Overbite

Question 1

Define overbite

Answer 1

The vertical overlap of the incisal edge of maxillary incisors over the mandibular incisors

Question 2

What are the 3 means of overbite reduction?

Answer 2

1. Extrusion of posterior teeth
2. Intrusion of incisors
3. Proclination of incisors

Usually is a combination of all 3

Question 3

What does overbite reduction depend on?

Answer 3

• vertical skeletal patterns
• inclination of incisors
• crowding
• growth - muscles can make eruption of teeth difficult

Question 4

How can fixed appliances reduce an overbite?

Answer 4

• arch wires -
flat stainless steel wires,
stainless steel wire with reverse curve of spee in lower and increased curve of spee in upper,
rocking chair NiTi wire

Question 5

What causes an increased overbite?

Answer 5

Dental
• over eruption of anterior teeth
• retroclined upper anterior teeth
• loss of posterior teeth

Skeletal
• forward growth rotation
• low FMPA angle

Soft tissues
• high lower lip line
• increased mentalis muscle activity

Question 6

What are methods of overbite reduction?

Answer 6

• ura with anterior bite plane
• fixed anterior bite planes
• lower arch wire with reverse curve of spee
• upper arch wire with increased curve of spee
• class II elastics
• bond lower second molars
• sectional mechanics
• orthographic surgery

Question 6

What is a normal overbite?

Answer 6

When upper incisors cover 1/2 to a 1/3 of lower incisors

Question 7

What are the skeletal causes of an increased overbite?

Answer 7

Low Frankfort mandibular planes angle (FMPA)

Question 8

What are the dental features which cause and increased overbite?

Answer 8

• excessive eruption of incisors
• retroclination of incisors
• bimaxillary retroclination

Question 9

What soft tissue factors cause an increased overbite?

Answer 9

• high lower lip line

* increased mentalis activity