Anterior crossbite
Introduction
Introduction to anterior teeth The abnormal relationship between the upper and lower arch of the upper and lower arch can be manifested as mandibular protrusion, mesial and anterior teeth. Due to poor breastfeeding posture, the anterior teeth of the anterior teeth are retained or lost early, the congenital loss of the upper permanent incisors, the bad habits, insufficient abrasion of the cuspidal teeth, systemic diseases and hereditary mandibular protrusion. Due to the degree of difference, the anterior teeth can be reversed, the molars are neutral, and in severe cases, the anterior teeth are reversed, the posterior teeth are close to the middle and the mandibular protrusion is present at the same time. basic knowledge Sickness ratio: 0.05% Susceptible people: no specific population Mode of infection: non-infectious Complications: depression
Cause
Anterior teeth
Bad oral habits (30%):
(1) Poor breast-feeding posture. If the bottle is not properly breast-fed, the jaw should be sucked forward and can cause the anterior teeth to reverse.
(2) Bite the upper lip or the lower jaw to reach a bad habit, which can lead to the anterior teeth and the mandibular protrusion.
Local disorders in the dentition period (25%):
(1) deciduous teeth or early loss, can cause individual anterior teeth, or most anterior teeth.
(2) The early deciduous teeth are lost early, and the upper anterior teeth are moved backwards to form the anterior teeth.
(3) Insufficient wear of the cuspidate teeth, higher than the dental arch, plane, in order to avoid the early contact of the upper and lower jaw canines, the lower jaw will move forward or sideways, forming with the anterior teeth, or the anterior teeth Inverse, the pseudo-mandibular protrusion.
(4) The upper permanent incisors are congenitally missing. For example, the common maxillary lateral incisors are congenitally missing, which may cause insufficient development of the anterior maxilla and form a anterior teeth.
Disease (20%):
(1) The mandibular advancement is stimulated by chronic inflammation of the tonsil or lingual tonsils, which may lead to anterior teeth and mandibular protrusions over time.
(2) Patients with cleft lip and palate often have insufficient maxillary development, which is easy to cause anterior teeth, and near-middle mistakes.
(3) Patients with rickets, their calcium and phosphorus metabolism disorders and abnormal muscles of the facial muscles often lead to more severe mandibular protrusions or anterior teeth opening and deformity.
(4) Endocrine disorders, such as hyperactivity of the anterior pituitary gland, can cause mandibular protrusion.
Prevention
Anterior teeth prevention
1. During breastfeeding, correct the bad breastfeeding posture and avoid excessive extension of the baby's jaw.
2. It is especially important to maintain the gap between the early deciduous teeth and to maintain the gap of the upper deciduous teeth. Remove the stagnant teeth, especially the early removal of the retained lower molars.
3. Due to chronic inflammation of the tonsils, tonsil disease should be treated promptly.
4. Due to the lack of wear of the cusps, the anterior teeth can be reversed by adjusting the excessively high interference.
5. Due to bad habits of oral cavity, bad habits should be eliminated as soon as possible.
Complication
Anterior teeth recombination complications Complications depression
This disease is accompanied by abnormal development of the teeth, so it can form facial deformities, causing the cheeks on both sides to bulge, causing the shape of the entire face to change. Secondly, due to abnormal development of the teeth, it can directly affect the chewing function, causing physical chewing of food, thereby causing digestive disorders. The disease can directly affect the appearance, so patients with depression tend to induce depression due to imperfections in appearance.
Symptom
Anterior teeth symmetry common symptoms molars mandibular anterior facial deformity dentition crowded jaw hyperplasia
Tooth origin
Due to local obstacles in the process of tooth eruption or replacement, it often appears as a simple anterior teeth, and the anti-cover is small. The molars are neutral or close to neutral. The shape of the mandible is basically normal. There is no obvious abnormality in the mandibular joint, the ankle is not protruding, the face is basically normal, and the mandible can retreat to the anterior teeth to the blade. X-ray cephalometry measures the abnormal structure of the bone, and the treatment is easy and the prognosis is good.
2. Osteogenic
Due to factors such as heredity and disease, in addition to the anterior teeth, it often shows that the anti-overmapping is large, the molars are near-middle, and the jaw deformity is accompanied by blunt mandibular angle, long mandibular body and short mandibular branch. Or the anterior maxillary development is insufficient, the ankle is obviously protruding, and the mandible often cannot retreat on its own. The face is mostly concave, sometimes accompanied by open jaw deformity. The treatment is difficult, and the effect of simple orthodontic treatment is not necessarily good.
This type of anterior teeth can be divided into 3 types according to the mechanism:
(1) The anterior maxilla is underdeveloped and the mandibular development is normal.
(2) The maxillary development is normal and the mandible is overdeveloped.
(3) Insufficient maxillary development with excessive development of the jaw.
3. Functionality
Due to poor breast-feeding posture and other causes of mandibular functional hyperextension, the mandibular protrusion and anterior teeth are reversed, but the shape and size of the mandible are basically normal, and the mandible can retreat to the anterior teeth to the blade, or shallow, some people call it a fake Sexual mandibular protrusion, if not treated early, may develop into a true mandibular protrusion.
Examine
Anterior tooth reversal
X-ray cephalometric measurement
(1) The angle of the SNB and the angle of the face are increased, indicating that the mandible is opposite to the skull base, the mandibular angle is enlarged, and the odontogenic anterior teeth are reversed. The above measurements are normal.
(2) Mandibular protrusion with maxillary retraction, SNB angle decreased S-Ptm, Ptm-6 decreased, and the above measurements were normal without maxillary retraction.
(3) The angles of ANB angle and AB plane increase, and the AO-BO value decreases, indicating that the upper and lower jaws are obviously not adjusted, and the odontogenic anterior teeth are reversed. The above measurements are basically normal.
(4) The surface bulge (G-Sn-Pg) increases, and the H angle (H line-N'P'g) decreases. The Z angle (FH-H line) increases, indicating that the soft tissue side protrusion is reduced, and the upper lip is protruding. Degree (Ls-SnPg) decreased or normal, lower lip protrusion (Li-SnPg) increased, maxillary protrusion (Sn-G) decreased or normal, and mandibular protrusion (Pg-G) line increased.
Diagnosis
Anterior tooth reverse diagnosis
1. Individual anterior teeth have little effect on chewing function and jaw bone, but may have adverse effects on temporomandibular joint.
2. Most of the anterior teeth have an effect on the function and maxillofacial development of the temporomandibular joint.
3. The more severe the anterior teeth of the unilateral side, the greater the locking effect on the occlusion and the dysfunction of chewing, and the greater the impact on the development of the jaw and the joint.
4. Most of the anterior teeth are underdeveloped in the anterior jaw, and the side of the face will also be concave.
5. Most of the anterior teeth of the bilateral anterior teeth are limited in the development of the upper arch and maxillary width. The maxillary arch is narrow and the face is narrow and long, but it is bilaterally symmetrical.
