Equine Odontoclastic Tooth Resorption and Hypercementosis: Histopathologic Features.

The study is about a painful tooth condition in older horses known as Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) which is often unrecognized or misdiagnosed by veterinary pathologists. Researchers in this study examined the detailed features of this disease in 17 affected horses in an effort to better understand and diagnose EOTRH.

Objective and Methodology

• EOTRH is a little-known progressive dental condition being studied by researchers with the aim to unravel its histopathological features and increase its awareness among the veterinary community.
• The study involved a thorough analysis of the dental health of 17 horses from the United States affected by EOTRH, taking into consideration the nature and extent of the condition, with samples spanning from a single affected tooth to the entire rostral mandible and maxilla of the horses.

Findings

• Investigations revealed that the affected teeth demonstrated cemental hyperplasia and lysis, sometimes causing significant enlargement in the intra-alveolar sections of teeth, presenting as a typical EOTRH feature.
• Several cases showed the presence of necrotic debris, bacteria, and part of chewed plants in the areas of cemental lysis. In every horse studied, at least one tooth exhibited dentinal lysis, often filled with necrotic debris as well.
• Endodontic disease was commonly found in association with EOTRH, characterized by inflammation, lysis, presence of necrotic debris, fibrosis, and/or a thin mineralized tissue layer in the pulp cavity without tubules or channels.
• Gum disease was also noted as a common feature, mainly showing moderate lymphoplasmacytic inflammation, a type of immune response.
• Resorption along with secondary hypercementosis seemed to begin on the external surface of teeth rather than inside the pulp cavity, providing an important clue in diagnosing EOTRH.

Implications for Diagnosis

• In order to accurately diagnose EOTRH, a comprehensive dental history is needed. This should include the location and count of the teeth affected, gross descriptions of regional hard/soft tissue health, and radiographic evidence.
• The results of this study contribute to a more detailed understanding of EOTRH, helping improve accurate diagnosis and treatment of this painful tooth condition in horses.