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Platelet-rich plasma (PRP) and other platelet-derived products represent a subset of regenerative medicine and have been researched in the veterinary community for the treatment of osteoarthritis, soft tissue wounds, tendinopathies, periodontitis, and fracture repairs. PRP is simple to produce, relatively affordable, safe, and can be delivered on site, making it an appealing therapeutic agent in veterinary medicine. As an orthobiologic for the treatment of osteoarthritis, it is one of few interventions with clinical study support that possess anabolic potential. Platelet product variability is wide ranging and often described in terms of cellular content or platelet enrichment. Growth factors associated with platelet activation and subsequent degranulation may mediate inflammation, modulate cellular immune response, and promote tissue repair. Product composition, dosage, and application likely influence treatment outcomes depending on the classification of the disease targeted. Sufficient canine data regarding the formulation and clinical application of canine PRP exist to warrant review. The aim of this narrative is to provide scientific background and clinical insight for veterinarians regarding platelet product content/formulation, mechanisms of action, considerations for use, and clinical application in dogs.

Objective: To report the complication rate of dogs undergoing oral oncological surgery when using a bone-cutting piezoelectric unit for osteotomies., Clinical Presentation and Procedures: Retrospective cohort evaluation of medical records from 2012 through 2022 for canine patients that underwent mandibulectomy or maxillectomy for the treatment of oral neoplasia at the Companion Animal Hospital at Cornell University. Cases were included if osteotomy was performed using a piezoelectric unit. Medical records were then reviewed for documentation of intraoperative hemorrhage and administration of blood products., Results: 41 maxillectomies and 57 mandibulectomies met the inclusion criteria (98 in total). Only 1 (1.02%) case was associated with excessive surgical bleeding requiring administration of blood products., Clinical Relevance: Results of this study show that intraoperative hemorrhage requiring the use of blood products during or immediately after a mandibulectomy or maxillectomy is rare when using a piezoelectric unit to perform osteotomies, and is substantially lower than that previously reported when using oscillating saws or other bone-cutting devices for maxillectomies.

Oral squamous cell carcinoma (OSCC) is the most common oral epithelial malignancy in dogs. It exhibits locally aggressive biological behaviour with the potential to metastasize, and a reported 1-year survival rate of 0% when left untreated. Expression studies suggest that aberrant MAPK signalling plays a key role in canine OSCC tumorigenesis, which is consistent with BRAF and HRAS MAPK-activating mutations reported in some tumours. Several morphological subtypes of canine OSCC have been described, with papillary, conventional, and basaloid as the most common patterns. We hypothesized that mutational differences may underlie these phenotypic variations. In this study, targeted Sanger sequencing and restriction fragment length polymorphism assays demonstrate that up to 85.7% of canine papillary OSCC (n = 14) harbour a BRAF p.V595E mutation. Assessment of neoplastic epithelial cell proliferation using Ki67 immunolabelling (n = 10) confirmed a relatively high proliferation activity, consistent with their known aggressive clinical behaviour. These findings underscore a consistent genetic feature of canine papillary OSCC and provide a basis for the development of novel diagnostic and targeted therapeutic approaches that can improve the quality of veterinary care., (© 2022 John Wiley & Sons Ltd.)

A sialocele is an accumulation of salivary fluid due to leakage into the interstitial space surrounding the affected salivary gland and/or its corresponding duct. Reported causes of salivary leakage include trauma, foreign bodies, sialoliths, and neoplasia, but in many cases the etiology is not identified. Clinical signs of sialoceles associated with the zygomatic salivary gland or corresponding duct usually include exophthalmos due to periorbital salivary accumulation, whereas sialoceles associated with the mandibular or sublingual glands or ducts usually manifest as cervical, pharyngeal and/or sublingual salivary accumulation. This case report describes an atypical cervical presentation of a zygomatic sialocele in a dog that resolved after zygomatic sialoadenectomy.

Ameloblastomas are odontogenic tumors that are rare in people but have a relatively high prevalence in dogs. Because canine acanthomatous ameloblastomas (CAA) have clinicopathologic and molecular features in common with human ameloblastomas (AM), spontaneous CAA can serve as a useful translational model of disease. However, the molecular basis of CAA and how it compares to AM are incompletely understood. In this study, we compared the global genomic expression profile of CAA with AM and evaluated its dental origin by using a bulk RNA-seq approach. For these studies, healthy gingiva and canine oral squamous cell carcinoma served as controls. We found that aberrant RAS signaling, and activation of the epithelial-to-mesenchymal transition cellular program are involved in the pathogenesis of CAA, and that CAA is enriched with genes known to be upregulated in AM including those expressed during the early stages of tooth development, suggesting a high level of molecular homology. These results support the model that domestic dogs with spontaneous CAA have potential for pre-clinical assessment of targeted therapeutic modalities against AM., (© 2021. The Author(s).)

Objective: To assess the frequency of clinical and radiographic evidence of inflammation (ie, evidence of inflammation) associated with retained tooth root fragments (RTRFs) in dogs and to determine whether evidence of inflammation was affected by RTRF length and position within the alveolar bone., Sample: 148 RTRFs in 66 dogs., Procedures: For each dog, demographic information was recorded, and full-mouth radiographs were obtained and reviewed for RTRFs. For each RTRF, the length of the fragment was measured on intraoral radiographic images, and its location and position relative to the alveolar bone margin were recorded. The presence or absence of evidence of inflammation in association with each RTRF was also recorded. Descriptive data were generated. Generalized linear mixed models were used to identify factors associated with evidence of inflammation around RTRFs., Results: 81 of 148 (54.7%) RTRFs had evidence of inflammation. For every 1-mm increase in RTRF length, the odds of inflammation increased by 17% (OR, 1.17; 95% confidence interval [CI], 1.04 to 1.34; P = 0.009). Odds of inflammation for RTRFs that protruded from the alveolar bone margin were 2.98 (95% CI, 1.02 to 8.72; P = 0.046) and 7.58 (95% CI, 1.98 to 29.08; P = 0.001) times those for RTRFs that were buried and level with the alveolar bone margin, respectively. Tooth root fragment length was a poor predictor of inflammation., Conclusions and Clinical Relevance: Results indicated that most RTRFs were associated with evidence of inflammation and supported the current recommendation for extraction of RTRFs whenever feasible.

Ameloblastoma is a locally aggressive odontogenic tumour that occurs in humans and dogs. Most ameloblastomas (AM) in humans harbour mutually-exclusive driving mutations in BRAF, HRAS, KRAS, NRAS or FGFR2 that activate MAPK signalling, and in SMO that activates Hedgehog signalling. The remarkable clinical and histological similarities between canine acanthomatous ameloblastoma (CAA) and AM suggest they may harbour similar driving mutations. In this study, aimed at characterizing the mutational status of SMO, BRAF, HRAS, KRAS, NRAS and FGFR2 in CAA, we used RNA sequencing, Sanger sequencing and restriction fragment length polymorphism assays to demonstrate that 94% of CAA (n = 16) harbour a somatic HRAS p.Q61R mutation. The similarities in MAPK-activating mutational profiles between CAA and AM implicate conserved molecular mechanisms of tumorigenesis, thus, qualifying the dog as a potentially useful model of disease. Given the relevance of RAS mutations in the pathogenesis of odontogenic tumours and other types of cancer, the results of this study are of comparative, translational, and veterinary value., (© 2019 John Wiley & Sons Ltd.)

Canine acanthomatous ameloblastoma (CAA) and oral squamous cell carcinoma (OSCC) are the most common oral tumours of epithelial origin in dogs. Overlapping clinical, radiographical and histological features can make distinction between CAA and OSCC difficult. The ability to distinguish tumour identity is critical due to their different biological behaviour and recommended treatment modalities, as well as respective comparative and translational applications as potential models of human disease. Based on marked differences in biological behaviour (i.e. benign versus malignant), it is reasonable to predict that the tumour cell proliferation activity is lower in CAA than in OSCC. However, to our knowledge, the epithelial cell proliferation activity of CAA has not been studied or compared with that of OSCC. Therefore, the aims of this study were to (1) compare the neoplastic epithelial cell proliferation activity of CAA and OSCC based on conventional mitotic index (MI) and Ki67 labelling index (LI), and (2) correlate these findings with clinical parameters including patient signalment, anatomical tumour location and degree of local invasion at the time of diagnosis as determined by computed tomography. We found that (1) the Ki67 LI of OSSC (n = 14) was significantly higher than that of CAA (n = 25), (2) the Ki67 LI correlated with a more aggressive locally invasive behaviour, and (3) the MI was not associated with tumour type. We conclude that the Ki67 LI, but not the MI, is a useful differential marker of CAA from OSCC, and that the epithelial cell proliferation activities of OSCC and CAA correlate with their known differences in biological behaviour., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

OBJECTIVE To determine and identify variables associated with outcomes of surgical repair of congenital palatal defects in dogs. DESIGN Retrospective case series with nested observational study. ANIMALS 26 dogs that underwent surgical repair of congenital palatal defects at 2 veterinary teaching hospitals from 2007 to 2016. PROCEDURES Data were collected from medical records regarding dog age and body weight at the time of surgical defect repair, prior surgical history, skull type (brachycephalic, mesocephalic, or dolichocephalic), surgical technique used for defect repair, and defect severity. Functional outcome as well as frequency and location of oronasal fistula (ONF) formation were recorded. These outcomes were compared among various groups. RESULTS Surgical defect repair achieved functional success in 22 of the 26 (85%) dogs. An ONF formed after initial repair in 13 (50%) dogs, and the most common location was the hard palate. Hard palate ONF formation was more common in dogs > 8 months of age at the time of initial repair; ONF at the junction between the hard and soft palates was more common in dogs > 8 months of age at the time of initial repair and in dogs with a history of failed surgical repair. An unsuccessful functional outcome was more common in dogs weighing < 1 kg (2.2 lb) at the time of initial repair. CONCLUSIONS AND CLINICAL RELEVANCE Patient age, patient size, and defect characteristics should be taken into consideration when planning and assessing prognoses for surgical repair of congenital palatal defects in dogs.

Canine chronic ulcerative stomatitis, also known as chronic ulcerative paradental stomatitis, is a painful condition of the oral cavity. The purpose of this study was to determine if there are commonalities in clinical and radiographic features among patients, whether the histopathologic evaluation might inform the pathogenesis, and whether the condition appears similar to human oral mucosal diseases. To do this, we prospectively collected clinical, radiographic, and histopathologic data from 20 dogs diagnosed with the disease. Clinical data were based on a clinical disease activity index, oral and periodontal examination parameters, and full-mouth dental radiographs. The histopathological and immunohistochemical data were based on oral mucosal samples obtained from erosive or ulcerated areas. Our findings revealed that canine chronic stomatitis is clinically characterized by painful oral mucosal ulcers of varying size, pattern, appearance, and distribution, most often associated with teeth with early periodontitis. Histologic examination revealed a subepithelial lichenoid band (interface mucositis) where B cells, T cells, and Forkhead-box protein 3 (FoxP3)- and interleukin-17-expressing cells were present. These cells might play a role in the underlying immune response and an immune-mediated pathogenesis is suspected. The clinical and histopathologic features of this chronic inflammatory mucosal disease in dogs resemble those of oral lichen planus in humans.

Objective: To report a staged approach that includes selective dental extractions before definitive double-layer hard palate defect closure in dogs., Study Design: Retrospective case series., Animals: Dogs (n = 6) with a palatal defect., Methods: Dogs had selective maxillary teeth extractions 4-8 weeks before definitive hard palate defect repair by double-layer local full-thickness mucosal flaps., Results: All palatal defects were considered complex. Complete hard palate closure was achieved after initial attempt in 3 dogs; 2 dogs had revision surgery before complete closure, and in 1 dog, closure failed and further treatment was declined. No complications or long-term consequences were associated with selective dental extractions., Conclusions: Selective dental extractions before definitive surgical repair using mucosal flaps in a double-layer approach is an effective alternative when treating complex hard palate defects in dogs., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objective: To evaluate craniomaxillofacial abnormalities in dogs with congenital palatal defects., Study Design: Retrospective computed tomography (CT) study., Animals: Dogs with congenital palatal defects (n = 9)., Methods: Medical records and CT reports (1995-2012) were searched for dogs with a diagnosis of cleft palate that had a CT study. Data retrieved were: breed, age, sex, weight, physical examination, and laboratory findings, number of previous palate surgeries, and oral/dental examination findings with the diagnosis of the cleft for each dog. CT studies of the head were reviewed on a structure-by-structure basis., Results: Tympanic bullae were most commonly found to be abnormal (8 dogs), followed by nasal turbinates (6), nasal septum, vomer, cribriform plate (4), frontal sinuses, and lateral ventricles (3). Other abnormalities were related to occlusion, teeth, incisive bones, maxillary bones, mandibles, hyoid apparatus, cranial bones, and nasopharynx. The soft tissue defect of the cleft was always smaller than the bony defect., Conclusions: Craniomaxillofacial abnormalities in dogs with congenital palatal defects are common and some of these may negatively affect the quality of life. Importantly for surgical planning, the soft tissue component of the cleft may underestimate the extent of the bony defect, especially in failed repairs., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objective: To determine applicability of the 2007 American Veterinary Dental College (AVDC) classification method for determining extent of tooth resorption in dogs., Animals: 224 dogs > 1 year old admitted for periodontal treatment or other dental procedures in 2007., Procedures: Full-mouth radiographs of all dogs were reviewed for evidence of tooth resorption. Tooth resorption in dogs was classified in accordance with the radiographic criteria described for use in human teeth and, when applicable, the guidelines described in the 2007 AVDC classification method., Results: 851 of 943 (90.2%) affected teeth met the radiographic characteristics of 1 of the 5 stages of tooth resorption described by the AVDC classification method. Among tooth resorption types described for human teeth, the AVDC classification method was totally applicable (100%) in 17 teeth with external surface resorption, 21 teeth with external replacement resorption, and 736 teeth with external cervical root surface resorption, but it was applicable in only 56 of 121 (46.3%) teeth with external inflammatory resorption and none of the teeth with internal resorption., Conclusions and Clinical Relevance: The AVDC classification method was useful to describe the extent of tooth resorption in dogs, but it did not reflect the radiographic patterns and location of lesions. The AVDC classification method was applicable in some, but not all, of the teeth with various resorption types in dogs. The AVDC classification method could be adapted best to lesions that have radiographic patterns of external replacement resorption and external cervical root surface resorption.

Objective: To determine the prevalence of tooth resorption in dogs and to evaluate whether a classification system for tooth resorption in humans is applicable in this species., Animals: 224 dogs > 1 year old admitted for periodontal treatment or other dental procedures in 2007., Procedures: Full-mouth radiographs of all dogs were reviewed for evidence of tooth resorption. Tooth resorption was classified in accordance with radiographic criteria described for use in humans. Patient signals and concurrent dental conditions were recorded and tabulated., Results: Tooth resorption was detected in 120 of 224 (53.6%) dogs and 943 of 8,478 (11.1%) teeth. The classification system for use in humans was applicable in 908 of 943 (96.3%) affected teeth. Tooth resorption was more frequent among older and large-breed dogs; no significant differences were found among sex categories. The 2 most common types of tooth resorption were external replacement resorption (77/224 [34.4%] dogs and 736/8,478 [8.7%] teeth) and external inflammatory resorption (58/224 [25.9%] dogs and 121/8,478 [1.4%] teeth). External cervical root surface resorption was detected in 13 of 224 (5.8%) dogs; external surface resorption was detected in 10 of 224 (4.5%) dogs, and internal inflammatory resorption and internal surface resorption were detected in 9 of 224 (4.0%) and 1 of 224 (0.4%) dogs, respectively. Internal replacement resorption was not detected., Conclusions and Clinical Relevance: The classification of tooth resorption in humans was applicable to tooth resorption in dogs. Resorption lesions, in general, and external replacement and external inflammatory resorption, in particular, were frequently detected in dogs.