Teething disorders

In many cases it is not a single alteration, but complex associations that are difficult to label because they cover concepts of different types of alterations at the same time. We distinguish different groups of anomalies in the dentition, with their respective characteristics:

Number anomalies

• Anodontia or Agenesis: Absence of the tooth because it has not been formed and, therefore, does not erupt in the mouth. It can be total or partial. The total is very rare and is due to an embryonic disorder, which is why it is usually associated with other alterations of the ectoderm. The partial affects one or a few teeth. The most frequent agenesis affect third molars, to the upper lateral incisors and the lower second premolars.
• Hypergenesis or Supernumerary Tooth: Formation of more teeth than normal, this leads to an increase in the number of some dental group. Is more common in permanent dentition and, particularly, in the maxilla. The shape of this tooth is usually similar to that of the group to which it belongs. In other cases it has a cone shape, regardless of the group to which it belongs. Its most frequent location is in the incisor region, especially between the central incisors, receiving a specific name: mesiodens. In the molar region it also receives a specific name: distomolar (or fourth molar) or paramolar (located in a second row). These disorders can occur isolated or associated with other developmental abnormalities such as cleft lip.

Size anomalies

• Microdontia: Tooth of a smaller than normal size. The entire tooth can be affected (it would be called total) or only a part of it (it would be partial). If it affects all the dental elements of the mouth, it is called microdontism. Total microdontia is usually more frequent in the permanent dentition and, especially, in lateral incisors, third molars and premolars. The morphology may or may not be similar to that of the natural tooth. Partial microdontia can affect the crown (especially in lateral incisors) or to the root (central incisors and third molars).
• Macrodontia: Tooth of a larger than normal size. It can be total (frequent in central incisors, canines and molars) in which case the shape of the tooth does not vary or partial (affecting the crown or the root) and in this case an abnormal tooth is appreciated.

Shape anomalies

• Conoidism or Conoid tooth: It is a tooth with the cone shaped crown. It is more frequent in anterior teeth, especially in the upper lateral incisor and in supernumerary teeth.
• Accessory cusps and tubercles: Refers to the anatomy of the crown with respect to number of cusps or outgrowths (tubers).
• Dens in dente or invaginated tooth: It is rare. Consists of the enamel penetration inside the crown. The radiographic image is very characteristic because it appears as if it were a tooth within another.
• Enamel pearls: It is an alteration in the root surface of the tooth. They are small rounded whitish formations and adhered to the root surface. Under normal conditions the outer layer of the root is cement.

Other root anomalies

• Dilaceration: Very marked kinking in the root portion giving rise to a very marked angle between the axis of the crown and that of the root.
• Bayonet root: It happens when the root has zigzag end.
• Root convergence: Roots joined by the apices.

Junction anomalies

• Fusion: Union of two contiguous normal teeth. It can be total or partial. They erupt already fused.
• Gemination: Union of a normal tooth and one supernumerary or two supernumeraries.
• Concrescence: Union of two different teeth through its roots.
• Coalescence: Union of two teeth using bone or fibrous tissue dense newly formed but each one retains its individuality.

Structure alterations

Also calls dysplasias. They are classified into three groups: simple, complex, and hereditary.

Simple

• Enamel stains: They are white or brownish in color. They do not evolve over time and are due to areas with mineralization deficit.
• Coronary hypoplasias: These are calcification disorders and can adopt different ways: linear, cuculiform, surface and cusp.

Complex

Associated with malformations, In its great majority.

• Hutchinson's tooth: Associated with Congenital syphilis.
• Turner's tooth: Presents a cement layer in the enamel area (which is immature)

Hereditary

• Amelogenesis imperfecta: It usually affects all dental elements. The crowns have a rounded outline and a light brown to gray-yellow coloration. It can go associated with crown hypoplasia.
• Dentinogenesis imperfecta: Normal tooth shape but opalescent or translucent appearance with different colors from yellow to blue-gray. It is usually accompanied by early wear.

Position anomalies

• Displaced tooth. in relation to the position that corresponds to him.
• Heterotypy: A dental element is located in a situation that does not correspond to it. In turn, it may be a ectopy (tooth in a place far from its usual place) or from a transposition (in the correct arch but in the position that corresponds to another).
• Inclusion or retention: The tooth remains in the bone thickness without eruption. Can be .
• Interlocking: Incomplete retention by stopping the eruption. It may be due to a loss of natural space.

Chromatic alterations

• By coloration or apposition: On the surface of the tooth a layer is positioned. There are many possible triggers: microbial, food (coffee, tea), tobacco (high tar content).
• By staining or pigmentation: Inside the tooth, at the level of hard tissues. According to him color that the tooth adopts We will suspect certain pathologies: brown coloration (poor hygiene), black coloration (bacterial accumulation), green coloration (poor hygiene in children) The most common causes would be: cavities, silver amalgams, drugs (tetracyclines give a characteristic appearance in yellow bands and brown), fluorosis (in areas with fluoride higher than normal values), diseases (porphyria).