Anomalies exist in number, shape, size, structure, position of teeth, as well as temporal disorders of teeth development and teething.
Orthodontics deals with teeth position anomalies.
Reduction of teeth number is called hypodontia (agenesis). Upper second incisor teeth and wisdom teeth are those teeth that are most often absent. A condition when groups of teeth are not formed is called oligodontia, if the teeth are not formed at all we call it anodontia. Increase in teeth number is called hyperodontia. Extra teeth are most often found between the central incisor teeth (mesiodens). A shape change may affect the crown, the root or the pulp chamber. The most common shape alterations are peg-shaped teeth or teeth with accessory cusps. An interesting anomaly of a crown and root is taurodontism. Proportional reduction in teeth size is called microdontia, enlargement of teeth is macrodontia. Defects of hard dental tissues formation can be divided into two groups:
the first group encompasses disorders that are caused by non-specific effects on a developing tooth
the second group includes genetically determined anomalies.
Among non-specific changes belong hypo-mineralization and the enamel hypoplasia. These disorders may be caused by common diseases of upper respiratory tract, otitis, diarrhea, deficiency (especially vitamin deficiency) states or endocrinopathies. Hypomineralization and hypoplasia are also a result of tetracycline antibiotics administration during the enamel formation and mineralization, i.e. from about the 6th week of the intrauterine life up to the 8th year of a child’s life. The first few years of life is especially risky since crowns of most permanent teeth are formed and mineralized at this age. Affected teeth have yellow-brownish colored enamel and numerous hypoplastic defects that are prone to decays and fractures. A child’s psychology is usually strongly affected by a defect of the cosmetic look. Enamel composition defects occur also as a consequence of erythroblastosis, lues congenita or as a result of fluorine overdosing (fluorosis) as well. Among genetically determined disorders there are dentinogenesis imperfecta hereditaria and amelogenesis imperfecta hereditaria. These disorders affect all teeth of both dentitions.
Teeth development and eruption may be either accelerated or, on the other hand, retarded.
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