Vertical Malocclusions

Question 1

Examples of Vertical Malocclusions

Answer 1

Dental: Deep bite or Open bite

Skeletal: Hypo/Hyperdivergent (Short/long face)

Question 2

Skeletal Aetiology of AOB

Answer 2

Vertical growth pattern: Downward and backward rotation of mandible

Associated with vertical maxillary excess and excess vertical growth of max posterior dentoalveolar complex

Question 3

Dental Aetiology of AOB

Answer 3

1. Bimaxillary proclination
2. Impacted teeth or ankylosis due to trauma → Localised AOB

Question 4

Soft Tissue Aetiology of AOB

Answer 4

1. Non-nutritive sucking habits

• Inhibit eruption anterior teeth
• Excess eruption of posterior teeth
• Maxillary constriction

2. Forward resting tongue posture

• Only if sustained, inhibit eruption of anterior teeth
• Affect vertical (AOB) and horizontal (proclination) planes

Question 5

What does the point of divergence of the AOB tell you?

Answer 5

Diverge anterior to 1st molars → Skeletal AOB

Diverge anterior to 1st premolars → Dental AOB

Question 6

Other possible aetiologies of AOB?

Answer 6

1. Condylar degenerative diseases
2. Trauma (Condylar ankylosis)
3. Localised failure of development (Clef lip and palate)

Question 7

Dental Characteristics of AOB

Answer 7

1. Rotation of jaws carry incisors forward → Protrusion
2. DAC -> Over-eruption of anterior teeth
3. Displacement of upper incisors labially and lower incisors lingually, increasing OJ

Question 8

Soft Tissue Characteristics of AOB

Answer 8

Lip incompetence

Question 9

Cephalometrics of AOB

Answer 9

1. Increased LAFH
2. Obtuse gonial angle
3. Divergent occlusal planes
4. Short ramus

Question 10

Skeletal Aetiology of Posterior Open Bite

Answer 10

1. Unilateral condylar hyperplasia
2. Unilateral idiopathic condylar resorption
3. Hemimandibular hyperplasia
4. Vertical Growth Pattern

Question 11

Dental Aetiology of Posterior Open Bite

Answer 11

1. Impacted teeth impede eruption
2. Ankylosis
3. Mesial tipping of molars due to early loss of E
4. Primary failure of eruption

• Genetic condition, usually bilateral
• Teeth fail to erupt and ankylosed
• Usually all teeth distal to most mesial affected tooth

Question 12

Soft Tissue Aetiology of Posterior Open Bite

Answer 12

Macroglossia such that tongue interposed between posterior teeth

Question 13

Definition of Anterior Open Bite

Answer 13

Vertical overlap does not exist when buccal segments are in occlusion

Question 14

Definition of Posterior Open Bite

Answer 14

Inter-occlusal space between posterior teeth when teeth in occlusion

Question 15

Definition of Deep Bite

Answer 15

Excessive incisal overlap in the vertical plane

Question 16

Normal overbite is?

Answer 16

2-4mm

Question 17

Aetiology of a Skeletal Deep Bite

Answer 17

Upward and forward rotation of mandible

Associated with low mandibular plane angle and convergent rotation of max and mand anteriorly

Question 18

Dental Characteristics of a Skeletal Deep Bite

Answer 18

1. Rotation of jaw carries incisors into overlapping position
2. Upright lingually displace incisors

Question 19

Soft Tissue Characteristics of a Skeletal Deep Bite

Answer 19

1. Increased nasiolabial angle
2. Prominent chin

Question 20

Cephalometrics of Skeletal Deep Bite

Answer 20

1. Decreased LAFH
2. Square gonial angle

Question 21

Aetiology of Dental Deep Bite

Answer 21

1. Excess eruption of anterior teeth (upper and/or lower)
2. Under-eruption of posterior teeth → Reduced OVD
3. Bimaxillary retroclination

Question 22

Characteristics of Excessive Anterior Teeth Eruption

Answer 22

1. Incisor display at rest
2. Increase curve of spee