Tooth Eruption and Exfoliation Patterns

• The presentation discusses tooth exfoliation and eruption and learning outcomes

Aim

• To enable students to understand the sequence and importance of the chronology for eruption and exfoliation of primary dentition and eruption of secondary dentition

Learning Outcomes

• To know terminology used in the eruption and exfoliation sequence
• To understand the reasons why learning this is important to be able to distinguish normal from abnormal
• To know calcification, eruption and exfoliation dates for both primary and permanent dentition

Reasons for Learning Eruption/Exfoliation Patterns

• The primary teeth hold space in the jaw for the permanent teeth, which move into place once primary teeth are shed
• Understanding the normal sequence of exfoliation and eruption allows for determining deviations from normal
• Girls' dentition tends to erupt sooner than boys'

Impact to Permanent Dentitions

• Systemic or local issues can impact permanent dentitions
• Systemic issues can cause:
  • Delayed eruption
  • Non-formation (missing dentition)
  • Molar-Incisor Hypomineralisation (MIH).
• Systemic factors include:
  • Genetics
  • Nutrition
  • Metabolic or hormonal disorders, systemic infections
  • Diseases like kidney issues or cancer
  • Medications (e.g., chemotherapy, epilepsy drugs)
  • Fluorosis
  • Low birth weight
  • Exposure to a smoking environment.

Impact to Permanent Dentitions - Generalised or Localised

• Local issues can cause:
  • Delayed eruption
  • Non-formation or Molar-Incisor Hypomineralisation
• Local factors include:
  • Early loss of deciduous teeth
  • Impacted or misplaced teeth (commonly maxillary 3s and mandibular 8s)
  • Missing dentition (usually maxillary 2s and mandibular 8s)
  • Supernumerary teeth
  • Trauma
  • Gingival hyperplasia or fibrosis
  • Oral clefts, eruption cysts

Deciduous Dentition Tooth Chronology - Maxillary (1)

• First Incisor (A):
  • Initial calcification at 3-4 months in utero (IU)
  • Crown completion at 4 months
  • Eruption occurs at 7.5 months
  • Root completion at 1.5-2 years
• Second Incisor (B):
  • Initial calcification at 4-5 months in utero (IU)
  • Crown completion at 5 months
  • Eruption at 8 months
  • Root completion at 1.5-2 years
• Canine (C):
  • Initial calcification at 5 months in utero (IU)
  • Crown completion at 9 months
  • Eruption at 16-20 months
  • Root completion at 2.5-3 years
• First Molar (D):
  • Initial calcification at 5 months in utero (IU)
  • Crown completion at 6 months
  • Eruption at 12-16 months
  • Root completion at 2-2.5 years
• Second Molar (E):
  • Initial calcification at 6 months in utero (IU)
  • Crown completion at 10-12 months
  • Eruption between 1.75-2.5 years
  • Root completion at 3 years

Deciduous Dentition Tooth Chronology - Mandibular (2)

• First Incisor (A):
  • Initial calcification at 4-5 months in utero (IU)
  • Crown completion at 4 months
  • Eruption at 4 months
  • Root completion at 1.5-2 years
• Second Incisor (B):
  • Initial calcification at 4-5 months in utero (IU)
  • Crown completion at 4.5 months
  • Eruption at 4.5 months
  • Root completion at 1.5-2 years
• Canine (C):
  • Initial calcification at 5 months in utero (IU)
  • Crown completion at 9 months
  • Eruption at 9 months
  • Root completion at 2.5-3 years
• First Molar (D):
  • Initial calcification at 5 months in utero (IU)
  • Crown completion at 6 months
  • Eruption at 6 months
  • Root completion at 2-2.5 years
• Second Molar (E):
  • Initial calcification at 6 months in utero (IU)
  • Crown completion at 10-12 months
  • Eruption occurs at 10-12 months
  • Root completion at 3 years

Order of Eruption

• Deciduous Maxillary: A-B-D-C-E
• Deciduous Mandibular: A-B-D-C-E

Permanent Dentition Eruption Chronology

• Maxillary Central Incisor (1s):
  • Initial calcification at 3-4 months after birth
  • Crown completion at 4-5 years
  • Eruption at 7-8 years
  • Root completion at 10 years
• Mandibular Central Incisor (1s):
  • Initial calcification at 3-4 months after birth
  • Crown completion at 4-5 years
  • Eruption at 6-7 years
  • Root completion at 9 years
• Maxillary Lateral Incisor (2s):
  • Initial calcification at 10-12 months after birth
  • Crown completion at 4-5 years
  • Eruption at 8-9 years
  • Root completion at 11 years
• Mandibular Lateral Incisor (2s):
  • Initial calcification at 3-4 months after birth
  • Crown completion at 4-5 years
  • Eruption at 7-8 years
  • Root completion at 10 years
• Maxillary Canine (3s):
  • Initial calcification at 4-5 months after birth
  • Crown completion at 6-7 years
  • Eruption at 11-12 years
  • Root completion at 13-15 years
• Mandibular Canine (3s):
  • Initial calcification at 4-5 months after birth
  • Crown completion at 6-7 years
  • Eruption at 9-10 years
  • Root completion at 12-14 years
• Maxillary 1st Premolar (4s):
  • Initial calcification at 18-21 months after birth
  • Crown completion at 5-6 years
  • Eruption at 10-11 years
  • Root completion at 12-13 years
• Mandibular 1st Premolar (4s):
  • Initial calcification at 21 months - 2 years
  • Crown completion at 5-6 years
  • Eruption at 10-12 years
  • Root completion at 12-13 years
• Maxillary 2nd Premolar (5s):
  • Initial calcification at 2.25-2.5 years
  • Crown completion at 6-7 years
  • Eruption at 10-12 years
  • Root completion at 12-14 years
• Mandibular 2nd Premolar (5s):
  • Initial calcification at 2.25-2.5 years
  • Crown completion at 6-7 years
  • Eruption at 11-12 years
  • Root completion at 13-14 years
• Maxillary 1st Molar (6s):
  • Initial calcification occurs at birth/slightly before
  • Crown completion at 2.5-3 years
  • Eruption at 6-7 years
  • Root completion at 9-10 years
• Mandibular 1st Molar (6s):
  • Initial calcification occurs at birth/slightly before
  • Crown completion at 2.5-3 years
  • Eruption at 6-7 years
  • Root completion at 9-10 years
• Maxillary 2nd Molar (7s):
  • Initial calcification occurs at 2.5-3 years
  • Crown completion at 7-8 years
  • Eruption at 12-13 years
  • Root completion at 14-16 years
• Mandibular 2nd Molar (7s):
  • Initial calcification occurs at 2.5-3 years
  • Crown completion at 7-8 years
  • Eruption at 11-13 years
  • Root completion at 14-15 years
• Maxillary 3rd Molar (8s):
  • Initial calcification occurs at 7-9 years
  • Crown completion at 12-16 years
  • Eruption at 17-21 years
  • Root completion at 18-25 years
• Mandibular 3rd Molar (8s):
  • Initial calcification occurs at 8-10 years
  • Crown completion at 12-16 years
  • Eruption at 17-21 years
  • Root completion at 18-25 years

Order of Eruption - Permanent Dentition

• Maxillary: 6-1-2-4-5-3-7-8
• Mandibular: 6-1-2-3-4-5-7-8

Dentopantomograph Issues

• Missing UL/ UR2
• Missing LL5

Radiographs

• Delayed Eruption/Impacted Upper Right Canine
• Impacted 8s
• Impact to Permanent Dentitions
• Trauma to primary teeth can affect the permanent successor
• Eruption Cysts
• Comparison of Radiograph and Teeth development at 6.5 years old

Explore the reasons for studying tooth eruption and exfoliation, the systemic factors influencing eruption timing, and the effects of early deciduous tooth loss. This resource will cover the impact of systemic issues and sex-based differences on dental development.