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Transcript of crossbite,
CROSS BITE Made by : hanin masarwa
Group : 3418
Cross bite
Cross bite is a condition where more than one tooth is positioned outward or inward in relation to the mouth as compared to the corresponding tooth above or below it. The severity of cross bite can vary from mild to extreme. It is a common condition, which is why you need to know some details about it.
CROSS BITE
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.
Lingual cross bite
The buccal cusps of the lower teeth occludebuccal to the buccal cusps of the upper
teeth
Buccal cross bite
the buccal cusps of the lower teeth occludelingual to the lingual cusps of the upper
teeth
Aetiology
Local causes Skeletal causes
Local /dental causes
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.
Skeletal crossbite
mismatch in the relative width of the arches e.g in thumb sucking, CLAP
Thumb sucking
Constriction of maxillary arch
Cross bite in clap
Skeletal crossbite
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
Cross bite in skeletal classlII patient
Skeletal crossbite
Cross bites can also be associated with true skeletal asymmetry e.g trauma to TMJ, Hemifacial microsomia, Hemimandibular hypertrophy
Asymmetry and cross bite
Types of cross bite
Anterior cross bite Posterior cross bite
anterior crossbite
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
Posterior cross bites
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
displacement2) Unilateral buccal crossbite with no
displacement3) Bilateral buccal crossbite4) Unilateral lingual crossbite5) Bilateral lingual crossbite (scissors bite)
Unilateral buccal crossbite with displacement
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
Unilateral buccal crossbite with no displacement
less common Can be dental/ skeletal
Bilateral buccal crossbite
more likely to be associated with a skeletal discrepancy, either in the
anteroposterior or transverse dimension, or in both.
Unilateral lingual crossbite
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
Bilateral lingual crossbite (scissors bite)
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
Scissors bite
How to differentiate b/w skeletal and dental cross bite
P.A cephalogram
Treatment of anterior cross bite (dental)
A developing cross bite can be managed by:
1) Tongue blade therapy2) Lower Inclined plane therapy3) Posterior bite block
Tongue blade therapy
CATALANS APPLIANCE OR LOWERANTERIOR INCLINED PLANE
Treatment of anterior cross bite (dental)
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)
Double cantilever spring or 'Z' spring
2x4 appliance
Treatment of anterior cross bite (skeletal)
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
Appliance for anterior maxillary expansion
Correction of anterior cross bite with a fixed appliance
Face mask therapy
Treatment of posterior crossbite (dental)
Cross elastics fixed appliance
Cross elastics
Fixed appliance
Treatment of posterior crossbite (skeletal)
Eliminate sucking habits Remove any tooth interferences Maxillary expansion (rapid/slow) Orthognathic surgery
Tongue crib/habit breaking appliance
Tooth interference leading to cross bite
Max expansion using quadhelix
Quadhelix on cast
Max expansion using banded expander (hyrax expansion screw)
split –plate expansion appliance (Schwartz plate.)
Rapid Palatal Expansion
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
Bonded expander
Slow Palatal Expansion
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
Correction of cross bite with orthognathic surgery