Page 757 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

732 CHAPTER 4

VetBooks.ir CEMENTAL HYPOPLASIA cheek teeth, into which food can become packed,
with a resultant discolouration indicating caries
Definition/overview
Developmental abnormalities in the infundibular of the cementum. This syndrome may represent a
benign variation on normal dentogenesis and has
cement can result in a defect in the cemental layer variously been described as infundibular necrosis
that can predispose the tooth to degenerative dis- and cemental caries. It is probable that teeth with
eases affecting the deeper layers. cemental hypoplasia are more predisposed to caries,
which if it penetrates deeper through the enamel into
Aetiology/pathophysiology the dentine, can predispose to weakness and fractur-
Cementum is laid down in the incisor and maxil- ing of the tooth through the infundibula (Fig. 4.23).
lary infundibula prior to eruption by the invasion Occasionally, deep caries can extend apically result-
of the invagination in the enamel surface by a layer ing in a communication with the apical foramen and
of cementoblasts. With maturation and increas- leading to pulpitis.
ing density of the cementoblasts, cement formation
occurs up until eruption, at which point the cemen- Differential diagnosis
tum becomes avascular and ceases to develop. The The cemental hypolasia is diagnosed when it leads to
condition is seen in maxillary cheek teeth, and the caries of the occlusal infundibula.
4 cheek tooth (109, 209) appears to be most com-
th
monly affected. Cementosis of the infundibulum is Diagnosis
frequently incomplete and areas of hypoplasia can The disease is diagnosed by careful oral examination,
occur at any point along its length. Such infundibula the use of dental probes (Fig. 4.24), and oral endos-
can appear from the occlusal view to be normal, with copy (Fig. 4.25), to demonstrate friable cementum
the cemental defect only appearing as occlusal car- and pitting. The depth of the defect is confirmed
ies after several years of wear. Mandibular occlusal using probes or burrs. CT can reveal cemental hypo-
caries is rare in the absence of infundibula, although plasia apically that is not exposed occlusally.
peripheral cemental hypoplasia is diagnosed in man-
dibular and maxillary teeth, and is often observed in
conjunction with periodontal disease, due to accu-
mulation of food around the buccal dental surfaces.
4.24
Clinical presentation
Cemental hypoplasia can be detected as an infundib-
ular pocket on the occlusal surface of the maxillary

4.23

Fig. 4.23 A post-mortem specimen showing caries Fig. 4.24 Using a probe and mirror to clear a packed
(grade 2) of maxillary infundibula (arrows). infundibular defect.