its types, etiological factor & management

CROSSBITE

4th Year Prof. B.D.S.Department of

Orthodontics, FJDC.

Salman Zahid

CROSS BITECross bite is a discrepancy in the

buccolingual relationship of the upper and lower teeth

CLASSIFICATION(1)BASED IN THE LOCATION

ANTERIOR CROSSBITE:When the lower incisors come in front of the upper incisors, this condition is called as anterior crossbite or reverse over jet.

ETIOLOGICAL FACTORS OF

Etiology of the anterior crossbite is based on:1. Dental factor.2. Skeletal factor.3. Soft tissue factor.4. Functional factor

ANTERIOR CROSS BITE

DENTAL FACTOR Anomalies of tooth sizes. Anomalies of tooth shape. Faulty eruption pattern where the tooth erupts

out of the normal position. Retained deciduous teeth. Ectopic eruption. Tooth ankylosis. Supernumerary teeth.

SKELETAL FACTOR

Asymmetric growth of maxilla or mandible due to:

Inherited growth pattern. Trauma during growth or at birth. Long standing functional problem.

SOFT TISSUE FACTOR Digit sucking. Habit of biting upper lip.

FUNCTIONAL FACTOR Habitual forward positioning of the

mandible for maximum intercuspation. This may lead to anterior crossbite.

SINGLE TOOTH CROSS BITE

It occurs when single tooth is involved.

SEGMENTAL CROSS BITE

It occurs when a single arch segment is involve.

POSTERIOR CROSS BITEDeviation from the ideal occlusion in the transverse plane is called as posterior

crossbite.

Etiological factors are also based on:1. Dental factor.2. Skeletal factor.3. Functional factor.4. Soft tissue factor.

ETIOLOGICAL FACTORS OF POSTERIOR CROSS BITE

DENTAL CROSS BITE Prolonged retention of the primary

teeth. Ectopic eruption of the permanent first

molar Cleft palate cases.

SKELETAL FACTOR Inheritance. Deficient lateral growth of maxilla. Abnormal mandibular growth laterally.

FUNCTIONAL FACTOR Deviation of mandible during jaw

closure because of the occlussal interference.

This results in unilateral posterior croossbite.

SINGLE TOOTH CROSS BITE

It occurs when single posterior tooth is involved.

when a single arch segment is involve.

SEGMENTAL CROSS BITE

When one side of arch is involved

UNILATERAL CROSS BITE

When both the arches are involved.

BILATERATAL CROSS BITE

When the buccal cusp of the maxillary posterior tooth(teeth) occlude lingual to the buccal cusp of the mandibular molar

teeth. Most commonly seen in clinical

practice.

SIMPLE POSTERIOR CROSS BITE

When the maxillary posterior teeth occludes completely on the buccal

aspect of the mandibular posterior teeth. Also called as scissor bite

BUCCAL NON-OCCLUSION CROSS BITE

It occurs when the maxillary upper molars occlude on the lingual aspect of

the mandibular lower molars.

PALATAL/LINGUAL NON-OCCLUSIONCROSS BITE

Skeletal crossbite occurs because of :1. Discrepancy in the size of

mandible/maxilla.2. Due to inheritance.3. Defective embryological development.

SKELETAL CROSS BITE

Dental crossbite occurs b/c of:1. Supernumerary teeth.2. Retained deciduous teeth.3. Deciduous tooth results in the displacement

of the permanent tooth germ.4. Lingual eruption of the anterior teeths.

DENTAL CROSS BITE

Forward positioning of the mandible due to habit.

Results in pseudo Class III.

FUNCTIONAL CROSS BITE

MANAGEMENT

Elimination of the factors that may lead to the anterior cross bite

Removal of occlusal prematurities Extraction of supernumerary tooth

before they cause displacement of other tooth.

Habit breaking appliance.

PRIMARY DENTITION(PREVENTIVE

ORTHODONTICS)

Equilibration to eliminate mandibular shift

Expansion of constricted maxillary arch Unilateral repositioning of teeth

MANAGEMENT OF POSTERIOR CROSS BITE IN

PREADOLESCENTS

Mostly observed in primary or early mixed dentition, a shift into posterior cross will be solely due to occlusal interferences caused by primary canine or molar

Child requires only limited equilibration of primary teeth to eliminate interference and lateral shift

EQUILIBRATION TO ELIMINATE MANDIBULAR

SHIFT

W Arch:-Fixed appliance constructed of 36 mil steel

wiresoldered to the molar bands.-Activated simply by opening apices of W.-Delivers proper force levels when opened4-6mm wider than passive width.

EXPANSION OF CONSTRICTED MAXILLARY ARCH

Quad helix Appliance:-Efficient fixed slow expansion appliance. -Expansion continued at a rate of 2mm permonth(1mm on each side) until cross bite is slightly overcorrected. -Most posterior crossbites require 2-3

months of active treatment and 3 months of retention (during which lingual arch left passively in place).

-The force from elastic is directed vertically as well as faciolingually which will extrude posterior teeth and reduce overbite

- Cross-elastics, typically run from the lingual of the upper molar to the buccal of the lower molar.

UNILATERAL REPOSITIONING OF TEETH

Tongue Blade: Used when a cross bite is seen at the

time the permanent teeth are making an appearance in the oral cavity.

This is continued for 1-2 hours for about 2 weeks.

MANAGEMENT OF ANTERIOR CROSS BITE IN

PREADOLESCENTS

 Used only in those cases where the cross bite is due to a palataly placed max incisors. (Constructed at 450 angulations on the lower anterior teeth by acrylic or cast metal).

CATLAN’SAPPLIANCE OR LOWER ANTERIOR INCLINED

PLANE

Used when anterior cross bite involving 1 or 2 max. anterior teeth.

Effective only when there is enough space for aligning the teeth.

DOUBLE CANTILEVER SPRING/

Z-SPRING

Rapid Maxillary Expansion (Hyrax Screw): Patients for opening the midpalatal suture

may have such severe crowding that even with this arch expansion, premolar extraction will be required.

Opening the midpalatal suture should be used primarily as a means of correcting a skeletal crossbite.

MANAGEMENT OF CROSS BITE IN PERMANENT

DENTITION

RPE:

Recommended for more mature patients.

Two turns initially and two turns per day until the suture opens

Forces transmitted on suture

SPE: Younger patients

because it is more physiologic and equally effective.

Slow expansion, with one turn(1/4 mm) of the screw every other day in these

Less pressure to teeth and suture

Three approaches to correction of less severe dental cross bites are feasible:

-a heavy labial expansion arch-an expansion lingual arch-cross-elastics

MANAGEMENT OF POSTERIOR CROSS BITE IN PERMANENT

DENTITION

Cross bite due to skeletal asymmetry Correction require orthognathic surgery

once growth has slowed to adult levels

SURGICAL ORTHODONTICS(AFTER THE ACTIVE GROWTH IS

COMPLETE)

A 12.8 year-old Caucasian girl presented for treatment complaining of an unpleasant smile.

Oral breathing, lip incompetence, and atypical swallowing.

An increased facial lower third and a convex profile.

Intraoral evaluation showed a Class II, division 1 malocclusion, and bilateral posterior crossbite

CASE-1

Treatment Plan

Palatal expansion, by a modified Haas-type expander,

Increasing the maxillary transversal dimension to correct the bilateral posterior crossbite.

A comprehensive orthodontic treatment initiated in order to improve the results obtained after expansion .

TREATMENT PROGRESS

Activation of the screw initiated immediately after appliance insertion with a complete turn.

After that, the patient was instructed to keep the activation with 2/4 turns in the morning and 2/4 turns in the afternoon, during eight days.

The expander passively maintained for a period of three months, followed by a removable retainer, which was used for another six months.

The whole treatment lasted about 1 year and 3 months.

Corticotomy was performed on the buccal and palatal side of the right maxillary segment

Expansion started 10 days after corticotomy and was performed using fixed orthodontic appliance and a heavy labial arch wire (0.040-in Stainless Steel wire).

Cross bite correction was achieved in 10 weeks. The lower left third molar was uprighted using a miniscrew.

Leveling, aligning, arch coordination, and finishing were continued using the fixed orthodontic appliance and intermaxillary elastics.

TREATMENT PLAN AND PROGRESS

Based on this case report, a rapid maxillary expansion protocol carried out at mixed dentition was effective and stable 21 years post treatment.

CONCLUSION

A 9-year-old boy was referred by his pediatric

dentist for an orthodontic consultation regarding

his anterior bite.

CASE-2

Extra Oral Examination: Balanced face with a pleasant profile maxillary dental midline coincide with the facial midline. The chin was deviated to the right side by 3 mm from the

facial midline, and the entireIntra Oral Examination: Mixed dentition stage with Class I left and half-cusp Class

II right molar relationships. The overbite was deep (100% on the left maxillary central

incisor) Anterior crossbite of 11 Unilateral (right) posterior crossbite were evident. Both crossbites were being expressed as a result of

functional shifts in the sagittal (i.e., forward) and transverse dimensions (to the right side). 

Based on the above findings,two treatment approaches were considered: Quad-helix expansion combined with bite

opening and bracket-bonding only the four maxillary incisors would permit simultaneous correction of both anterior and posterior crossbites. However, expansion with the quad-helix would not control the palatal tipping of the right posterior segment mesial to the first molar (especially the primary maxillary right canine).

Removable appliance was chosen to better control the canine and the adjacent palatal tipping.

TREATMENT PLAN

The removable appliance option included the use of two upper removable appliances. The first incorporated a jackscrew set to act in an anteroposterior direction to tip the maxillary right permanent central incisor labially and bilateral posterior bite planes (about 4 mm thick) to disengage the bite and facilitate tooth movement.

Another removable appliance with a midpalatal jackscrew and bilateral posterior bite planes (of minimal thickness) to further expand the right maxilla (differential expansion). Two Adams clasps and two ball clasps were incorporated in both appliances to aid retention.

The first appliance was used for 7 weeks to achieve a positive overjet of the maxillary right central incisor.

After anterior crossbite correction, a bilateral, posterior open bite resulted from use of the posterior bite planes that caused intrusion of mostly the mandibular posterior segments.

Use of the second appliance was followed for 8½ weeks

Expansion was continued until the desired transverse correction of the maxillary right posterior segment was achieved.

The total active treatment period was about 4 months. For both appliances, the patient was seen during the first week after appliance insertion to ensure comfort and monitor cooperation. Thereafter, follow-up appointments were scheduled every 3–4 weeks.

Upon completion of treatment,the right molar relationship was restored to Class I.

the left molar relationship had a tendency to Class III and chin asymmetry was reduced.

The upper Hawley was then used full-time (day and night) for 6 months.

The patient was then asked to wear the retainer only at night for another 4 months. The case was followed up out of retention for an additional 4 months.

Use of the Hawley retainer promotes retention and resolution of any residual lateral posterior open bite.

Stable anterior and posterior relationships were evident, and continued spontaneous alignment of the mandibular incisors was noticed. Furthermore, there was a spontaneous decrease in the maxillary diastema