Equine odontoclastic tooth resorption and hypercementosis: Investigating individual incisor disease patterns using radiological classification

Abstract

Background Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a destructive, painful and underdiagnosed dental disorder. Radiography is necessary to fully assess the disease as early stages occur on clinically normal teeth. Objectives To investigate the distribution pattern of appearance of EOTRH within the incisor arcade. In particular, we aimed to determine the influence of tooth position and horse age on the severity of EOTRH as well as on the frequency of the individual severity stages. Study design Retrospective cross‐sectional radiographic case study. Methods Digital radiographs of 142 horses (10 years and older) presented for routine dental examination at our Equine Hospital were obtained and evaluated for changes related to EOTRH. Radiological findings were classified in terms of EOTRH severity, and each tooth was evaluated individually (tooth stage). Results The tooth stages of EOTRH showed a bilateral symmetrical distribution pattern over the entire incisor arcade. There was a significant positive correlation between age and tooth stages (p < 0.001, rho = 0.48, 95% CI 0.43–0.51), and the frequency of higher tooth stages increased from central incisors to middle and corner incisors. Main limitations Individual head anatomy in some male horses lead to superimposition of the lower jaw corner incisors and canine teeth. The radiographic technique proved difficult in smaller and uncooperative horses. Differentiating between mild pathological signs of EOTRH and age‐related radiological changes was not possible in all cases. Conclusion These results reconfirm an age‐correlated progression of EOTRH. EOTRH affects the incisor arcade in a bilaterally symmetrical pattern with the corner incisors being the most severely affected.

Computed tomographic findings in incisors and canine teeth with equine odontoclastic tooth resorption and hypercementosis: a retrospective study in 115 Warmblood horses

“…Apart from the 4 th quadrant, EOTRH were more commonly found on 2 nd incisors compared to 3 rd incisors. These findings are in agreement with previous studies concluding that EOTRH-associated changes are most frequent in 2 nd incisors (Rehrl et al 2022).…”

“…Hypercementosis and widening of the periodontal space at the root of incisors and canine teeth were observed significantly more often in teeth of the lower jaw, whereas clubbing of the root was more common in the upper jaw. Other recent studies have come to contradictory conclusions regarding the occurrence of hypercementosis in the upper jaw compared to the lower jaw; while our findings align with those of Rehrl et al (2022) they stand in contrast to previous studies stating that resorption and hypercementosis are more frequent in teeth of the upper jaw (Henry et al 2017).…”

“…In this study, the overall prevalence of incisors affected by EOTRH -both at the level of the individual tooth as well as the horse -was considerably lower compared to previous radiographic studies. In particular, moderate and severe abnormalities were less common than previously described (Henry et al 2017, Rehrl et al 2018, Rehrl et al 2022. These discrepancies can be at least partially explained by the different populations of horses included in these studies: while the current study examined Warmblood horses between 5-29 years of age, other studies that used radiographic images to diagnose EOTRH also included ponies (Rehrl et al 2018, Rehrl et al 2022 and Thoroughbreds (Henry et al 2017, Rehrl et al 2018, Rehrl et al 2022) spanning a larger age range.…”

“…In particular, moderate and severe abnormalities were less common than previously described (Henry et al 2017, Rehrl et al 2018, Rehrl et al 2022. These discrepancies can be at least partially explained by the different populations of horses included in these studies: while the current study examined Warmblood horses between 5-29 years of age, other studies that used radiographic images to diagnose EOTRH also included ponies (Rehrl et al 2018, Rehrl et al 2022 and Thoroughbreds (Henry et al 2017, Rehrl et al 2018, Rehrl et al 2022) spanning a larger age range. Apart from the different populations of horses examined, the evaluation criteria and techniques used also differed between the current study and previously published studies using radiographic criteria to diagnose and categorize EOTRH.…”

“…A recent study found that all horses older than 14 years showed radiographic changes of EOTRH, and all horses older than 28 years had at least moderate radiological changes on the incisors (Rehrl et al 2018, Albers et al 2022. This indicates that mild changes are associated with the normal aging process (Rehrl et al 2018, Rehrl et al 2022. Radiographically, an increased probability of resorption and hypercementosis was observed with increasing age without significant differences between genders (Smedley et al 2015, Henry et al 2017, Limone 2020 or breeds (Henry et al 2017).…”