1. Dr. JUNAID DAYAR

2. A discrepancy in the buccolingual relationship of the
upper and lower teeth.
By convention the transverse relationship of the
arches is described in terms of the position of
the lower teeth relative to the upper teeth.

3. The buccal cusps of the lower teeth occlude
buccal to the buccal cusps of the upper teeth

4. the buccal cusps of the lower teeth occlude
lingual to the lingual cusps of the upper teeth

5.  Local causes
 Skeletal causes

6.  The most common local cause is crowding
where one or two teeth are displaced from the
arch
 early loss of a second deciduous molar causing
a second premolar to erupt palatally/lingually
 retention of a primary tooth can deflect the
eruption of the permanent successor leading to
a cross bite.

8.  mismatch in the relative width of the arches e.g
in thumb sucking, CLAP

12.  an anteroposterior discrepancy, which results
in a wider part of one arch occluding with a
narrower part of the opposing jaw e.g sk.cl II,
sk cl III

14.  Cross bites can also be associated with true
skeletal asymmetry e.g trauma to TMJ,
Hemifacial microsomia, Hemimandibular
hypertrophy

16.  Anterior cross bite
 Posterior cross bite

17.  An anterior crossbite is present when one or
more of the upper incisors is in linguo-
occlusion (i .e. in reverse overjet) relative to the
lower arch
 Anterior crossbites are frequently associated
with displacement on closure

20.  Cross bites of the premolar and molar region
involving one or two teeth or an entire buccal
segment.
 can be subdivided as follows.
1) Unilateral buccal crossbite with displacement
2) Unilateral buccal crossbite with no
displacement
3) Bilateral buccal crossbite
4) Unilateral lingual crossbite
5) Bilateral lingual crossbite (scissors bite)

22.  deflecting contact on closure into the cross
bite.
 can affect only one or two teeth (dental)
 maxillary arch is of ”similar width” to the
mandibular arch (i.e. it is too narrow) with the
result that on closure the buccal segment teeth
meet cusp to cusp. In order to achieve a more
comfortable and efficient intercuspation, the
patient displaces their mandible to the left or
right

23.  less common
 Can be dental/ skeletal

24.  more likely to be associated with a
skeletal discrepancy, either in the
anteroposterior or transverse dimension, or in
both.

26.  This type of crossbite is most commonly due to
displacement of an individual tooth as a result
of crowding or retention of the deciduous
predecessor

27. This crossbite is typically associated with an
underlying skeletal discrepancy. often a Class
II malocclusion with the upper arch further
forward relative to the lower so that the lower
buccal teeth occlude with a wider segment of
the upper arch

31.  A developing cross bite can be managed by:
1) Tongue blade therapy
2) Lower Inclined plane therapy
3) Posterior bite block

34.  A.C.B which ha s already developed can be
treated by:
1)Double cantilever spring with posterior bite
plane
2)Fixed appliance(2 x4)

37.  Maxillary expansion
 Proclination of upper and retoclination of
lower anterior teeth by fixed appliance (class III
camouflage)
 Facemask therapy
 Orthognathic suregry to correct the jaw at fault

41.  Cross elastics
 fixed appliance

44.  Eliminate sucking habits
 Remove any tooth interferences
 Maxillary expansion (rapid/slow)
 Orthognathic surgery

51.  Done in adolescents and adults where strong
interdigitation of suture is present
 This creates 10 to 20 pounds of pressure across
the suture-enough to create microfractures of
interdigitating bone spicules
 rate of 0.5 to I mm/day
 2 to 3 week
 The expansion device is left in place for 3 to 4
months new bone forms in the space at the
suture, and the skeletal expansion is stable

53.  Done in preadolescent children esp with cleft
 2 pounds of pressure
 0.5 mm-1mm per week
 damage and hemorrhage at the suture are
minimized
 expansion is completed in 2 to 3 months