4DIFFERENCES OF THE CROWN Primary TeethPermanent TeethLighter 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 to5-6 yearsDuration: 6 years onwardsNumber: 20Number: 32Smaller in dimensionLarger in dimension
5DIFFERENCES OF THE CROWN Crowns are wider mesiodistally.Crowns are wider cervico incisallyCervical ridges are prominent especially on buccal aspectCervical ridges are less prominentNarrow occlusal tablesLess convergence of buccal and lingual surfacesSharp cervical constrictionLess constriction of the neck
6DIFFERENCES OF THE CROWN Enamel 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 DEJEnamel rods are oriented gingivallySupplemental grooves are moreSupplemental grooves are less
7DIFFERENCES OF THE CROWN Mammelons absentMammelons are present on newly erupted teethFirst molar is smaller in dimension than second molarFirst molar is larger in dimension than second molar
9DIFFERENCES OF THE ROOT The roots are larger and slender compared to crown sizeRoots are more bulbous and shorter in comparison to crownRoot trunk is smallerRoot trunk is largerRoots flare outward to accommodate permanent teethMarked flaring is absentPhysiologic resorption during sheddingPhysiologic resorption is absent
10DIFFERENCES IN THE PULP Pulp chamber is larger in relation to crown sizePulp chamber is smaller in relation to crown sizePulp horns are more prominent and are closer to the outer surfacePulp horns are comparatively away from the outer surfaceHigh degree of cellularity and vascularity in tissueComparatively less degree of cellularity and vascularity
11DIFFERENCES IN THE PULP High potential for repairLess potential for repairGreater thickness of dentin over the pulpal wall at the occlusal fossa of molarsComparitively lesser dentin on the occlusal surfaceRoot 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 numberFloor of pulp chamber does not have any accessory canals.
12HISTOLOGICAL DIFFERENCES Enlarged apical foramen Abundant blood supply demonstrates typical inflammatory responseForamens are restricted Reduced blood supply favours calcific responseReparative dentin formation is more extensive and irregularReparative dentin formation is lessDensity of innervation is less of which primary teeth are less sensitiveDensity of innervation is moreLocalisation of infection and inflammation is poorer in pulpInflammation and infection in pulp is localised.
13MINERAL CONTENT Enamel and dentin are less mineralized Enamel and dentin are highly mineralizedNeonatal lines are presentNeonatal lines seen only in first molarDentinal tubules are less regularDentinal tubules are more regularDentin is less dense. It cuts more easilyDentin is difficult to cut as it more dense.
14PERIODONTAL DIFFERENCES Cementum is very thin. Secondary cementum is absentThe secondary cementum is presentAlveolar atrophy is rareAlveolar atrophy occursGingivitis is generally absent in healthy childGingivitis is common in adult.