Congenital tooth diseases are characterised by agenesis (a condition in which teeth fail to develop) or polygenesis (in which numerous additional teeth occur). In cats, these diseases are defined by the number of teeth compared to normal dentition:
- Hyperdontia refers to the presence of more than the normal number of teeth
- Hypodontia refers to an absence of more than 6 teeth
- Oligodontia is an absence of more than six teeth
- Anodontia is the complete absence of teeth.
The partial absence of teeth (oligodontia and hypodontia) is slightly more common in cats than has been reported in other species. Non-syndrome (e.g. non-Downs syndrome) forms of tooth absence in humans are well described and are the result of defects in two genes, MSX1 and PAX9. In humans, with defective MSX1 and PAX9 genes, the permanent teeth are most frequently affected rather than the deciduous teeth. In dogs, hypodontia and oligodontia mostly occur in the small breeds and usually involves the molars. Hypodontia and oligodontia are infrequent in felines, but are generally characterised by the absence of the upper second premolar.
Adontia is a rare condition in all species, including humans. In cats, there are a few documented cases and most cases are incidental findings, with little clinical significance due to cats ability to eat most foods with minimal chewing. One reported complications of this condition was reduced reproductive performance in male cats due to their inability to grasp the female during coitus.
Adontia/Oligodontia is often confused with chronic lymphocytic plasmacytic stomatitis, where tooth loss is a common sequela, and this disease must be considered a differential when considering dental disease.
- Vieira, ALS et al (2009) Congenital oligodontia of the deciduous teeth and anodontia of the permanent teeth in a cat. JFMS 11
- Elzay, RP & Hughes, RD (1969) Anodontia in a cat JAVMA 154:667-670
- Kapadia, H et al (2007) Genes affecting tooth morphogenesis. Orthod Craniofac Res 10:237-244