeth.



Lower central Incisior

6-8 months (6 MONTHS)

Upper central Incisior

7-9 months (7 MONTHS)

Upper lateral Incisior

7-9 months (8 MONTHS)

Lower lateral Incisior

10-12 months (9 MONTHS)

First Molar

12-14 months (12 MONTHS)


17-18 months (18 MONTHS)

Second Molar

20-30 months (24 MONTHS)

  1.  Sequence of eruption of permanent teeth





First Molar

6-7 years (6 YEARS)



Central Incisior

6-8 years (7 YEARS)



Lateral Incisior

8-9 years (8 YEARS)



First Premolar

9-10 years (9 YEARS)



Second Premolar

10-11 years (10 YEARS)




11-12 years (11 YEARS)



Second Molar

12-14 years (12 YEARS)



Third Molar

17-25 years (18 YEARS)




Temporary teeth start falling after the eruption of first permanent Molar/Mixed Dentition: Both temporary and Permanent teeth present in the age group of 6-11 yrs.


Total No. of teeth during mixed dentition is always 24 (Temporary + Permanent = 24)

Age Number of permanent teeth
9 yrs 12
10 yrs 16
11 yrs 20
  1. Methods to know the age
      The AGE estimation of adult over 21 years depends on the physiological age changes in each of the dental tissue.
      The various criteria used in gustafson’s method is:
      1. SECONDARY DENTINE: It develops within the pulp cavity and decrease the size of the cavity, start from base and reach the apex, finally obliterates the cavity.
      2. CEMENTUM OPPOSITION: Near the end of root, increase cementum increases thickness, it is deposited throughout life and forms incremental lines.
      3. ROOT RESORPTION: Because of cementum and dentine, absorption of root starts at the base and extends upwards.
      4. ATTRITION: Due to wear and tear upper surface of the teeth destroys gradually, first involving the enamel then dentine then pulp.
      5. PARAODONTOSIS: Regression of gums and periodontal tissue surrounding the teeth, exposing the neck and adjacent part of root. Estimated before tooth extraction.
      6. TRANSPARENCY OF THE ROOT: Most RELIABLE criteria of gustafson’s. Seen after 30 years of age. Canal in the dentine at first widens, increases with age because of deposition of minerals. They become invisible and dentine becomes transparent. It is a microscopic study.
        • It is a method used for dead
        • Anterior teeth are more reliable then posterior so merit of this method decrease from incisors to premolars.
    2. ​​Boyde’s method: Cross strations develop in the enamel of teeth, till the complete formation of enamel. They represent daily incremental lines. The age of an individual can be calculated in terms of days by counting the number of lines from the neonatal line onwards. It is useful to estimate the age of a dead infant.
    3. Stack’s method: It is a method to know the age of infants from the weight and height of the erupting teeth of the infant. This method can be used on both deciduous and permanent teeth during their erupting phase.
    4. Rule of Haase:
      A rough method for calculating the age of the fetus
      1. During the first five months of pregnancy the square root of the length gives the approximate age of the fetus in months.
      2. During the last five months, the length in cm divided by five gives the age in months.

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