Early incisor lesions and Equine Odontoclastic Tooth Resorption and Hypercementosis: Reliability of radiographic findings.

BACKGROUND: In clinical practice, early diagnosis of Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) and other resorptive incisor diseases is difficult to achieve. The radiographic appearance of subtle pathological changes has not been described in detail and might be confused with age-related changes. OBJECTIVES: The study was performed to define typical radiographic signs of early incisor lesions and to evaluate the reliability of the radiographic findings. STUDY DESIGN: Descriptive and comparative study using post mortem clinical, radiographic, macroscopic and microCT examination. METHODS: The incisor region of 20 cadaveric horse heads, divided into three different age groups, was examined visually and by palpation. Intraoral radiographs were taken. After extraction, each incisor was macroscopically evaluated. Micro-computed tomography (microCT) scans were obtained. These scans were processed with Scry (v6.0, Kuchel & Sautter GbR) to obtain surface meshes which then were transferred to Meshlab (ISTI-CNR, version 2016.12). Attached tissues were virtually removed and surface curvature was computed to visualise and evaluate the quantity of unevenness (roughness) of the teeth's surface. Scoring systems for each diagnostic modality were developed. Scores were compared to describe and evaluate the radiographic appearance of early incisor lesions. RESULTS: The prevalence and severity of incisor lesions increased with age. Early, subtle lesions develop on the palatal/lingual side of incisors. While radiographically detected lesions were confirmed macroscopically and on the microCT scans, numerous teeth which were radiographically classified as healthy displayed lesions by macroscopic inspection (13.7%) and microCT analysis (58.1%). MAIN LIMITATIONS: Cadavers were studied and dental history was unknown. CONCLUSIONS: The detection of early and subtle incisor lesions indicating first signs of EOTRH on dorsoventral intraoral radiographs is limited due to the typical localisation of the lesions on the palatal/lingual side of the incisors.