(5) A missing incisor

Question 1

What age should the permanent central incisors emerge?

Answer 1

7 years old

Question 2

What is a method to speed up the eruption of permanent successors?

Answer 2

Extraction of correspodning deciduous tooth (±adjacent teeth)

Question 3

Illustrate a way to chart the early mixed dentition

Answer 3

Question 4

Which region of the oral cavity would you check for the missing central incisor?

Answer 4

Upper labial sulcus

Question 5

What are the possible causes of an apparently absent upper central incisor?

Answer 5

• Missing
  
  • Developmentally absent
  • Extracted
  • Avulsed
• Failure to erupt
  
  • Dilaceration and/or displacement as a result of trauma
  • Scar tissue preventing eruption
  • Supernumerary tooth preventing eruption
  • Insufficient space as a result of crowding
  • Pathological lesion
    
    • Cyst
    • Odontogenic tumor

Question 6

What specific question would you ask to the parent of the patient with missing incisor?

Answer 6

• Trauma-related question (avulsion or dilaceration)
• Deciduous predecessor discolored?
  
  • Loss of vitality
• Previous injury to face/lip/teeth

Question 7

What can cause a shift in the centre line?

Answer 7

• Crowding
• Early exfoliation of the canines

Question 8

What is dilaceration?

Answer 8

• An angulation, or a sharp bend or curve, in the root or crown of a formed tooth
• Caused by intrusion

Question 9

Can crowding cause delay in eruption of permanent successor?

Answer 9

• Yes, but it would not delay eruption uf up to 2 years

Question 10

What radiographs would be taken in this instance?

Answer 10

• Dental panoramic radiograph
  
  • General view
  • Presence/absence of permanent teeth
  • Supernumeraries (?)
• Periapical radiographs
  
  • Root morphology
  • Adjacent structures
    
    • Supernumerary teeth
    • Pathological lesions
  • PA view should include adjacent teeth
  • SLOB rule
• Lateral view
  
  • Distrotion of tooth

Question 11

What action would need to be taken if dilaceration was severe?

Answer 11

• Extraction of dilacerated tooth
• Immediate replacement of incisor by dentureadhesive bridge with permanent restoration or single tooth implant

Question 12

What pre-conditions need to be met for orthodontic realignment (extrusive traction)?

Answer 12

• Dilaceration of tooth not too severe
• Dilaceration lies in apical portion of the root

Question 13

What factors need to be considered in the selection of a particular treatment?

Answer 13

• Position and seveirty of dilaceration
• Size of overjet
• Degree of crowding
• Position and condition of the other permanent teeth
• General condition of the mouth
• Attitude of the child and parent