Class II Div II Malocclusion

Question 1

Define Class II Div II incisal relationship.

Answer 1

• Lower incisor edges occlude posteriort o the cingulum plateau of the upper incisors.
• Upper incisors are retroclines.
• Overjet may be normal or increased

Question 2

What is the incidence of Class II Div II?

Answer 2

5-18%

Question 3

What is the skeletal aetiology of Class II Div II malocclusion?

Answer 3

• commonly associated with mild Class II A-P skeletal pattern
• LAFH and FMPA and MMPA are reduced due to a forward (anticlockwise) rotational growth pattern

Reduced LAFH + Class II jaw relationship = absence of an occlusal stop to the lower incisors thus increasing the overbite through further eruption

Question 4

What is the soft tissue aetiology of Class II Div II malocclusion?

Answer 4

• high lower lip line will tend to retrocline the upper incisors
• lateral incisors (shorter crown length) will escape the action of the lips and will be of average inclination or proclined instead + mesiobuccally rotated due to crowding
• active muscular lips may also cause bimaxillary retroclination

Question 5

What is the dental aetiology of Class II Div II malocclusion?

Answer 5

• retroclination of upper centrals
• upper laterals often crowded + mesio-bucally rotated
• upper laterals may be of average inclination or proclined (depending on their position relative to lip line)
• reduced arch length, thus exacerbated crowding
• lower incisors may occlude with thhe upper incisors or palatal mucosa

Increased overbite is due to the lack of effective occlusal stop to limit eruption of the lower incisors. This results in their continued eruption and an increased inter-incisal angle.

Question 6

What are the common features of a Class II Div II malocclusion?

Answer 6

Extra-oral features:
* mild class II skeletal pattern with reduced LAFH
* prognathic mandible due to forward rotational growth pattern
* more pronounced labio-mental fold

Occlusal features:
* retroclined upper centrals
* average angulation or proclined laterals (depending on their position relative to the lip line)
* crowding
* traumatic overbite where lower incisors cause ulceration on palatal tissues, or retroclination of the upper incisors cause stripping of the labial gingiva of the lower incisors
* lingual crossbite in the premolar region

Question 7

What is torque?

Answer 7

Movement of the root apex buccolingually, either with no or minimal movement of the crown in the same direction

Question 8

What are the treatment options for Class II Div II malocclusion?

Answer 8

Accept
* acceptable aesthetics
* patient not concerned
* OB not a significant problem

Growth modification
* growing patient (boys 14 ± 2 years; girls 12 ± 2 years)
* mild to moderate skeletal class II pattern
* functional appliance to procline upper incisors (modified twin block, springs or screw, upper sectional fixed appliance)

Camouflage
* accept unnderlying skeletal relationship
* careful extraction to make space
* fixed appliance to reduce overbite and reduce inter-incisal angle

Orthognathic treatment
* too severe a malocclusion for orthodontics alone
* non-growing patient
* profile concerns