increased overbite/ Class II div 2

Question 1

what is the definition of an overbite?

Answer 1

> overlapping of the upper anterior teeth over the lowers in a vertical plane

> normal value = 3-4mm

Question 2

what is the definition of an increased overbite?

Answer 2

upper incisors overlap lowers by more than 4mm

Question 3

what is a reduced over bite?

Answer 3

> less than 3mm overlap

Question 4

what is the significance of an increased overbite?

Answer 4

> Trauma – soft tissues of anterior palate

> Prevents overjet reduction during treatment

> Dentofacial aesthetics

> Restorative difficulties

Question 5

what are the extra oral features of an increased overbite?

Answer 5

> reduced lower face height

> often class II skeletal relationship

Question 6

what is the incidence of increased overbite?

Answer 6

> Increased overbite is a feature of many malocclusions

1. Most Class II Div 2 malocclusions
2. Many Class II Div 1 malocclusions
3. Some Class III and Class I malocclusions

Question 7

what is the aetiology of an increased overbite?

Answer 7

> AP skeletal discrepancy (Class II, III)

> Increased interincisal angle (Class II Div2)

> Reduced lower face height

> Unopposed lower incisors - can cause trauma

Question 8

why do we treat an increased overbite?

Answer 8

> Allow overjet reduction

> Facilitate a Class I incisor relationship

> Improve post-treatment stability

> Facilitate restorative treatment

Question 9

how do we reduce an increased overbite in growing patients (eg <14)

Answer 9

> Anterior Biteplane

> Functional Appliance (eg. Andresen, Twinblock)

> Fixed appliances

Question 10

how do we reduce an increased over bite in non growing patients (>14)

Answer 10

> Orthognathic surgery often required

> Sometimes fixed appliances alone

> Therefore refer deep bite patients early

Question 11

what are the key features in an anterior bite plane in the treatment of growing patients with an increased over bite?

Answer 11

> Biteplane only contacts with lower incisors

> Posterior mandibular rotation

> Eruption of molars due to separation

> has no active component

Question 12

what are the key features of functional appliance in treatment of an increased over bite?

Answer 12

> for Class II Div 1 malocclusions

> Anterior biteplane effect = the posterior teeth are separated vertically when wearing the appliance allowing eruption

> Trimming posterior inter-occlusal acrylic allows eruption of posterior teeth

> This also facilitates full overjet reduction

Question 13

how does fixed appliance reduce an increased overbite?

Answer 13

> Overbite reduction is mostly due to molar extrusion

> Some incisor intrusion is possible, apical force can cause small amount of vertical movement

Question 14

what is the definition of Class II div 2 malocclusion ?

Answer 14

> Lower incisor edges are palatal to the cingulum plateau of the upper incisors and the upper central incisors are retroclined.

> The overjet is usually average but may be increased

Question 15

what is the incidence of class II div 2 malocclusion in the population?

Answer 15

> 5-10%

Question 16

what is the extra oral features of a class II div 2 malocclusion?

Answer 16

> skeletal II relationship

> reduced lower face height

Question 17

what are the intraoral features of Class II Div 2 malocclusion?

Answer 17

> Retroclined upper (and lower incisors)

> Increased inter-incisal angle

> Deep overbite

Question 18

what is the cephalometry for class II div 2 malocclusion?

Answer 18

> Upper incisors retroclined
UI / Mx < 105º

> Often Class II skeletal
ANB > 4º

> Increased overbite

> Reduced lower facial proportions

Question 19

what is the significance of a class II div 2 malocclusion?

Answer 19

> Poor dental appearance

> Traumatic overbite

> Reduced lower face height

Question 20

what is the treatment aims of a class II div 2 malocclusion?

Answer 20

> Relieve crowding and align arches

> Reduce overbite

> Produce a stable incisal relationship

> Improve facial profile

Question 21

what are the treatment options for class II div 2 malocclusions?

Answer 21

1. Fixed appliances
   - Often also use URA to help overbite reduction
2. Fixed Appliances + Surgery

Question 22

what type of movement do fixed appliances allow us to do while treating class II div 2 cases?

Answer 22

> Torqueing

> root control required to upright and then bodily retract upper incisors

Question 23

which class II div 2 malocclusion cases suitable for treatment with fixed appliances?

Answer 23

> Crowded upper arch requiring extractions

> Crowded lower arch requiring extractions and alignment

> Acceptable facial profile

> Only in growing patients if there is a deep overbite

Question 24

what is common treatment plan for someone requiring treatment for a class II div 2 malocclusion?

Answer 24

> Anterior biteplane usually used with fixed appliances to reduce the overbite

> Usually extract upper 1st premolars

Question 25

what are the stages of treatment for a class II div 2 malocclusion with fixed appliances?

Answer 25

1. stage 1 - overbite reduction - An upper removable biteplane and lower fixed appliance is an efficient way to reduce a deep overbite
2. stage 2 - torquing upper incisors

Question 26

which cases of CII div2 are suitable for surgical treatment?

Answer 26

> Adult patients (non-growing)
- too old for functional appliances

> Poor facial profile
- vertical: reduced lower face height
- AP: Class II skeletal pattern

> Deep overbite

Question 27

what are the stages of surgical class 2 div 2 malocllsuion?

Answer 27

1. Correction of incisor inclinations
   using fixed appliances
2. Surgical correction of jaw relationship

Question 28

what is the prognosis of class II div 1 malocclusion treatment?

Answer 28

> Stability depends on correction
of the inter-incisor angulation

> Must achieve Class I incisors