1. Anterior Crossbite

2. （A）the etiology of Anterior Crossbite
Genetic and congenital factors：
mandibular prognathism
Acquired factors：
bad feeding posture
the primary canines interference
mouth breathing
bad habits
cleft palate

3. （B）The performance of anterior crossbite
Malocclusion
Jaw dysplasia and Craniofacial anomalies

4. （C）Class III presentations
In accordance with Pathogenic mechanism
dental
skeletal (Three) ：
1 Maxillary involvement : Maxillary Deficiency
2 Mandibular involvement: Mandibular Excess
3 Maxillary and mandibular involvement
Functional

5. （C）The categories of anterior crossbite
crossbite of dental origin：
Anterior crossbite
Usually class I skeletal pattern Neutrocclusion of molars
Normal soft tissue profile
Anterior teeth can retrude edge to edge
(Convenience shift of mandible)

6. （C）Categories crossbite of skeletal origin：
It is due to excessive mandibular growth，in addition to anterior crossbite ，there are obvious mandibular deformity、protrusive、obtuse mandibular angle，class Ⅲ malocclusion；Soft tissue profile is concave-type.A skeletal problem, without the ability to bring the incisors to edge-to-edge.

7. （C）Categories crossbites of skeletal origin：
The skeletal class Ⅲ malocclusion is characterized by mandibular prognathism , maxillary deficiency , or a combination of both. The patients may have a retrusive nasomaxillary area and a prominent lower third of the face , with a reverse overjet.

8. Peking University, sagittal bone-derived typing

9. （C）categories crossbite of functional origin ：
By factors such as primary canine lack of occlusion wear, or habitual mandibular protrusion caused pseudo-mandibular protrusion. Such patients also have a normal skeletal mandibular pattern，the incisors show negative overjet in CO but touch edge-to-edge in CR. Anterior teeth can retrude edge-to-edge

10. （C）Categories
According to the relationship between vertical facial points
hyperdivergent , high-angle
hypodivergent , low-angle
average-angle

11. （D） The differential diagnosis
Dental
Functional
Skeletal
Profile type
normal
Staight
Concave
ANB angle
00 ～10
<-40
Mandible CO\CR
Can
Can not

12. （E）Treatment planning
characteristic
1.complexity
2.timeliness
3.recrudescence
Crossbite should be treated as soon as it’s discovered，it can be treated successfully through early orthodontic and orthopedic intervention.

13. （E）Treatment planning
Crossbite occlusion: be dental or functional.No matter what reason, early treatment is very important.

14. a、primary crossbite Treatment ：
1 . Occlusal adjustment： occlusal interference leading to a mandibular shift.Early occlusal adjustment contribute to normal growth and development of the mandible.

15. a、 crossbite of primary dentition
Treatment ：
2. plate appliance：Can be applicable to primary tooth roots which are still not resorbed entirely ，Since the anterior crossbite are caused by the lingual incisors . The plate appliance need enough anchorage, take the advantage of lingual spring push the incisors out in order to correct the crossbite relationship.

16. a、crossbite of primary dentition
Treatment ：
2. plate appliance ： As the primary teeth root labial movement, permanent teeth root will also be with the side to the same direction, guiding the permanent anterior teeth erupt normally .But the correct of the primary dentition crossbite doesn’t mean the treatment of the permanent dentition crossbite.

17. a、 crossbite of primary dentition
3. FR-3 appliance：

18. b、Mixed-dentition crossbite
dental
skeletal
A hand-wrist x-ray can be helpful in assissing whether the patient has substantial growth remaining
Functional

19. b、 crossbite of Mixed-dentition
Treatment ：
a. Bite appliance
b plate appliance

21. b、 mixed-dentition Treatment ：
3 protraction appliance：Applicable to patients with maxillary deficiency.The orthopedic facial mask is attached to hooks on a bonded expander by way of strong elastics that produce up to 450 g of force per side. Producing a forward movement of the maxilla.

22. b、 mixed-dentition Method ： c protraction appliance ： Mouth parts
Clasp retention
Archwire
plate
hook

23. b、Mixed dentition crossbite
Treatment ：
3 reverse headgear：
Facemask
Forehead anchorage
chin anchorage
hook

24. b、 Mixed dentition crossbite
Therapy ：
4. chin cup: anterior crossbite with a relatively normal maxilla and a moderately protrusive mandible can be treated with a chin cup. The force line is directed through the head of condyle，About 400g on each side.

25. c、 crossbite of Permanent
Dental
mild skeletal 　　　　
camouflaged orthodontic technique
serious skeletal : orthognathic surgery

26. c、 Permanent crossbite
Treatment method ：
1. fixed appliance：
Applicable to dental crossbite and straight profile type，fixed appliance can be used to move the upper incicors out of crossbite ，combination of class III elastics to adjust the arch relationship.

27. c、 Permanent crossbite
Treatment method ：
2. orthodontic – orthognathic surgery ：
class III patients with significant anteroposterior jaw discrepancies that cannot be camouflaged with orthodontic tooth movement will have to be treated surgically.

28. c、 Permanent crossbite
Treatment ：
2. orthodontic – orthognathic surgery ：
procedure ：Mainly due to bone malformations and remove the existence of compensatory tooth in order to correct the angle the teeth of the jaw . So that the maxillary teeth to the lingual position, mandible teeth to labile potion .

29. c、 Permanent crossbite
therapy：
2.orthodontic – orthognathic surgery：
surgery progress ：the maxilla may be brought forward with a lefort Ⅰsurgical osteotomy procedure or the mandible may be set back with a bilateral sagittal split osteotomy , also can be at the same time do either maxillary and mandible surgery .

30. Dental skeletal functional
Summary
Anterior crossbite
Dental skeletal functional
Primary dentition
Mixed-dentition
Permanent dentition