DIFFERNCES BETWEEN DECIDUOUS AND PERMANENT TEETH
DIFFERENCES OF THE CROWNPrimary Teeth Permanent Teeth
Lighter in colour, bluish white/ milk teeth (R.I. is same as milk i.e. 1)
Darker in colour, grayish or yellowish white.
Duration: 6 months to
5-6 years
Duration: 6 years onwards
Number: 20 Number: 32
Smaller in dimension Larger in dimension
DIFFERENCES OF THE CROWN
Crowns are wider mesiodistally.
Crowns are wider cervico incisally
Cervical ridges are prominent especially on buccal aspect
Cervical ridges are less prominent
Narrow occlusal tables Less convergence of buccal and lingual surfaces
Sharp cervical constriction Less constriction of the neck
DIFFERENCES OF THE CROWNEnamel is thinner and uniformly thick(1mm).
Enamel is about 2-3 mm thick.
Contact areas are broader and flatter and gingival.
Contact points are more occlusally situated.
Enamel rods at the cervical slopes occlusally from DEJ
Enamel rods are oriented gingivally
Supplemental grooves are more
Supplemental grooves are less
DIFFERENCES OF THE CROWN
Mammelons absent Mammelons are present on newly erupted teeth
First molar is smaller in dimension than second molar
First molar is larger in dimension than second molar
DIFFERENCES OF THE ROOT AND PULP
DIFFERENCES OF THE ROOT
The roots are larger and slender compared to crown size
Roots are more bulbous and shorter in comparison to crown
Root trunk is smaller Root trunk is larger
Roots flare outward to accommodate permanent teeth
Marked flaring is absent
Physiologic resorption during shedding
Physiologic resorption is absent
DIFFERENCES IN THE PULP
Pulp chamber is larger in relation to crown size
Pulp chamber is smaller in relation to crown size
Pulp horns are more prominent and are closer to the outer surface
Pulp horns are comparatively away from the outer surface
High degree of cellularity and vascularity in tissue
Comparatively less degree of cellularity and vascularity
DIFFERENCES IN THE PULP
High potential for repair Less potential for repair
Greater thickness of dentin over the pulpal wall at the occlusal fossa of molars
Comparitively lesser dentin on the occlusal surface
Root canals are ribbon like. Radicular pulp is thin, tortuous and branch.
Root canals are well defined with less branching.
Floor of pulp chamber is porous. Accessory canals are present in good number
Floor of pulp chamber does not have any accessory canals.
HISTOLOGICAL DIFFERENCES
Enlarged apical foramen Abundant blood supply demonstrates typical inflammatory response
Foramens are restricted Reduced blood supply favours calcific response
Reparative dentin formation is more extensive and irregular
Reparative dentin formation is less
Density of innervation is less of which primary teeth are less sensitive
Density of innervation is more
Localisation of infection and inflammation is poorer in pulp
Inflammation and infection in pulp is localised.
MINERAL CONTENT
Enamel and dentin are less mineralized
Enamel and dentin are highly mineralized
Neonatal lines are present Neonatal lines seen only in first molar
Dentinal tubules are less regular
Dentinal tubules are more regular
Dentin is less dense. It cuts more easily
Dentin is difficult to cut as it more dense.
PERIODONTAL DIFFERENCES
Cementum is very thin. Secondary cementum is absent
The secondary cementum is present
Alveolar atrophy is rare Alveolar atrophy occurs
Gingivitis is generally absent in healthy child
Gingivitis is common in adult.
CLINICAL IMPLICATIONS
• Cavity cutting
• Root canal treatment.
Doubts??
