Tooth development cap stage

Tooth development stages

1. TOOTH DEVELOPMENT MARWA TARIQ FIRST PROFESSIONAL BDS KHYBER COLLEGE OF DENTISTRY PESHAWAR

2. 3 stages: 1.Bud Stage 2.Cap Stage 3.Bell Stage TOOTH DEVELOPMENT

3. CAP STAGE

4. CAP STAGE Unequal growth in different parts of tooth buds leads to formation of cap stage shallow invagination on deep surface of the bud

5. HISTOLOGY OF CAP STAGE Enamel organ composed of three different types of cells: 1) Inner Enamel Epithelium 2) Outer Enamel Epithelium 3) Stellate Reticulum

6. OUTER ENAMEL EPITHELIUM Covers the convex part of enamel organ. tall columnar cells. Seperated from dental sac by a distinct basement membrane.

7. INNER ENAMEL EPITHELIUM Covers the concave part of enamel organ. These are cuboidal cells. Seperated from dental papillae by a distinct basement membrane

8. STELLATE RETICULUM Polygonal shaped cells located in the center of enamel organ of cap and bell stage

9. Conversion of Polygonal shaped cells into Star shaped cells Mechanism Stellate reticulum GLYCOSAMINOGLYCANS(GAGS ) into intercellular spaces between epithelial cells . GAGs being hydrophilic pulling of water into enamel organ forcing apart of cells results in the change of polyhedral cells into star-shaped cells. Star shaped cells is refered to as stellate reticulum. FUNCTION: 1) Shock absorber 2) Protects enamel forming cells.

10. Conversion of Polygonal shaped cells into Star shaped cells

11. TRANSITORY STRUCTURES OF ENAMEL ORGAN 1) ENAMEL KNOT 2) ENAMEL CORD 3) ENAMEL SEPTUM 3) ENAMEL NAVEL 4) ENAMEL NICHE

12. TRANSITORY STRUCTURES OF ENAMEL ORGAN ENAMEL KNOT Non-dividing ectodermal cells at deepest part of enamel organ which projects into enamel organ. FUNCTIONS Signalling centre Determines shape of tooth

13. TRANSITORY STRUCTURES OF ENAMEL ORGAN ENAMEL CORD Condensation of ectodermal cells in a linear pattern extending from enamel knot to outer enamel epithelium

14. TRANSITORY STRUCTURES OF ENAMEL ORGAN ENAMEL SEPTUM Sometimes enamel cord becomes thick in buccolingual direction forming a septum dividing the enamel organ.

15. TRANSITORY STRUCTURES OF ENAMEL ORGAN ENAMEL NAVEL Small depression seen in the area where enamel cord joins the outer enamel epithelium

16. TRANSITORY STRUCTURES OF ENAMEL ORGAN ENAMEL NICHE: Enamel organ is attached to oral epithelium by two dental laminae;one buccal and one lingual seprated by area filled with mesenchymal tissue referred to as enamel niche.