SCISSOR BITE
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