Overview
Hypercementosis, often referred to as Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH), is a complex and multifaceted condition affecting the teeth of horses, particularly those over 15 years of age. This condition is characterized by excessive cementum deposition and tooth resorption, leading to significant dental pathology. The pathophysiology of hypercementosis is influenced by a variety of factors, including metabolic disorders, genetic predisposition, and environmental influences. Understanding the diverse etiologies and clinical manifestations is crucial for accurate diagnosis and effective management. This guideline aims to provide clinicians with a comprehensive overview of hypercementosis, encompassing its pathophysiology, epidemiology, clinical presentation, diagnostic approaches, differential diagnoses, management strategies, potential complications, and prognosis.
Pathophysiology
The pathogenesis of hypercementosis involves intricate interactions between mechanical forces, systemic health, and local dental factors. Initially, periodontal inflammation often transitions into resorptive lesions, facilitated by the presence of gram-negative bacteria such as Treponema and Tannerella, which contribute to the inflammatory cascade [PMID:39777419]. This inflammatory environment triggers odontoclastic activity, leading to tooth resorption. Subsequently, reparative mechanisms manifest as excessive cementum formation (hypercementosis) as the body attempts to stabilize the affected teeth [PMID:40626519]. Metabolic disorders, such as pituitary pars intermedia dysfunction (PPID) and equine metabolic syndrome (EMS), are implicated in exacerbating these processes, suggesting a role for systemic health in the development of hypercementosis [PMID:40626519].
Histopathological studies reveal detailed alterations in the tooth structure, including irregular Sharpey fibers and frequent interruptions near the cementum-dentin junction, alongside heavily stained lacunae indicative of cellular degeneration [PMID:79581]. These changes highlight the degenerative nature of the condition, affecting both cellular and acellular cementum layers. Notably, cementocytes exhibit fragmentation of their protoplasmic prolongations, underscoring the cellular pathology underlying hypercementosis [PMID:79581]. Additionally, the presence of multiple potential aetiologies—ranging from occlusal forces and ongoing tooth eruption to systemic diseases like Paget's disease—indicates a multifaceted pathophysiology [PMID:19082395]. A systematic review further supports this complexity by identifying eight distinct potential causes, emphasizing the need for a comprehensive approach to understanding and managing hypercementosis [PMID:36495812].
Epidemiology
Hypercementosis exhibits notable epidemiological patterns, particularly in specific breeds and age groups. Icelandic horses appear to have a higher susceptibility to EOTRH, with studies reporting a prevalence of 72.2% in aged Icelandic horses [PMID:40626519]. Radiological studies in Northeast German horses and ponies also reveal significant prevalence rates, with 94% showing minor changes and 62% exhibiting moderate to severe changes associated with EOTRH [PMID:39777419]. Epidemiological data indicate that on average, 3.8 teeth per individual are affected, with premolars being predominantly impacted [PMID:19082395]. The prevalence of EOTRH increases significantly with age, with a notable risk factor identified in horses over 15 years old (P = .004) [PMID:37734718]. Gender also plays a role, with male horses showing a predisposition (P = .032), and geographical factors, such as place of birth, influencing susceptibility (P = .017) [PMID:37734718]. Retrospective studies further highlight the widespread nature of EOTRH, with 10.1% of horses admitted for dental procedures between 2004 and 2017 exhibiting clinical signs [PMID:37646096]. Cone-beam computed tomography (CBCT) studies reveal that hypercementosis affects 2.4% of the equine population, predominantly impacting mandibular teeth (71.4%) over maxillary teeth (28.6%), with molars more frequently involved than premolars [PMID:28656927]. Notably, incisors remain unaffected, suggesting specific anatomical or functional reasons for this exclusion [PMID:28656927].
Clinical Presentation
The clinical presentation of hypercementosis varies widely, ranging from asymptomatic cases to severe manifestations that significantly impact a horse's quality of life. Mild cases may present with subtle changes such as a non-age-correlated bite angle of the incisors, gingival recession, and localized swelling [PMID:40626519]. More severe presentations often include dysphagia, pain during eating, and behavioral changes, potentially leading to weight loss and decreased performance [PMID:39777419]. Microscopic examination reveals thickened cementum layers and irregular apical cementum deposition, which can alter root morphology and create multiple foramina, complicating clinical assessment [PMID:19082395]. The variability in clinical signs underscores the importance of a thorough dental examination, as the nature and extent of hypercementosis can provide clues to its underlying aetiology [PMID:36495812]. Clinical signs such as nasal discharge, facial swelling, and concurrent dental lesions further complicate the clinical picture, often necessitating a comprehensive evaluation to differentiate hypercementosis from other dental pathologies [PMID:35996329]. Unilateral involvement is common, with a slight predilection for the right side (69.6%) [PMID:28656927].
Diagnosis
Diagnosing hypercementosis relies heavily on clinical examination and radiographic imaging, though these methods have limitations. Radiography remains the primary diagnostic tool, revealing varying degrees of tooth resorption and bulbous enlargement of the tooth roots [PMID:40626519]. However, early-stage detection can be challenging due to the indistinguishable radiodensity between cementum and dentin, potentially delaying intervention [PMID:39777419]. Radiographic staging systems, such as the modified system by Rehrl et al. (2018), classify severity from 0 to 3, aiding in the characterization of disease progression [PMID:37646096]. Advanced imaging techniques like cone-beam computed tomography (CBCT) offer superior resolution, enabling detailed visualization of hypercementosis in 2.4% of cases, predominantly affecting mandibular molars and premolars [PMID:28656927]. CBCT not only confirms the presence of hypercementosis but also helps in assessing lesion distribution and characteristics, crucial for surgical planning [PMID:28656927]. Histological techniques, such as the Achucarro-Hortega method, provide invaluable insights into cementum structure and cementocyte health, enhancing diagnostic accuracy [PMID:79581]. Despite these advancements, the diagnosis often requires integrating clinical findings with imaging results to achieve a comprehensive understanding of the condition.
Differential Diagnosis
Differentiating hypercementosis from other dental conditions is essential for appropriate management. Several conditions can mimic hypercementosis, including dental fractures, periodontal disease, and other forms of tooth resorption such as equine odontoclastic tooth resorption (EOTR). The presence of multiple aetiologies complicates differential diagnosis, necessitating a broad approach [PMID:36495812]. For instance, measurements of the interincisal angle on lateral radiographs do not correlate with the severity or age of EOTRH, highlighting the need for additional diagnostic criteria beyond simple radiographic assessments [PMID:37646096]. Clinicians must consider systemic diseases like PPID and EMS, which can influence dental health, and genetic predispositions, particularly in breeds like Icelandic horses, to refine their differential diagnosis [PMID:40626519]. Comprehensive clinical evaluation, including detailed dental examination and advanced imaging, is crucial to rule out other potential causes and confirm hypercementosis.
Management
The management of hypercementosis primarily involves surgical intervention, with extraction of affected teeth being the standard approach. However, this method carries risks, including the potential for neighboring teeth to develop similar conditions, underscoring the importance of preventive strategies [PMID:39777419]. Tailoring endodontic techniques to address morphological changes, such as altered root canal diameters and foramina, is critical for managing residual tooth structures [PMID:19082395]. Characterizing hypercementosis using proposed scoring systems can guide more precise management strategies, aligning treatment with the underlying aetiology [PMID:36495812]. Surgical extraction, while effective, can be complicated, with post-extraction issues requiring additional interventions in approximately 5% of cases [PMID:35996329]. Preventive measures, such as regular dental examinations and addressing metabolic disorders, are essential to mitigate the risk of hypercementosis progression and recurrence.
Complications
Post-extraction complications are a notable concern in the management of hypercementosis. Studies report that complications arise in about 5% of cases, necessitating further interventions in approximately 4% of these instances [PMID:35996329]. These complications can include infection, malocclusion, and persistent pain, which may require additional surgical or medical management to ensure optimal recovery and prevent long-term sequelae.
Prognosis & Follow-up
Despite the challenges associated with hypercementosis, the prognosis for affected horses is generally favorable when managed appropriately. Most horses return to their intended activities, including riding and pasture turnout, following successful treatment [PMID:35996329]. Regular follow-up evaluations are crucial to monitor for recurrence or complications and to ensure that preventive measures are effectively implemented. Long-term management often involves ongoing dental care and monitoring for systemic conditions that could exacerbate dental health issues.
Key Recommendations
References
1 Tretow M, Hain AM, Bienert-Zeit A. Aetiological relevance of haematological, biochemical and endocrine parameters on equine odontoclastic tooth resorption and hypercementosis (EOTRH). Equine veterinary journal 2026. link 2 Jensen A, Clarke EJ, Nugent Z, Paice E, Gringel I, Yamamoto K et al.. Inflammation and response to bacterial infection as potential drivers of equine odontoclastic tooth resorption and hypercementosis: A proteomics insight. Equine veterinary journal 2025. link 3 Pinheiro BC, Pinheiro TN, Capelozza AL, Consolaro A. A scanning electron microscopic study of hypercementosis. Journal of applied oral science : revista FOB 2008. link 4 Tretow M, Hain AM, Bienert-Zeit A. Widespread prevalence of Equine Odontoclastic Tooth Resorption and Hypercementosis detected in German Icelandic horse population: impact of anamnestic factors on etiology. Journal of the American Veterinary Medical Association 2023. link 5 Igel P, Fürst AE, Jackson MA. 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. Schweizer Archiv fur Tierheilkunde 2023. link 6 Massé L, Garot E, Maureille B, Le Cabec A. Insights into the aetiologies of hypercementosis: A systematic review and a scoring system. Archives of oral biology 2023. link 7 Brown JA, Murphy BG, Clapp KS, LaDouceur EEB. Clinical, Diagnostic and Histological Findings Involving Cheek Teeth Hypercementosis in Nine Horses. Journal of veterinary dentistry 2022. link 8 Eren Y, Erdal O, Serdar B, Emin KO, Enes G. Evaluation of the frequency and characteristics of hypercementosis in the turkish population with cone-beam computed tomography. Nigerian journal of clinical practice 2017. link 9 Lia RC, Lauand F, Marcantonio E, Neto CB. A contribution to the histological study of hypercementosis using metal staining. Journal of dental research 1978. link