The main difference between deciduous and permanent teeth is that deciduous teeth are the temporary teeth that develop at birth and fall off at the age of 5 -6 years, while permanent teeth develop at the age of 5-6 years and remain permanent throughout life

Three periods of dentition, since the deciduous and permanent dentitions overlap in time. These periods are summarized in the following manner:

1. Primary dentition period

2. Mixed dentition period

3. Permanent dentition Period

	Deciduous teeth	Permanent teeth
Eruption	about six months to two years of age
No of teeth	20 2 incisor, 1canine 2 molars	32 2 incisor, 1canine 2 premolars,3 molars

Eruption pattern

DECIDUOUS TOOTH

Upper Teeth	When tooth emerges	When tooth falls out
Central incisor	8 to 12 months	6 to 7 years
Lateral incisor	9 to 13 months	7 to 8 years
Canine (cuspid)	16 to 22 months	10 to 12 years
First molar	13 to 19 months	9 to 11 years
Second molar	25 to 33 months	10 to 12 years

 

Lower Teeth	When tooth emerges	When tooth falls out
Central incisor	8 to 10 months	6 to 7 years
Lateral incisor	10 to 16 months	7 to 8 years
Canine (cuspid)	17 to 23 months	9 to 12 years
First molar	14 to 18 months	9 to 11 years
Second molar	23 to 31 months	10 to 12 years

PERMANENT TOOTH

Upper Teeth and when tooth emerges

Central incisor	7 to 8 years
Lateral incisor	8 to 9 years
Canine (cuspid)	11 to 12 years
First premolar (first bicuspid)	10 to 11 years
Second premolar (second bicuspid)	10 to 12 years
First molar	6 to 7 years
Second molar	12 to 13 years
Third molar	17 to 21 years

Lower Teeth and when tooth emerges

Central incisor	6 to 7 years
Lateral incisor	7 to 8 years
Canine (cuspid)	9 to 10 years
First premolar (first bicuspid)	10 to 12 years
Second premolar (second bicuspid)	11 to 12 years
First molar	6 to 7 years
Second molar	11 to 13 years
Third molar (wisdom tooth)	17 to 21 years

On the basis of morphological changes

Deciduous teeth	Permanent teeth
Teeth Crown: - Shorter	Bigger
Narrow Occlusal table	Broad Occlusal table
Constricted in cervical portion	Cervical constriction is not well marked.
Thinner enamel and dentin layers	Thick enamel and dentin layer
Enamel rods in the cervical area directed Occlusally	Enamel rod in the cervical area directed Gingivally
Broad and flat contacts	Point contacts
Color is usually lighter	Color is much darker.

 

Mesio-buccal cervical bulge seen in primary molars	Less prominent cervical bulge seen in permanent molars
Incisors have no developmental grooves or mammelons	Incisors have developmental grooves or mamelons on newly erupted teeth
Wide apical foramen	Constricted apical foramen
Mesiodistal diameter of crown is more then cervico incisal length	Cervico incisal length is more then the mesiodistal dimensio
Edge to edge tooh relation	Intercuspation relation
Develops directly from dental lamina	Develops as lingual or distal extension of dental lamina.
Neonatal lines are seen.	Neonatal lines is not seen in Permanent teeth except in Permanent 1st molars
Dentin is less mineralised	Dentin is more mineralised

 

More prone to acid attack and decay	Less prone to acid attack
Lamina dura relatively thick	Relatively thin

Pulp

Pulp Chamber Larger	Pulp Chamber smaller
Root Canals More Ribbon like (hour glass appearance)	Well defined with less branching
pulp horn are more prominent	Less prominant
Cellularity and Vascularity High degree	Less degree
Accessory Canals Present	May be Absent

On the basis of root features

Shape Larger, more Slender and Diverge widely	Shorter, Bulbous and non-divergent
Root trunk smaller	larger
Physiologic resorption	absent

Histologic Differences

Enlarged apical foramens. The abundant blood supply	Restricted, Reduced blood supply
Reparative dentin more	less
Density of innervation more	less
Localization of infection poor	better