1. CHRONOLOGY OF
PRIMARY AND
PERMANENT DENTITION.
M. BHARATH REDDY

2. OBJECTIVES
• INTRODUCTION
• DEFINITION
• TYPES
• CHRONOLOGY OF PRIMARY
DENTITION
• MIXED DENTITION PERIOD
• CHRONOLOGY OF PERMANENT
DENTITION
• SIGNIFICANCE OF CHRONOLOGY

3. INTRODUCTION
• Chronology of dentition is based upon data
of Logan and kronfeld reported in 1933.
• Careful review was done by
• masseler and shour in 1941.
• morrees and fanning and hunt in 1963
• kraus and jordan in 1965
• Nystrom in 1977

4. DEFINITION
• Chronos-time
• Logos-study
• Chronology is defined as “a study which
deals with the timings of various stages
of tooth development. starting with the
initiation of the first dental tissue laid
down to the emergence of tooth in the
oral cavity and its completion of
calcification”.

5. Age of attainment
Types of chronologies
Age of prediction Maturity assesment

6. • AGE OF ATTAINMENT:
3. IT IS BASED UPON TOOTH
EMERGENCE
5. IT IS USED CLINICALLY TO AVOID
DAMAGE TO DEVELOPING TOOTH
DURING TREATMENT

7. • AGE OF PREDICTION:
3. IT IS BASED ON THE AVERAGE AGE
OF THE SUBJECTS IN A STAGE OF
DEVELOPMENT
5. AGE PREDICTION ARE USED FOR
ASSESSING UNKNOWN AGE OF
PATIENTS AND FORENSIC
ARCHEALOGICAL APPEARANCE

8. MATURITY ASSESSMENT:
3. HERE THE STAGES ARE AVERAGED
RATHER THEN SUBJECT AGES.
5. SUCH SCALES ARE USEFUL WHEN
MATURITY IS ASSESSED OF
KNOWN AGE

9. CHRONOLOGY OF PRIMARY
DENTITION

11. SEQUENCE OF EMERGENCE OF
PRIMARY TEETH
• THE PREDOMINAT SEQUENCE OF
ERUPTION OF PRIMARY TEETH IN
THE INDIVIDUAL JAW IS
• (A) CENTRAL INCISOR
• (B) LATERAL INCISOR
• (D) FIRST MOLAR
• (C) CANINE
• (E) SECOND MOLAR

12. SEQUENCE OF ERUPTION
AB D C E
A B D CE

14. MIXED DENTITION PERIOD
• THE FIRST MIXED DENTITION BEGINS
WITH THE EMERGENCE AND
ERUPTION OF MANDIBULAR FIRST
PERMANENT MOLARS
• IT ENDS WITH THE LOSS OF THE LAST
PRIMARY TOOTH WHICH USUALLY
OCCURS AT 11-12YRS

15. PERMANENT DENTITION IS COMPLETED FROM 18 TO 25 YRS Of
AGE IF 3RD MOLAR INCLUDED

16. CHRONOLOGY OF PERMANENT
DENTITION

17. Importance of
chronology
• TO AVOID TREATMENT THAT CAN
DAMAGE DEVELOPING TEETH
• TO ASSESS UNKNOWN AGE OF THE
PATIENT
• TO ASSESS GROWTH
• TO AVOID MALFORMATIONS OF THE
TEETH

18. REFERENCES
• WHEELER’S
• SHOBHA TANDON
• INTERNET