Crossbite
With regular teeth, the buccal cusps (facing the cheek) of the lower jaw posterior teeth bite in the middle between the cusps of the upper jaw posterior teeth . Similarly, the incisal edges of the lower anterior teeth meet the palatal (facing the palate) surfaces of the upper anterior teeth. The normal size ratio of the upper jaw to the lower jaw is made clear by the slipper comparison : The foot (= lower jaw) fits into the slipper (= upper jaw).
If hump on hump bite , one speaks of a head bite ; if the buccal cusps of the mandibular posterior teeth bite laterally past the buccal cusps of the upper posterior teeth, a cross bite is present. If the lower posterior tooth bites completely past the upper posterior tooth, one speaks of a scissor bite or a buccal nonocclusion . Similarly, there is at the incisors frontal head bite (cutting edge on cutting edge) and the frontal cross bite (lower incisors are in front of the maxillary incisors).
When the jaw is closed, a cross bite often causes a forced displacement of the mandible to the side or forwards (forced bite, displacement of the retral contact position to the intercuspid position, RKP / ICP displacement). The extent of this shift is decisive for the classification of the need for treatment of the crossbite according to the IOTN (Index of Orthodontic Treatment Need).
Cross bites very often occur in Progenie , which in turn is immediately evident from the slipper comparison. Impaired nasal breathing, impaired muscle functions, scars and the position and movement of the tongue can also play a role.
Individual evidence
- ↑ Watzer, G and Watzer, A: IOTN and PAR index in Austria - manual for the correct and proper application. Published by the Association of Austrian Orthodontists, 2020, ISBN 978-3-9519790-0-7 .
