Graded diagnosis of mandibular angle hypertrophy

One: Mandibular angle hypertrophy is mainly manifested in the impact on facial image and psychology. The characteristics of medical practitioners are as follows:

(1) From the front, the lower third of the face is obviously wide and square, and most of them are accompanied by dysplasia of the vertical height of the chin, and the height of the lower third of the face is too short.

(2) Viewed from the side, the mandibular angle is sharp, protruding backward and downward, and the bones are abnormally enlarged.

(3) The thickness of soft tissue in this area is sometimes obviously thickened, but the soft tissue in this area is soft by palpation, and there is no lump and tenderness. When instructing patients to grind their teeth hard, they can feel the obviously enlarged and compact masseter muscle.

The features of X-ray cephalometric films mainly include:

① The distance between mandibular angles on both sides increased, even greater than the distance between zygomatic processes.

② On lateral X-ray film, the mandibular angle (Ar-Go-Me angle) became sharper, which was 120 in normal people. The mandibular plane angle (MP-FH angle) and the mandibular plane-anterior skull base plane angle, which can reflect the downward protrusion of mandibular angle, are straight, and the more obvious the downward protrusion, the smaller the angle. The anteroposterior angle between the ascending branch plane and the anterior skull base plane, which can reflect the mandibular angle kyphosis, increases with the aggravation of mandibular angle kyphosis. Through the measurement and analysis of lateral radiographs, the hypertrophy and protrusion of mandibular angle in the downward and backward directions can be determined.

Second, the degree of mandibular angle hypertrophy is influenced by many factors, including the angle of mandibular angle, the angle of mandibular valgus, the thickness of mandibular body, the degree of masseter muscle hypertrophy, the fullness of cheeks, and the relative proportional relationship with the width of the middle plane. At present, there is no unified diagnostic standard for mandibular angle hypertrophy, and its judgment is often influenced by subjective factors of patients and doctors, as well as different geographical and cultural backgrounds. Some people have made statistics on the lateral X-ray films of mandibular angle, and 59% of Chinese people have the mandibular angle between 1 10 ~ 120, and the diagnosis can be made only if it is < 1 10. Others believe that the positive width of mandibular angle is equal to or greater than the width of cheekbone.

Three sets of aesthetic evaluation data proposed by Barlett et al. are of guiding significance for the diagnosis of mandibular angle hypertrophy:

(1) the distance from the point under the nose (sn) to the chin (gn) in the lateral photo should be1/3 of the whole face length;

⑵ The widest transverse diameter of the face is the distance between the zygomatic arches on both sides, and the distance between the temples on both sides should be equal to the distance between the mandibular angles and smaller than the distance between the zygomatic arches10%;

(3) The angle of mandibular angle is generally 105 ~ 1 15. In 198 1, Farkes put forward many related aesthetic clinical data by measuring the faces of westerners, which also pointed out that from the front, the distance between mandibular angles should be shorter than the distance between cheekbones 10%. However, due to the wide cheekbones of oriental women themselves, although they sometimes meet the measurement standards of Fawkes, their square faces are still obvious.

Thirdly, the face emphasizes harmony and unity, and the diagnosis of mandibular angle hypertrophy is the result of comprehensive consideration. When considering the diagnosis of mandibular angle, especially the treatment, it is necessary to comprehensively consider the mandibular angle, mandibular spacing, facial proportion and so on. And make a comprehensive judgment considering the overall coordination of facial contours. In addition, in order to avoid misdiagnosis, it should be differentiated from some diseases, such as parotid gland disease, hypertrophy of buccal fat pad, tumor, inflammation of lower cheek and myositis ossificans.