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Similar to Morphological differences between permanent and deciduous teeth.pptx
Morphological differences between permanent and deciduous teeth.pptx
- 1. morphological difference betweendeciduous and permanentteeth. BY: Ahmad Wafiq Mennat Allah Alkaram Under supervision of: Professor Nagwa Khattab
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- 4. 1.Size • Smaller inall dimensions • MD width of primary incisors and canines is less than their permanent successors • The MD width of the primary molars is wider than their successors(premolars) but smaller than their corresponding permanents.
- 5. Thickness of Eand D in primary teeth is half the thickness in permanent teeth. Clinical consideration: The occlusal cavity in primary teeth must be shallower.
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- 7. 2. Color: • Primaryteeth color is bluish white • The color of permanent teeth ranges from grayish white to yellowish white
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- 9. 3.crown • Wider inMD diameter than in OG height • Ant. teeth cup - shaped • Post. Teeth square - shaped
- 10. 3.Crown (cont.) • 2.Primary molars are bulbous due to: • Markedly constricted necks. • Pronounced cervical ridges. • Clinical consideration: • Difficulty in application of the matrix band. • Special care in the placement of the gingival floor in class II cavity preparation.
- 11. 3.Crown (cont.) • Theprimary molars have: • 3. Narrow occlusal table: • (B and L surfaces converge sharply occlusally) • Clinical consideration: • The isthmus portion of a class ǁ amalgam filling is very narrow and liable to fracture
- 12. 3.Crown (cont.) : •4. The buccal and lingual inclines flatter above the cervical bulge. • 5. In primary teeth the contact is large ellipsoid and flattened area (wider proximal box). • 6. Cusp heights are less steep than permanent (more flexible interdigitating).
- 13. 3.Crown (cont.) : •7. The enamel cap in primary teeth is thinner and has a constant depth. • 8. The enamel cap in primary molars ends abruptly at the CEJ (feather-edge in permanent).
- 14. 3.Crown (cont.) : •9. The enamel rods at the cervix slope occlusally in primary teeth instead of gingivally in permanent teeth. • Clinical consideration • There is no need for beveling of gingival floor in class ǁ cavity preparation in primary molars.
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- 16. 4. Roots • Theroots of primary teeth are: • Narrower mesiodistally. • Longer and more slender in comparison to the crown (1:2). • Flare out near the cervix leaving no root trunk.
- 17. 4. Root (cont.) •d. Diverge as they reach the apex to envelop the permanent successor (post.) • Clinical consideration: • Special care in extraction of primary molars with un resorbed root. • e. Curved roots, thin walls • (Difficult mech. Prep. of canals).
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- 19. 5. Pulp • Thepulp outline follows the DEJ more closely in primary than in permanent teeth. • The pulp chambers are proportionally larger than permanent teeth . • The pulp horns are higher in primary molars especially the mesial horn. • Clinical consideration: • Special attention should be taken when establishing the depth of cavities in primary teeth.
- 20. 5. Pulp (cont.) •The root canals of the primary molars show: • D. more lateral branching and apical ramifications. • Clinical consideration: • This makes it impossible to remove all pulp tissue in the root canals during root canal therapy. • • E. The apical foramina in primary teeth are relatively wider than in permanent teeth.
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- 22. 6. Histological Variations •Deciduous Develop directly from the main dental lamina • Permanent Develop from lingual (for permanent successors) or distal extension (for permeant molars) from dental lamina
- 23. • Deciduous Enamel andDentin are less mineralized More prone to acidic attack Easier in cavity preparation • Permanent More Mineralized Less prone More difficult Histological Variations
- 24. POC Deciduous Permanent Cellularity and Vascularity Highdegree Low degree Density of Innervation Less More Localization of Infection Poorer Better
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