Equine odontoclastic tooth resorption and hypercementosis

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.

Malocclusions and Dental Diseases in Privately Owned Horses in the Mazovia Region of Poland

Dental disorders, a term encompassing both malocclusion and dental disease, constitute a serious health problem in horses worldwide. As horse populations differ among countries and regions, a geographically specific characterization of the occurrence of various dental disorders may be helpful for local equine practitioners. This study investigated the prevalence and frequency distribution of selected malocclusions and dental diseases in horses housed in the Mazovia region of Poland, with attention paid to variations among age, gender, and breed categories. Routine dental examinations were conducted on 206 privately owned horses (n = 206). Disorders were recorded using a dental chart and classified as either malocclusions or dental diseases. Out of all examined horses, 95% demonstrated at least one dental disorder, with a roughly equal distribution of these disorders among incisor teeth (31%) and cheek teeth (31% each for premolars and molars). More specifically, there were disorders noted in 14 incisors, 3 canines, 2 wolf teeth, and 15 cheek teeth. Across all age, gender, and breed groups, malocclusions of incisor, premolar, and molar teeth occurred with a higher prevalence than did dental diseases. Curvatures and calculus were the most commonly reported pathologies in incisor teeth, whereas sharp enamel points and caries predominated in cheek teeth.

A histological description of alpaca (Vicugna pacos) cheek teeth: Findings and anatomical variations in macroscopically normal molars

Scientific literature on veterinary dentistry in alpacas has historically focused on the description of tooth root abscesses. However, recent studies have shown a variety of other, sometimes preceding dental conditions to be widespread in this species. To allow the development and finetuning of treatment strategies in this species, a more thorough understanding of the underlying etiopathogenesis of dental disease is required. Histological studies focusing on normal dental and surrounding tissues might serve as a basis for this purpose. Nine teeth, extracted from seven alpacas were collected. All samples were retrieved from animals that died or were euthanized for non-dental reasons. Histological sections were prepared at three different levels in each tooth and examined using light microscopy focusing on the assessment of pulp tissue, dentin, cementum, periodontal tissues and the apical region. The histological appearance of the investigated dental tissues in alpacas showed great similarities with other hypsodont species. However, a rather rare type of dentin called “vasodentin” could be identified in all examined cheek teeth. Another species-specific finding was the extremely close proximity of varying neighboring tooth roots that seemed to be responsible for inducing massive resorptive lesions. The results of this study might contribute to a better understanding of the etiopathogenesis of some dental diseases in the alpaca.

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.

Equine Incisor Lesions: Histologic Confirmation of Radiographic, Macroscopic, and Micro-Computed Tomographic Findings

Simple Summary

Incisor diseases are a common problem in equine medicine. However, Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) and other lesions are often only diagnosed in advanced stages. In this study, the incisors of 20 horses were examined. The findings of X-rays, macroscopical inspection, and micro-computed tomography (µCT) were compared. Five categories from healthy to severely affected teeth were formed and selected teeth from each category were additionally examined by means of histology. Odontoclastic resorption of dental hard substances, infiltration of inflammatory cells, areas of irregular dental cementum, and formation of granulation tissue were observed. Resorptive lesions previously detected by µCT were confirmed by microscopical imaging, however, not all resorptive lesions were regarded as a pathological condition like EOTRH. Detailed microscopical inspection revealed the presence of so-called surface resorptions which represent repaired resorptive lesions without any pathological consequence for the horse. Nevertheless, some incisors which appeared healthy on the X-rays featured histological findings related to EOTRH. Therefore, the detection of early incisor lesions in equine medicine remains challenging.

Abstract

Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) and other incisor lesions are often diagnosed only in advanced stages. The incisors of 20 horses were examined radiographically, macroscopically, and via micro-computed tomography (µCT) to discriminate EORTH-affected teeth. Five categories from healthy to severely affected teeth were formed and teeth from each category were examined histologically to evaluate the opportunity of earlier radiographic diagnosis. Histologically, odontoclastic resorptive lesions, leukocytic infiltrations, and areas of irregular cementum and granulation tissue were observed. The extent and severity of histological findings were correlated to the µCT data. Micro-CT imaging was suitable to detect subtle irregularities in the dental substances which were referred to as resorptive lesions. Although histological examinations confirmed the presence of resorptive lesions, not all of them were classified as pathological conditions. Instead, repaired surface lesions were documented which were regarded as a physiological condition. Nevertheless, incisors which were radiographically regarded as healthy can also feature histological signs of EOTRH. Therefore, due to the possibility of misinterpreting radiographic findings combined with superimpositions on intraoral radiographs, the detection of early resorptive lesions remains challenging.

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 age on the severity and its frequency of the individual tooth.

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 EORTH. 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.

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.

Application of Hyperbaric Oxygen Therapy (HBOT) as a Healing Aid after Extraction of Incisors in the Equine Odontoclastic Tooth Resorption and Hypercementosis Syndrome

Hyperbaric Oxygen Therapy (HBOT) is a stress-free, relatively safe method supporting the treatment of many different diseases. Although it is widely used in human medicine (including dentistry), in veterinary medicine, especially in the treatment of horses, there are not many scientifically described and documented cases of its use. Equine Odontoclastic Tooth Resorption and Hypercementosis syndrome is a disease that affects older horses and significantly reduces their quality of life. The only effective treatment for this condition is extraction of the incisors. The described case compares the recovery process of the alveolar area after extraction of incisors during the course of EOTRH syndrome without and with the use of a chamber, in horses with the same clinical picture of the disease, of the same age, and living in the same conditions. According to the authors' knowledge, the presented case describes the use of a chamber in equine dentistry for the first time.

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.