The mandible in horses is the lower jawbone, essential for mastication and articulation with the skull. It comprises two halves that fuse at the mandibular symphysis and supports the lower teeth, playing a key role in the horse's ability to graze and process food. The mandible also provides attachment sites for muscles involved in chewing and facial expressions. Research on the equine mandible often focuses on its anatomy, development, and the impact of various dental and skeletal disorders. This page compiles peer-reviewed research studies and scholarly articles that investigate the structure, function, and clinical implications of the mandible in equine health and management.
Oliveira LLV, Caldas MCAR, Marval LME, Marval CA, Carvalho JGS, Matos JJRT, Malacarne BD, Paz CFR.A 2-year-old mixed-breed mare was examined at the property due to swelling and fistula on the right mandible. Oral examination and radiographs revealed the presence of an apical abscess involving the 410 tooth. The tooth was extracted entirely and confirmed radiographically. One year later, the owner reported a reoccurrence of clinical signs. A new radiographic evaluation revealed a radiopaque area in the alveolar socket of the 410 tooth filled with spongy-looking bone. An extraoral approach to the alveolar socket was performed, and the content removed had the appearance of a dental element.
Mendes RP, Lima AE, da Cunha R, Bittar MJ, Vasconcelos CC, Piñeros DDV, Corrêa RR.Radiographic examination of the skull is a well-established and indispensable procedure for the diagnostic evaluation of dental and paranasal sinus disorders in horses. Complementary projections make significant contributions to radiographic diagnosis in nasal conchae disorders. This article describes a complementary radiographic projection designed for the evaluation of the conchal sinuses and bullae in horses. Six equine cadaveric heads were used. Specimens were dissected, and openings were created in the ventral and dorsal nasal conchae for the introduction of radiopaque material. The new r...
Ostmeier M, Schellenberger F, Troillet A, Scharner D.Mouth specula with incisor bite plates shift the pressure from all teeth exclusively to the incisors in the opening phase which leads to increased forces on dental, osseous, and soft tissue structures of the horse's head. The potentially pathological character of these forces is described clinically by single reports of maxilla and mandible fractures occurring during the use of opened mouth specula. This study describes these forces on incisor teeth in horses during odontoplasty of cheek teeth under sedation. Measurements were documented using a modified "Günther" mouth speculum fitted with a...
Nourinezhad J, Abdi A, Moarabi A, Hanafi MG, Fatahian Dehkordi RA, Tomańska A.Visualizing the major salivary glands (MSGs) in domestic mammals using plain radiology and identifying damaged their structures is impossible. To accurately display MSGs, the knowledge of normal sectional imaging anatomy is essential for veterinarians, aiding them significantly in identifying the exact relations and position of MSGs; however, no reports on the MSGs sectional imaging anatomy in this species have been made. Objective: This study aimed to evaluate computed tomography (CT), magnetic resonance imaging (MRI) and gross sections of MSGs. Methods: Seven healthy adult donkeys were used ...
Clayton HM, Murray R, Williams JM, Walker V, Fisher M, Fisher D, Nixon J, Mackechnie-Guire R.Noseband adjustment should avoid discomfort and allow some jaw movement. Objective: To determine pressure beneath a cavesson noseband at five tightness levels during standing and chewing. It was hypothesised that increased noseband tightness is associated with increases in nasal and mandibular pressures while standing and chewing, accompanied by increases in eye temperature and blink rate. Methods: Experimental. Methods: Eight highly-trained dressage horses wore a snaffle bridle with their own bit. Pressure mats over the nasal bones and beneath the mandibular rami recorded sub-noseband pressur...
MacKechnie-Guire R, Murray R, Williams JM, Nixon J, Fisher M, Fisher D, Walker V, Clayton HM.Poor noseband adjustment could create high pressures that may risk pain or tissue damage. Objective: To quantify sub-noseband pressures dorsally over the nasal bone and ventrally over the mandibular rami for a Cavesson, Swedish (crank), Drop and Flash noseband at five tightness levels (2.0 to 0.0 finger equivalents). Methods: In vivo experiments. Methods: Eight high-level dressage horses were ridden at the trot in a straight line by their usual riders. Two small pressure mats, attached to the noseband over the nasal bone and the mandibular rami, collected force (N) and pressure (kPa) data from...
Rapezzano G, Foote A, Petrini F, Pereira R, Marcatili M.A newborn Thoroughbred filly presented with a large mass located on the ventro-rostral aspect of the mandible. The mass was surgically removed under general anaesthesia. Upon gross examination, the mass was well circumscribed with a heterogeneous lobulated appearance. The results of histopathology and immunohistochemistry were consistent with a diagnosis of congenital fetal rhabdomyoma. On follow-up at six months post-surgical excision, no abnormalities were noted on clinical examination.
Lima AE, Piñeros DDV, Alibrando BB, Bittar MJ, de Souza AF, Mendes RP, de Freitas SH, Bernardino T, Corrêa RR.The anatomical variations of the maxillary septum and the septal bullae can generate challenges during the interpretation of radiographs of the horses' heads and make it difficult to accurately identify the sites affected in sinus disorders. The description of the radiographic appearance of these structures is currently scarce in the scientific literature. This work aims to describe the anatomical and radiographic characteristics of the maxillary septum and maxillary septal bullae in horses. Six chemically preserved equine cadaver heads were used which, after being submitted to the maxillary o...
de Preux M, Precht C, Guevar J, Graubner C, Thenhaus-Schnabel S, Buser L, Lukes A, Koch C.A 16-year-old warmblood mare was referred with a progressive history of behavioral changes and left-sided blindness. Following neuroanatomical localization to the forebrain, magnetic resonance imaging of the head revealed a well-delineated, 4.5 cm in diameter, round pituitary mass causing marked compression of the midbrain and optic chiasm. Euthanasia was recommended but declined by the owners. Veterinary specialists and a human neurosurgeon collaboratively prepared for surgical case management. A novel navigated transmandibular lateral transsphenoidal approach was developed to access the re...
Schäfer J, Graubner C, Gerber V, Drögemüller C, Underberg J, Gurtner C, Unger L.This case series describes the clinical course of ocular and non-ocular squamous cell carinoma (SCC) in the Haflinger horse and is intended to raise awareness of the high recurrence rate and tendency to metastasize. Eight Haflingers with histologically confirmed SCC were included, five ocular and three non-ocular, who were presented at the Institut Suisse de Médecine Équine (ISME) Bern between July 2015 and January 2022. The ocular SCC cases were all presented because of an apparent mass, which in most cases was post-treatment recurrence. The occurrence of recurrences was observed between 3 ...
Spoormakers TJ, Heim C, Vermunt L, Fürst A, Rovel T.To describe clinical and imaging features and surgical treatment of equine mandibular aneurysmal bone cysts (ABCs) with β-tricalcium phosphate (TCP). Methods: 3 horses (cases 1, 2, and 3) and 1 pony (case 4) with histologically confirmed ABC. Methods: All cases had mandibular swelling with intact adjacent skin. Cases 1 to 3 had a body condition score of 3/5 and case 4 had 2/5 and showed quidding during mastication and, at oral examination, large interdental spaces and loose elements adjacent to the swelling. Radiography or CT was performed in all cases. In cases 1, 3, and 4, an expansile sept...
Bordin C, Raspa F, Harris P, Ellis AD, Roggero A, Palestrini C, Bergero D, Valle E.The application of hay feeding devices, such as the use of hay nets or slow feeders, can help with the management of weight in ponies; however, there is still a lack of knowledge regarding their effect on equine posture. Therefore, the aim of the study was to assess the effect of different feeding devices on the posture of ponies using morphometric analysis. Two different breed types, Shetland type (SH, n = 5) versus Welsh Cob type (WC, n = 4), were fed the same forage in four different ways: on the ground (G), using a fully filled haynet (HF), using a partially filled haynet (HL) and...
Erasha AM, Nazih M, Ali S, Alsafy M, El-Gendy S, Sayed RKA.A significant extent of researches in veterinary study have been focused on dental structure; however, there are scanty ones on the orientation and identification of their cusps. Therefore, the present article aimed to spot a light on arrangement pattern of dental cusps in the camel as a folivorous and graminivorous animal. This study was conducted on eight heads of adult, healthy camel of both sexes, collected from slaughter houses. To perform exact orientation of cusps of molar teeth, additional radiological and CT scans were performed on the mandible as a landmark that should facilitate the...
Vidović A, Jansen D.The first part of this case report describes the surgical treatment of a unilateral mandibular fracture in the standing horse by using a fixateur type I. By the time of implant removal, the fracture had completely healed. However, during implant removal, an implant failure of 2 of the 4 implants occurred with fragments remaining in the bone. The second part of the report focuses on the development of a special surgical instrument that was designed for removal of the implant fragments. Furthermore, the surgical method allowing the entire extirpation of the fragments within a second surgery is d...
Godoy VM, Oliveira NFOE, Paretsis NF, Silva SCD, Souza AF, De Zoppa ALDV, Corrêa RR.This report describes the combination of two surgical fracture repair techniques and the postoperative management of a mandibular diastemal fracture in a two-year-old mare. The mare was referred to a veterinary hospital with a laceration over the body of the right mandible. Radiographic assessment revealed two mesial fracture lines involving the second premolar tooth and a ventrally displaced bone fragment. The mare was treated under general anesthesia and the fracture was corrected using open reduction and plate fixation. A 3.5 mm narrow 15-hole locking compression plate with seven locking ...
Larsen EA, Lack AC, Wassack E.The use of poloxamer 407 gels have been reported in several studies to prolong the release of drugs at the injection site. Oral lesions unrelated to dental disease are rare but may result in ulceration and sequestration of bone. To date, there have been no reports on the use of penicillin G potassium poloxamer 407 gel and its effect on wound healing. The present case report describes the use of a penicillin G potassium poloxamer 407 gel for the treatment of a sublingual abscess involving the mandible in a 20 year old Arabian mare who initially presented with acute onset of dysphagia, hypersali...
Gfrerer L, Michel S, Fürst AE, Piskoty G, Weisse B, Montavon S, Jackson MA. The goal of this study was to generate mandibular fractures in three regions of the diastema using a metal impactor to simulate a kick from a horse and to determine the mean deceleration in the initial phase of the impact event, the maximum contact force, the impact energy necessary to create a fracture and the duration of the impact. Methods: Thirty heads of horses aged between 5 and 20 years and euthanatized for various reasons were used. The heads were attached to a steel bar at the occiput at an axial angle of 45 degrees so that the body of the mandible was positioned horizontally ...
Perez JA, Weber KL, Bender SJ, Wulster KB, Parente EJ.To describe the use and outcome of sclerotherapy with intralesional doxycycline foam in a horse with a mandibular aneurysmal bone cyst. Methods: Case report. Methods: Client-owned 1 year old Standardbred filly. Methods: The horse presented for progressive mandibular swelling. A 10 mg/mL doxycycline foam was prepared for intralesional injection. Three doses were injected into the lesion under computed tomographic guidance at 6 and 15 weeks after initial treatment. Volume reduction was monitored after each treatment with 3D volumetric rendering and region of interest segmentation using commer...
Maggi R, Mudimba D, Marruchella G.A 11-year-old, Haflinger breed mare developed a slowly growing mass, protruding on the ventral aspect of the mandible. On palpation, the lesion was pedunculated, very firm, cold and not painful. Radiographic examinations showed a radiopaque, multi-lobular, "mushroom-like" lesion, which arose from the mandibular cortex without involving the bone marrow cavity. Thereafter, the mass was excised for cosmetic purposes. Microscopically, the lesion mainly consisted of bone trabeculae, covered by a thick layer of connective tissue resembling the periosteum. History and clinical findings allowed the te...
White SA, Canada NC, Carmalt JL, Schumacher J, Amitrano FN, Ortved K, Henry TJ, Brounts SH, Arnold CE.There are no reports describing the long-term outcome of sport horses undergoing unilateral mandibular condylectomy with meniscectomy (UMC) for treatment for severe temporomandibular joint (TMJ) disease (TMD). Whether horses undergoing UMC require a specialized diet, can return to riding with a bit, or return to intended function after surgery is unknown. Unassigned: To determine the long-term outcome of horses undergoing UMC for treatment of severe TMD. Unassigned: A multi-institutional, retrospective study. Unassigned: Medical records obtained from seven equine referral hospitals of horses w...
Carmalt JL, Pimentel KL.Definitive diagnosis of equine temporomandibular joint osteoarthritis (TMJ-OA) may require advanced diagnostic imaging. Arthroscopy is a modern, minimally invasive, diagnostic, and treatment modality. Standing arthroscopic treatment of joint disease is a relatively recent advance in equine surgery, despite which there are few published comparisons between the available arthroscopic systems. Unassigned: To compare and contrast two arthroscopic systems for assessing the equine temporomandibular joint compartments in cadavers and standing horses. Unassigned: Experimental study. Unassigned: Phase ...
Lee S, Lee EB, Park KW, Jeong H, Shin KY, Kweon YP, Seo JP.The equine temporomandibular joint (TMJ) has a complex anatomical structure that makes diagnosis of TMJ disorders difficult. Computed tomography (CT) is now available in equine medicine; hence, TMJ evaluation has become more convenient. Objective: The objectives of this study were to describe the CT features of the TMJ in Jeju horses and to compare these features with those of Thoroughbreds. Methods: In this report, the TMJs of 10 Jeju horses (mean age: 4.5 ± 1.9 yr; mean body weight: 282.6 ± 40.3 kg) and 6 Thoroughbreds (mean age: 7.3 ± 1.6 yr; mean body weight: 479.7 ± 44.0 kg) were exam...
Schreeg ME, Radkin M, Haugland J, Murphy BG, Rushton S, Linder KE.Ameloblastic carcinoma is a malignant odontogenic neoplasm that has been reported only rarely in veterinary species. A 16-y-old Arabian crossbred mare was presented for evaluation of a hard mass on the body of the mandible, with evidence of osteolysis on radiographs. Incisional biopsies revealed an invasive neoplasm comprised of spindloid epithelial cells with a high mitotic count and partial dual cytokeratin-vimentin immunoreactivity. The horse was euthanized because of rapid tumor progression 3 mo after presentation. Postmortem evaluation revealed partial obliteration of the mandible by a ...
Sterkenburgh T, Schulz-Kornas E, Nowak M, Staszyk C.Equine mastication, as well as dental wear patterns, is highly important for the development of treatments in equine dentistry. During the last decades, the stress and strain distributions of equine teeth have been successfully simulated using finite element analysis. Yet, to date, there is no simulation available for dental tooth wear in equines. In this study, we developed a simplified two-dimensional computer simulation of dental wear. It provides a first tentative explanation for the development of the marked physiological inclination of the occlusal surface and for pathological conditions...
Mählmann K, Noguera Cender A, Ehrle A, Lischer CJ.To describe a novel fixation of open, unstable, unilateral mandibular fractures applying a locking compression plate as an external skeletal fixator (ESF-LCP). Methods: Four horses and one dromedary. Methods: Short case series. Methods: Animals presented with unstable, open, unilateral fractures of the mandible. Fracture fixation was performed under general anesthesia. A 4.5/5.5 narrow LCP was applied externally above the level of the skin and combined with intraoral tension band wiring. Results: Fracture fixation was achieved successfully using an ESF-LCP. Minimal tissue manipulation was requ...
Cirilli O, Pandolfi L, Rook L, Bernor RL.Evolution of the genus Equus has been a matter of long debate with a multitude of hypotheses. Currently, there is no consensus on either the taxonomic content nor phylogeny of Equus. Some hypotheses segregate Equus species into three genera, Plesippus, Allohippus and Equus. Also, the evolutionary role of European Pleistocene Equus stenonis in the origin of the zebra-ass clade has been debated. Studies based on skull, mandible and dental morphology suggest an evolutionary relationship between North American Pliocene E. simplicidens and European and African Pleistocene Equus. In this contributio...
Raspa F, Roggero A, Palestrini C, Marten Canavesio M, Bergero D, Valle E.The effects of specific feeding positions upon the horse's shape variations of the back and neck postures as well as the variations of the mandibular angle have never been objectively studied. For this reason, geometric morphometrics was applied. Six horses, aged 14 ± 8 years (mean ± standard deviation, SD), were video-recorded while using three different feeding positions: on the ground-control position (CP); neck held 15 ± 3° below withers height with low hay net position (LP); neck held 15 ± 3° above withers height with high hay net position (HP). Data were analyzed using principal co...
Nelson BB, Easley J, Steward SKT, Smanik LE, Koch DW, Rawlinson JE, Easley JT.To report the radiographic, surgical and postoperative features in horses with unstable oblique mandibular fractures secured with polyaxial pedicle screws (PPS) external fixation construct and intraoral wiring. Methods: Three client-owned horses. Methods: Short case series. Methods: Two horses each had a unilateral fracture, which did not improve after conservative management, and one horse had bilateral fractures. Clinical and radiographic features were documented. Polyaxial pedicle screw external fixators and intraoral tension band wiring were applied in standing horses after combining sedat...
Nottle BF, Tatarniuk DM, Caldwell FJ, Bell CD, Caston SS, Merkatoris PT, Gillen AM, Katzman SA.To describe the presentation, diagnosis, treatment, and outcome for horses with fibro-osseous lesions of the craniofacial complex. Methods: Retrospective multicenter case series. Methods: Thirty horses evaluated for fibro-osseous lesions of the skull from January 1, 2001 through December 31, 2019 in four centers. Methods: Medical records were reviewed for signalment, clinical presentation, histological and diagnostic imaging findings, treatment instituted, and outcome. Long-term outcome information was obtained by owner questionnaire or the medical record. Results: Diagnoses included ossifying...
Leitzen E, Stumpf S, Zimmermann C, Bienert-Zeit A, Hellige M, Baumgärtner W, Puff C.A fast growing, circumscribed, unilateral swelling of the right mandible of a juvenile horse was observed. Within few weeks, the continuously growing mass reached dimensions ranging from 7 to 10 cm in diameter and resulted in loss of the first deciduous premolar of the affected side. The animal was euthanized due to lesion progression. Histologically the mandibular swelling consisted of numerous variably sized vascular structures, partly filled with erythrocytes and embedded in a loosely arranged fibrous stroma within the medullary cavity of the mandible. Juvenile mandibular angiomatosis was d...
Ross CF, Dharia R, Herring SW, Hylander WL, Liu ZJ, Rafferty KL, Ravosa MJ, Williams SH.Modulation of force during mammalian mastication provides insight into force modulation in rhythmic, cyclic behaviors. This study uses in vivo bone strain data from the mandibular corpus to test two hypotheses regarding bite force modulation during rhythmic mastication in mammals: (1) that bite force is modulated by varying the duration of force production, or (2) that bite force is modulated by varying the rate at which force is produced. The data sample consists of rosette strain data from 40 experiments on 11 species of mammals, including six primate genera and four nonprimate species: goat...
Heck L, Wilson LAB, Evin A, Stange M, Sánchez-Villagra MR.In horses, the morphological changes induced by the process of domestication are reportedly less pronounced than in other species, such as dogs or pigs - although the horses' disparity has rarely been empirically tested. We investigated shape differences and modularity of domesticated horses, Przewalski's horses, donkeys and zebras. Mandibular and tooth shape have been shown to be valuable features for differentiating wild and domesticated forms in some mammals. Results: Both mandible and teeth, show a pattern of shape space occupation analogous to that of the cranium, with domesticated horses...
Björnsdóttir S, Frey R, Kristjansson T, Lundström T.Oral lesions related to the use of the bit and bridle are reported to be common findings in horses worldwide and represent an important animal welfare issue. In order to provide an overview of bit-related lesions in Icelandic competition horses, a field examination of the rostral part of the oral cavity was performed in 424 competition horses coming to the two major national horse events in Iceland in 2012. Records from repeated examination of 77 horses prior to the finals were used to assess potential risk factors. Results: Mild lesions were recorded in 152 horses (36%) prior to the prelimina...
Di Stefano DA, Artese L, Iezzi G, Piattelli A, Pagnutti S, Piccirilli M, Perrotti V.In the case of localized ridge atrophy, a ridge augmentation procedure, with the use of bone substitutes and barrier membranes, may then be necessary. Objective: The aim of the present study was a clinical, histological, and immunohistochemical evaluation of an equine spongy bone in alveolar ridge augmentation procedures. Methods: Five patients showing horizontal mandibular ridge defects participated in this study. A ridge augmentation was performed through an onlay apposition of equine bone covered by a titanium-reinforced membrane. After 6 months of healing, five bone cores from nonaugmented...
Bonin SJ, Clayton HM, Lanovaz JL, Johnston T.Previous studies have suggested that temporomandibular joint (TMJ) kinematics depend on the type of food being masticated, but accurate measurements of TMJ motion in horses chewing different feeds have not been published. Objective: The temporomandibular joint has a larger range of motion when horses chew hay compared to pellets. Methods: An optical motion capture system was used to track skin markers on the skull and mandible of 7 horses as they chewed hay and pellets. A virtual marker was created on the midline between the mandibles at the level of the 4th premolar teeth to represent the ove...
Huthmann S, Staszyk C, Jacob HG, Rohn K, Gasse H.The forces generated during equine mastication influence the teeth, as well as the periodontium, the jaw bones, the temporomandibular joints and materials used in dental therapy. Due to the limited accessibility of the cheek teeth located farther caudal in the equine oral cavity the measurement of the masticatory forces on these teeth is virtually impossible. The calculation of such forces is an appropriate, indirect alternative to direct measuring. Hence, a mathematical model, which respects several morphological features of the equine dentition, e.g. the Curve of Spee, is presented. The rele...
Dixon PM, Tremaine WH, Pickles K, Kuhns L, Hawe C, McCann J, McGorum BC, Railton DI, Brammer S.Of 400 referred horses with dental disorders, 349 cases suffered from primary disorders of their cheek teeth, ninety of these from disorders of development or eruption, or displacements. These included 20 cases with rostral maxillary and caudal mandibular cheek teeth overgrowths, 16 with diastemata, 15 with grossly enlarged mandibular 'eruption cysts', 4 with grossly enlarged maxillary cheek teeth 'eruption cysts', 10 cases with supernumerary cheek teeth and 23 cases with displaced cheek teeth. These displacements were believed to be developmental in 16 cases and acquired in the remaining 7 ca...
Carmalt JL, Kneissl S, Rawlinson JE, Zwick T, Zekas L, Ohlerth S, Bienert-Zeit A.Published descriptions of nonseptic arthritis of the equine temporomandibular joint (TMJ) are rare and large studies investigating variations in the TMJ for asymptomatic horses are lacking. The objectives of this cross-sectional, retrospective, multi-institutional study were to describe anatomical variations in the TMJ detected using computed tomography (CT) in an equid population asymptomatic for TMJ disease and determine whether these variations were associated with patient signalment, reason for CT examination, or CT slice width. Medical records at eight hospitals were searched for horses t...
Morse CC, Saik JE, Richardson DW, Fetter AW.Benign proliferative fibro-osseous lesions of the rostral mandible in six young horses are classified as equine juvenile mandibular ossifying fibroma. Histologically there is a characteristic abrupt transition from subgingival fibroblastic stroma to a zone of proliferating osteoblasts that form irregular spicules of osteoid. The layer of proliferating osteoblasts blends with a deeper zone of bony trabeculae rimmed by osteoblasts and separated by intertrabecular spaces of moderate cellular density. Incomplete surgical excision resulted in local recurrence, while rostral mandibulectomies resulte...
Dacre I, Kempsot S, Dixon PM.There is little published information on the pathology of idiopathic fractures of cheek teeth (CT). Objective: To perform pathological examinations on equine CT with idiopathic fractures in order to establish fracture patterns and to gain information on their aetiopathogenesis. Objective: Gross and histological examination of CT with idiopathic fractures, including measurements of dentinal thickness, will provide information on fracture patterns, and on the duration and aetiopathogenesis of these fractures. Methods: Of 35 CT with idiopathic fractures that were examined to determine their fract...
Di Stefano DA, Greco GB, Cinci L, Pieri L.The present work describes a horizontal ridge augmentation in which a titanium mesh was preshaped by adapting it to a stereolithographic model of the patient's jaw that was fabricated from CT scans. Guided bone regeneration (GBR) involves covering the augmentation site with a long-lasting barrier to protect it from the invasion of surrounding soft tissues. Among barriers, titanium meshes may provide a successful outcome, but the intraoperatory time needed to shape them is a disadvantage. The 54-year-old patient, missing the right mandibular second bicuspid, first molar, and second molar, had h...
Kirkland KD, Baker GJ, Manfra Marretta S, Eurell JA, Losonsky JM.To document age-related changes in the morphology of the endodontic system, reserve crown, and roots of equine mandibular cheek teeth. Methods: Equine mandibular cheek teeth from horses of various ages were compared, using radiography, x-ray computed tomography, and histologic examinations. Methods: 48 right hemi-mandibles from horses 2 to 9 years old. Methods: Hemi-mandibles were radiographed, imaged by computed tomographic reconstruction, and reformatted. Histologic examination was used to identify and correlate tissue types. Results: Permanent mandibular cheek teeth of the horse, at the tim...
Bröjer JT, Parsons DA, Linder KE, Peregrine AS, Dobson H.An 8-year-old, Arabian mare presented with acute progressive ataxia and a firm swelling over the right mandible. Radiographs revealed multiple radiolucent areas on the mandibles. The mare's neurological signs progressed, she was consequently euthanized. Postmortem examination revealed mandibular granulomatous reactions and meningoencephalitis due to the nematode Halicephalobus gingivalis.
Carmalt JL, Tucker ML.To develop an arthroscopic approach to the discomandibular joint (DMJ), the ventral compartment of the temporomandibular joint (TMJ) of the horse. Methods: Experimental study. Methods: Nine cadaveric equine heads and two live horses. Methods: A 2.5-mm 30° arthroscope was used to explore the DMJ after joint distension. The first portal was created caudally, allowing placement of a rostral portal under visual guidance. Nasotracheal intubation of the live horses allowed mandibular manipulation, which is required for complete visualization of the joint. Results: A novel injection technique allowe...
Nagy AD, Simhofer H.To report use of mandibular condylectomy for treatment of advanced degenerative joint disease of the temporomandibular joint (TMJ) caused by sepsis. Methods: Clinical case report. Methods: Two-year-old Noriker filly. Methods: Computed tomography (CT) was used to confirm advanced degenerative joint disease of the left TMJ and for follow-up after mandibular condylectomy and removal of necrotic meniscus. Results: Painful swelling (3 weeks duration) with drainage located just caudal to the left lateral canthus of the eye was associated with atrophy of the left masseter muscle, masticatory problems...
Bonin SJ, Clayton HM, Lanovaz JL, Johnson TJ.To develop a method of measuring 3-dimensional kinematics of the temporomandibular joint (TMJ) in horses chewing sweet feed. Methods: 4 mature horses that had good dental health. Methods: Markers attached to the skin over the skull and mandible were tracked by an optical tracking system. Movements of the mandible relative to the skull were described in terms of 3 rotations and 3 translations. A virtual marker was created on the midline between the rami of the mandibles at the level of the rostral end of the facial crest to facilitate observation of mandibular movements. Results: During the ope...
May KA, Moll HD, Howard RD, Pleasant RS, Gregg JM.To develop an arthroscopic approach to, and describe the arthroscopic anatomy of, the equine temporomandibular joint (TMJ). Methods: Cadaveric study, after which the technique was tested in horses. Methods: Ten cadaveric equine heads and 5 normal horses (age, 5-13 years; weight, 425-545 kg). Methods: Specimens or horses were positioned in right lateral recumbency. After fluid distention of the TMJ, arthroscopic portals were made in the dorsal compartment over the most prominent portion of the joint outpouching (caudodorsal approach) and in rostral and intermediate locations. The joint was expl...
Janis CM, Constable EC, Houpt KA, Streich WJ, Clauss M.It is often assumed that horses chew food more intensively during ingestion than cattle, which - as ruminants - complete part of the mastication during rumination. This has been proposed as a reason for more robust mandibles, larger masseter insertion areas and larger masseter muscles in horses as compared to cattle and other grazing ruminants. In this study, we evaluate results of comparative feeding trials with three horses (338-629 kg) and three cows (404-786 kg), on four different roughages. Ingestion time (s/g dry matter) and chewing intensity (chews/g dry matter) differed among animals w...
Coomer RP, Fowke GS, McKane S.To report the technique and results of cheek teeth repulsion in standing, sedated horses. Methods: Case series. Methods: Horses (n = 12), ponies (6). Methods: Medical records (2006-2009) of horses that had cheek tooth repulsion while standing were reviewed. Inclusion criteria included: maxillary or mandibular cheek tooth disease diagnosed by clinical and radiographic examination where attempted oral extraction failed necessitating repulsion. Horses were sedated and a local nerve block performed. Intraoperative radiographs facilitated instrument positioning and ensured repulsion of all dental r...
Rodríguez MJ, Agut A, Gil F, Latorre R.The minute anatomy of the temporomandibular joint (TMJ) in horses is poorly documented in the literature. Objective: To examine in detail the anatomy of the normal equine TMJ and the relationship of the joint to adjacent structures. Methods: The anatomy of the TMJ was examined in 12 equidae using dissections, synovial and vascular injections and frozen and plastinated sections. Relevant structures were photographed. Results: Rostral and caudal compartments were identified in the dorsal and ventral synovial pouches of the TMJ. Lateral and caudal ligaments were identified and attachments of the ...
Pérez-Manrique L, León-Pérez K, Zamora-Sánchez E, Davies S, Ober C, Wilson B, McGreevy P.Restrictive nosebands are used in equestrian sports to hold the bit in place and reduce mouth-opening, a response that can attract penalties in some sports and is thought to reduce the rider's control of the horse. Sustained pressure from such tightly fitted (restrictive) nosebands denies normal behaviour and thus, causes frustration and distress that can jeopardise horse welfare. It also may push the cheek against the molar teeth, compress soft tissues including blood vessels and nerves, and possibly induce chronic changes to underlying bone. This study of mature cavalry horses (n = 144) was ...
Warmerdam EP, Klein WR, van Herpen BP.Diagnostic imaging and treatment of unilateral destructive temporomandibular joint disease in two horses is described and discussed. Computed tomography appeared to be the best imaging technique for these lesions. The disease can be followed by functional recovery after the infection has resolved.
Ferguson R, van Dreumel T, Keystone JS, Manning A, Malatestinic A, Caswell JL, Peregrine AS.An 8-year-old horse was presented with a submandibular swelling. Biopsy of the lesion indicated granulomatous osteomyelitis due to Halicephalobus gingivalis. In the absence of evidence of involvement of the central nervous system at the time of diagnosis, the horse was treated with ivermectin. Unfortunately, the horse did not survive. Un cheval âgé de 8 ans a été présenté pour une enflure sous-mandibulaire. Une biopsie de la lésion a révélé une ostéomyélite granulomateuse causée par En l’absence de signes d’atteinte du système nerveux central au moment du diagnostic, le c...
Henry T, Pusterla N, Guedes AG, Verstraete FJ.Local anaesthesia is often required to facilitate invasive procedures in equine dental patients under standing sedation. Objective: To show that an intraoral approach can be used to desensitise the inferior alveolar nerve in horses and report complications seen with this technique. Methods: The distance of the mandibular foramen from the distal (caudal) edge of the mandibular third molar tooth, rostral edge of the mandibular ramus and ventral margin of the mandible were measured in 26 adult equine skulls of various ages and breeds. Computed tomography (CT) was used to verify the placement of t...
Morgan RE, Fiske-Jackson AR, Hellige M, Gerhauser I, Wohlsein P, Biggi M.Odontogenic tumors present as locally invasive, slow growing, firm swellings on the face. They are rare in all species and are characterized histologically by the degree of differentiation and dental tissue of origin. Radiographic appearance is not pathognomonic for these lesions. Computed tomographic (CT) examination allows exact determination of tumor extension and aggressiveness. The objectives of this retrospective, case series study were to describe the clinical presentation, CT characteristics, and outcome in horses with histologically confirmed odontogenic tumors, and to identify imagin...
Cirilli O, Pandolfi L, Rook L, Bernor RL.Evolution of the genus Equus has been a matter of long debate with a multitude of hypotheses. Currently, there is no consensus on either the taxonomic content nor phylogeny of Equus. Some hypotheses segregate Equus species into three genera, Plesippus, Allohippus and Equus. Also, the evolutionary role of European Pleistocene Equus stenonis in the origin of the zebra-ass clade has been debated. Studies based on skull, mandible and dental morphology suggest an evolutionary relationship between North American Pliocene E. simplicidens and European and African Pleistocene Equus. In this contributio...
Casey MB, Pearson GR, Perkins JD, Tremaine WH.The most prevalent type of equine dental pulpitis due to apical infection is not associated with coronal fractures or periodontal disease. The pathogenesis of this type of pulpitis is not fully understood. Computed tomography (CT) is increasingly used to investigate equine dental disorders. However, gross, tomographic and histopathological changes in equine dental pulpitis have not been compared previously. Objective: To compare gross, CT and histological appearances of sectioned mandibular cheek teeth extracted from horses with clinical signs of pulpitis without coronal fractures or periodont...
Carmalt JL, Pimentel KL.Definitive diagnosis of equine temporomandibular joint osteoarthritis (TMJ-OA) may require advanced diagnostic imaging. Arthroscopy is a modern, minimally invasive, diagnostic, and treatment modality. Standing arthroscopic treatment of joint disease is a relatively recent advance in equine surgery, despite which there are few published comparisons between the available arthroscopic systems. Unassigned: To compare and contrast two arthroscopic systems for assessing the equine temporomandibular joint compartments in cadavers and standing horses. Unassigned: Experimental study. Unassigned: Phase ...
Smyth TT, Carmalt JL, Treen TT, Lanovaz JL.Diseases of the temporomandibular joint (TMJ) are well reported in man and some domestic animals other than the horse. The pathophysiology of equine TMJ disease and the effects of disease on the kinematics of mastication are unknown. Objective: To determine whether transient unilateral inflammation of the equine TMJ results in alterations in the masticatory cycle. Methods: An experimental controlled study utilising 6 horses of various ages with normal dentition. Methods: Each horse was equipped with an optical motion tracking (kinematic) system. Horses were observed chewing grass hay over 3 m...
Townsend NB, Cotton JC, Barakzai SZ.To (1) describe a tangential radiographic projection of the equine temporomandibular joint (TMJ) and (2) optimize the radiographic angle and determine its use in standing sedated horses. Methods: Descriptive study. Methods: Cadaveric equine skulls (n=11); 8 horses with a history of quidding or headshaking. Methods: Tangential radiographic projections were taken of a TMJ of a cadaveric skull before and after intra-articular injection of radiographic contrast. Additional tangential radiographic projections were taken after TMJ dissection and placement of a wire along the articular surface of the...
