DIFFERENCE BETWEEN DECIDUOUS &

PERMANENT DENTITION

Difference between deciduous & permanent dentition

according to-

Anatomical

Histological

Clinical

DECIDUOUS PERMANENT

i). Total no. of teeth

20 32

ii). Dental formula DI 2 DC 1 DM 2 2 1 2

1 2 C 1 P 2 M 3 2 1 2 3

iii). Chronology of Maxillary Teeth

Eruption (In months)

Eruption (in years)

CI 10 (8-12) 7-8 Years LI 11 (9-13) 8-9 Years C 19 (16-22) 11-12 Years

1st Premolar - 10-11 Years2nd Premolar - 10-12 Years

1st Molar 16 (13-19) Boys

16 ( 14-19) Girls 6-7 Years

2nd Molar 29 ( 24-33) 12-13 Years 3rd Molar - 17-21 years

DECIDUOUS PERMANENT Chronology of Mandibular Teeth

Eruption (In months)

Eruption (in years)

CI 8 (6-10) 6-7 Years

LI 13 (10-16) 7-8 Years

C 20 (17-23) 9-10

1st Premolar - 10-12 Years

2nd Premolar - 11-12 Years

1st Molar 16 (14-18) 6-7 Year

2nd Molar 27(23-31) Boys27 ( 24-30) Girls

11-13 years

3rd Molar - 17-21 Years.

Anatomical Difference between deciduous and permanent dentition

DECIDUOUS PERMANENT

Size Smaller Larger

Colour White in Colour (Because Less

Mineralized enamel So it is more opaque

and whiter

Less Whiter ( Because Highly

Mineralized enamel so it is yellowish)

Crown-root Ratio

Crown Shorter than root

Not so.

Cervical constriction

Present Absent

Enamel Thickness

Thinner Thicker

Mineralization Very Quickly attrited because they are less

mineralize

Less attrited because they are highly

mineralize

DECIDUOUS PERMANENT

Crown Dimension

Longer Mesiodistally than incisocervically

Longer Incisocervically than

mesiodistally

Developmental lines

Labial Surface of incisors are smooth

they don’t show any depression and

developmental lines

Labial Surface of incisors smooth and convex with to faint vertical development

lines & grooves

Cingulum More prominent Less Prominent

Mamelons Absent Incisal ridge consist of three prominent

mamelons

Anatomical Difference between anterior crowns of Deciduous & Permanent Dentition

DECIDUOUS PERMANENT Length of the

maxillary teeth Crown height Crown Height

CI 6.0mm 10.5mm

LI5.6mm 9.00mm

C6.5mm 10.00mm

1st Premolar -- 8.5mm

2nd Premolar -- 8.5mm

1st Molar 5.1mm 7.5mm

2nd Molar 5.7 7mm

3rd Molar -- 6.5mm

Length of the mandibular

teeth Crown height Crown Height

CI 5mm 9mm

LI5.2 mm 9.5mm

C6mm 11mm

1st Premolar -- 8.5mm

2nd Premolar -- 8m

1st Molar 6mm 7.5mm

2nd Molar 5.5mm 7mm

3rd Molar -- 7mm

Anatomical Difference between Posterior crowns of Deciduous & Permanent

Dentition

DECIDUOUS PERMANENT Cervical Bulge

Buccal & lingual surface are flatter about the cervical

bulge

More convex

Chewing Surface

Narrow Broad

Occlusal Surface

- Cusps are short - Ridges are not pronounced - Fossae are not deep

-Cusps are large & Sharp - Ridges are more Pronounced - Fossae are more deep

Mesial cervical ridge

Prominent Not Prominent

DECIDUOUS PERMANENT

Contact Areas

Broader, flatter & situated more gingivally

Narrower convex and situated more

occlusally

Size of Molars

2nd Molar Larger than 1st Molar

2nd Molar Smaller than 1st Molar

Anatomical Difference between Roots of Deciduous & Permanent Dentition

DECIDUOUS PERMANENT

Root Formation

Root fully form about one year after

eruption

Take a longer duration of about 3

years

Root Resorption

Physiological Pathological

Anterior Root

-Narrower mesioditaslly & longer compare to crown size

-Wider mesiodistally

- Roots bend labially in their apical third to ½ by 100

Roots bend distally

DECIDUOUS PERMANENT

Posterior Root

- Longer & Slendar

- Roots are more flare to 1st molar

- Shorter Root

- Roots are less flared

Histological Difference betweenDeciduous & Permanent Dentition

DECIDUOUS PERMANENT Mineralization Less More

Enamel Thickness

Thinner Thicker

Surface Shape More Closely to the pulp chamber

Not So.

Pulp Size Larger Shorter

Pulp Horn Extends Closer to the Outer surface of

the Cusp

Not So.

DECIDUOUS PERMANENT Thickness of

Pulp Protective Dentin

Less More

Number of Accessory

Canal

Increased Normal

Porosity Present Absent

Root Canal Ribbon Like & Multiple Pulp Filaments with more numerous

accessary canals

Not So.

DECIDUOUS PERMANENT

Reticular & Collagenous

Fibers

Present as a cap like zones

Not So

Apical foramen opening

Wider Narrower

Blood Supply

More Reduced ( Because of more

calcified nodules & ground substance

present )

Clinical Difference betweenDeciduous & Permanent Dentition

DECIDUOUS PERMANENT

Sensitivity to Pain

Less More

Response to

Infection & Inflammation

Typical Less

Localization of Infection

& Inflammation

Poor Better