Evaluation of the Rostral Inferior Alveolar Nerve Block via the Mental Foramen in Equids: In Vivo Efficacy Testing.

The use of proper sedative and regional anesthetic protocols is essential when performing equine dental surgical procedures under standing sedation. The efficacy of the rostral inferior alveolar nerve block via the mental foramen has not been previously studied. Aims of this study included determining the efficacy of the block, investigating whether any region (labial mucosa, alveolar mucosa, or teeth) was more reliably anesthetized, and if differences in efficacy existed between bilateral and unilateral blocks. In this blinded trial, 10 horses each were randomly assigned to receive a left unilateral block, right unilateral block or bilateral blocks and 5 horses were bilateral controls. For unilateral groups, the contralateral side of the horse acted as its own unilateral control. Mechanical nociceptive stimulus methods were used to determine response to stimulus at time points pre-sedation, post-sedation, and post-injection at 10, 30, 60, and 90 min. Results were evaluated in 4 groups: unilateral blocks, unilateral controls, bilateral blocks and bilateral controls. Overall, all groups were significantly less likely to respond to stimulus at time points post-sedation, T10, and T30, whereas only blocked sites were less likely to respond at T60 and T90 compared to pre-sedation. There was no significant difference in response to stimuli of blocked sites between the 3 regions at all time points. Overall, at T60 and T90, blocks produced regional anesthesia in 73% and 55% of sites, respectively. This study demonstrated the equine mental foramen regional nerve block has varied efficacy, producing partial or incomplete regional anesthesia in some cases.

Impacts of Antiretroviral Therapy on the Oral Microbiome and Periodontal Health of Feline Immunodeficiency Virus Positive Cats.

Feline immunodeficiency virus (FIV) is the domestic cat analogue of HIV infection in humans. Both viruses induce oral disease in untreated individuals, with clinical signs that include gingivitis and periodontal lesions. Oral disease manifestations in HIV patients are abated by highly effective combination antiretroviral therapy (cART), though certain oral manifestations persist despite therapy. Microorganisms associated with oral cavity opportunistic infections in patients with HIV cause similar pathologies in cats. To further develop this model, we evaluated characteristics of feline oral health and oral microbiome during experimental FIV infection over an 8-month period following cART. Using 16S metagenomics sequencing, we evaluated gingival bacterial communities at four timepoints in uninfected and FIV-infected cats treated with cART or placebo. Comprehensive oral examinations were also conducted by a veterinary dental specialist over the experimental period. Gingival inflammation was higher in FIV-infected cats treated with placebo compared to cART-treated cats and controls at study endpoint. Oral microbiome alpha diversity increased in all groups, while beta diversity differed among treatment groups, documenting a significant effect of cART therapy on microbiome community composition. This finding has not previously been reported and indicates cART ameliorates immunodeficiency virus-associated oral disease via preservation of oral mucosal microbiota. Further, this study illustrates the value of the FIV animal model for investigations of mechanistic associations and therapeutic interventions for HIV oral manifestations.

Age of Dental Apical Closure in Domestic Cats.

Data on the age of apical closure in felines is limited. Moreover, differences in age of apical closure between male and female cats have not been studied. The aim of this study was to determine the timing of apical closure in cats and determine if sex or position in the dental arch affected closure. In this retrospective descriptive study, intraoral radiographs were obtained at monthly or multiple-monthly intervals for 18 cats. Nine were intact females and 9 were neutered males, ranging from 6 to 9.4 months of age at the start of the study which ranged over an 8-month period. Radiographs were evaluated to establish age of apical closure for all canine teeth as well as the mandibular premolar and molar teeth. Mandibular canine tooth apices closed between 10 and 12 months of age and maxillary canine tooth apices closed between 12 and 14 months of age. The mesial and distal root apices of both the mandibular third and fourth premolar teeth closed between 8 and 9 months. The mandibular first molar tooth mesial and distal root apices closed between 8 and 8.5 months. Root apices of canine teeth closed earlier in female cats than in male cats with mandibular canine tooth root apices closing significantly earlier than maxillary canine tooth roots in both sexes. These findings suggest that there are notable differences in age of apical closure between male and female cats and discernible trends in timing of apical closure among teeth in the dental arcade.

Prognostic indicators for feline craniofacial trauma: a retrospective study of 114 cases.

Craniofacial traumatic injuries contribute significantly to the morbidity and mortality of domestic felines. Previous studies focused on feline craniofacial injuries have investigated the origin of injury, injuries sustained, and effectiveness of diagnostic tools. The aim of the study is to identify prognostic indicators for feline craniofacial trauma patients and determine their association with negative and positive outcomes. The Veterinary Committee on Trauma (VetCOT) Trauma Registry and Dentistry and Oral Surgery Case Logs were utilized to identify feline craniofacial trauma cases that were presented to Colorado State University's Veterinary Teaching Hospital between 2014 and 2020. Prognostic indicators evaluated included: etiology of injury, signalment (age and sex), the Modified Glascow Coma Scale (MGCS), Animal Trauma Triage (ATT) scores, craniofacial examination findings, diagnostic imaging technique, and injuries identified via imaging. Outcomes were determined via patient status upon discharge. Outcomes were grouped into the following categories: survival to discharge at initial presentation to CSU Urgent Care (SDIP), survival to discharge after injury treatment/repair by CSU DOSS or another specialty service (SDTX), euthanized due to grave prognosis at initial presentation (EUGP), euthanized due to financial limitations at initial presentation (EUF), and euthanized due to grave prognosis and financial limitations (EUGP + EUF). The continuous data was described using means and standard deviations. To determine the associations of various groupings of clinical signs and imaging findings with outcome a principal component analysis was performed. Patient sex, trauma etiology, cumulative MGCS and ATT scores on initial presentation and clinical signs on initial presentation were identified as prognostic indicators with intact males, vehicular and animal altercations, lower MGCS cumulative scores, higher ATT scores and the presence of altered mentation identified as negative prognostic indicators. Prognostic indicators for feline craniofacial trauma can be associated with outcomes and help guide clinical decision making.

Combination Antiretroviral Therapy and Immunophenotype of Feline Immunodeficiency Virus.

Feline Immunodeficiency Virus (FIV) causes progressive immune dysfunction in cats similar to human immunodeficiency virus (HIV) in humans. Although combination antiretroviral therapy (cART) is effective against HIV, there is no definitive therapy to improve clinical outcomes in cats with FIV. This study therefore evaluated pharmacokinetics and clinical outcomes of cART (2.5 mg/kg Dolutegravir; 20 mg/kg Tenofovir; 40 mg/kg Emtricitabine) in FIV-infected domestic cats. Specific pathogen free cats were experimentally infected with FIV and administered either cART or placebo treatments (n = 6 each) for 18 weeks, while n = 6 naïve uninfected cats served as controls. Blood, saliva, and fine needle aspirates from mandibular lymph nodes were collected to quantify viral and proviral loads via digital droplet PCR and to assess lymphocyte immunophenotypes by flow cytometry. cART improved blood dyscrasias in FIV-infected cats, which normalized by week 16, while placebo cats remained neutropenic, although no significant difference in viremia was observed in the blood or saliva. cART-treated cats exhibited a Th2 immunophenotype with increasing proportions of CD4+CCR4+ cells compared to placebo cats, and cART restored Th17 cells compared to placebo-treated cats. Of the cART drugs, dolutegravir was the most stable and long-lasting. These findings provide a critical insight into novel cART formulations in FIV-infected cats and highlight their role as a potential animal model to evaluate the impact of cART on lentiviral infection and immune dysregulation.

Clinical Evaluation of Intraoral Suture Patterns Using Poliglecaprone 25 in Greyhound Dogs.

To evaluate healing and complications of extraction sites closed with a simple interrupted pattern (SI) and a simple continuous (SC) suture pattern in a prospective randomized clinical trial. Greyhounds were selected from a rescue with a standardized environment and naturally occurring disease. Surgical extractions were performed (35 sites) and all mucogingival flaps were closed with 4-0 poliglecaprone 25 using either SI or SC randomly assigned by surgical site. Oral healing/dehiscence, suture inflammation, suture loss, accumulation of debris, presence/nature of discharge, necrotic tissue and adjacent contact ulceration were evaluated. Fisher's exact test was used to compare categorical data and two-tail T tests used to compare continuous data. Results showed SC was faster to apply. No new dehiscence events were detected after Recheck 1. There was no significant difference for dehiscence scores between SI and SC. A trend was seen towards more major dehiscence in the SI group. This study concluded SC is an alternative to SI for closure of occlusal surfaces in the mouth. Mandibular canine tooth extraction sites were more likely to have a high dehiscence score than all other sites combined regardless of surgical technique.

Cadaveric Evaluation of Load to Failure in Canine Gingiva Apposed With Varied Suture Patterns Using Poliglecaprone 25.

The purpose of the study was to determine the effect of suture pattern and repair length on the load to failure in an ex vivo canine gingival model. Healthy mandibular gingiva and mucosa were harvested from fresh cadavers euthanized for purposes unrelated to the study. Samples were randomly assigned by length and pattern. Lingual and buccal free gingival margins were apposed using a simple interrupted (SI), cruciate (XT), simple continuous (SC), or unidirectional knotless continuous barbed suture (SF) closure technique with USP 4-0 poliglecaprone 25i, ii applied over 2 lengths (3 cm and 6 cm). A custom template was used to ensure uniform suture bite application. Surgical time was recorded. Using a soft tissue mechanical testing frame, samples were tensioned to failure. Testing was video recorded and reviewed in conjunction with the tension trace data for tension at initial failure (Tfail) and maximum tension sustained (Tmax). Two factor ANOVA by length and pattern was performed followed by individual one way T-tests. Statistically significant findings were XT-SC-SF patterns were quicker to perform than SI. SF was more likely to fail by suture breakage than tissue tearing, and SF withstood less tension at the 3 cm length than SI-XT-SC. No significant difference was detected in Tmax or Tfail between SI and SC or XT. The study demonstrates that SC and XT are comparable to SI in tension resistance and faster to perform suggesting that SC and XT could replace SI for extraction site closure although further in vivo testing is required.

Cadaveric Evaluation of Injectate Distribution for Two Maxillary Nerve Block Techniques in Cats.

Regional nerve blocks have been shown to decrease general anesthetic drug requirements and improve pain management in patients undergoing surgery. Regional nerve blocks are used routinely in patients undergoing oral surgery, such as dental extractions. There is little published information regarding the efficacy of feline maxillary and infraorbital nerve blocks. The goal of the study was to compare injectate distributions of the infraorbital foramen and percutaneous maxillary nerve block techniques in feline cadavers using a combined dye and radiopaque contrast media solution to simulate an injection. There was no significant difference in length of stained nerve between the two different techniques. It was not necessary to advance the needle into the infraorbital canal to achieve effective staining of the maxillary nerve. There was no significant difference in injectate distribution between two different injectate volumes, 0.2 and 0.4 ml, indicating that the smaller volume injected at the infraorbital foramen resulted in adequate nerve staining.

Polyaxial pedicle screw external fixation to stabilize oblique mandibular fractures in three standing, sedated horses.

OBJECTIVE: 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. ANIMALS: Three client-owned horses. STUDY DESIGN: 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 sedation and regional nerve anesthesia. Intraoral wires were implanted through a lateral buccotomy between teeth (two horses) or burred through exposed crown (one horse) and then secured around the incisors. The PPS were inserted under radiographic guidance to avoid tooth roots. Healing was assessed with radiographic examination. The PPS external fixator rod and intraoral wires were removed first. The mandible was manipulated, and, if it was stable, the PPS were removed. RESULTS: Implants were removed at 6, 8, or 10 weeks after the mandibles were palpably stable. Complications included broken wires in one horse, bone sequestration in one horse, and infection in one horse. Follow-up communication with the owners 12 to 18 months later confirmed complete healing without further complications of the fractured mandibles or teeth. CONCLUSION: Polyaxial pedicle screw external fixation led to fracture healing and a return to function in all three horses. The complications encountered did not preclude a successful outcome. CLINICAL SIGNIFICANCE: Polyaxial pedicle screw external fixation coupled with intraoral wiring provides an alternative to treat unstable equine mandibular fractures without general anesthesia.

Regional and Distant Metastasis of Oral Squamous Cell Carcinoma in a Male Castrated Llama: A Case Report.

A 19-year-old male castrated llama presented with a 3-year history of tooth root abscesses and an osseous mass on the left mandible. Surgical excision of the affected teeth and mass was performed, and histopathologic review indicated that the mass was an oral squamous cell carcinoma. The patient was admitted to the hospital again 4 months later in severe respiratory distress with submandibular edema, and bicavitary effusion. Necropsy results revealed regional and distant metastatic squamous cell carcinoma.

Computed Tomography Analysis of the Feline Infraorbital Foramen and Canal.

Feline skull anatomic variation is plain to see with casual observation. Obtaining an in-depth understanding of this anatomic variability is critical to performing safe and effective regional anesthesia for dental procedures and maxillofacial surgeries. Maxillofacial anatomic variability is proven to impact the placement and efficacy of nerve blocks in dogs and horses, but similar studies have not been performed in cats. This study's main objective was to evaluate the anatomy of the infraorbital foramen and canal in relation to regional anatomic landmarks in brachycephalic and mesaticephalic cats. Significant anatomic variability was identified, particularly among cats with brachycephalic skulls.

Dental Pathology of the Domestic Pig (Sus Scrofa Domesticus).

Antemortem domestic pig (Sus scrofa domesticus) dental pathology literature is sparse. This observational descriptive study evaluated 23 client-owned pigs that while sedated/anesthetized for routine annual care had intraoral dental radiographs and an oral examination performed. Age, gender, weight, and breed for each pig were recorded. Oral examination and radiographic findings were reviewed to create a comprehensive list of dental abnormalities identified. Descriptive statistics were performed to summarize the data. The study population included 14 castrated males and 20 Vietnamese pot-bellied mini-pigs. The median age was 3 years (range 2-12 years), and the median weight was 39 kg (range 11-140 kg). The most common finding was missing teeth (21/23 pigs); the first premolar tooth was the most likely to be absent (64/106 missing teeth). Periodontal disease was common (20/23 pigs). Advanced stages primarily affected the first molar teeth frequently in the form of a mucogingival defect. Supernumerary roots were discovered on the maxillary canine teeth in female pigs only (10/25 teeth with supernumerary roots). The most common persistent deciduous tooth was the maxillary second incisor (15/19 persistent deciduous teeth). Non-age or gender related open apices were most likely associated with mandibular first and second incisor teeth (26/96 teeth with open apices). Tooth resorption was also identified (7/23 pigs). The study findings prove that pet pigs commonly have dental pathology; therefore, thorough oral examinations with intraoral radiographs should be included in porcine routine health care regimens.

The Air-Driven Dental Unit: Form and Function at a Mechanical Level.

The goal of this article is to provide an overview at a mechanical level of how the dental machine functions. A description of the low-speed handpiece and its air-driven micromotor as well as the high-speed handpiece and turbine will be provided. The compressor, rheostat, air-water syringe, suction, fiber-optic light, and handpiece couplings will also be discussed. It is important to understand the function of equipment to allow for troubleshooting problems and understanding maintenance requirements to keep equipment functioning optimally.

Prevalence of Malocclusion of Deciduous Dentition in Dogs: An Evaluation of 297 Puppies.

A total of 297 dogs between 8 and 12 weeks of age were examined during a 1-year period to evaluate occlusion. Dogs were categorized either as individual dogs or members of a litter and purebred or mixed breed. Occlusion was evaluated by class: normal, class 1 malocclusion (MAL1), class 2 malocclusion (MAL2), or class 3 malocclusion (MAL3). Dogs with MAL3 were also subdivided based on whether MAL3 was considered a breed standard; dogs with breed standard MAL3 were considered under normal occlusion for statistical analyses. Malocclusions were further categorized as mild, moderate, or severe. Twenty-six percent (77/297) were identified as having a malocclusion. For single dogs, purebreds had a significantly higher percentage of malocclusions compared to the mixed breeds (33.8% and 20% respectively; P = .042). For dogs in litters, there were no purebreds with malocclusion, which was significantly less than the number of mixed breeds with malocclusions (0% and 23.5%, respectively; P = .0023). No significant difference in prevalence was noted between mixed breed and purebred dogs. Occlusal evaluation is important for all dogs to allow for early recognition of malocclusion and, if necessary, intervention in a timely manner.

Evaluation of the equine mental foramen block: cadaveric and in vivo injectate diffusion.

OBJECTIVE: To describe injectate diffusion for two equine mental foramen block techniques. STUDY DESIGN: Descriptive anatomic study. ANIMALS: A total of 12 equine heads and three live horses. METHODS: Equine heads were longitudinally sectioned to create 24 hemi-heads for testing two mental foramen block techniques (T1 and T2) and two injectate volumes (3 and 5 mL) of mixed dye and contrast medium. T1 needles were directed rostrocaudally into the mental foramen for 3 cm, and T2 needles were directed dorsolaterally to ventromedially into the foramen for 1 cm. Hemi-heads were randomly assigned one injection technique and volume. Radiographs evaluated needle tip positioning, distance traveled by injectate and injectate diffusion pattern. Specimens were dissected to measure the length of circumferential nerve staining. The more effective technique was tested in three live horses and evaluated via computed tomography. Summary statistics described results. RESULTS: Neither injection technique nor injectate volume had a significant impact on circumferential nerve staining. Circumferential nerve staining, median (range), was 15 (0-33) mm for T1 and 10 (0-42) mm for T2. Injectate diffusion patterns revealed that injectate was more likely to thread alongside the inferior alveolar nerve for T1 (9/12) and bolus around the rostral inferior alveolar nerve for T2 (9/12). Bolus diffusion patterns were associated with increased circumferential nerve staining ≥1 cm (9/24) when compared with thread patterns (6/24). Diffusion of injectate within the mandibular canal was greater with 5 than 3 mL. In vivo testing of T2 with 5 mL injectate resulted in decreased incidence of circumferential nerve staining ≥1 cm [median (range) 5 (0-14) mm]. CONCLUSION AND CLINICAL RELEVANCE: T2 created an injection diffusion pattern more likely to result in circumferential nerve staining ≥1 cm, but the low incidence of in vivo circumferential nerve staining ≥1 cm suggests that block efficacy may vary.

Use of crown height of the maxillary first molar tooth to approximate the age of horses.

OBJECTIVE To identify whether age, sex, or breed is associated with crown height of the left and right maxillary first molar tooth (M1) measured on CT images, to develop a mathematical model to determine age of horses by use of M1 crown height, and to determine the correlation between M1 crown height measured on radiographic and CT images. SAMPLE CT (n = 735) and radiographic images (35) of the heads of horses. PROCEDURES Crown height of left and right M1 was digitally measured on axial CT views. Height was measured on a lateral radiographic image when available. Linear regression analysis was used to identify factors associated with crown height. Half the data set was subsequently used to generate a regression model to predict age on the basis of M1 crown height, and the other half was used to validate accuracy of the predictions. RESULTS M1 crown height decreased with increasing age, but the rate of decrease slowed with increasing age. Height also differed by sex and breed. The model most accurately reflected age of horses < 10 years old, although age was overestimated by a mean of 0.1 years. The correlation between radiographic and CT crown height of M1 was 0.91; the mean for radiographic measurements was 2.5 mm greater than for CT measurements. CONCLUSIONS AND CLINICAL RELEVANCE M1 crown height can be used to predict age of horses. Results for CT images correlated well with those for radiographic images. Studies are needed to develop a comparable model with results for radiographic images.

Intraoperative and postoperative complications of partial maxillectomy for the treatment of oral tumors in dogs.

OBJECTIVE To characterize and identify factors associated with intraoperative and postoperative complications of maxillectomy in dogs with oral tumors. DESIGN Retrospective cohort study. ANIMALS 193 dogs that underwent maxillectomy for oral tumor excision from 2000 through 2011. PROCEDURES Data were extracted from the medical records regarding dog signalment, tumor location and size, histologic findings, clinical stage, maxillectomy category, surgical approach, and additional treatments provided. These factors were examined for associations with recorded intraoperative and postoperative outcomes. RESULTS The most common intraoperative complication was excessive surgical bleeding (103/193 [53.4%]), for which 44 (42.7%) dogs received an intraoperative blood transfusion. These outcomes were both significantly associated with tumor size and location, maxillectomy type, and surgical approach. Dogs treated with a dorsolateral combined intraoral surgical approach were more likely to have excessive surgical bleeding (48/58 [83%]) and had a longer mean duration of surgery (106 minutes) than those treated with an intraoral approach (29/54 [54%] and 77 minutes, respectively). Complications developing within 48 hours after surgery included epistaxis (99/193 [51.3%]), excessive facial swelling (71/193 [36.8%]), facial pawing (21/193 [10.9%]), and difficulty eating (22/193 [11.4%]). Complications developing within 48 hours to 4 weeks after surgery included lip trauma (22/164 [13.4%]), oronasal fistula formation (18/164 [11.0%]), wound dehiscence (18/164 [11.0%]), and infection (13/164 [7.9%]). CONCLUSIONS AND CLINICAL RELEVANCE Complications associated with maxillectomy in dogs were generally minor. Aggressive surgical planning, preparedness for hemorrhage and transfusion, careful tissue dissection, and comprehensive pain control are recommended, particularly for dogs with large, caudally located oral tumors requiring extensive excision.

Anatomic analysis of the equine mental foramen and rostral mandibular canal using computed tomography.

OBJECTIVES: To characterize the anatomy of the mental foramen and determine associations with age, weight, sex and breed. STUDY DESIGN: Retrospective descriptive study. ANIMALS: Forty-one horses, 0.6-25.2 years and weighing 136-820 kg. METHODS: Computed tomography (CT) studies of equine heads performed over 5 years were evaluated in multiplanar and three-dimensional reconstruction. Measurements obtained were positioning of the foramen along the mandible, foramen height and width, foramen-canal angulation and rostral canal mineralization. Exploratory statistical analyses investigated associations between measurements and age, weight, sex and breed. RESULTS: Evaluation of 41 CT studies revealed foramen positioning was one-third of the horizontal distance of the incisor-premolar space from the second premolar and one-third of the vertical distance in the mandible from the dorsal surface of interproximal space at the level of the foramen. Age was negatively correlated to horizontal positioning [r = -0.42; 95% confidence intervals (CI), -0.64 to -0.13]. Mean foramen width was 6.4 (range, 2.3-17.1) mm and height 5.6 (range, 2.1-10.3) mm. Age and foramen height (r = 0.32; 95% CI, 0.01 to 0.57) and width (r = 0.30; 95% CI, -0.01 to 0.30) were positively correlated. Thoroughbred and Warmblood/Draft horses had increased foramina heights compared with Quarter horses [analysis of variance (anova)p = 0.02]. Males had wider foramina (95% CI, -2.66 to 0.07). Angulation of the foramen-canal was mean ± standard deviation 68.3 ± 12.8° (range, 37.9-105.6°) transverse plane, 28.3 ± 4.1° (range, 18.2-39.0°) saggital plane and 41.4 ± 8.45° (range, 22.2-58.6°) dorsal plane. Older horses had decreased mineralization of the rostral canal (anova, left p = 0.015, right p = 0.025). CONCLUSIONS: The size, shape, positioning and angulation of the mental foramen varies. Mineralization of the canal is decreased in older horses. CLINICAL RELEVANCE: This study improves understanding of mental foramen anatomy and complications with needle placement.

COMPUTED TOMOGRAPHIC APPEARANCE OF THE TEMPOROMANDIBULAR JOINT IN 1018 ASYMPTOMATIC HORSES: A MULTI-INSTITUTION STUDY.

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 that had head/neck CT scans and no clinical signs of TMJ disease. Age, breed, sex, clinical presentation, and CT slice width data were recorded. Alterations in CT contour and density of the mandibular condyles, mandibular fossae, and TMJ intra-articular discs were described for each horse. Generalized logistic regression was used to test associations between anatomical variations and horse age. A total of 1018 horses were sampled. Anatomical variations were found in TMJ CT images for 40% of horses and 29% of joints. These were dichotomous with regard to age. Horses <1 year old commonly had alterations in the shape and density of the mandibular condyle. Older horses commonly had spherical hypodensities within the mandibular condyles consistent with bone cysts; and hyperdense regions of the intra-articular disc consistent with dystrophic mineralization. Findings indicated that TMJ anatomic variations were common in CT images of younger and older horses asymptomatic for TMJ disease. Future studies are needed to more definitively characterize these CT variations using gross pathology and histopathology.