Prävalenz und Erscheinungsbild von Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) bei Islandpferden in ihrem Heimatland

Examination of elderly horses generally reveal high prevalences of EOTRH. By use of clinical and radiographic examination a population with low prevalence of EOTRH could be found. Clinical and radiographic aspects were brought into relation with anamnestic parameters.
In Iceland, the rostral oral cavity of 191 horses, aged 15 years and above, was examined clinically and radiographically. In addition, each owner was asked to answer an anamnestic questionnaire which contented information about the feeding practice, husbandry management and dental care. The health of the rostral oral cavity was documented by report and photography. For radiographic examination intraoral images of the maxilla and mandible were taken. If the corner mandible incisors were superimposed by the canines, oblique pictures were added.
The anamnestic questionnaire was completed for 187 horses. Evaluation of clinical parameters could be accomplished in 170 cases. Radiographic images of 188 horses were sufficient for evaluation. Analysis of the radiographic images was performed by three person who were blinded to identity and clinical status of the horses in order to minimize errors. Each clinical and radiographic parameter was evaluated by use of a scoring system.
The majority of the horses was kept on pasture almost throughout the year (82,4 % (154/187) in 9 to 12 months). The study horses showed a good clinical health of the rostral oral cavity. Gingivitis and gingival recession were detected in 5,3 % of the horses (mild: 4,7 %; moderate: 0,6 %) and 61,9 % (mild: 50,0 %; moderate: 11,3 %; severe: 0,6 %). Incisor and canine calculus was found in 49,4 % (84/170) and 74,2 % (96/128) of the horses. The probability for incisor calculus was strongly correlated with age. Fistulae, bulbous enlargement of the root and increased mobility or tooth lost because of EOTRH was not present at all. The radiographic prevalence of EOTRH-like lesions was 27,7 % (mild: 26,6 %; moderate: 1,1 %). Appearance of radiographic alterations was significantly age-dependent. Accompanied by low clinical findings of the rostral oral cavity, it is very likely that the presented radiographic findings are caused by age.
The current study is the first one picturing a horse population with very low clinical and radiological prevalence of EOTRH. Special living conditions of the horses could have had a positive effect on the dental health. Pasturing - promoting a natural feeding posture and continuous food intake - and extensive pasture management in Iceland probably had a promoting impact on the dental health.
The current study may initialise new approaches for the research of EOTRH, especially in the field of prophylaxis, even though, the presented relations between clinical and radiographic findings and anamnestic parameters are unproven yet. Further research of chemical and physical properties of forage plants and soils and its effect on equine dental health are required for better understanding of possible influences.