Primary teeth differ from permanent teeth in several key ways: - Primary teeth are smaller with more prominent cervical ridges, narrower necks, and lighter color compared to permanent teeth. - The crowns of primary teeth are wider than their length while primary roots are narrower and longer. - Primary molar roots are more slender, longer, and flare out more beyond the crowns to allow space for developing permanent teeth. - Primary teeth have thinner enamel, larger pulp chambers and horns, and more pronounced cervical ridges than permanent teeth.

1. DIFFERENCE BETWEEN
PRIMARY AND
PERMANENT TEETH
Dr. Amitha G
Dept of Oral pathology

2. Major Contrasts between Primary and Permanent Teeth
In comparison with their counterparts in the permanent
dentition,
• Primary teeth are smaller in overall size and crown
dimensions.
• They have markedly more prominent cervical ridges
• Narrower at their “necks,”
• Lighter in color
• Have roots that are more widely flared
• Buccolingual diameter of primary molar teeth is less than that
of permanent teeth

3. More specifically, in comparison with permanent teeth, the
following differences are noted:
•
The crowns of primary anterior teeth are wider
mesiodistally in comparison with their crown length than
are the permanent teeth.
• The roots of primary anterior teeth are narrower and
longer comparatively.
• Narrow roots with wide crowns
present an arrangement at the cervical third of crown and
root that differs markedly from that of the permanent anterior
teeth

4. 3. The roots of the primary molars accordingly are longer and
more slender and flare more, extending out beyond projected
outlines of the crowns. This flare allows more room between
the roots for the development of permanent tooth crowns
4. The cervical ridges of enamel of the anterior teeth are more
prominent. These bulges must be considered seriously when
they are involved in any operative procedure
5. The crowns and roots of primary molars at their cervical
portions are more slender mesiodistally.

5. 6. The cervical ridges buccally on the primary molars are
much more pronounced, especially on the maxillary and
mandibular first molars
7. The buccal and lingual surfaces of primary molars are
flatter above the cervical curvatures than those of permanent
molars, which narrows the occlusal surfaces.
8. The primary teeth are usually less pigmented and are
whiter in appearance than the permanent teeth.

6. Pulp Chambers and Pulp Canals
A comparison of sections of primary and permanent teeth
demonstrates the shape and relative size of pulp chambers and
canals which is noted here:
1. Crown widths in all directions are large in comparison with root
trunks and cervices.
2. The enamel is relatively thin and has a consistent depth.
3. The dentin thickness between the pulp chambers and the enamel
is limited, particularly in some areas (lower second primary molar).
4. The pulp horns are high, and the pulp chambers are large
5. Primary roots are narrow and long when compared with crown
width and length

8. Comparison of maxillary, primary, and permanent second molars,
linguobuccal cross section.
1. The enamel cap of primary molars is thinner and has a more
consistent depth.
2. Comparatively greater thickness of dentin is over the pulpal wall at
the occlusal fossa of primary molars.
3. The pulpal horns are higher in primary molars, especially the
mesial horns, and pulp chambers are proportionately larger.
4. The cervical ridges are more pronounced, especially on the buccal
aspect of the first primary molars.

10. 1. The enamel rods at the cervix slope occlusally instead of
gingivally as in the permanent teeth.
2. The primary molars have a markedly constricted neck
compared with the permanent molars.
3. The roots of the primary teeth are longer and more slender in
comparison with crown size than those of the permanent teeth.
4. The roots of the primary molars flare out nearer the cervix than
do those of the permanent teeth.

14. Thankyou
Reference:
Wheelers – Dental Anotomy, Physiology and Occlusion- 9th edition.