ISSN 2398-2977      

Teeth: maleruption



  • Cause: disruption of the complex relationship between dental morphogenesis and vascular forces that create the eruption pathway. Impaction from overcrowding.
  • Signs: teeth do not erupt into the expected position at the expected time.
  • Diagnosis: oral examination, radiography.
  • Treatment: depends on type; routine dental care   →   surgical removal.
  • Prognosis: depends on type of maleruption.




  • Absence of temporary and permanent teeth due to failure of genesis, ie no germ cells.
  • Affects incisors or molars.
    Missing teeth
  • Traumatic or infectious damage to germ buds during their maturation.
  • Particularly affects incisor arcades.
  • Can cause significant deformity.
  • Maleruption of molars may only become obvious in older horses (>4 years).
  • Can cause facial swelling with a discharging sinus tract or nasal discharge.
  • Supernumerary incisors   Teeth: supernumerary incisor  or molars.
  • Multiple teeth arising from a single germ bud of a permanent tooth.
  • Affects incisors more commonly.
  • May be a couple of teeth or a complete row.
  • Lack of wear causes soft tissue trauma.
  • Affected molars may have an associated sinus tract   Paranasal sinus: sinusitis 05 - frontomaxillary drainage  to side of face or into maxillary sinus.
    Delayed eruption
  • One tooth may be slow to erupt, eg canines.
    Retained deciduous teeth
  • Most commonly affects incisors.
  • Permanent teeth erupt behind deciduous teeth. Fail to occlude blood supply to temporary teeth or to push them out.
  • Usually loose and easily removed.
    Persistent dental caps
  • Premolars (molars do not have a deciduous equivalent).
  • Deciduous teeth remain attached on permanent teeth as they erupt from underneath.
  • Can be difficult to identify.
  • May cause trauma to soft tissue or impede mastication.
  • Many resolve spontaneously, otherwise removal by leverage necessary.
  • Relative shortening of mandible or maxilla reduces space available for complete arcade to erupt.
  • Results in either third premolar being displaced medially or painful facial swelling and diffuse alveolar periostitis. Can progress to periapical infection and sinus formation.
    Normal eruption of permanent teeth may cause symmetrical, non-painful swelling of mandible   Mandible: dental lumps  or face due to periapical hyperemia and alveolar bone resorption. This resolves spontaneously


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Tremaine H & Casey M (2012) A modern approach to equine dentistry 2. Identifying lesions. In Pract 34 (2), 78-89 VetMedResource.
  • Dixon P M, Tremaine W H, Pickles K et al (1999) Equine dental disease Part 1 - a long-term study of 400 cases - disorders of incisor, cannie and first premolar teeth. Equine Vet J 31 (5), 369-377 PubMed.
  • Dixon P M et al (1999) Equine dental disease Part 2 - a long-term study of 400 cases - disorders of development and eruption and variations in position of the cheek teeth. Equine Vet J 31 (6), 519-528 PubMed.
  • Mueller P O et al (1998) Dental sepsis. Vet Clin North Am Equine Pract 14 (2), 349-363 PubMed.
  • Lane J G (1994) A review of dental disorders of the horse, their treatment and possible fresh approaches to management. Equine Vet Educ (1), 13-21 Wiley Online Library.

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