Generalized Hypercementosis in Geriatric Horses

Abstract

Hypercementosis has been described in the horse associated with painful tooth root resorption and infection in and around the roots of incisor teeth, or as painful swellings in the oral cavity in elderly horses. A screening radiological examination of 16 clinically normal horses older than 15-years showed varying amounts of hypercementosis, especially around the reserve crown and apices of the incisor teeth in 9 cases. The amount of cementum formation varied from several mm to 2-cm especially associated with the roots of the maxillary and mandibular third incisor teeth. The periodontal ligament of the incisor teeth was always seen radiographically as a homogeneous and distinct radiolucent line surrounding the roots. Computed tomographic evaluation indicated that the hypercementosis was more pronounced on the labial aspect. The distinction between the enamel and cementum was more clearly delineated on computed tomographic imaging. Teeth in horses with acute angles between the maxillary and mandibular incisor teeth had greater hypercementosis than incisor teeth with more vertical angulation supporting the theory that stress on incisor teeth may be an etiological factor. Hypercementosis was also noted in the interradicular area of worn cheek teeth but not exceeding the original outer shape of the roots. Histological examination of hypercementosis affected teeth showed no evidence of tumor or infection regardless of the location of the tooth. As in humans, hypercementosis does not require specific treatment unless secondary complications occur.