Page 778 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.1 The upper gastrointestinal tr act 753

VetBooks.ir 4.68 gradual correction to maintain occlusion and mas-
ticatory efficiency is advisable and, in aged horses,
preservation of viable functional dental tissues is
desirable. Dietary manipulation using less abrasive
sources of fibre is also helpful in conjunction with
any interventional treatment.
Step mouth should be corrected gradually using
a diamond-coated, water-cooled mechanical burr,
with the eventual aim of reducing the prominent
tooth to the level of the arcade and bringing the
remainder into occlusion. The pulp may extend to
within a few mm of the occlusal surfaces and correc-
tion of large (>1 cm) step mouth should be carried
Fig. 4.68 This cadaver specimen shows a wave out gradually with repeated treatments.
profile of the upper arcade and a step at the caudal
mandibular molar. GERIATRIC DENTAL DISEASE

Geriatric (>20 years of age) horses are increas-
Aetiology/pathophysiology ingly kept in work. With age there is an increasing
Abnormal masticatory movement can also result prevalence of periodontitis, severe caries and oligo-
in one area of the arcade undergoing attrition at an dontia, and such horses require their dentition to be
increased rate relative to other parts. The result is an carefully maintained to enable them to retain body
arcade in which the occlusal surface undulates, with condition. In addition, dietary manipulation such as
areas involving one or more teeth with a longer clini- geriatric diets and oil supplementation and avoiding
cal crown and adjacent areas in which the crown is long-fibre roughage can compensate for loss of mas-
shorter. The undulations on the maxillary and man- ticatory effectiveness with age.
dibular arcades complement each other when the
arcades come into occlusion. This observation is com- EQUINE ODONTOCLASTIC
mon in aged horses that have suffered chronic reduced TOOTH RESORPTION AND
masticatory movements. Step mouth is the conse- HYPERCEMENTOSIS (EOTRH)
quence of a local oligodontia or displacements allow-
ing super-eruption or drastically reduced attrition on Definition/overview
a single tooth. Such teeth can develop a crown that is EOTRH is a syndrome afflicting incisors and
prominent (>1 cm) to the remainder of the arcade. canines of geriatric (>20 years of age) horses that
results in destruction of the reserve crown of the
Clinical features and diagnosis tooth with severe painful gingivitis (Fig. 4.69).
Severe step and wave mouth can be the consequence
or cause of additional masticatory disorders and can Aetiology/pathophysiology
be associated with oral pain. Oral examination and The cause of EOTRH is unclear but mechanical and
careful digital palpation will reveal the presence of immune factors are possible. An osteolytic deminer-
significant unevenness of the arcade. alisation of the cementum and dentine of the reserve
crown and alveolar bone is observed and may be
Management accompanied by a severe chronic gingivitis and peri-
Correction of wave mouth is possible until dental odontitis. Subsequently there is hypercementosis
eruption ceases (at about 20 years of age) and once around the affected teeth. Histologically an infiltra-
normal mastication is restored the tendency for tive gingivitis surrounds odontoclastic destruction
the condition to recur is reduced. In severe cases, of the alveolar bone and dentine.