When the mandible of the natural dentition is in the cusp dislocation, the straight distance from the nose bottom to the chin bottom is called the vertical distance of the occlusal position; when the mandible is in the rest position, the straight distance from the nose bottom to the chin bottom is called the vertical distance of the rest position. The proper vertical distance can keep the height of the lower third of the face, which is related to the fullness and beauty of the face, and can also make the condyle in a moderate and comfortable position in the TMJ fovea. After the loss of the whole teeth, the support between the upper and lower jaw was lost, the lower three points of the face became shorter, the lips and cheeks were sunken, which obviously affected the face image. Moreover, because the mandible is often in the position of over lifting, the condyle moves backward, which will cause temporomandibular joint symptoms for a long time. Therefore, it is an important step to make a complete denture and restore the original vertical distance.
However, when making complete dentures to determine the vertical distance, due to lack of experience, it often appears too high or too low, which will affect the quality of dentures, and some even need to be made again. Common symptoms are as follows:
(1) The vertical distance is too high: the vertical distance determined by the complete denture is too high, the lower part of the face becomes longer, the muscles of the labiobuccal part are tense, the upper and lower lips cannot be closed, the nasolabial groove and the mentolabial groove become shallow, as if there is something in the mouth; When speaking, the upper and lower teeth often have collision sound, and the denture is poorly retained: there is tenderness when occluding, and there is discomfort in both sides of the temporal part: for a long time, it will lead to some symptoms of the temporomandibular joint, such as snapping and pain when occluding, and there may be mouth opening limitation in the severe cases.
(2) The vertical distance is too low: the vertical distance determined by the complete denture is too low, the lower part of the face becomes shorter when occluding, the upper and lower lips contact too tightly, the lips turn outwards or inwards, the mouth depression is not full, showing an old face shape: when occluding, the lower jaw needs to be raised higher than when the vertical distance is normal to make the upper and lower jaw artificial teeth contact, so it is hard to chew, and the chewing efficiency is low: for a long time, it will also cause temporal jaw Symptoms of the joint.
In order to avoid the above situation, when making a complete denture to determine the vertical distance, in addition to using the measurement method (the vertical distance of the rest position minus 2mm), we should also pay attention to observing whether the proportion between the length of the lower three parts of the face and the length of the face is harmonious, especially whether the upper and lower lips can just contact, whether the nasolabial groove and