cl II malocclusion

Class II Malocclusion

In sagittal plane this malocclusion is called as postnormal occlusion or distoclusion.
According to Angles classification indicates that mandibular arch is in a distal relation to that of the maxilla.
The mesiobuccal cusp of the maxillary first molar occlude more than one half cusp width anterior to mesiobuccal groove of the mandibular first molar.



Class II division 1 : The molar relationship in class II with the upper anterior teeth proclined.
Subdivisions of Class II Malocclusion



Class II division 2: The molar relationship in class II with the upper central incisor are retroclined and overlapped by the lateral incisors.
In more sever cases both upper central and lateral incisors are retroclined and overlapped by canines.
Subdivisions of Class II malocclusion

2- skeletal class II malocclusion:

1- maxillary protrusion.
2- mandibular retrusion.
3- combination of above.
Classification of Class II malocclusion
1- Dentoalveolar Class II malocclusion:
Normal maxillo-mandibular skeletal relation but the defect in alveolar bone or dentition

Mandibular Retrognathisim

Maxillary prognathisim
Maxillary dento-alveolar protrusion


Class II Division 1 malocclusion

Etiology

1- skeletal genetic component
Prognathic maxilla
Retrognathic mandible
Combination of above

2- soft tissue factor

Incompetent lips (proclined upper incisors)
Lower lip trap behind upper incisors
Tongue thrust

3- habits

Digit sucking habit (proclination of upper incisor, retroclination of lower incisor, anterior open bite)
Mouth breathing habit

Features of class II division 1 malocclusion:

Extraoral features
1- Convex profile.
2- Posteriorly divegent face
3- Deep mentolabial sulcus
4- Oval shaped face (mesocephalic to dolichocephalic in frontal view.
5- Incompitant lips.
6- Short hypotonic upper lip.
7- Everted lower lip.
8- Hyperactive mentalis muscle.
9- Abnormal perioral musculature.
10- Deficient lower facial height.
11- Lip trap (sometimes).

Intraoral features:

1- Class II molar relationship
2- Class II incisor and canine relationship
3- Increased overjet
4- Narrow V shaped upper arch
5- Deep palate
6- Over eruption of lower incisor
7- Deep bite may be traumatic
8- Exaggerated curve of spee
9- Other features may be seen like posterior cross bites or open bites

Management of class II division 1 malocclusion

Treatment is depend on:
1- patient age.
2- severity of malocclusion.
3- patient facial profile.
4- etiology of malocclusion.

There are three approach for the treatment of class II malocclusion:

1- Prevent malocclusion from occurrence.

2- Intercept the developing malocclusion.

3- Correct an already existing malocclusion.


Timing of the treatment is an important factor in the amount of changes that can be produced.

Optimum time for growth modification is prepubertal growth spurt.

Therefore proper diagnosis of the patient at early age and the use of correct functional appliances will cause the patient to avoid surgery.

Management of functional disturbances:

Mouth breathing – habit breaking appliances

Abnormal tongue position and swallowing patterns – fixed or removable habit breaking appliances

Lip posture and activity – lip exerciser

Finger sucking habit - fixed or removable habit breaking appliances

functional appliances is indicated for growth modification in growing patients.

Mild to moderate class II division 1
Proclined upper incisors
No lower and upper arch crowding
Deep overbite
Average or reduced lower facial height

Skeletal Class II In growing patient:

Mixed dentition period (modifying growth)

Prognathic maxilla – headgears

Retrognathic mandible – activator, frankle and other bite jumping devices

Dentoalveolar class II is treated with:

Removable appliances – robert retractor

Fixed appliances

Indication of removable appliances (Robert retrector)

1- Proclined upper incisors

2- Spaced upper incisors
3- Normal or reduced overbite

3- fixed appliances

Indicated for most complicated tooth movements which involve bodily tooth movement, intrusion, extrusion

Use class II elastics

Skeletal class II

Dentoskeletal compensation for the skeletal defect through reduction of tooth material is the treatment of choice ( camouflaging).

Generally maxillary first premolars are extracted.

Indicated in adults with no growth potential

mandibular advancement
Indication : skeletal class II caces with mandibular deficiency

The intraoral sagittal split ramus osteotomy is the popular technique for surgical mandibular advancement.
Orthognathic surgery

Maxillary impaction (Le Fort 1 maxillary osteotomy)

Indication : Vertical maxillary excess

Anterior maxillary sub-apical set back

Indication : maxillary excess in antero-posterior dimentional mid-face protrusion ( no vertical excess)

Orthognathic surgery

Combined surgical approaches : maxillary and mandibular

Indication : maxillary excess and mandibular deficiency
Orthognathic surgery


For overjet reduction to be stable , anterior lip seal must be achieved, lower lip contact the upper incisor

Appliances used for retention

1- lingual fixed retainer
2- Howly labial arch
Retention and stability