Deciduous teeth

Deciduous teeth , dental anatomy , pediatric dentistry , free dental slide show , free dental books

1. Description of The Deciduous Dentition DR : Abdelrhman Alaa Nosair

2. The Deciduous Teeth Primary , milky, baby, temporary teeth 20 in number Small in size

3. Common nicknames for them are : “ primary teeth ” “ milk teeth, ” “ baby teeth, ” “ temporary teeth, ” all of which, unfortunately, denote a lack of importance.

4. The deciduous teeth are actually in the mouth functioning for from about 6 months (mandibular central incisor) to 11-12 years (maxillary canine) so the life span for them is from 6months........11-12 years They play a very important role during the childhood in the proper alignment, spacing, and occlusion of the permanent dentition. When deciduous teeth are lost prematurely , this can cause destructive results and should be avoided by use space maintainer.

5. IMPORTANT FUNCTIONS OF SOUND DECIDUOUS TEETH *Efficient mastication of food. *Maintenance of a normal facial appearance . *Formulation of clear speech . *Maintenance of space for the emergence of permanent teeth.

6. PRIMARY DENTITION PERMANENT DENTITION

7. Deciduous Set of Teeth.: 2 incisors, 1 canine, 2 molars in each quad. Permanent Set of Teeth.: 2 incisors, 1 canine, 2 premolars, 3 molars in each quad.

8. ERUPTION From 6 months to 2 years:  pure deciduous dentition From 6y to 12 y:  mixed dentition From 12 y onwards :  pure permanent dentition

9. Differences between Deciduous & Permanent teeth 1-Number: Deciduous: 20 Permanent: 32

10. 2-Size: Deciduous: Smaller Permanent : Larger

11. 4- Shape: Deciduous: Cusps are pointed, crowns bulbous, Permanent: Cusps are blunt, crowns not bulbous,

12. 5- Color: Deciduous: Whiter, Permanent: bluish white to yellowish white 6- Cervical ridge: Deciduous: prominent ( in upper & lower first molars Ds Mesiobuccal cervical ridge is prominent) Enamel ends abruptly. Permanent: Less prominent Enamel ends gradually .

13. 7- Occlusal area: Deciduous: BL narrower as B & L surfaces are converging Permanent: BL wider as B & L are not converging

14. 8- Roots: Deciduous: more slender Longer compared to crown length close to crown  short or no root trunk widely divergent to allow space for the developing permanent successors . Permanent Longer & stronger Longer root trunk Less divergent roots

15. The deciduous teeth have shorter crowns with respect to their roots. **The crown root ratio is 1/1.5 in permenant teeth **The crown root ratio is 1/2 in deciduous teeth

16. The crown root ratio is 1/2

17. 9-Pulp cavity: Deciduous: Enamel is thinner Dentin is thinner Pulp cavity  larger Pulp horns  high in cusp region Permanent: Enamel is thick Dentin is thick Pulp cavity  smaller Pulp horns  lower in cusp region

18. 10-Eruption & shedding: Deciduous: Eruption starts at 6m. Are physiologically Shed Their roots begin to resorbe at about 4 years Permanent: Eruption at 6 years Not shed physiologically If lost  pathologically

19. CHRONOLOGY OF THE HUMAN DECIDUOUS TEETH Shedding Beginning of root resorption Root completed Eruption Beginning of calcific- ation Enamel organ appearance Tooth 7 y. 7 y. 4 y. 4 y. 1.5 y. 1.5 y. 7 m. 6 m. 4 m.i.u. 7 w.i.u. A A 8 y. 8 y. 5 y. 5 y. 2 y. 1.5 y. 8 m. 7 m. 4.5 m.i.u. 7 w.i.u. B B 11 y. 9 y. 8 y. 8 y. 3 y. 3 y. 18 m. 16 m. 5 m.i.u. 8 w.i.u. C C 10 y. 9 y. 6 y. 6 y. 2.5 y. 2.5 y. 14 m. 12 m. 5 m.i.u. 8 w.i.u. D D 10 y. 10 y. 7 y. 7 y. 3 y. 3 y. 24 m. 20 m. 6 m.i.u. 9 w.i.u. E E

20. Beginning of root res. Root completed (Y) Eruption (m.) Beg. Of calc. (m.i.u) A A B B C C D D E E 4 5 4.5 6 7 6 7 8 24 14 12 16 18 20 1.5 3 2.5 3 - 3 years before shedding

21. E 6

22. E 6

23. The deciduous mandibular second molar is larger than the first one, but it is smaller than the permanent mandibular first molar . It resembles the permanent mandibular first molar *The number of cusps (five cusps), the number of roots (two roots)is the same. *All the elevations and depressions that are present in the permanent mandibular first molar are present in this tooth.

24. The general differences between the deciduous and permanent teeth that were mentioned before (e.g. size, colour, bulbous crown, prominent cervical ridge, thin and divergent roots, and absence of root trunk) **However, there are many differences that enable us to differentiate between these two teeth such as: 1-The three cusps on the buccal surface of the deciduous first molar are of nearly equal size 2-The three buccal cusps are named ; MB, B and DB cusps. (Compare with cusps of the permanent first mandibular molar MB,DB,D cusps). 3-The geometric outline of occlusal……… is Rectangular (in permanent first molar it is hexagonal)

25. Occlusal Aspect of lower E