How to Radiograph the Erupted (Clinical) Crown of Equine Cheek Teeth

Diseases of the erupted (clinical) crown are being recognized with increasing frequency. Conventional “closed mouth” radiographic projections of the cheek teeth allow only limited evaluation of the erupted crowns and occlusal surfaces, due to superimposition of the opposing arcade. Open-mouthed oblique (OMO) radiographic projections are taken with a gag placed between the incisors, thus separating the maxillary and mandibular arcades and allowing more accurate assessment of the erupted crowns. They can therefore highlight lesions that are not visible on standard oblique views. The use of these techniques in clinical cases has proved to be of great value in diagnosing and evaluating lesions of the erupted crown, such as diastemata, abnormalities of eruption and wear, and coronal fractures. The open-mouthed 15° ventrolateral-lateral oblique gives an optimal view of the erupted crowns of the maxillary cheek teeth, and the open-mouthed 10° dorsolateral-lateral oblique optimally images the corresponding area of the mandibular arcades.