Three-Dimensional Segmentation Assisted with Clustering Analysis for Surface and Volume Measurements of Equine Incisor in Multidetector Computed Tomography Data Sets.

Dental diagnostic imaging has progressed towards the use of advanced technologies such as 3D image processing. Since multidetector computed tomography (CT) is widely available in equine clinics, CT-based anatomical 3D models, segmentations, and measurements have become clinically applicable. This study aimed to use a 3D segmentation of CT images and volumetric measurements to investigate differences in the surface area and volume of equine incisors. The 3D Slicer was used to segment single incisors of 50 horses' heads and to extract volumetric features. Axial vertical symmetry, but not horizontal, of the incisors was evidenced. The surface area and volume differed significantly between temporary and permanent incisors, allowing for easy eruption-related clustering of the CT-based 3D images with an accuracy of >0.75. The volumetric features differed partially between center, intermediate, and corner incisors, allowing for moderate location-related clustering with an accuracy of >0.69. The volumetric features of mandibular incisors' equine odontoclastic tooth resorption and hypercementosis (EOTRH) degrees were more than those for maxillary incisors; thus, the accuracy of EOTRH degree-related clustering was >0.72 for the mandibula and >0.33 for the maxilla. The CT-based 3D images of equine incisors can be successfully segmented using the routinely achieved multidetector CT data sets and the proposed data-processing approaches.

Widespread prevalence of Equine Odontoclastic Tooth Resorption and Hypercementosis detected in German Icelandic horse population: impact of anamnestic factors on etiology.

OBJECTIVE: To compare anamnestic factors in Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) in affected and nonaffected horses to detect risk factors for horses developing EOTRH. ANIMALS: A total of 154 Icelandic horses, aged 15 years and older, examined at 22 locations in Lower Saxony, Germany. The investigations took place from October 2020 to December 2021. METHODS: Anamnestic data were collected using an owner-completed questionnaire. Horses underwent a thorough physical examination and CBC. The rostral oral cavity was clinically examined, and intraoral radiographs of the incisors were taken. Clinical and radiographic findings were scored. Based on the results, the study population was separated into "EOTRH-affected" and "EOTRH-healthy" horses. Both groups were compared to identify differences within the anamnestic factors. In case of inconclusive findings, some horses were classified as "suspicious". RESULTS: The diagnosis of EOTRH was made in 72.2% (109/151) of horses. The risk of contracting the disease increased with the age of the horse (P = .004). In addition, there was a predisposition for male animals (P = .032). Feeding, keeping, and dental treatments showed no significant influence, while place of birth seemed to influence horses developing EOTRH (P = .017). CLINICAL RELEVANCE: The results highlight how widespread EOTRH is among the German Icelandic horse population and the need for raising awareness of EOTRH, as many horses were not suspected of having EOTRH beforehand. Moreover, numerous etiological propositions exist, but, to date, no studies have investigated their relevance.

The prevalence of equine odontoclastic tooth resorption and hypercementosis and the role of interincisal angulation in disease severity in a representative cohort of horses in Switzerland.

INTRODUCTION: Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is an increasingly diagnosed degenerative dental disease in aged horses. The primary aim of this retrospective study was to determine the prevalence of EOTRH in horses admitted to the Equine Hospital, University of Zurich, for dental procedures from 2004 to 2017. A secondary goal was to measure and compare interincisal angles on two-dimensional radiographs of horses with EOTRH to determine whether the interincisal angle is associated with age and severity of the disease. Radiographs were assessed for the presence of lysis and/or hypercementosis, and the number and position of the teeth affected were determined. Each tooth was also evaluated using the modified classification system introduced by Rehrl et al. (2018), in which stage 0 indicates no radiographic abnormalities and stage 3 denotes severe abnormalities. The overall stage was defined by the tooth with the most severe lesions. The interincisal angle was determined in horses that had suitable radiographs. The medical records of 838 horses admitted for dental procedures were evaluated, and 85 (10,1 %) had clinical evidence of EOTRH. The mean interincisal angle was 136,06 ° in horses with mild to moderate EOTRH and 135,10 ° (SD = 11,90 °) in severely affected patients. In conclusion, the angle measurements on lateral radiographs were highly reproducible. However, the interincisal angle was not associated with age or the severity of EOTRH. The interincisal angle and the disease pattern were not correlated.

INTRODUCTION: La résorption et l'hypercémentose odontoclastique des dents chez le cheval (EOTRH) est une maladie dentaire dégénérative de plus en plus diagnostiquée chez les animaux âgés. L'objectif principal de cette étude rétrospective était de déterminer la prévalence de l'EOTRH chez les chevaux admis à l'Hôpital équin de l'Université de Zurich pour des interventions dentaires entre 2014 et 2017. Un objectif secondaire était de mesurer et de comparer les angles inter-incisifs sur des radiographies bidimensionnelles de chevaux atteints d'EOTRH afin de déterminer si cet angle est associé à l'âge et à la gravité de la maladie. Les radiographies ont été évaluées pour la présence de lyse et/ou d'hypercémentose, et le nombre et la position des dents affectées ont été déterminés. Chaque dent a également été évaluée à l'aide du système de classification modifié introduit par Rehrl et al. (2018), dans lequel le stade 0 indique l'absence d'anomalies radiographiques et le stade 3 indique des anomalies graves. Le stade global a été défini par la dent présentant les lésions les plus sévères. L'angle inter-incisif a été déterminé chez les chevaux qui avaient des radiographies appropriées. Les dossiers médicaux de 838 chevaux admis pour des interventions dentaires ont été évalués et 85 (10,1 %) présentaient des signes cliniques d'EOTRH. L'angle inter-incisif moyen était de 136,06° chez les chevaux présentant une EOTRH légère à modérée et de 135,10° (écart-type = 11,90°) chez les patients gravement atteints. En conclusion, les mesures d'angle sur les radiographies latérales étaient très reproductibles. Cependant, l'angle inter-incisif n'était pas associé à l'âge ou à la sévérité de l'EOTRH. L'angle inter-incisif et le profil de la maladie n'étaient pas corrélés.

An application of the density standard and scaled-pixel-counting protocol to assess the radiodensity of equine incisor teeth affected by resorption and hypercementosis: preliminary advancement in dental radiography.

BACKGROUND: Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) syndrome is a dental disease where the radiographic signs may be quantified using radiographic texture features. This study aimed to implement the scaled-pixel-counting protocol to quantify and compare the image structure of teeth and the density standard in order to improve the identification of the radiographic signs of tooth resorption and hypercementosis using the EOTRH syndrome model. METHODS AND RESULTS: A detailed examination of the oral cavity was performed in 80 horses and maxillary incisor teeth were evaluated radiographically, including an assessment of the density standard. On each of the radiographs, pixel brightness (PB) was extracted for each of the ten steps of the density standard (S1-S10). Then, each evaluated incisor tooth was assigned to one of 0-3 EOTRH grade-related groups and annotated using region of interest (ROI). For each ROI, the number of pixels (NP) from each range was calculated. The linear relation between an original X-ray beam attenuation and PB was confirmed for the density standard. The NP values increased with the number of steps of the density standard as well as with EOTRH degrees. Similar accuracy of the EOTRH grade differentiation was noted for data pairs EOTRH 0-3 and EOTRH 0-1, allowing for the differentiation of both late and early radiographic signs of EOTRH. CONCLUSION: The scaled-pixel-counting protocol based on the use of density standard has been successfully implemented for the differentiation of radiographic signs of EOTRH degrees.

Equine odontoclastic tooth resorption and hypercementosis (EOTRH): microspatial distribution of trace elements in hypercementosis-affected and unaffected hard dental tissues.

Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) is a common, painful and poorly understood disease. Enamel, dentin and cementum accumulate both essential and toxic trace elements during mineralization. Characterization of the spatial accumulation pattern of trace elements may provide insight into the role that toxic elements play and inform biological processes affecting these hard dental tissues for future research. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to map the distribution of multiple trace elements and heavy metals across equine healthy and diseased (hypercementosis-affected) hard dental tissues among four teeth extracted from horses with EOTRH. Results showed banding patterns of some trace elements (lead, strontium, barium), reflecting the temporal component of accumulation of trace elements during dentin mineralization. Essential elements zinc and magnesium did not show banding patterns. Comparison to the unaffected cementum and dentin adjacent to the hypercementosis region showed that there is an underlying incremental pattern in the uptake of some metals with spatial irregularities. This supports a possible metabolic change involved in hypercementosis lesion development. This represents the first use of LA-ICP-MS to study the microspatial distribution of trace elements in equine teeth, establishing a baseline for elemental distribution in normal and EOTRH impacted dental hard tissue.

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 µCT 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 (µCT) 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 µCT scans, numerous teeth which were radiographically classified as healthy displayed lesions by macroscopic inspection (13.7%) and µCT 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.

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

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.

Equine Odontoclastic Tooth Resorption and Hypercementosis.

Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a recently described painful and progressive condition of unknown etiology that occurs in middle-aged and geriatric equines. It predominantly affects the permanent incisor and canine teeth and, less commonly, the premolar and molar dentition. EOTRH was first reported in peer-reviewed literature in 2008, with subsequent publications of case reports, histological studies and retrospective case series. There have been few significant research developments related to this disease. The existing studies have primarily involved single case studies or small sample sizes, without control groups. This review aimed to report current information about EOTRH in terms of clinical, histopathological, diagnostic, radiological, and therapeutic aspects, by searching the available peer-reviewed scientific literature.

Clinical, Diagnostic and Histological Findings Involving Cheek Teeth Hypercementosis in Nine Horses.

Hypercementosis is infrequently reported to affect the cheek teeth of horses and presents as mineral deposits either attached (peripheral) or solitary ovoid (nodular) structures in the tooth bearing region. There is overlap between radiological and histological appearance of hypercementosis, cementoma, and equine odontoclastic tooth resorption and hypercementosis (EOTRH). The clinical presentation, imaging features, surgical management, and histological findings of nine horses that presented for dental lesions and associated hypercementosis of cheek teeth are reported. Horses were 4-15 years old and presented for either nasal discharge or facial swelling. Peripheral and nodular mineral structures were identified using radiographs or computed tomography in six and three horses, respectively. Eight of nine cases involved maxillary cheek teeth. Of six cases with peripheral hypercementosis, three had enlargement of the apical cross-sectional area that was greater than the coronal cross-sectional area thus preventing extraction along the normal eruption pathway and necessitating sectioning (two cases) and repulsion. Nodular hypercementosis lesions were extracted in three of the four cases. Post-extraction complications occurred in five cases; four cases required additional procedures. All horses returned to their intended use, ie riding or pasture. Histology of extracted dental and proliferative mineral material revealed hypercementosis characterized by large sheets of eosinophilic matrix with lacunae (usually empty; presumed artifact) and frequent, irregular, basophilic cement lines. All cases had evidence of chronic inflammation, such as caries, chronic fractures and/or pulpitis. The findings of this case series share many features with previous published descriptions of cementoma and with histological findings of hypercementosis lesions of EOTRH. Further investigation into differentiation of these entities is warranted.

Selection of Filtering and Image Texture Analysis in the Radiographic Images Processing of Horses' Incisor Teeth Affected by the EOTRH Syndrome.

Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is one of the horses' dental diseases, mainly affecting the incisor teeth. An increase in the incidence of aged horses and a painful progressive course of the disease create the need for improved early diagnosis. Besides clinical findings, EOTRH recognition is based on the typical radiographic findings, including levels of dental resorption and hypercementosis. This study aimed to introduce digital processing methods to equine dental radiographic images and identify texture features changing with disease progression. The radiographs of maxillary incisor teeth from 80 horses were obtained. Each incisor was annotated by separate masks and clinically classified as 0, 1, 2, or 3 EOTRH degrees. Images were filtered by Mean, Median, Normalize, Bilateral, Binomial, CurvatureFlow, LaplacianSharpening, DiscreteGaussian, and SmoothingRecursiveGaussian filters independently, and 93 features of image texture were extracted using First Order Statistics (FOS), Gray Level Co-occurrence Matrix (GLCM), Neighbouring Gray Tone Difference Matrix (NGTDM), Gray Level Dependence Matrix (GLDM), Gray Level Run Length Matrix (GLRLM), and Gray Level Size Zone Matrix (GLSZM) approaches. The most informative processing was selected. GLCM and GLRLM return the most favorable features for the quantitative evaluation of radiographic signs of the EOTRH syndrome, which may be supported by filtering by filters improving the edge delimitation.

EOTRH Syndrome in Polish Half-Bred Horses - Two Clinical Cases.

The aim of this paper is to thoroughly describe the etiology, diagnostic processes and recommended treatment of equine odontoclastic tooth resorption and hypercementosis (EOTRH). It is a relatively recently described disease. Most recent reports show that it is a common problem involving older equine patients. The most common and significant symptom of EOTRH is oral pain. The main clinical signs include periodontitis and gingivitis with a gingival recession, alveolar bone protrusion, periodontic fistulas and soreness of the incisors. When establishing the final diagnosis, it is necessary to compare the results of the clinical and radiological examination, because in the early stage, the disease may not show any symptoms. Authors used two clinical cases of Polish Half-Bred horses to present some aspects of diagnostic and surgical techniques. The knowledge presented in the paper may be valuable for equine practitioners working in the field to achieve more beneficial outcomes and provide a higher level of welfare for their equine patients. Nevertheless, further research and observations are necessary, since the etiology of the disease remains unclear.

Update on Equine Odontoclastic Tooth Resorption and Hypercementosis.

Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a progressive, painful disease, affecting incisors, canines, and cheek teeth. Examination findings include gingival inflammation, gingival recession and/or hyperplasia, subgingival swelling, bulbous enlargement of teeth, associated periodontal disease, pathologic tooth fracture, and/or tooth mobility and loss. Current hypotheses include biomechanical stresses and secondary bacterial involvement. Early recognition allows case management, but it is a progressive disease. Owner education is crucial; horses with complete or multiple extractions have a favorable prognosis. Human oral and dental health may be affected by bisphosophonate use; long-term effects of these drugs are currently unknown in horses.

History, clinical findings and outcome of horses with radiographical signs of equine odontoclastic tooth resorption and hypercementosis.

The progression of equine odontoclastic tooth resorption and hypercementosis (EOTRH) has not been completely evaluated, and currently, the only effective treatment is extraction of severely affected teeth. We aim to describe how the disease relates to the history and clinical findings and to report on the outcome in individual horses. This case series comprises data collected from 20 horses (age 14-29 years old) with radiographic findings of EOTRH in their incisor and/or canine teeth. Most horses affected with EOTRH in this study were admitted for dental problems, but some for other complaints such as colic. Of the 288 teeth evaluated radiographically, 224 teeth were abnormal. Radiographic findings were most frequently located in the apical aspect and reserve crown of the teeth, and lesions were also commonly found in clinically normal teeth. Histopathology of extracted teeth showed inflammation in the periodontal ligament and revealed that resorption often extended to the dentine. Some owners were unwilling to allow extraction of their horses' severely affected teeth, even though this treatment has been shown to increase the wellbeing of the horse. As EORTH is a life-long condition, the progression of the disease has to be continuously monitored and the treatments adjusted accordingly.

Radiological prevalence of equine odontoclastic tooth resorption and hypercementosis.

BACKGROUND: Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a painful and progressive dental disease that mainly affects the incisors and canine teeth of aged horses. Diagnosis is based on radiographs to detect early stages of the disease. EOTRH is probably underdiagnosed and its prevalence in Germany unknown. OBJECTIVE: This study was performed to determine the radiological prevalence of EOTRH in a large horse population in Berlin-Brandenburg, Germany. STUDY DESIGN: Prevalence study. METHODS: The study population (142 horses) consisted of all horses 10 years and older that were presented at the Equine Hospital for a routine dental examination. The horses were either presented as clinical cases (CC population) or belonged to a riding school (RS population). Digital radiographs of the incisor dentition were taken and evaluated for changes related to EOTRH, leading to an overall classification for each horse. RESULTS: The mean age of the study population was 21 years and ranged from 10 to 37 years. Overall, 94% of all horses had at least minor and 62% had moderate to severe radiological changes of the incisor teeth associated to EOTRH. No horse older than 14 years was without radiological signs of EOTRH and all horses over 28 years of age had at least moderate radiological changes of the incisor teeth. MAIN LIMITATIONS: The clinical cases group might have a bias towards horses with existing dental problems such as EOTRH, because they were presented explicitly for dental care to a clinic. CONCLUSION: Focusing on radiological changes, this study shows that EOTRH is a common condition of horses in Berlin-Brandenburg. With older age, disease is more frequent and radiological changes become more severe. Since no horse older than 14 years was without radiological findings, it is likely that mild changes may be associated with the normal tooth ageing process.

Hematologic, Biochemical, and Endocrine Parameters in Horses With Tooth Resorption and Hypercementosis.

BACKGROUND: Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a frequently diagnosed condition in adult horses. The underlying etiology is still unknown. Hematologic, biochemical, and endocrine values have not been reported in EOTRH-affected horses. OBJECTIVES: The main objective of the study was to describe the hematologic, biochemical, and endocrine parameters in horses with EOTRH. STUDY DESIGN: Descriptive cross-sectional study of client-owned animals with EOTRH. METHODS: A complete blood count, biochemistry panel, and endocrine profile were performed in horses diagnosed with EOTRH. Diagnosis was based on oral and radiographic examination findings and confirmed with histopathology. RESULTS: Eighteen horses with EOTRH aged 10 to 32 years from various regions of the United States were sampled. The only consistent abnormality on the complete blood cell count and chemistry panel was hypoalbuminemia (88%). Endocrine parameters demonstrated no major abnormalities in the functioning of the thyroid and pituitary pars intermedia. The parathyroid hormone concentration was increased in 7 (47%) of 15 horses with an elevated 25-hydroxy vitamin D in 3 (17%) of 17 horses. Main Limitations: The main limitations of this study are the small sample size and lack of age-matched and management-matched control horses. CONCLUSIONS: The relevance of elevated parathyroid hormone in this study cannot be determined due to the lack of age-based controls and large population studies. With the small population evaluated in this study, there are no obvious hematological, biochemical, and endocrine changes evident. Further evaluation with signalment-matched controls will be necessary to evaluate some trends noted in the laboratory values.

Radiographic evaluation in clinical practice of the types and stage of incisor tooth resorption and hypercementosis in horses.

BACKGROUND: There are several reports of incisor tooth resorption and hypercementosis in horses but, to date, studies have been limited in case numbers and to advanced lesions. Tooth resorption in other species is a radiographic diagnosis of types of resorption that are often identified before clinical signs. Our goal was to evaluate radiographically incisor tooth resorption in a large population of horses, utilising interpretation criteria from canine and human dentistry. OBJECTIVE: To document and classify incisor tooth resorption and hypercementosis. STUDY DESIGN: Retrospective descriptive case series. METHODS: Horses presented for routine dental care >5 years old were included only if owners were unaware of incisor pathology. Radiographs (three views) were obtained of the incisor teeth and incisor teeth resorption was classified according to the radiographic criteria described for man and dogs. Hypercementosis and its location were recorded. RESULTS: Tooth resorption was detected in 149 of 169 (88.2%) horses and 951 of 1952 (48.7%) of incisor teeth. The classification system used was applicable in 926 (97.2%) of 951 affected teeth. Hypercementosis was detected in 34 (20.1%) horses and 148 (7.6%) teeth. As horses increased in age, resorption and hypercementosis was more frequent; no significant differences were found among sex or breed categories. All horses with hypercementosis had resorption, but only 23.4% of horses with resorption had hypercementosis. Advanced (stage ≥3) resorption was detected in 159 (8.1%) teeth and 54 (32.0%) horses in an otherwise clinically healthy population. MAIN LIMITATIONS: Certain horses' anatomy precluded isolation of the mandibular third incisor teeth from the canine teeth due to superimposition. CONCLUSIONS: Incisor tooth resorption, in particular external replacement resorption and external inflammatory resorption, is common in horses. Hypercementosis is consistently associated with resorption, but the inverse association is inconsistent.

Clinical treatment and prognosis of equine odontoclastic tooth resorption and hypercementosis.

REASONS FOR PERFORMING STUDY: Equine odontoclastic tooth resorption and hypercementosis is an infrequent and underdiagnosed form of severe dental disease in horses that can affect quality of life. The study was performed to compare the clinical, radiographic, histological and prognostic findings specific to equine odontoclastic tooth resorption and hypercementosis in horses. Removal of affected teeth is currently the best treatment. OBJECTIVES: The goals are to report salient clinical and histological features of the disease and its management in a case series describing an under-reported syndrome in horses and the long-term prognosis. STUDY DESIGN: Retrospective case series. METHODS: Medical records from New Bolton Center, University of Pennsylvania from January 2000 to December 2012 were reviewed from horses that had a diagnosis of 'cementoma' or 'hypercementosis' and any associated dental-related diagnosis affecting the teeth and oral cavity. Radiographic, surgical and histological reports were collated and the clinical cases compared and tabulated to provide a better description of the equine disease. RESULTS: A total of 18 cases were identified, 17 of which were geldings and one of which was a nonbreeding stallion; no mares had the disease. The mean age at diagnosis was 24 years, with a range of 17-29 years. There was no breed predilection, and varied clinical signs relating to the mouth were found. Some teeth involved had only radiographic changes of disease and not gross clinical evidence. The mandibular incisors were generally affected earlier than the maxillary incisors, but the disease is progressive, and eventually, all of the incisors and sometimes the canines are involved. No premolars or molars were affected in this case series. CONCLUSIONS: Based on this case series, all teeth, and particularly the incisors, should be examined for signs of gingivitis and hypercementosis and subsequently radiographed for an early diagnosis and management. When compared with our hospital population, older geldings were more likely to be affected with cementoma formation and its accompanying resorptive process. Removal of clinically and radiographically affected teeth carries a good prognosis for improved quality of life.

Novel treatment of equine odontoclastic tooth resorption and hypercementosis of incisor teeth in a 22-year-old Arabian mare.

Equine odontoclastic tooth resorption and hypercementosis is a rarely reported condition in the incisor and canine teeth of older horses. Histologically, there is internal and external resorption of the tooth with formation of excessive cementum. Once lesions become infected or supragingival this condition is very painful. The clinical manifestation, diagnosis and treatment of hypercementosis in an Arabian mare are described.

Traitement innovateur de la résorption dentaire odontoclasique et de l'hypercémentose de la dent incisive chez une jument arabe âgée de 22 ans. La résorption dentaire odontoclasique et l'hypercémentose représentent une affection rarement signalée des dents incisives et canines chez les chevaux âgés. Sur le plan histologique, il se produit une résorption interne et externe de la dent avec une formation excessive de cément. Une fois que les lésions deviennent infectées ou supra-gingivales, cette affection est très douloureuse. La manifestation clinique, le diagnostic et le traitement de l'hypercémentose sont décrits chez une jument arabe.(Traduit par Isabelle Vallières).

Equine Odontoclastic Tooth Resorption and Hypercementosis: Histopathologic Features.

Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a painful progressive condition of older horses that involves multiple teeth, including canines and incisors. EOTRH is uncommonly recognized by veterinary pathologists and in some cases may be misdiagnosed as cementoblastoma. The cause is unknown. The goals of this study were to describe the histopathologic features of EOTRH in 17 affected horses from the United States and to increase awareness of this condition. Samples ranged from affected tooth to the entire rostral mandible and maxilla. Affected teeth exhibited cemental hyperplasia and lysis. The marked proliferation of cementum in severe cases caused bulbous enlargement of the intra-alveolar portions of affected teeth. Several teeth contained necrotic debris, bacteria, and plant material in the regions of cemental lysis. All horses exhibited dentinal lysis in at least affected tooth, and several contained necrotic debris in these regions. Endodontic disease was often present with inflammation, lysis, necrotic debris, fibrosis, and/or a thin rim of atubular mineralized tissue in the pulp cavity. Periodontal disease was a common feature that was primarily characterized by moderate lymphoplasmacytic inflammation. Resorption with secondary hypercementosis appears to begin on the external surface of the teeth rather than within the pulp cavity. Distinguishing EOTRH from other diseases requires a complete history that includes the number and location of affected teeth, a gross description of regional hard/soft tissue health, and radiographic findings.

Isolation of Treponema and Tannerella spp. from equine odontoclastic tooth resorption and hypercementosis related periodontal disease.

REASONS FOR PERFORMING STUDY: Red complex bacteria, i.e. Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, are involved in the onset and progression of periodontal disease in man, yet seldom inhabit the oral cavity of healthy individuals. Periodontal disease is also encountered in horses, with equine odontoclastic tooth resorption and hypercementosis (EOTRH) constituting a particular form of disease. However, only little is known about the oral microbiome of healthy and periodontitis-affected equids. OBJECTIVE: We aimed to test the hypothesis that red complex bacteria are also associated with EOTRH-related periodontal disease. STUDY DESIGN: Controlled cross-sectional study. METHODS: We screened DNA purified from crevicular fluid derived from 23 EOTRH-affected and 21 disease-free horses for the presence of Treponema spp., Tannerella spp. and Porphyromonas gingivalis DNA by polymerase chain reaction. Subsequently, amplified DNA was bidirectionally sequenced and identified via BLAST analysis. RESULTS: Treponema and/or Tannerella DNA was detected in 100% of periodontitis-related samples and in 52.2% of DNA derived from healthy horses. Twenty-six amplicon sequences were 98-100% homologous to published bacterial sequences, which mostly corresponded to Treponema pectinovorum, oral Treponema clones JU025 and OMZ 840, and Tannerella forsythia. P. gingivalis DNA was only found in 3 EOTRH-related samples. Forty-three amplicon sequences revealed weaker homologies ranging between 80% and 97% to known Treponema or Tannerella strains, partly because of their heterogeneity, partly because they obviously represented so far unknown types. CONCLUSIONS: This is the first report in which known and novel Treponema and Tannerella spp. were isolated in association with EOTRH-related periodontal disease.