Pediatric Primary Tooth Anatomy- Dr. Webb Flashcards Preview

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Flashcards in Pediatric Primary Tooth Anatomy- Dr. Webb Deck (33)
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1

Life Cycle of the tooth: Stages

  • Initiation
  • Proliferation
  • Histodifferentiation
  • Morphodifferentiation
  • Apposition
  • Calcification
  • Eruption

2

Initiation stage

  • Aka Bud Stage
  • 6th week of embryo 
  • epithelial thickening that becomes dental lamina
  • Permanent Molars and primary teeth arise from dental lamina
  • Permanent Incisors, canines, and premolars develop from their primary predecessors

3

Congenital Absence of a tooth

  • Lack of initiation or arrest in the proliferation of cells

4

Supernumerary teeth

Continued budding of teeth

5

Proliferation

  • Aka Cap Stage
  • unequal growth of different parts of the bud
  • Peripheral cells of the cap form the outer and inner enamel epithelium

6

Dificiency in proliferation results in

Fewer than normal number of teeth

7

Excessive proliferation results in

cysts, odontomas or supernumery tooth

8

Histodifferentiation

  • Aka Bell stage (& morphodifferentiation)
  • dental papilla cells differentiate into odontoblasts
  • inner enamel epithelium differentiate into ameloblasts

9

Disturbances in histodifferentation results in 

  • Abnormal structure of dentin or enamel
    • amelogenesis imperfecta=most common

10

Morphodifferentation stage

  • Aka Bell stage (&histodifferentiation)
  • Formative cells arranged to form the tooth
  • Boundary between inner enamel epithelium and odontoblast become DEJ

11

disturbances in morphdifferentation stage results in

  • Abnormal forms and sizes of teeth
    • peg teeth (Peg Laterals)
    • Microdontia
    • Macrodontia

12

Apposition Stage

  • Ameloblasts and odontoblasts secrete tissue matrix
    • Begin their work at sites called growth centers

13

Apposition stage disturbances result in

  • Systemic disturbance or local trauma that injures the ameloblasts during enamel formation or arrest in matrix apposition results in ENAMEL hyperplasia

14

Calcification Stage

  • Precipitation of calcium in the matrix
  • Further precipitation of original nidus with concentric laminations
  • fusion of individual calcopherites
  • 11th week in utero=first indication
    • 14th week=Primary Central Incisors
    • 15.5 week=Primary 1st Molars
    • 16th week= Primary Lateral Incisors
    • 17th week=Primary Canines
    • 18th week= Primary 2nd molar
    • 28th week=Permanent 1st molar

15

Calcification stage disturbance

  • Lack of fusino of calcospherites in dentin=Interglobular dentin

16

Calcification stage: Anterior Primary Teeth, Posterior Primary teeth, Permanent molar

  • 11th week in utero=earliest indication 
    • 14th week=Primary Cental Incisor
    • 15.5 week=first primary molar
    • 16th week= Primary Lateral incisor
    • 17th week=Primary Canine
    • 18th week=Second Primary molar
    • 28th week= first permanent molar

17

How many primary teeth are their?

  • 20 teeth
    • 8 incisors
    • 4 canines
    • 8 molars
  • Missing Premolars!

18

Primary teeth are also called

  1. Temporary Teeth
  2. Milk Teeth
  3. Baby Teeth

19

Eruption Sequence

  • Mandibular teeth before maxillary teeth
  • Teeth erupt in pairs (Left and Right
  • Permanent teeth erupt earlier in girls than boys
  • Primary Teeth
    • Incisors-6 month old
    • cuspids-18 month old (Canine)
    • Molars- 12 and 24 months 

20

Primary Vs permanent Dentition

  • Tooth
    • Thinner Enamel
      • Primary=0.5-1mm
      • Permanent= 1-2mm
    • Ligher in color (whiter)
    • Apical enamel rods curve toward incisal/occlusal
    • Smaller in all dimensions
      • except mandibular molars are wider M-D than the premolars
    • Wider M-D than their height
      • short and squatty
    • B-L smaller bc it converges toward the occlusal
    • Cervial Ridges (Height of contour) more pronounced 
  • Roots
    • No Root Trunk
    • long, flared and thin
  • Pulp Chamber
    • Large compared to size of the tooth
    • closer to tooth's surface
  • Contact Area
    • Broad and flat (Vs point contact)
    • more gingival

21

Primary Dentitioin: Pulp chambers and Pulp Canal

  • Crown widths in all direction is large compared to root trunks and cervices
    • roots narrow and long
    • molar roots thin and flare
  • Dentin thickness b/w pulp chamber and enamel is limited
    • especially in lower second primary molar
  • High Pulp Horns
  • Large Pulp Chambers

22

Primary Maxillary Cental Incisor

  • Crown
    • Wide> taller
    • No developemental lines
      • smooth labial surface
    • straight incisal edge
    • Lingual Surface
      • distinct cingulum
      • well developed marginal ridge
  • Root:
    • Cone shaped
    • tapered sides

23

Primary Maxillary Lateral Incisor

  • Crown Outline similar to cental incisor,
    • crown is smaller in all dimensions
      • Length>width
  • Root outline similar to central incisor
    • but longer when compared to crown

24

Primary Maxillary Canine

  • Crown:
    • more constricted at cervical region than incisors
    • incisal and distal surfaces=more convex
  • Sharp Cusp, well developed
    • straight incisal edge-incisors
  • Root:
    • Long, slender, tapering root
    • more than 2x length of crown
    • curves distally-apical to middle 1/3

25

Incisal View of Maxillary Primary Anteriors

  • Incisal edge:
    • straight
    • centered over crown
  • Labial Surface
    • is broader and smoother than lingual surve
  • Lingual surface
    • tapers toward cingulum

26

27

Primary Maxillary First Molar

 

  • Crown:
    • Largest dimension: M-D Contact area
      • crown converges toward crvical region
    • ML cusp:
      • largest and sharpest
    • DL cusp=not well defined
      • small
      • rounded
    • Buccal Surface
      • smooth
      • little evidence of developement grooves
  • Roots:
    • long, slender
    • widely spread/Flared

28

Primary Maxillary Second Molar

Resembles maxillary 1st molar

  • 2 well defined buccal cusps
    • developmental groove between them
  • Crown is larger than first primary molar

29

Primary Mandibular Central Incisor

  • Crown:
    • Smaller than maxillary central incisor
      • F-L measurement=1mm less
    • Buccal 
      • flat surface
      • development grooves
    • Lingual
      • marginal ridge and cingulum
    • Straight incisal edge
      • bisects crown labiolingually
  • Root
    • twice as long as the crown

30

Primary Mandibular Lateral Incisor

  • Crown outline similar to central incisor
    • except larger in all dimensions except F-L
  • Lingual surface
    • greater concavity b/w marginal ridges
  • Incisal edge
    • slopes toward distal