¾ between deciiduous permanent dent i t i on · pdf file1 occur? ¾teeth exert p...

1

How Does Shedding Occur?

¾The permanent teeth exert pressure against

Deciduous Teeth

p gthe deciduous rootscausing their resorption Anterior Teeth

¾ Shedding (root resorption)takes about 3-4 years

Posterior Teeth

Retained Deciduous tooth

Differences Between id & i iDeciduous & Permanent Dentition

¾ Anatomical

¾Histological ¾Histological

Differences Between Deciduous & Permanent Dentition

1. Number2. Size 3. Color4. Development5. Calcification6. Root Resorption7. Hardness8. Morphologic Differences

1. Number1. Number2. Size 3. Color4. Development5. Calcification6. Root Resorption7. Hardness8. Morphologic Differences

20 Deciduous TeethPredecessors

Permanent Teeth32 successors

Non-successors20

12

2

¾ The crowns are smaller

2. Size1. Number2. Size3. Color4. Development5. Calcification6. Root Resorption7. Hardness8. Morphologic Differences

¾ The roots are shorter

¾Whiter in color

3. Color1. Number2. Size 3. Color4. Development5. Calcification6. Root Resorption7. Morphologic Differences

¾ Less whiter

Deciduous Teeth

Permanent Teeth

¾ Shorter time for crown development

4. Development of Teeth


p( Deciduous incisor 4 M.I.U 4 M.)

( Permanent incisor 4 M. 4-5 Y.)

¾ Shorter time for complete

Crown completed

Evidence of calcification

Deciduous Dentition

4 M4 M.I.U. Central incisors

5¾ Shorter time for completeroot formation

( Deciduous incisor (1-1.5 Y.) ( Permanent incisor ( 2-3 Y.)

5 M4.5 M.I.U

Lateral incisors

9 M5 M.I.U Canines

6 M5 M.I.U. First molars

10-12 M6 M.I.U Second molars

9 Prenatal systemic disturbancesAffect calcification of primary teeth

5. Calcification


9 Postnatal systemic disturbances

Affect calcification of primary teeth

yAffect calcification of permanent teeth

3

from the pressureDue to permanent successors


6. Root Resorption

7. Hardness

Less harder than permanent teeth

8. Morphologic Differences

Anterior Teeth


a. Wider mesiodistally in comparison to their length

b. Prominent cervical ridge

Crowns

a. Narrowb. Labial inclination (upright position)c. Twice length of crown ( C1: R 2 )

Roots

Posterior TeethDeciduous Teeth

a. Prominent buccal ridgeb. Constricted tooth neckc. Narrower occlusal surface buccolingually

Crowns

a. Slender, long & flatb. Flarying out apicallyc. Very short trunks or absent

Roots

lEnamel

• Enamel• Dentin

• Pulp

Histological Differences betweenDeciduous and Permanent Teeth

Deciduous Molar

Enamel

DentinThin

Dentinlimited thickness and less hardness

Enamel-dentin junctionRelatively smooth

Enamel

Dentin

Permanent Molar

4

Large size of the pulp and prominent pulp horns

Permanent Molar

Deciduous Molar

Deciduous Teeth

Morphology of TeethMorphology of TeethMorphology of TeethMorphology of Teeth

M h ll i i

It resembles the permanent maxillary central incisor EXPECT:

DeciduousMaxillary Central Incisor

¾ Much smaller in size

¾ The crown mesiodistally is greater than cervicoincisally

¾ The labial surface is smooth without developmental lineswithout developmental lines

¾ The lingual surface shows less developed marginal ridge and cingulum

It resembles the permanent maxillary lateral incisor EXCEPT:

Deciduous Maxillary Iateral Incisor

Deciduous Teeth

¾ Smaller than permanent lateral

¾ The crown length cervicoincisally is greater than its mesiodistal width

¾ The distoincisal angle is more rounded

5

Deciduous Maxillary Canine

It is similar to the permanent maxillary canine EXCEPT:

Deciduous Teeth

¾ Smaller in size

¾ More constricted at the cervix

¾ MCA & DCA at the center of the middle thirdmiddle third

¾ Longer and sharper cusp

¾ Root length twice crown length

Deciduous Mandibular Canine

It is similar to the permanent:EXCEPTmandibular canine

Deciduous Teeth

¾ Smaller in size

¾ More pointed cusp tip

¾ Developmental depression along the labial surface of the root

Deciduous MaxillaryFirst & Second molar

Deciduous Teeth

¾ It is much wider PR

¾ Four cusps and three roots

Deciduous Maxillary First Molar

mesiodistally at the contact areas than at the cervix

¾ The occlusal line is scalloped with no definite cusp

MBRDBR

PR

¾ The buccal surface is smooth

¾ The roots are long and slender with short root trunk Buccal Aspect

6

¾ The crown converges in a lingual direction

DeciduousMaxillary First molar

DBR¾MLC is the longest and sharpest of all cusps¾DLC cusp is poorly develop and sometimes absent

¾ All three roots are seen from

PR

MBR

DBR

¾ All three roots are seen from this aspect and the palatal root is larger than the others

MLC DLC

Lingual Aspect

¾ Prominent cervical ridge

h d


¾The crown is wider buccolingually at the cervical ridge than at the occlusal third

MBR LR

¾The LR appears slender and extends lingually to a marked degree Mesial Aspect

¾ Rectangular with shortest sides represented by the marginal ridges

¾ Four cusps and two fosse; central and mesial triangular


¾ Oblique ridge connecting the MLC with DBC

¾ Central developmental groove¾ Buccal developmental groove

Th d l t l MLC

DBCMBC

DLC

¾Three developmental grooves radiating from the mesial triangle fossa; one buccally, one lingually and one toward the marginal ridge

Occlusal Aspect

Occlusal Aspect

MBCBDG

DBC

MBC

CDG

MTFCF

BDG

MLCDLC

7

¾ Five cusps and three rootsMBR

DBR

DR

¾ It is similar to the permanentmaxillary first molar EXCEPT:

Deciduous Maxillary Second Molar

¾The crown is more constricted at the cervix


¾ The rootsDBC MBC

maxillary first molar EXCEPT:

¾ Root Trunk is short and sometimes absent

More slender and twice the length of the crown and greatly flare out

MLCDLC

V

d d b lDeciduous Mandibular First molar & Second molar

¾ Mesial outline is straight

¾ Four cusps and two roots

Deciduous Mandibular First Molar

¾ Cervical line dipping apically where it joins with the mesial root

DCA

¾ Distal outline is marked convex making the DCA extends distally to a great degree

Mesial

¾ Roots long, slender and flaring greatly

¾ Short root trunk

Buccal Aspect

MRDR

¾The crown and root

DeciduousMandibular First MolarLingual Aspect

converge lingually MLC DLC

¾ MLC is long & sharp¾ DLC is rounded and well develop

8

¾ The crown is roughly h b id l

MBCMLC

DeciduousMandibular First MolarMesial Aspect

rhomboidal


¾ MBC & MLC connected by developed MMR

MR

by developed MMR

¾ Mesial rootParallel outlines with long developmental depression along the full length of the root

Mesial Aspect

MBCMLC

DeciduousMandibular First Molar

The prominent cervical ridge is observed from this aspect

Occlusal AspectDeciduous

Mandibular First Molar

¾ Four cusps , MLC is the largest cusp

¾ Central fossa and mesial

CR

¾ Central fossa and mesial triangle fossa with CDG extends between them

¾ It has five cusps and two roots¾ It is similar to the permanent

Deciduous Mandibular Second Molar

¾ Smaller in size

¾ MBC, DBC, DC are almost equal in size

MB DBDC

p:EXCEPTmandibular first molar

¾ The roots are more slender, flaring out

¾ Short root trunk

9

DBC MBCDC

Occlusal AspectDeciduous

Mandibular second molar

CF

CDG

MBTRDBTR

MLTRDLTR

DTR

MTFDTF

MLCDLC

MLTR

3 years oldOcclusal Dental formula

A B C D EA B C D E

A B B C C D D E EA M1/3 D 2/3 MS DS M 1/3 D 2/3 1/5 4/5

Deciduous Teeth

Occlusion of Deciduous Teeth

Occlusal Dental formula

A M1/3

D2/3 MSDS M1/3

D2/3 1/5 4/5

5 years old

Deciduous Teeth

Occlusion of Deciduous Teeth

¾ between deciiduous permanent dent i t i on · pdf file1 occur? ¾teeth exert p...

Documents