The document presents a comprehensive overview of the differences between primary (deciduous) and permanent dentition, highlighting aspects such as eruption times, crown morphology, clinical significance, and anatomical variations. It discusses the characteristics of teeth, including enamel and dentin properties, pulp anatomy, and root structures, emphasizing their significance in dental procedures. Additionally, the conclusion underscores the importance of understanding these differences for effective dental treatment.

1. Department of Pedodontics
By: Akshdeep singh
Roll no: 07
Submitted To:
Dr. Virinder Goyal, Prof. & HOD
Dr. Kanika Gupta Verma, Prof.
Dr. Suruchi Juneja Sukhija, Reader
Dr. Sakshi Bamba, Sr. Lecturer

3. Introduction
 Humans possess 2 type of dentition:
 Deciduous dentition
No of tooth: 20
Eruption time: 8-29 months
Eruption Sequence: AB DC E
A B D CE
 Permanent dentition
No of tooth: 32
Eruption time: 6-21 years
 Eruption Sequence:
Maxillary teeth:6 1 2 4 3 5 7 or 6 1 2 4 5 3 7
Mandibular teeth: 6 1 2 3 4 5 7

4. Crown
Primary Permanent
 Shorter
 Constricted in cervical
portion i.e. are narrower at
their necks.
 Cervical ridges on buccal
aspect are more prominent
 Bigger
 Cervical constriction is not
well marked
 Cervical ridges on permanent
crowns are flatter

5. Primary Permanent
 Primary teeth are lighter in
color. They appear bluish-
white (milky white) and are
also called as milk teeth.
 Crowns are wider
mesiodistally in comparison
to their crown height
 This gives a cup-shaped
appearance to anterior teeth
and “squat” shaped
appearance to deciduous
molars
 Permanent teeth are darker in
color. They appear yellowish,
white or grayish, white
 The crowns teeth appear
longer as their cervicoincisal
height is greater than
mesiodistal width
 This gives a square shaped
appearance to anterior and
trapezoidal to permanent
molars.

7. Clinical Significance
 As deciduous dentition is lighter in colour when
compared to permanent dentition. Thus while
restoring primary teeth lighter shades are used.

8. Incisors
Primary Permanent
 Primary incisors do not
exhibit mamelones.
 They are noticeably wider
mesio-distally than they are
long cervico-incisally.
 Newly erupted permanent
incisors exhibit mamelons.
 They are longer cervico-
incisally than they are wider
mesio-distally.

9. mamelones

10. Canines
Primary Permanent
 Primary canines tend to be
more conical in shape and
cusp tip is more pointed and
sharp
 Permanent canines are less
conical i.e. their cusps tips are
less pointed

11. Premolars
Primary Permanent
 No premolars in deciduous
dentition.
 There are two premolars in
each quadrant

12. Molars
Primary Permanent
 There are only 2 molars in each
quadrant.
 Crown of 2nd molar is larger than
the crown of 1st molar.
 Molars are more bulbous, bell-
shaped and with marked
cervical constriction.
 Buccal and lingual surfaces of
molars, especially that of 1st
molars converge sharply
occlusally, thus forming narrow
occlusal table in buccolingual
dimension
 There are 3 molars in each
quadrant.
 1st molar is larger than 2nd
and 3rd molars.
 Permanent molars have less
constriction of neck
 There is less convergence of
buccal and lingual surfaces of
molars towards occlusal
surface. Thus have broader
occlusal table

13. (A) Prominent cervical ridge;
(B) Flatter cervical ridge
(A)Primary molars have
narrow occlusal table
(B) Permanent molars
have wider occlusal
table

14. Clinical Significance
 Cervical ridges are more pronounced especially on
buccal aspect of 1st primary molars.
 These cervical bulges have to be reproduced during
restoration/ crown prosthesis.
 Sharp cervical constriction has to be kept in mind and
special care should be taken while forming gingival
floor during class II cavity preparation.
 During class II cavity preparation for amalgam buccal
and lingual extensions/walls of class II cavity should
be located in selfcleansing areas.

15.  Occlusal plane is
relatively flat.
 Supplemental grooves
are more
 Contact areas between
molars are broader,
flatter and situated
gingivally.
 Occlusal plane have
more curved contour
 Supplemental grooves
are less
 Contact areas between
molars are narrower and
situated occlusally

16. More supplementary grooves in
primary molar
Less supplementary grooves in
permanent molar

17. Clinical Significance
 Deciduous molars are functionally adapted to
withstand less occlusal load.
 Occlusal cavity preparations should be kept narrow in
buccolingual plane.
 Primary molars are more caries prone due to easy food
lodgment because of more supplementary grooves . Pit
and fissure sealants are advisable to prevent caries

18.  Maxillary 1st molar has 3
cusps (resembles a
premolar)
 Maxillary 2nd molar has 4
cusps + one accessory
cusp (resembles
permanent upper 1st
molar)
 Maxillary 1st molar has 4
cusps + 1 accessory cusp.
 Maxillary 2nd molar has 4
cusps

19. Maxillary deciduous
1st molar
Maxillary
deciduous 2ndmolar
Permanent
maxillary 1st molar Permanent
maxillary 2ndmolar

20. Primary Permanent
 Mandibular 1st molar has 4
cusps (does not resemble any
permanent tooth)
 Mandibular 2nd molar has 5
cusps (resembles permanent
lower 1st molar)
 Mandibular 1st molar has 5
cusps
 Mandibular 2nd molar has 4
cups.

21. Mandibular
deciduous 1st molar
Mandibular
deciduous 2nd molar
Permanent
mandibular 1st molar
Permanent mandibular
2nd molar

22. Enamel
Primary Permanent
 Enamel is thinner and is
about 1 mm thick but of
uniform thickness
 Enamel rods at the cervical
third of primary crowns are
directed occlusally instead of
gingivally as seen in
permanent teeth
 Enamel is 2–3 mm thick and
is not uniform in thickness.
 Enamel rods at the cervix are
directed apically

23. Enamel rods are directed occlusally at
the cervical 3rd
Enamel rods at cervical 3rd directed
apically

24. 1. Less enamel thickness
2. Less dentin thickness
3. Higher pulp horns

25. Clinical Significance
 Less pressure/force is required during cavity
preparation of primary teeth. Depth of the cavity
preparation is less.
 Etching time in primary teeth is prolonged to 90–120
seconds whereas Usual etching time for permanent
teeth is 30 seconds due to difference between their
mineralisation.

26. Dentin
Primary Permanent
 Dentin thickness is half that
of permanent teeth.
 Dentinal tubules are less
regular.
 Greater thickness of dentin
over pulpal roof.
 Dentinal tubules are more
regular.

28. Less regular dentinal tubules in
deciduous dentition
More regular dentinal tubules in
permanent dentition

29. Clinical Significance
 Depth of occlusal cavity preparation in primary molars
should be kept shallow (There is less thickness of
protective dentin over pulp).

30. Histological features
Primary Permanent
 Incremental lines of Retzius
are less common in enamel.
 Primary enamel is less
mineralized and more
organic content is present.
 Interglobular dentin is
absent.
 Lines of Retzius are more
common in enamel.
 Enamel is highly mineralized.
 Interglobular dentin is
present beneath the
wellcalcified mantle layer of
dentin.

31. Common for both enamel and
dentin
Primary Permanent
 Both enamel and dentin are
less mineralized and less
dense.
 Neonatal lines are present in
all primary teeth both in
enamel and dentin.
 Enamel and dentin are more
mineralized.
 Neonatal lines are seen only
in 1st molar (since
mineralization begins at
birth)

32. Clinical Significance
 This difference can be easily appreciated clinically by
the resistance offered during cavity cutting.

33. Pulp
Primary Permanent
 Pulp chambers are
proportionately larger when
compared to crown size
 Pulpal outline follows DEJ
more closely
 Pulp horns are higher and
closer to outer surface
 Root canals are more ribbon-
like, follows a thin, tortuous
and branching path.
 Pulp chamber is smaller in
relation to crown size
 Pulp outline follows DEJ less
closely
 Pulp horns are comparatively
lower and away from outer
surface
 Root canals of permanent
teeth are well-defined and
less branching

34. Pulp chamber size is smaller in permanent
teeth when compared to deciduous teeth

35. Primary Permanent
 Floor of the pulp chamber is
more porous. Accessory
canals in pulp chambers
directly lead to inter-
radicular furcation areas
 Floor of the pulp chamber do
not have many accessory
canals. Accessory canal are
present in apical third area.

36. Primary Permanent
 Apical portion of the canal is
less constricted and apical
foramen is wider.
 Thus primary teeth have
abundant blood supply and
exhibit a more typical
inflammatory response.
Thus, poor localization of
infection and inflammation.
 Apical portion of the canal is
constricted and apical
foramen is smaller/narrower.
 Reduced blood supply follows
healing by calcific scarring.
Thus, infection and
inflammation are
comparatively well-localized.

37. Primary Permanent
 Primary pulp is less densely
innervated. Nerve fibers
terminate near odontoblastic
zone as free nerve endings.
 Permanent pulp is densely
innervated. Nerve fibers
terminate among
odontoblasts and even pass
beyond predentin.

38. Clinical Significance
 Depth of cavity preparation in primary teeth should be
kept shallow as pulp horns are near DEJ. Care should
be taken not to expose the pulp.
 Multiple ramification of primary pulp make complete
debridement (almost) impossible.
 Inflammation/infection from pulp can easily reach
periodontium and vice versa in case of primary molars.
 Enamel of underlying permanent successor teeth may
become hypoplastic due to spread of inflammation.
This can result in ‘turner’s hypoplasia’ of permanent
tooth.

39.  Primary pulp is less densely innervated, thus primary
teeth are less sensitive to operating procedure
compared to permanent teeth.

40. Cementum
Primary Permanent
 In primary teeth the
cementum is thin and made-
up of only primary cementum
 Cementum is thick. Both
primary and secondary
cementum present.

41. Clinical Significance
 As cementum is only made of primary cementum in
deciduous dentition anchorage of primary teeth is
comparatively less firm and easily resorbed, and can be
easily extracted as compared to permanent teeth.

42. Root
Primary Permanent
 Primary roots are more
delicate.
 Roots are proportionately
longer and more slender in
comparison to crown size
 Roots are narrower
mesiodistally
 Furcation of molar roots is
placed more cervically thus
root trunk is much smaller.
 Permanent roots are stronger
and provide good anchorage
in jaw bone.
 They are shorter and bulkier
in comparison to their crown
 Roots are broader
mesiodistally
 Furcation in molars is placed
more apically and thus root
trunk is larger

43. Primary Permanent
 Roots of primary molars flare
out markedly from cervical
area to their tips.
 Primary roots undergo
physiologic resorption and
the primary teeth are shed
naturally.
 Marked flaring of roots is
absent.
 Physiologic resorption is
absent.

44. Marked flaring of roots in primary teeth

45. Clinical Significance
 Roots of primary molars are flared out to
accommodate permanent tooth buds between their
roots

46. Peridontium
Primary Permanent
 Primary teeth are less firmly
attached and easily resorbed,
and can be easily extracted
 Primary teeth have abundant
blood supply and exhibit a
more typical inflammatory
response. Thus, poor
localization of infection and
inflammation.
 Permanent teeth are firmly
anchored in alveolar bone
and are not easily resorbed.
 Reduced blood supply
follows healing by calcific
scarring. Thus, infection and
inflammation are
comparatively well-localized.

47. Conclusion
 Both primary and permanent dentition are unique in
their anatomy, histology and physiological function
and their pattern of eruption.
 Due to uniqueness in their anatomy, while doing any
procedure anatomic differences should be taken care
of.

48. Reference
 Textbook Of Dental Anatomy, Physiology And
Occlusion; Rashmi G S (Phulari)
 Wheeler’s Dental Anatomy, Physiology And
Occlusion; Stanley J. Nelson
 Finn Clinical Pedodontics; Sidney B. Finn