all the differences of primary and permanent dentition

1. DR J R SWAIN
IDS

2. OBJECTIVES
INTRODUCTION
ANATOMICAL FEATURES
MORPHOLOGICAL FEATURES
HISTOLOGICAL FEATURES
APPLIED ASPECTS
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3. INTRODUCTION
 The human dentition are usually categorized as being
primary and permanent dentition .
 The primary dentition is first set of teeth and also
called deciduous teeth, Baby teeth, temporary
teeth, milk teeth .
 Primary teeth start to form during the embryo phase
of pregnancy that is from 6th week of intra uterine life .
 The permanent dentition are the second set of teeth
and also known as adult teeth .
 The first permanent tooth usually appears in mouth at
around six years of age .

4. MORPHOLOGICAL FEATURES
PRIMARY TOOTH PERMANENT TOOTH
 DURATION :-
6 month – 51/2 year
 NUMBER :-
20 (2 incisors, 1 canine,
2 molars)
 ENAMEL :-
thinner(about 1 mm)
 OCCLUSAL PLANE :-
relatively flat
 MAMMELEONS :-
absent
 DURATION :-
61/2 year onward
 NUMBER :-
32 (2 incisors, 1 canine
2 premolars, 3 molars)
 ENAMEL :-
thicker (about 2-3 mm)
 OCCLUSAL PLANE :-
more curved contour
 MAMMELEONS ;-
present

5. THE CROWN
PRIMARY TOOTH PERMANENTY TOOTH
 CUSPS:-
1ST upper molar – 3
2nd upper molar – 4
1st lower molar – 4
2nd lower molar – 5
 CUSPIDS :-
slender and tends
to be more conical
 SUPPLEMENTAL GROOVES:-
more
 CUSPS:-
1st upper molar – 4
2nd upper molar – 4
1st lower molar – 5
2nd lower molar - 4
 CUSPIDS:-
less conical
 SUPPLEMENTAL GROOVES:-
less

7. PRIMARY TOOTH PERMANENT TOOTH
 SHAPE:-
larger and more
slender
 ROOT TRUNK :-
smaller
 WIDTH :-
narrower
mesiodistally
 PHYSIOLOGICAL
RESORPTION :-
during shedding of life
 SHAPE :-
shorter and bulbous
 ROOT TRUNK :-
larger
 WIDTH :-
broader
mesiodistally
 PHYSIOLOGICAL
RESORPTION :-
absent
THE ROOT

9. THE PULP
PRIMARY TOOTH PERMANENT TOOTH
 PULP CHAMBER :-
larger
 ROOT CANAL :-
more ribbon like
(hour glass
appearance)
 ACCESSORY CANAL :-
present (towards
furcation area )
 VASCULARITY :-
high
 PULP HORN :-
more prominent and
closer to the outer surface
 PULP CHAMBER :-
smaller
 ROOT CANAL :-
well defined
 ACCESSORY CANAL :-
present (towards
apical portion)
 VASCULARITY :-
low
 PULP HORN :-
flattend and not closer
to the outer surface

10. Permanent teeth Primary teeth

11. HISTOLOGICAL FEATURES
PRIMARY TOOTH PERMANENT TOOTH
 BLOOD SUPPLY :-
enlarged apical foramen
so abundant blood
supply
 REPARATIVE DENTIN :-
more
 LOCALISATION OF
INFECTION:-
poorer
 BLOOD SUPPLY :-
restricted and
reduced blood supply
 REPARATIVE DENTIN :-
less
 LOCALISATION OF
INFECTION :-
better

12. DENTIN
PRIMARY TOOTH PERMANENT TOOTH
 DENTINAL TUBULES :-
less regular
 DENTIN FORMING
CELLS:-
functionally active by 360
days
 INTERGLOBULAR
DENTIN:-
absent
 DENTIN :-
usually less dentin
 DENTINAL TUBULES :-
more regular
 DENTIN FORMIG CELLS:-
functionally active by 700
days
 INTERGLOBULAR
DENTIN:-
present
 DENTIN :-
more dentin

13. ENAMEL
PRIMARY TOOTH PRIMARY TOOTH
 BANDS OF RETIZUS :-
less common
 BANDS OF RETIZUS :-
more common

14. MINERAL CONTENT
PRIMARY TOOTH PERMANENT TOOTH
 ENAMEL :-
less mineralised
 DENTIN :-
less mineralised
 NEONATAL LINE :-
present
 ENAMEL :-
more mineralised
 DENTIN :-
more mineralised
 NEONATAL LINE :-
only seen in permanent
molar

15. PERIODONTAL LIGAMENT
PRIMARY TOOTH PERMANENT TOOTH
 SECONDARY CEMENTUM:-
absent
 ALVEOLAR ATROPHY :-
rare
 GINGIVITIS :-
generally absent in
healthy child similarly
recession infrequent
 SECONDARY CEMENTUM:-
present
 ALVEOLAR ATROPHY:-
occurs
 GINGIVITIS :-
common in adult

16. APPLIED ASPECTS
 CROWN :- Morphological features of primary and
permanent helps us for cavity preparation in both
primary and permanent tooth(as enamel thickness is
less in primary and enamel is delicate, there is a
restriction in cutting efficiency) .
 THE ROOT :- Morphological features of primary and
permanent tooth helps in extraction (as primary tooth
root is short, physiolo0gical resorption occurs, so
during extraction care should be taken)
 Root length, root trunk and shape of root helps during
endodontic treatment.

17.  Size, shape, color, mammelons and number of tooth are
helps in identification of tooth .
 CONTACT AREA :- as contact area is broad in primary
tooth, so its more prone to carries .
 PULP CHAMBER:- Structures of pulp chamber is used for
pulp therapy
 ACCESSORY CANAL:- In primary tooth accessory canals
found near furcation area, so infections mainly seen near
furcation area . But in permanent teeth furcation present
toward apex, so infection occours in root apex .
 DENTIN :-as dentin is more dense in permanent tooth, its
difficult to cut during cavity preparation .