Page 758 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.1 The upper gastrointestinal tr act 733

VetBooks.ir 4.25 conspicuous overcrowding, such as Shetland ponies
and Welsh section A ponies. Acquired incisor oligo-
dontia in the young horse can be a consequence of
traumatic injury to the developing permanent sec-
ondary dentition prior to eruption.

Clinical presentation
The condition presents as a malocclusion subse-
quent to uneven wear due to the absence of a tooth.
Secondary dental disorders, including periodontitis,
can ensue.

Diagnosis
Fig. 4.25 Occlusal oroscopic view of an infundibulum The diagnosis is made by careful oral examination in
showing grade 1 caries (within physiologically normal conjunction with oral endoscopy (to count the teeth)
limits). and radiography, if indicated, or if delayed dental
eruption is observed.

Management Management
The presence of cemental hypoplasia may be clini- Loss of a cheek tooth in a mature horse frequently
cally insignificant. It has been suggested that such leads to a digitally palpable space between the
cases are likely to predispose to caries. Currently, remaining teeth and invagination of the empty alve-
teeth with advanced caries usually require removal olus with fibrous tissue, then eventually bone and
by extraction, repulsion or buccotomy. Debridement finally normal oral epithelium. Super-eruption of
of carious infundibula (with full etch bonding and the tooth opposing the absent one can occur in the
restoration using composites) is sometimes used to opposing arcade. More frequent reduction of over-
delay progression to a tooth fracture, although this growths in the super-erupting and adjacent teeth
treatment’s efficacy is not yet validated. may be required. Developmental hypodontia can
be clinically insignificant but malocclusion is likely
OLIGODONTIA/HYPODONTIA unless it is symmetrical.

Definition/overview POLYDONTIA (HYPERDONTIA)
Oligodontia is defined as the loss or absence of mul-
tiple teeth in an arcade or row. Hypodontia is a sub- Definition/overview
normal number of teeth in a row. The presence of extra (supernumerary) dentition
in the arcade exceeding the normal dental formula.
Aetiology/pathophysiology This can be the consequence of retained deciduous
Oligodontia (absence of multiple teeth) or hypodon- dentition or developmental poly- or hyperdontia.
tia (the absence of an individual tooth) is occasion-
ally observed and most acquired cases result from RETAINED DECIDUOUS TEETH
acquired tooth loss following periodontal disease Aetiology/pathophysiology
in aged horses, interventional exodontia or after Retained deciduous incisors are a common presenting
trauma in younger animals. Following loss of a finding during routine dental examinations. During
tooth, migration of the adjacent teeth occurs that normal eruption the permanent incisors emerge on
can result in complete obliteration of the interproxi- the palatal and labial aspects of their deciduous coun-
mal space and shortening of the overall length of the terparts, which are shed as their gingival attachments
arcade. However, developmental hypodontia occurs are lost due to the emergence of the permanent den-
in certain breeds quite commonly where there is tition. Occasionally, the permanent dentition erupts