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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