46TH
ANNUAL
CONGRESS
OF
THE
SAEVA
SKUKUZA
16-‐20
FEBRUARY
2014
121
Further planning for a diagnostic study should include the following mental checklist:
Obliquity – varies with anatomic region of interest
Beam center
Beam angle
Film focal distance
kVp and mAs
The number of views constituting a complete examination is arguable, however, in
general, a complete radiographic examination includes a minimum of 4 views. The
views should be chosen based on the clinical and oral examinations. The lateral and
oblique projections can be made with a block between the incisor teeth to obtain
open-mouth views. The views should include a dorsoventral, laterolateral and
opposing oblique projections. The open mouth views improve visualization of the
occlusal and interdental regions.
Intra-oral radiographs provide improved evaluation of the individual teeth and their
relationship with the supporting structures. Specialized or modified equipment is
required to examination of the cheek teeth. Readily available radiographic
equipment is appropriate and adequate to provide intra-o ral evaluation of the incisor
teeth. In both cases chewing motions should be minimized by either performing the
examination at peak sedation or by using a higher level of sedation. The cassette
(detector) is placed within the oral cavity. Beam angle is dependent on the tissue of
interest.
Although teeth have a complicated internal architecture, their relationship to the
mandible, incisive bone and maxilla have similar characteristics. The external surface
of each tooth is comprised of cementum that operates as a single functional unit with
the periodontal ligament. The ligament appears as clearly demarcated radiolucent
line. The lucent line abuts the thin shelf of very dense bone termed the dental
lamina dura. The lamina dura appears as a thin, well-defined radio-opaque line. In
the mandible, incisive bone and rostral maxilla the lamina dura is more opaque than
the surrounding trabecular bone often term the alveolar bone. The caudal maxillary
cheek teeth have reserve crown and roots that reside within the rostral and caudal
maxillary sinuses. In the normal horse, the radiolucent periodontal ligament and the
radioopaque lamina dura are readily evident. Because dental disease frequently
results in infectious or inflammatory lesions of the sinuses and surrounding bone,
these characteristics are pivotal in the accurate identification of abnormal teeth.
The radiographic appearance of the dentition changes with advancing age. This is
particularly evident when evaluating the pulp horns and tooth roots. In very young
horses, the germinal tissue of the teeth appear as wide radiolucent zones with some
evidence of radioopaque dental tissue within the respective bones. With aging, the
pulp horns become better defined and smaller. All of the cheek teeth have more
than one pulp horn; the pulp horns should appear as radiolucent, smoothly margined
structures. Comparison of one arcade to the contra-lateral arcade can be
performed to identify changes in pulp horn and tooth root size and shape.
Abnormalities of pulp are particularly difficult to identify. The pulp horns should be
evaluated for size, shape, margination and symmetry when compared to the ispi- and
contra-lateral arcades.
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