Eruption and Occlusion of the Permanent Dentition

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Eruption and Occlusion of the Permanent Dentition

Mark H. Taylor, D.D.S., F.A.C.D.
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Dont Fake Knowledge!

• Know Nolla's stages of calcification
• Know time of eruption of permanent teeth

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Nolla's 10 Stages of Calcification

• Stage 2 - initial calcification
• Stage 6 - eruptive movement begins (crown
  formation complete)
• Stage 8 - alveolar crest pierced (2/3 root
  development)
• Stage 9 - gingival margin pierced (3/4 root
  development)
• Interval between Stage 6 and full interdigitation
  is about 5 years

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Time of Eruption (Years)
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Why Know Calcification Times?
Enamel hypoplasia
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Fluorosis
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Fluorosis and Hypoplasia
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Fluorosis and Hypoplasia
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Factors Affecting Eruption

• Genetics - sequence timing mostly genetically
  controlled
• Nutrition
• Premature loss of a primary tooth

Eruption heh heh get it?
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Eruption Facts

• Girls 5 months faster than boys
• 6-1-2-4-3-5-7 and 6-1-2-4-5-3-7 most common in
  maxilla
• (6-1)-2-3-4-5-7 and (6-1)-2-4-3-5-7 most common
  in mandible

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Mesial Drift and Anterior Component of Force

• Mesial drift
• Ectopic eruption
• Axial inclination produces mesial force
• Space maintenance

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Ectopic Eruption
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Ectopic Eruption
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Ectopic Eruption
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Space Maintenance - PHA
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Space Maintenance - LLHA
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Space Maintenance - BLS
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Space Maintenance - Distal Shoe
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Crossbites

• Unilateral vs. bilateral
• Dental vs. skeletal
• Appliance types

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Functional Cross Bite
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Functional Cross Bite
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Functional Cross Bite
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Functional Cross Bite
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Quad Helix Appliance
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Quad Helix Appliance
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Distalizing Appliance
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Absence of Permanent Teeth

• 4-6 congenital absence
• Females more frequently missing teeth
• Most common congenitally absent teeth
• mandibular 2nd premolar
• maxillary lateral incisor
• maxillary 2nd premolar

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Missing Permanent Teeth
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Extra Permanent Teeth

• Supernumerary teeth found most frequently in the
  maxillary incisor region (mesiodens), and
  occasionally in the premolar area
• 2-3 supernumerary teeth, males more common

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Supernumerary Teeth
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Supernumerary Teeth
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Supernumerary Teeth
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Supernumerary Teeth
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Supernumerary Permanent Tooth
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Supernumerary Permanent Tooth
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Supernumerary Permanent Tooth
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Changes in Arch Width

• Intercanine and intermolar growth
• significant increases between 6 weeks and 2 years
  of age
• significant increases between 3 and 13 years
• mandibular intercanine width established by 8
  years of age
• after permanent teeth erupted, slight decrease in
  arch width in the intercanine area

Bishara, et al Arch width changes from 6 weeks
to 45 years of age AJO, April 1997
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Changes in Arch Length and Overbite

• Arch length decreases
• late mesial shift, mesial drift, interproximal
  wear
• do not affect interach relationships
• Overbite
• decreases in primary dentition
• increases in mixed dentition
• OB/OJ relatively stable in adult

Harris, A longitudinal study or arch size and
form in untreated adults AJO, April 1997.
(20-55 yoa)
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Intercanine Growth
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Angle Classification

• Class I Molar (65)
• Class II Molar (30)
• Class III Molar ( 5)

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Class I Molar
Mesial
Distal
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Class II Molar
Mesial
Distal
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Class III Molar
Mesial
Distal
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Cuspid Classification

• Neutro (Class I)
• Disto (Class II)
• Mesio (Class III)

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Neutro Cuspid (Class I)
Mesial
Distal
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Disto Cuspid (Class II)
Distal
Mesial
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Mesio Cuspid (Class III)
Mesial
Distal
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Divisions of Class II

• Division I - excess OJ
• Division II - "rabbited" incisors
• Subdivision - one side

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Divisions of Class IIDivision 1
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Divisions of Class IIDivision 1
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Divisions of Class IIDivision 1
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Divisions of Class IIDivision 2
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Divisions of Class IIDivision 2
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Divisions of Class IIDivision 2
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Divisions of Class IIDivision 2
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Six Keys to Occlusion

• Class I molar relationship
• Mesial crown angulation
• Proper crown inclination
• No rotations
• Tight contacts
• Flat occlusal plane

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Types of Faces

• Brachycephalic - broad short
• Dolichocephalic - long narrow
• Mesocephalic - normal

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Brachycephalic
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Dolichocephalic
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Mesocephalic
For the ladies.
For the gentlemen...
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Mesocephalic
For the moviegoer.
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Mesocephalic
For the intellectual dental student.
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You Tell Me.
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Profile?
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Overbite - Overjet?
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Occlusion?
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Huskers!!!!