Insufficient number of teeth
Introduction
Introduction The number of normal human teeth is 20 deciduous teeth and 28-32 permanent teeth. The abnormal number of teeth is manifested by insufficient or excessive number of teeth. Insufficient number of teeth, also known as congenital missing teeth, there are individual missing teeth, partial missing teeth and full mouth missing. Congenital missing teeth can occur in the deciduous teeth, or in the permanent dentition. Deletion of the deciduous column is less common. Generally, the maxillary side incisor, the mandibular incisor and the cuspidate. The most frequently missing teeth in the permanent dentition are: mandibular second bicuspid, maxillary lateral incisor, third molar, maxillary second bicuspid, mandibular lateral incisor and incisor. The number of deletions is most common, followed by one, and the absence of more than five is rare.
Cause
Cause
Congenital missing teeth occur in the early stages of tooth formation, ie the period of bud formation. It can be produced for different reasons:
1. Embryonic dysplasia is affected by physical obstacles or broken teeth. For example, the mouth-to-face-to-finger syndrome, the lower incisor area is covered by a proliferating ligament and mechanically interferes with the dental plate.
2, space is limited, creating pressure, so that the tooth germ can not be degraded by minimal nutrition, especially the third molar.
3. Failure of epithelial tissue function and/or mesenchymal induction below it.
Examine
an examination
Related inspection
Oral endoscopic oral X-ray examination
Clinically, there is a lack of teeth in the mouth, which is not enough to prove that there is no tooth. It may be because the teeth are not erupted (such as ambush, late) or early loss of trauma. This is done after a medical history is asked, and an auxiliary examination such as an X-ray film can be used to make a diagnosis.
Congenital missing teeth can occur in the deciduous teeth, or in the permanent dentition. Deletion of the deciduous column is less common. Generally, the maxillary side incisor, the mandibular incisor and the cuspidate. The most frequently missing teeth in the permanent dentition are: mandibular second bicuspid, maxillary lateral incisor, third molar, maxillary second bicuspid, mandibular lateral incisor and incisor. The number of deletions is most common, followed by one, and the absence of more than five is rare. There is no obvious systemic meaning of missing teeth. On the contrary, when there are many missing teeth, you should check your body for other abnormalities such as skin and hair. Often a manifestation of ectodermal dysplasia syndrome, a systemic congenital malformation. Children with congenital loss of deciduous and permanent teeth, accompanied by abnormal development of skin and hair. It is a degenerative developmental deformity, mostly male. According to whether the child is sweating, it is clinically divided into two types: sweat-type ectodermal dysplasia and non-sweat ectodermal dysplasia.
No sweat type: There is a lack of sweat glands in the whole body, so the child does not sweat or sweats very much, the body temperature regulation disorder, the heat of the abdomen, the sebaceous glands, the hair follicles and the hair are all scarce or rare, so that the skin is dry and rough. Hair, eyebrows sparse, thin and yellow, like fetal hair, nose sag, no nose hair. Therefore, it is impossible to filter the dust in the air; the nasal mucosa is dry and easily causes chronic atrophic rhinitis. In the oral cavity, most of the teeth are missing, only a few teeth, the residual tooth distance is sparse, the tooth shape is small, the cone is shaped, and the lips are prominent.
Sweat type: also known as hair-nail-tooth syndrome. When the temperature rises, the child has sweat, indicating that some sweat glands exist. At the same time, hair, hair, beards, etc. are sparse, slender or curly, and easily broken. Finger dysplasia, thin and brittle. It is streaked and dull, and it can often cause infection of the sulcus and cause the methylation of the finger (toe) to disintegrate, causing the nail to be missing or thickened. Congenital loss or developmental malformation or enamel dysplasia of the teeth, thin enamel is prone to horizontal stripes or small dimples. Some children have scaly or sputum or corns in their hands and feet, and less subcutaneous fat.
Diagnosis
Differential diagnosis
Symptoms of insufficient number of teeth
Abnormal dental morphology: including curved teeth, deformed teeth, deformed tongue, deformed tongue, deformed central teeth, oversized teeth, too small teeth.
Abnormal tooth structure: more common enamel hypoplasia, tetracycline stained teeth, dentin dysplasia.
Abnormal teeth eruption: more common in permanent teeth. Including early teeth, late teeth, teeth ectopic eruption.
