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Prof Abdalla > Week 4- Tooth Impaction > Flashcards

Week 4- Tooth Impaction Flashcards

1
Q

Outline the permanent eruption sequence for mx

A

1st Molar: 6.25
Central: 7.25
Lateral: 8.25
1st Premolar: 10.25
2nd Premolar: 11
Canine: 11.5
2nd Molar: 12.5
3rd Molar: 20

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2
Q

Outline the permanent eruption sequence for md

A

1st Molar: 6
Central: 6.25
Lateral: 7.25
Canine & 1st Premolar: 10.5
2nd Premolar: 11.25
2nd Molar: 12
3rd Molar: 20

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3
Q

What is the difference between biological/dental and chronological age?

A

They can be coincident but not always. Huge variations amongst children in terms of biological/dental age.

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4
Q

When do teeth finish erupting on average?

A

Females: 12.5 years
Males: 13 years

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5
Q

What is dental age determined by?

A
  • Which teeth have erupted
  • The amount of resorption of the primary teeth
  • The amount of development of the permanent teeth
  • Demirjian & Nolla’s staging methods
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6
Q

Why is dental age important?

A

Often determines the appropriate time for ortho intervention

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7
Q

What is a retained vs over-retained deciduous tooth?

A
  • Retained: tooth that remains in place beyond its normal, chronological shedding time due to the absence or retarded development of the permanent successor
  • Over-retained: tooth whose unerupted permanent successor exhibits a root development in excess of ¾ of its expected final length
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8
Q

What are systemic factors that can lead to eruption problems?

A
  • Cleidocranial dysplasia
  • Ectodermal dysplasia
  • Gardner Syndrome
  • Apert syndrome
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9
Q

What are local factors that can lead to eruption problems?

A
  • Barriers in the eruption pathway
  • Abnormal tooth position
  • Tooth deformity
  • Bone deficit (CLP)
  • Lack of space
  • Dilaceration
  • Ankylosis
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10
Q

What is primary failure of eruption?

A

All posterior teeth fail to erupt despite clear eruption pathway. Caused by specific gene.

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11
Q

How should primary failure of eruption be treated/managed?

A
  • Early ortho intervention
    futile (and can even make things
    worse)
  • Wait until completion of vertical
    growth
  • Segmental osteotomy, distraction
    osteogenesis, bone grafting and
    implants
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12
Q

What is ankylosis?

A

Fusion of cementum or dentine with alveolar bone. Affected tooth remains in place while adjacent teeth continue to erupt. Teeth do not respond to orthodontic force

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13
Q

What is the definition of tooth impaction?

A

Failure of a tooth which exhibits more than ¾ of final root length to erupt into a normal functional position.

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14
Q

What are common causes of tooth impaction?

A
  • Failure of resorption of deciduous teeth
  • Abnormal eruptive pathway
  • Supernumerary teeth
  • Dental crowding
  • Dentigerous cysts
  • Disturbance in the eruption mechanism of the tooth
  • Ankylosis
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15
Q

What is treatment of tooth impactions based on?

A
  • Cause of the impaction
  • Position of the impacted tooth
  • Ability to move the tooth orthodontically
  • Likelihood of causing damage to adjacent teeth
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16
Q

What are treatment options for tooth impaction?

A
  • Extraction
  • Make space +/- surgical exposure
  • Make space and transplantation
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17
Q

What are common orthodontic indications for third molar removal?

A
  • Distalisation of lower molars
  • Preparation for orthognathic surgery
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18
Q

What is an ectopic tooth vs an impacted tooth?

A
  • Ectopic: tooth is following an abnormal eruption path
  • Impacted: eruption is delayed and tooth unable to erupt without assistance
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19
Q

Is ectopic eruption of first molars more common in mx or md and male or female?

A
  • More common in maxilla
  • More common in males
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20
Q

What is the aetiology of ectopic eruption of first molars?

A
  • Larger than normal first molars
  • Small mx
  • Class III skeletal pattern
  • More pronounced angle of eruption
  • Genetic
  • Association with other dental anomalies (impacted canines, peg laterals)
21
Q

How is ectopic eruption of first molars diagnosed?

A
  • Often indicated on BW’s
  • Tipping of 2nd deciduous molar
  • Infra-occlusion of 1st permanent molar
22
Q

What is the issue with ectopic eruption of first molars?

A
  • Loss of space
  • Impaction of second premolars
  • Over eruption of opposing first molar
23
Q

How is the ectopic eruption of first molars managed?

A
  • Brass wire
  • Separator (elastomeric)
  • Fixed appliances
  • Extraction of deciduous molar
24
Q

How can you diagnose impacted incisors?

A
  • The eruption of contralateral tooth
    occurred greater than 6 months prior
  • Both central incisors remain unerupted 12 months after lower central incisors have erupted
  • Any deviation from normal sequence of eruption
25
Q

What is the aetiology of impacted incisors?

A
  • Supernumerary teeth
  • Dilacerated teeth
  • Early loss of deciduous teeth
  • Retained deciduous teeth
26
Q

How should children up to 9 years with incomplete root development of impacted permanent incisor be managed

A
  • Remove obstruction
  • Create space if required
  • Monitor eruption for 18 months.
27
Q

Why is it essential that impacted incisors are diagnosed early?

A

Late referral (over 10 years) means more invasive tx is required.

28
Q

What happens if patients are referred over 10 years old for impacted incisors?

A

Surgical intervention likely required.

  1. Remove obstruction
  2. Expose and bond bracket
29
Q

What are the most commonly impacted teeth after 3rd molars?

A

Maxillary canines

30
Q

What is the aetiology of ectopic maxillary canines?

A
  • Unclear
  • Prolonged retention of primary canine
  • Association with small/absent lateral incisors
  • Family hx?
31
Q

When should buccal sulcus be palpated for mx canines?

A

By age 10

If the canine cannot be palpated, radiographic investigation is indicated.

32
Q

How are impacted canines diagnosed?

A
  • OPG, PA, Occlusograph
  • SLOB rule
  • CBCT
33
Q

What is the biggest complication of impacted maxillary canines?

A

Resorption of lateral or central incisors (not very common)

34
Q

How can we prevent canine impaction?

A

If permanent canine is distal to midpoint of lateral incisors, can extract primary canine and should erupt spontaneously (91%) after 18 months.

35
Q

How much impaction of the mx canine would not allow for spontaneous eruption if primary canine was extracted?

A

If permanent canine is past midpoint of central incisor

36
Q

How can we treat canine impaction?

A
  • No Treatment / Extraction
  • Surgical exposure and alignment (usually best tx, not always possible, long tx time)
37
Q

What age does resorption of incisors from impacted canines become unlikely?

A

After age 14

38
Q

What is the management of impacted permanent 2nd molars?

A
  • Ortho repositioning
  • Exo and allow third molar substitution
  • Exo of 2nd premolar and move lower 1st molar forwards
39
Q

What are the following OPG’s of 12 year olds each indicating?

A
  • LHS: delayed exfoliation
  • RHS: delayed development
40
Q

What age is spontaneous resolution of ectopic first molars unlikely?

A

Spontaneous resolution unlikely after age 7

41
Q

Which of these photos is the correct time to refer for delayed eruption of central incisor?

A

Far left pic

42
Q

What is the rationale for extracting impacted canines

A

If pt doesn’t want to go through long tx (2.5yrs+ of ortho)

Space can be closed orthodontically

May be only option if tooth can’t be moved orthodontically

43
Q

What is the issue with leaving deciduous canine in place long term?

A

Poor prognosis as root will usually resorb and exfoliate by age 20-25

44
Q

What is happening in this radiograph?

A

Ectopic eruption of first molar

45
Q

What is happening in this radiograph?

A

Ectopic eruption of first molars

46
Q

What tx is being performed here and why?

A

Separating elastic to manage ectopic first molar

47
Q

What is happening in this radiograph?

A

Root resorption of 11 due to impacted mx canine

48
Q

What is the issue in this radiograph?

A

Maxillary canine impaction

Prof Abdalla (6 decks)

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