The teeth are arranged disorderly due to insufficient space, that is, the amount of teeth (the sum of crown width) is relatively large, while the amount of bone (the total length of alveolar arch) is relatively small, and the labial (buccal) lingual dislocation or torsion of teeth in varying degrees.
There is a gap between teeth, that is, the amount of teeth (the sum of crown width) is relatively small, while the amount of bone (the total length of alveolar arch) is relatively large. Sometimes, it can be accompanied by different phenomena such as proximal and distal dislocation of teeth, lip and tongue dislocation and so on.
Jaw opening refers to the vertical non jaw contact of the upper and lower teeth in the median and non median jaw positions. Serious cases are not only easy to cause jaw relationship disorder, but also lead to facial deformity, affecting the patient's oral function and face.
It is usually called ground Baotian, which means that the lower teeth bite on the outside of the upper teeth, including forward and backward anterior crossbite and horizontal posterior crossbite. From the formation mechanism, it is divided into dental crossbite and bone crossbite.
It is usually called bucktooth, which means that the distance from the cutting edge of the upper anterior teeth to the lip surface of the lower anterior teeth is too large horizontally, and the maximum horizontal distance from the cutting edge of the upper anterior teeth to the lip surface of the lower anterior teeth exceeds 3mm.
The distance between the upper anterior teeth and the lower anterior teeth is too large, that is, the cutting edge of the upper anterior teeth covers more than 1 / 3 of the crown length of the lower anterior teeth or the lower anterior teeth bite more than 1 / 3 of the lingual side of the upper anterior teeth.
a