Development of the Child from Development of the Child from conception to Three Yearsconception to Three Years

Dental Changes

Development of teeth

Germ layer Formative tissue Tooth structure

Ectoderm Dental organ ENAMEL

Mesoderm

Dental papilla DENTIN

PULP

Dental sac CEMENTUM

PERIODONTAL LIGAMENT

Tooth development Initiation of tooth

Odontogenesis-Factors from first archOdontogenesis-Factors from first arch

Ones ability acquired maintained by Ones ability acquired maintained by dental papillary cells dental papillary cells

6 wks In utero6 wks In utero

• Tooth BudsTooth Buds

• Dental LaminaDental Lamina

Life Cycle of the ToothLife Cycle of the Tooth

• GrowthGrowth• InitiationInitiation• ProliferationProliferation• HistodifferentiationHistodifferentiation• MorphodifferentiationMorphodifferentiation• AppositionApposition

• CalcificationCalcification• EruptionEruption• AttritionAttrition

Primary Epithelial band/ 6Primary Epithelial band/ 6thth week week

Continuous band of thickened epithelium

Roughly horse shoe shapedThickening first seen in ant

midline

Contd thickening of DL in 10 areas of upper/ lower arch

Thickenings correspond to position of future primary dentn

ProliferationProliferation

• Multiplication of the Multiplication of the cells of the initiation cells of the initiation stagestage

• Formation of the tooth Formation of the tooth germ germ

• Cap Stage Cap Stage • formation of the formation of the Dental Dental

PapillaPapilla• Stellate reticulum – Stellate reticulum –

Enamel pulpEnamel pulp• 9-11 weeks9-11 weeks

HistodifferentiationHistodifferentiation

• Bell StageBell Stage

• Dental papilla Dental papilla

• Dental OrganDental Organ

• Dental SacDental Sac

• Dental LaminaDental Lamina

1414thth week week

Morphodifferentiation Morphodifferentiation

• Advanced bell stageAdvanced bell stage..• Inner enamel Inner enamel

epitheliumepithelium• Formation of DentinFormation of Dentin• Fate of the Dental Fate of the Dental

LaminaLamina

1818thth week week

AppositionApposition

• appositional, additive and regular. appositional, additive and regular.

CalcificationCalcification• Begins at the Begins at the

cusp tips or cusp tips or incisal edges incisal edges and proceeds and proceeds cervically cervically

Lines of Retzius Lines of Retzius

Neonatal lineNeonatal line

Stages in tooth growth

Morphologic stage physiologic Morphologic stage physiologic stage stage

Dental lamina and Bud stage Initiation

Cap stage

Bell stage[ Early]

Bell stage {advanced}

Proliferation

Hiisto defferentiation

Morpho defferentitiation

Formation of enamel and dentin matrix

Apposition

Formation of Single and Multirooted Teeth

Formation of multirooted teeth

Eruption of teethEruption of teeth• Pre-eruptive Pre-eruptive

phasephase• Eruptive Phase Eruptive Phase

(Prefunctional)(Prefunctional)• Eruptive phase Eruptive phase

functionalfunctional

Theories of EruptionTheories of Eruption

• Root Formation TheoryRoot Formation Theory

• Proliferation of the Hertwig’s Epithelial Proliferation of the Hertwig’s Epithelial Root SheathRoot Sheath

• Proliferation of the connective tissue of the Proliferation of the connective tissue of the papillapapilla

• Simultaneous growth of the jawSimultaneous growth of the jaw

• Pressures from muscular actionPressures from muscular action

• Apposition and resorption of boneApposition and resorption of bone

Exfoliation of the Primary Exfoliation of the Primary Tooth Tooth

• Pressure on the roots by the erupting Pressure on the roots by the erupting permanent toothpermanent tooth

• Development of osteoclastsDevelopment of osteoclasts

• Successive resorption of tooth root, Successive resorption of tooth root, cementum, dentin and adjacent bone cementum, dentin and adjacent bone due to the action of the osteoclasts.due to the action of the osteoclasts.

Attrition

• Normal wearing of the teeth during contact with opposing teeth during occlusion

• Primate spacesPrimate spaces