This document compares the anatomical, morphological, histological, and applied aspects of primary and permanent teeth. It outlines key differences between primary and permanent teeth, including their duration, number, enamel thickness, occlusal plane, cusps, roots, pulp chamber, dentin, and periodontal ligament structures. The morphological and histological differences between primary and permanent teeth have important applications in procedures like cavity preparation, extraction, endodontic treatment, and pulp therapy.

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 .