SCISSOR BITE

ACCORDING TO GRABER

Cross bite is a condition where one or more teeth may be abnormally malposed buccal or lingually or labially with reference to opposing teeth.

CLASSIFICATIONBased on Location

ANTERIOR CROSS BITE POSTERIOR CROSS BITE

a. According to no. of teeth involved a. According to no. of teeth involved

Single tooth Cross bite

Segmental Cross bite

Single tooth Cross bite

Segmental Cross bite

b. According to side involved

Unilateral Bilateral

c. According to extent

Single postureCross bite

BuccalNon-occlusion

LingualNon-occlusion

Cross bite

DEFINITION

A scissor bite is defined as buccal displacement of a maxillary posterior tooth, with or without contact between the lingual surface of the maxillary lingual cusp and the buccal surface of the mandibular antagonist's buccal cusp

Also known as Brodie bite

ETIOLOGY

Combination of excessive maxillary width and a narrow mandibular alveolar process.

Although the width of the mandibular base is usually normal or it can be limited to one quadrant.

SCISSORS-BITE IS CHARACTERIZED BY

labial eruption of the upper molar and/or lingual tipping of the lower molar caused by an arch-length discrepancy in the posterior region.

The upper molars are positioned outward or the lower molars are positioned inward.

When the mouth is closed the molars miss each other and overlap with no contact.

FEATURES IN SCISSOR BITE

Facial profile:The scissor bite has no significant influence on the facial profile, except in unilateral case that often leads to minor facial asymmetry.

Airway:The scissor bite is not known to reduced airway.

Chewing function: The chewing function is bad since the molars make no contact with each other.

Jaw joints: Patients may experience a clicking or pain in the jaw joints since the jaw is usually forced to function in a deviated position during the chewing process.

TREATMENT

SEVERAL TREATMENT PROCEDURES HAVE BEEN PROPOSED TO TREAT SCISSORS-BITE

intermaxillary cross-elastic

Multibracket appliance

transpalatal arch appliance (TPA) with intra-maxillary elastic.

Lingual arch appliance with intra-maxillary elastic.

these generate extrusive forces on the second molars in both jaws and might induce an undesirable decrease in overbite, clockwise rotation of the mandible, and premature contact.

In addition, treatment results might depend on patient cooperation if intermaxillary elastic is used.

RECENTLY dental implants, miniplates, and screws

have been used as skeletal anchorage.

Skeletal anchorage provides stationary anchorage for various tooth movements without the need for active patient compliance and with no undesirable side effects.

TITANIUM MINISCREWSclinical advantages:

minimal anatomic limitations on placement.

lower medical costs, and simpler placement with less invasive surgery.

MINI IMPLANT

CORRECTION BY BITE PLANE