CROSS BITECROSS BITE

What is normal BITE?

What is CROSS BITE??

• It’s a condition where one or more teeth may be abnormally malposed buccally or lingually or labially with reference to the opposing tooth or teeth –Graber

• Discrepancy in the buccolingual relationship of the upper and lower teeth –Laura

• An abnormal buccolingual (labiolingual) relationship of the teeth –Moyer

• Post X-bite: Deviation from ideal occlusion in the transverse plane of space. -Proffit

PREVALANCE• Gender??• Ethnic group??

• Buccal crossbite• Lingual crossbite/complete lingual• Palatal crossbite/lingual• Unilateral crossbite• Bilateral crossbite• Functional lateral crossbite• Complete mandibular • Complete maxillary• Complete crossbite• Scissor bite• Anterior crossbite• Posterior crossbite

BUCCAL CROSSBITE• The buccal cusps of the lower teeth occlude

buccal to the buccal cusps of the upper teeth

LINGUAL CROSSBITE• The buccal cusp of the lower teeth occlude

lingual to the lingual cusps of the upper teeth

PALATAL CROSSBITE• Palatal displacement of the maxillary teeth as it

relates to the antagonist teeth

FUNCTIONAL LATERAL CROSSBITE

• Caused by an occlusal interference that requires the mandible to shift either anteriorly or laterally in order to achieve maximum occlusion

• COMPLETE MANDIBULAR CROSSBITE

When all the mandibular teeth are buccally positioned to all the maxillary teeth if the

mandibular arch is wide

• COMPLETE MAXILLARY CROSSBITE When the maxillary dental arch is wide

COMPLETE CROSSBTEwhen all teeth in one arch are positioned either inside or outside to the all teeth in the opposing arch.

SCISSOR BITE

is present when one or more of the adjacent posterior teeth are either positioned completely buccally or lingually to the antagonistic teeth and exhibit a vertical overlap.e.g: brodie syndrome, pierre robin syndrome---primary,mixed! Chewing,muscle,normal growth of Mn.

ANTERIOR CROSSBITE

A malocclusion in which one or more of the upper anterior teeth occlude lingually to the mandibular incisors; the lingual malpositions of one or more maxillary anterior teeth in relation to the mandibular anterior teeth when the teeth are in centric relation occlusion

This is when the upper incisors are in reverse overjet and occlude lingual to the lower incisor. An example of this would be an extreme class III incisor relationship.

POSTERIOR CROSSBITEWhen one or more posterior teeth locked in an abnormal relation with the opposing teeth of the opposite arch; can be either buccal or a lingual cross-bite and may be accompanied by a shift of the mandible.

CLASSIFICATION

ETIOLOGY

•DENTAL• SKELETAL• FUNCTIONAL• SOFT TISSUE

SOFT TISSUE

DIAGNOSIS• History• Clinical examination• Study models• Cephalogram lateral ceph for anterior crossbite P.A view for posterior crossbite

TREATMENT

TRIAGE

PRE-ADOLESCENT CHILDREN

1. Equilibration to eliminate mandibular shift2. Expansion of a constricted maxilla3. Unilateral repositioning of teeth

• MOVIE

II- MIXED DENTITION• Rationale for Early Interceptive Treatment:• Little possibility for self-correction • To save permanent dentition.• Postponing Rx---greater complexity• Can cause growth modifications and dental

compensations • Permanent deviation & craniofacial asymmetry &

masticatory patterns• Condylar deviation & TMJ sounds

• Interference with growth of the middle third of the face

• Abnormal speech patterns• Loss of arch integrity• Periodontal disease• Undesirable esthetics• Root resorption of central incisors

• Those that deliver rapid-heavy-intermittent forces:

• Fixed inclined bite planes• Constructed of acrylic• Placed onto the mandibular incisors• Treat lingually locked maxillary incisors• Do not require patient compliance• May open the bite, create a temporary• speech defect, or traumatize the dentition• No significant long-term side effects

• Reversed stainless steel crowns• Anterior stainless steel crowns cemented

backwards on the maxillary teeth• Stainless steel crown needs to open the bite 2 to

3 mm and establish at least a 25 percent overbite for successful treatment

• If they worsen or fail to treat the crossbite, add crown

• Tongue Blades• Usually employed as a follow up to treatment

with inclined plane• Simplest but least successful approach• Works best if the bite is normal and the involved

tooth is newly erupted

PERMANENT DENTITION• Individual teeth displaced into anterior

crossbite• Transverse maxillary expansion by opening the

midpalatal suture

HYRAX SCREW

RAPID PALATAL EXPANSION-Activation is 0.5 mm per day i.e. 2 turns for the screw-force is 10-20 lbs of forces applied -Forces transmitted on suture

SLOW PALATAL EXPANSION-Activation is 1mm per week-2lbs pressure applied-less pressure to teeth and sutures

SEQUELAE

• Movement of the lateral and medial poles of the working condyle during mastication in patients with unilateral posterior crossbite• condylar movements in patients with

unilateral posterior crossbites might be related to the susceptibility to TMJ disc displacement

• Ultrasonographic Thickness of the Masseter Muscle in Growing Individuals with Unilateral Crossbite

• The masseter muscle in untreated individuals with unilateral crossbite is thinner in the crossbite side when compared to the non-crossbite side possibly due to asymmetric activity of the masticatory muscles. Such an asymmetry in thickness of the masseter muscle could not be detected some years after the successful correction of the crossbite.

Is it important to correct cross bite in every

patient?

F L O B R U S H

I S

N T S M I L E E E

T H A N K Y O U H