From Dog
Missing incisors (oligodontia), characteristic of ectodermal dysplasia[1]

Congenital dental diseases are characterised by agenesis (a condition in which teeth fail to develop) or polygenesis (in which numerous additional teeth occur).

In dogs, 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 six teeth and is an autosomal-recessive condition[2]
  • Oligodontia is an absence of more than six teeth, usually with only a few teeth remaining and is a polygenic condition[3]
  • Anodontia is the complete absence of teeth[4] - very rare in dogs

Two breeds, the Affenpinscher and Kerry Blue Terrier appear predisposed, as well as dogs affected by distemper[5], ectodermal dysplasia[1], trisomy-X[6] and pre- and postnatal oral or whole-body irradiation[7].

There appears to be a weak relationship between litter size and hypodontia in the Kerry Blue Terrier[8].

In dogs, hypodontia and oligodontia mostly involves the premolars. In Kerry Blue Terriers, two different patterns of missing teeth were identified, one consisting of agenesis of a second premolar, often in combination with agenesis of neighbor teeth, including the fourth premolar. In the second pattern, agenesis of a fourth premolar is expressed as an isolated abnormality. These two dental abnormalities are controlled by different genes[9].

In dogs post-distemper infection, dental impaction, partial eruption, oligodontia, enamel hypoplasia and dentin hypoplasia may be observed.

Adontia/Oligodontia may be confused clinically with chronic gingivitis, where tooth loss is a common sequela, and this disease must be considered a differential when considering dental disease[1].

Diagnosis is usually based on visual inspection of teeth during physical examination, but radiographs are necessary to confirm the absence of deciduous tooth root buds in pups[10].

Many affected dogs, although affected with prehension difficulty and esthetic complications for the owner, appear to cope well with eating and have a good quality of life.


  1. 1.0 1.1 1.2 Lewis JR et al (2010) Dental abnormalities associated with X-linked hypohidrotic ectodermal dysplasia in dogs. Orthod Craniofac Res 13(1):40-47 Cite error: Invalid <ref> tag; name "Oli" defined multiple times with different content
  2. Aksenovich TI et al (2004) Inheritance of hypodontia in Kerry Blue Terrier dogs. Genetika 40(5):658-666
  3. Kniazev SP et al (2003) Oligodontia and its inheritance in Kerry blue terrier. Genetika 39(6):805-812
  4. Lin BC et al (2012) Root resorption of primary molars without successor teeth. An experimental study in the beagle dog. Eur J Oral Sci 120(2):147-152
  5. Bittegeko SB et al (1995) Multiple dental developmental abnormalities following canine distemper infection. J Am Anim Hosp Assoc 31(1):42-45
  6. Switoński M et al (2000) X trisomy in an infertile bitch: cytogenetic, anatomic, and histologic studies. J Hered 91(2):149-150
  7. Lee AC et al (1989) Hypodontia in the beagle after perinatal whole-body 60Co gamma irradiation. Radiat Res 118(3):467-475
  8. Zorkaltseva IV et al (2006) Changes in litter size in Kerry blue terrier dogs with abnormal dentition. Genetika 42(3):427-429
  9. Aksenovich TI et al (2006) Polymorphism of dental formula and segregation of its variants in a pedigree of kerry blue terrier dogs. Genetika 42(3):414-420
  10. Fiani N & Arzi B (2009) Diagnostic imaging in veterinary dental practice. J Am Vet Med Assoc 235(3):271-273