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Orthodontics > Vertical and Transverse Malocclusions > Flashcards

Vertical and Transverse Malocclusions Flashcards

1
Q

What plane is angle’s classification and BSI classification in?

A

Sagittal

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2
Q

What impacts do vertical and transverse malocclusions have on patients?

A
  • Aesthetics
  • Function
  • Treatment Need
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3
Q

What are some types of transverse malocclusions?

A
  1. Facial Asymmetry
  2. Mandibular Buccal Crossbite (Uni/Bilateral + Localised/Generalised)
    - Scissorsbite (Uni/Bilateral + Localised/Generalised)
    - Dental vs facial midline deviations
    - Lateral functional shift
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4
Q

If a patient has bilateral generalised crossbite/scissorsbite, what is the likely aetiology?

A

Skeletal

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5
Q

What are the possible aetiologies of facial asymmetry and how do you determine it?

A

Skeletal or soft tissue or combination of both

Using Radiographic tools: OPG, Lat Ceph, Posteroanterior cephalogram (PA ceph)

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6
Q

What are the different types of facial asymmetry?

A
  • Middle (max) or lower vertical third (man - condyle, body or ramus) asymmetry or both
  • Transverse cant in occlusal plane
  • Midline deviation
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7
Q

What are the possible Skeletal asymmetry aetiologies?

A
  1. Unilateral excess growth
    - Unilateral condylar hyperplasia
    - Hemimandibular elongation (AP growth)
    - Hemimandibular hyperplasia (AP + Vertical growth)
  2. Unilateral deficiency
    - Unilateral deficient condylar growth (due to trauma or infection)
    - Hemifacial microsomia
    - Unilateral idiopathic condylar resorption (teenage females, resulting in AOB + Class II malocclusion)
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8
Q

Definition of crossbite

A

Discrepancy in the buccolingual relationship of the upper and lower teeth (ant/post)

Convention: position of lower relative to upper

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9
Q

Definition of buccal crossbite (post)

A

Buccal cusps of lower teeth occlude buccal to the buccal cusps of upper teeth

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10
Q

Definition of lingual crossbite (post)

A

Buccal cusps of lower teeth occlude lingual to the lingual cusps of upper teeth

Scissorsbite

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11
Q

Skeletal causes of mandibular buccal crossbite

A
  1. True/Absolute transverse discrepancy
    - Maxillary constriction
    - Wide mandible
    - Combination
  2. Relative transverse discrepancy
    - Anterior-posterior relationship
    - Skeletal asymmetry
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12
Q

Features of mandibular buccal crossbite

A
  • Reduced intermolar width (max) compared to norms/man
  • Reduced arch perimeter
  • Increased curve of wilson (DAC)
  • Increased buccal corridors
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13
Q

When does maxillary constriction not lead to buccal crossbite

A

When there is DAC by having an increase in the curve of wilson (increased buccal inclination of max and increased lingual inclination of man)

Feature: both max and man skeletal widths are narrow

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14
Q

Dental causes of mandibular buccal crossbite (usually unilateral + localised)

A

Displacement
Rotation
Inclination

of tooth

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15
Q

Soft tissue causes of mandibular buccal crossbite

A
  • Non nutritive sucking habits (constriction of max arch by increased lingual pressure of buccinators and reduced buccal pressure from lowered tongue)
  • Macroglossia/lateral tongue spread
  • Mouth breathing
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16
Q

Additional causes of mandibular buccal crossbite

A
  • Cleft lip and palate (teeth grows upwards towards cleft –> AOB, surgery when theyre 1 causes scarring and restricts growth of maxilla)
  • Lateral functional shift (Single tooth interference, Arch width discrepancy)
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17
Q

What are the differences between a patient with marked and moderate bilateral maxillary constriction?

A

Marked: CR=MI, bilateral posterior crossbite
Moderate: CR=/ MI, posterior interference to closure, lateral shift into apparent unilateral posterior crossbite

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18
Q

Skeletal and Dental causes of Scissorsbite

A
  1. True/Absolute transverse discrepancy
    - Mandibular constriction
    - Wide Maxilla
    - Combination
  2. Relative transverse discrepancy
    - Anterior-posterior relationship (Class II patient)
    - Skeletal asymmetry

Dental:
Displacement
Rotation
Inclination

of tooth

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19
Q

Causes of Dental vs Facial midline deviations

A

Skeletal:
1. Skeletal asymmetry:
Chin point deviation
2. Lateral functional shift

Dental:
1. Crowding/Malalignment/ Tooth displacement
2. Missing teeth
3. Irregularly sized teeth (eg. peg shaped lateral)

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20
Q

Treatment options for typical skeletal asymmetry

A

Depends on the cause.
If cause is:
1. Deficient growth - early treatment
2. Excess growth - wait for growth cessation before proceeding with orthodontic camouflage or surgery; UNLESS aesthetic/functional concerns

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21
Q

Treatment options for lateral function shift

A

To be corrected ASAP (even if CR is symmetrical, it can remodel to become permanent asymmetry)

Eliminate the cause!
1. Dental interference
2. Maxillary constriction

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22
Q

Treatment options for mandibular buccal crossbites/Scissorsbite

A

Depends on the cause!
If patient is still growing and cause is:
1. Maxillary constriction or retrusion - Growth modification (Reverse full headgear/facemask for retrusion)
2. Habits - early habit cessation
3. Skeletal Class II - Growth modification (Twinblock)

If patient is post pubertal and cause is:
1. Dental - align teeth
2. Skeletal - Orthodontic camouflage or orthognathic surgery (severe cases)

23
Q

Orthopedic expansion devices to correct maxillary constriction

A
  1. Removable hyrex expander
  2. Banded hyrax expander
  3. W-arch
  4. Quadhelix
23
Q

Treatment for dental midline deviations

A

Depends on the cause!
1. Premature loss of primary tooth - early intervention to open space for unerupted permanent teeth
2. Extractions in contralateral quad of crowding/with midline deviation

24
Q

What are some types of vertical malocclusions

A
  1. Open bite
  2. Deep bite
  3. Anterior
  4. Posterior
25
Q

What is the definition of anterior open bite (AOB)

A

Vertical overlap does not exist when the buccal segments are in occlusion

26
Q

What is the definition of posterior open bite (POB)

A

(Inter-occlusal) space between posterior teeth when the other teeth are in occlusion (Occurs less frequently)

27
Q

What are the causes of anterior open bite?
Skeletal, Dental, Soft tissue and others

A

Skeletal:
1. Vertical growth pattern
Dental:
1. Bimaxillary proclination
2. Impacted tooth (localised)
3. Ankylosis of traumatised teeth (localised)
Soft tissue:
1. Non-nutritive sucking habits
2. Forward resting tongue posture
Others:
1. Condylar degenerative diseases - Idiopathic condylar resorption, Juvenile rheumatoid arthritis
2. Trauma - Arrested condylar growth/ Condylar ankylosis
3. Cleft alveolus

28
Q

How does a vertical growth pattern cause AOB?

A
  1. Excess maxillary height (esp in the posterior region)
  2. Upward tipping of palatal plane anteriorly
  3. Excess vertical growth of maxillary posterior dentoalveolar complex (molars)

All these result in a downwards and backwards mandibular rotation.

29
Q

What are some signs of vertical maxillary excess?

A

Increased incisor display at rest (not due to short upper lip or extruded incisors)

30
Q

What are the Lat ceph features of a skeletal AOB
9

A
  1. Short ramus (short PFH, Long AFH)
  2. Reduced UAFH:LAFH
  3. Antegonial notching
  4. Obtuse gonial angle
  5. Divergent occlusal planes
  6. Distal condylar inclination
  7. Straight mandibular canal
  8. Long and thin symphysis
  9. Acute intermolar and interincisal angulation
31
Q

What are the Dental features of a skeletal AOB

A
  1. Rotation of the jaws will carry incisors forward,. causing dental protrusion
  2. Dentoalveolar compensation: over-eruption of anterior teeth
32
Q

What are the Soft tissue features of a skeletal AOB

A
  1. Parallel skeletal findings - Eg. high mandibular plane angle
  2. Increased inter-labial gap –> lip incompetence
33
Q

How does sustained forward resting tongue posture cause malocclusion?

A

It affects teeth in the vertical (AOB) (inhibits eruption) and horizontal (proclination) (pushes teeth forward) planes

34
Q

How does non-nutritive sucking habits cause AOB?

A
  • Thumb inhibits the eruption of anterior teeth (can be unilateral or central)
  • Supra-eruption of posterior teeth due to mouth being open for a long time
34
Q

How does non-nutritive sucking habits cause AOB?

A
  • Thumb inhibits the eruption of anterior teeth (can be unilateral or central)
  • Supra-eruption of posterior teeth due to mouth being open for a long time
35
Q

What are some features of a patient with a non-nutritive sucking habit?

A
  • Labial displacement of upper incisors (change in inclination)
  • Lingual displacement of lower incisors (change in inclination)
  • Increased overjet
  • Maxillary constriction
36
Q

What is the main difference between a skeletal open bite and a dental open bite

A

Where the occlusal planes generally diverge from.
Skeletal: first molar anteriorly
Dental: first premolar anteriorly

37
Q

What are the treatment goals and options for the excess development of posterior dentoalveolar complex in a GROWING CHILD

A

Aim: Control eruption of molars
- High-pull headgear
- Posterior bite blocks

38
Q

Why is treating excess development of posterior dentoalveolar complex in a GROWING CHILD challenging

A

This is because vertical growth continues into the post-adolescent years.

39
Q

What are the treatment options for the excess development of posterior dentoalveolar complex in an adult

A
  • Intrusion of molars
  • Orthognathic surgery
40
Q

What are the treatment goals and options for non-nutritive sucking habits in a GROWING CHILD

A

Aim: Habit cessation to allow for spontaneous resolution
- Reminders
- Appliance therapy eg. tongue spurs (sharp things on the palatal surface of incisors

41
Q

What treatment option is there if there is no spontaneous resolution of AOB after habit cessation

A

Active orthodontic closure
1. Vertical elastics for anterior extrusion BUT incisor and gingival display must be checked
2. Extraction therapy - indicated when there is proclination of incisors and crowding.

42
Q

Skeletal causes of posterior open bite

A

Skeletal Asymmetry:
1. Unilateral condylar hyperplasia
2. Unilateral idiopathic condylar resorption (ICR) - POB occurs on contralateral side
3. Hemimandibular hyperplasia
Vertical growth pattern:
POB extends posteriorly to 1st molar

43
Q

Soft tissue causes of posterior open bite

A
  1. Macroglossia
  2. Lateral tongue spread
44
Q

Dental causes of posterior open bite

A
  1. Impaction
  2. Ankylosis
  3. Mesial tipping of molars (Early extraction of Es)
  4. Primary failure of eruption (PFE) - all teeth posterior to affected tooth will be affected as well
45
Q

Definition of deep overbite

A

Excessive incisal overlap in the vertical plane (>40%)

46
Q

What overbite is considered normal?

A

2-4mm or
25-40% without functional problems

47
Q

What type of patients often have deep overbites

A

Class II Div 2 malocclusions

48
Q

Skeletal features of a deep bite (which parallels soft tissue features)

A
  1. Forward and upwards mandibular rotation
  2. Horizontal palatal plane (parallel to mandibular plane)
  3. Convergent rotation of maxilla and mandible (anteriorly)
  4. Low mandibular plane angle
  5. Reduced LAFH
  6. Square gonial angle
49
Q

Dental features of a deep bite

A
  1. Jaw rotation carries incisors into an overlapping position
  2. Upright upper incisors displacing the lower incisors lingually
50
Q

What are the dental causes of a deep bite

A
  1. Excess eruption of anterior teeth (upper and/or lower)
    - check gingival margins
    - check upper incisor display at rest
    - check lower curve of spee (will be increased)
  2. Under eruption of posterior teeth
  3. Loss of OVD - severe attrition, loss of tooth structure, posterior bite collapse (exo)
  4. Bimaxillary Retroclination

These can occur simultaneously

51
Q

What are the treatment options for deep bite + factors to consider

A

Aetiology dependent!
If cause is:
1. Extrusion of ant - Intrusion of upper and lower incisors +/= incisor proclination with the use of intrusion or utility arches
2. Intrusion of posteriors - Extrusion of upper and lower posterior teeth with the use of Anterior bite plate/Functional appliances, Cervical-pull headgear
3. Very severe - Orthognathic surgery

Factors to note first:
- Incisor display at rest
- Gingival display on smiling
- Interlabial gap

52
Q

Is deep bite easier to correct in children or adults?

A

Easier to correct in growing patients.
However, intrusion of anteriors is considered more stable in adults

Orthodontics (18 decks)

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