A large case-control study indicates a breed-specific predisposition to feline tooth resorption.

Tooth resorption (TR) is one of the most common dental diseases of cats. It is a painful condition leading to tooth loss. The etiology of TR remains unclear, but old age, breed, other oral and dental diseases, and environmental factors are suspected predisposing factors. In our study, we used part of the data from the extensive feline health online survey of 8115 Finnish cats. As TR is difficult to detect and as the feline health survey included diagnoses defined by both veterinarians and the owners, we limited our study to a subpopulation of cats diagnosed with oral or dental disease by a veterinarian and had dental examination or surgery under sedation (n=944). We utilized case-control study analysed by multivariable logistic regression to determine the risk factors and breed variation of feline TR. The 202 cats diagnosed with TR were defined as TR cases and the remaining 742 cats as controls. The frequency of veterinarian-diagnosed TR was 3.9% in the health survey data (316/8115) and 21% in the subpopulation (202/944). The risk of TR increased with age (14.7% in youngest and 25.3% in oldest age group). Our finding that TR was significantly associated with gingivitis or periodontitis in cats that had also calculus (OR: 2.49 and 3.70, respectively) suggests that inflammatory changes caused by calculus increase the risk of TR. We found that Cornish Rex, European, and Ragdoll are at higher risk for TR (OR: 2.44, 2.98 and 2.90, respectively). Exotic-Persians breed group had lower risk (OR: 0.28). TR was not observed in Turkish van or Devon Rex. The differences between breeds highlight a genetic contribution. In addition, female cats that had food available constantly had significantly less TR than female cats that had feeding times (OR: 0.44). The underlying reasons for this remain unexplained in our study.

Expression of Toll-like receptor and cytokine mRNAs in feline odontoclastic resorptive lesion (FORL) and feline oral health.

Feline odontoclastic resorptive lesion (FORL) is a common chronic inflammatory condition whose aetiopathogenesis remains unclear. FORL affects 20-75% of cats and causes excruciating pain and tooth loss. The purpose of this study was to evaluate chronic inflammation in FORL by assessing differences in Toll-like receptor (TLR) and cytokine transcripts in gingival tissues between diseased and healthy cats. Gingival tissue samples were collected from 14 healthy cats with no known clinical signs of oral disease and 41 cats with FORL. Levels of mRNA encoding TLR2, TLR3, TLR4, TLR7, TLR9 and the cytokines interleukin-1ß (IL-1ß), IL-4, IL-6, IL-10, IL-12, interferon-γ (IFN-γ) and tumour necrosis factor-α (TNF-α) was evaluated using quantitative real-time PCR. Statistical significance of the results was assessed using non-parametric tests. Levels of TLR and cytokine transcripts were upregulated in gingival tissue from cats with FORL as compared with healthy gingival tissue: TLR2, TLR3 and TLR9, p ≤ 0.001; TLR4 and TLR7, p ≤ 0.01; IFN-γ, IL-4, IL-6, IL-10, IL-12, IL-1ß and TNF-α, p ≤ 0.001). In conclusion, expression of TLR and both pro- and anti-inflammatory cytokines were significantly increased, confirming an ongoing chronic inflammatory response to the microbiome in FORL. It is likely that dysbiosis of the oral microbiota in cats with FORL activates the innate immune response, leading to active inflammation that results in tooth resorption.

Clinical, Diagnostic and Histological Findings Involving Cheek Teeth Hypercementosis in Nine Horses.

Hypercementosis is infrequently reported to affect the cheek teeth of horses and presents as mineral deposits either attached (peripheral) or solitary ovoid (nodular) structures in the tooth bearing region. There is overlap between radiological and histological appearance of hypercementosis, cementoma, and equine odontoclastic tooth resorption and hypercementosis (EOTRH). The clinical presentation, imaging features, surgical management, and histological findings of nine horses that presented for dental lesions and associated hypercementosis of cheek teeth are reported. Horses were 4-15 years old and presented for either nasal discharge or facial swelling. Peripheral and nodular mineral structures were identified using radiographs or computed tomography in six and three horses, respectively. Eight of nine cases involved maxillary cheek teeth. Of six cases with peripheral hypercementosis, three had enlargement of the apical cross-sectional area that was greater than the coronal cross-sectional area thus preventing extraction along the normal eruption pathway and necessitating sectioning (two cases) and repulsion. Nodular hypercementosis lesions were extracted in three of the four cases. Post-extraction complications occurred in five cases; four cases required additional procedures. All horses returned to their intended use, ie riding or pasture. Histology of extracted dental and proliferative mineral material revealed hypercementosis characterized by large sheets of eosinophilic matrix with lacunae (usually empty; presumed artifact) and frequent, irregular, basophilic cement lines. All cases had evidence of chronic inflammation, such as caries, chronic fractures and/or pulpitis. The findings of this case series share many features with previous published descriptions of cementoma and with histological findings of hypercementosis lesions of EOTRH. Further investigation into differentiation of these entities is warranted.

Dental Pathology of the Iberian Lynx ( Lynx pardinus), Part II: Periodontal Disease, Tooth Resorption, and Oral Neoplasia.

The Iberian lynx is an endangered felid that has been subject to an intensive, ongoing conservation program to save it from extinction. Identification of dental pathologies could play an important role in the survival of this endangered species. The prevalence of periodontal bone loss, tooth resorption, and oral neoplasia was evaluated in this species. Skulls of 88 adult specimens of the Iberian lynx ( Lynx pardinus) from the Doñana Biological Station (EBD-CSIC), Seville, Spain, were examined macroscopically and full-mouth dental radiographs of all specimens were performed. Different stages of periodontal disease were identified in 81.3% of teeth. Approximately two-thirds (64.8%) of the specimens examined had at least 1 tooth affected by stage 3 or 4 periodontal disease. Maxillary and mandibular incisor teeth accounted for a majority (59.4%) of teeth affected by stage 3 or 4 periodontal disease. Tooth resorption affected 12 teeth (0.63% of evaluated teeth) in 6 skull specimens (6.8% of skulls evaluated). Five of the teeth with resorptive lesions were detected on 1 skull specimen. Six teeth (50%) of those affected by tooth resorption were incisor teeth. Only 1 (1.1%) adult specimen showed signs of oral neoplasia. Our study concluded that there is a high prevalence of periodontal disease that could lead to impaired hunting ability, as well as may represent a threat to overall health and subsequent survival of this endangered species. The extremely low prevalence of tooth resorption in L pardinus could open new pathways in the discovery on the pathogenesis of tooth resorption in felids.

Clinical treatment and prognosis of equine odontoclastic tooth resorption and hypercementosis.

REASONS FOR PERFORMING STUDY: Equine odontoclastic tooth resorption and hypercementosis is an infrequent and underdiagnosed form of severe dental disease in horses that can affect quality of life. The study was performed to compare the clinical, radiographic, histological and prognostic findings specific to equine odontoclastic tooth resorption and hypercementosis in horses. Removal of affected teeth is currently the best treatment. OBJECTIVES: The goals are to report salient clinical and histological features of the disease and its management in a case series describing an under-reported syndrome in horses and the long-term prognosis. STUDY DESIGN: Retrospective case series. METHODS: Medical records from New Bolton Center, University of Pennsylvania from January 2000 to December 2012 were reviewed from horses that had a diagnosis of 'cementoma' or 'hypercementosis' and any associated dental-related diagnosis affecting the teeth and oral cavity. Radiographic, surgical and histological reports were collated and the clinical cases compared and tabulated to provide a better description of the equine disease. RESULTS: A total of 18 cases were identified, 17 of which were geldings and one of which was a nonbreeding stallion; no mares had the disease. The mean age at diagnosis was 24 years, with a range of 17-29 years. There was no breed predilection, and varied clinical signs relating to the mouth were found. Some teeth involved had only radiographic changes of disease and not gross clinical evidence. The mandibular incisors were generally affected earlier than the maxillary incisors, but the disease is progressive, and eventually, all of the incisors and sometimes the canines are involved. No premolars or molars were affected in this case series. CONCLUSIONS: Based on this case series, all teeth, and particularly the incisors, should be examined for signs of gingivitis and hypercementosis and subsequently radiographed for an early diagnosis and management. When compared with our hospital population, older geldings were more likely to be affected with cementoma formation and its accompanying resorptive process. Removal of clinically and radiographically affected teeth carries a good prognosis for improved quality of life.

Tooth resorption in cats: pathophysiology and treatment options.

PRACTICAL RELEVANCE: Tooth resorption is common in the domestic cat and the incidence has been reported to increase with increasing age. Cats with clinically missing teeth have also been found to be more likely to have tooth resorption. All types of teeth in the feline dentition may be affected, but lesions seem to be more common in certain teeth. CLINICAL CHALLENGES: Tooth resorption can be difficult to detect, with cats often masking signs of oral discomfort or pain. Routine radiography is required for timely diagnosis, as clinical (visual and tactile) methods only detect late-stage lesions - that is, when they become evident in the crown. The aetiology of many tooth resorptions is not clear. A large number of lesions appear to be idiopathic and, to date, there is no known treatment that prevents the development and/or progression of this category of tooth resorption. Tooth extraction is the gold standard treatment but teeth with resorptive lesions are notoriously difficult to extract and coronal amputation is often indicated. Determining the best treatment option in an individual case again relies on radiography. AUDIENCE: This review is aimed at feline and general practitioners, as well as veterinarians with expertise in dentistry. EVIDENCE BASE: The author draws on the published literature and her clinical experience and own research to review current thinking about the epidemiology, aetiology and pathogenesis of tooth resorptions, and to offer advice on diagnosis and treatment options.

Clinical feline dental radiography.

Dental radiography is a necessary diagnostic modality in small animal practice. It is not possible to accurately assess and diagnose tooth resorption, periodontal disease, endodontic disease, neoplasia and injury without it. Dental radiography is also necessary for treatment and assessment of the patient postoperatively.

Prevalence and types of tooth resorption in dogs with oral tumors.

OBJECTIVE: To determine the prevalence and types of tooth resorption in dogs with oral tumors and to compare findings with those for control dogs. ANIMALS: 101 dogs with oral tumors and 128 control dogs that did not have oral tumors and for which dental radiographs were available. PROCEDURES: Exclusion criteria for dogs included systemic disease, long-term administration of anti-inflammatory drugs, traumatic occlusion, severe semigeneralized or generalized periodontitis, and endodontic disease. For each dog with an oral tumor, histologic sections of biopsy specimens of tumors were examined. Dental radiographic images of dogs were examined, and the presence and type of tooth resorption were determined for each tooth. Statistical analyses were performed to compare data regarding prevalence of tooth resorption. RESULTS: Teeth at tumor sites in dogs with nonodontogenic tumors were significantly more frequently affected with external inflammatory resorption, compared with teeth at tumor sites in dogs with odontogenic tumors. Teeth at sites distant from tumors in dogs with oral tumors were 3.2 times as likely to have external surface resorption (OR, 3.2; 95% confidence interval, 1.3 to 7.9) and 83.4 times as likely to have external inflammatory resorption (OR, 83.4; 95% confidence interval, 9.7 to 719.6) as teeth in control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Resorption of teeth at tumor sites and at sites distant from tumors was common in dogs with oral tumors. Results of the present study will contribute to an understanding of the complex effects of oral tumors on local and distant hard tissues.

Osteoclast progenitors from cats with and without tooth resorption respond differently to 1,25-dihydroxyvitamin D and interleukin-6.

Both vitamin D and inflammatory cytokines can stimulate osteoclast formation and activity. We studied the effect of 1,25-dihydroxycholecalciferol (1,25(OH)(2)D), and interleukin-6 (IL-6), on the formation and activity of feline osteoclasts, using peripheral blood mononuclear cells (PBMCs) from cats with and without tooth resorption (TR(+) and TR(-)) as a source of osteoclast precursors. The formation of osteoclast-like cells (defined as multinucleated, tartrate-resistant acid phosphatase-positive cells) was assessed at 7 and 14 days. In the presence of M-CSF and RANKL, with and without IL-6, more osteoclasts were formed from TR(-) PBMCs than from TR(+) PBMCs on plastic. More osteoclasts were formed from TR(+) PBMCs on bone slices in the presence of M-CSF/RANKL with 1,25(OH)(2)D. This opposite effect may be due to a higher expression of the vitamin D receptor (VDR) in TR(+) osteoclasts and precursors on bone. Formation of resorption pits was analyzed and confirmed with scanning electron microscopy. In conclusion, we propose that TR(+) PBMCs when cultured on bone are sensitive to 1,25(OH)(2)D, whereas the differentiation of TR(-) PMBCs on bone seem more sensitive to IL-6, suggesting that osteoclast precursors from cats with and without tooth resorption respond differently to osteoclast stimulating factors.

Inflammatory cytokines and the nuclear vitamin D receptor are implicated in the pathophysiology of dental resorptive lesions in cats.

Dental resorptive lesions (RL) are a common oral disease in cats (Felis catus) associated with pain and tooth destruction. The aetiology of RL in cats is unknown, but inflammation is often seen in conjunction with RL. Vitamin D involvement has been suggested because 1,25-dihydroxyvitamin D (1,25(OH)(2)D) stimulates osteoclastogenesis, through up-regulation of the nuclear vitamin D receptor (nVDR). The aim of this study is to determine the involvement of inflammatory cytokines and the possible role of vitamin D in the pathophysiology of RL using quantitative PCR. We measured the mRNA expression of cytokines with stimulatory (IL-1beta, IL-6, and TNF-alpha) and inhibitory effects (IL-10 and IFN-gamma) on osteoclastogenesis, and the mRNA expression of the receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), and nVDR in RL samples. We found increased expression of mRNA levels for inflammatory cytokines and nVDR, but not for RANKL and OPG, in tissue from RL-affected cats compared with tissue from radiological confirmed healthy controls. The mRNA levels of nVDR were positively correlated with mRNA levels of pro-inflammatory (IL-1beta, IL-6, TNF-alpha, and IFN-gamma), anti-inflammatory (IL-10), pro-resorptive (IL-1beta, IL-6, and TNF-alpha), and anti-resorptive (IFN-gamma and IL-10) cytokines in the course of resorptive lesions. These data are consistent with our view that both inflammation and an overexpression of the nVDR are likely to be involved in RL in cats.

Oral examination and radiographic evaluation of the dentition in wild cats from Namibia.

Feline tooth resorption has been widely reported in domestic cats and sporadically described in other felidae. The goal of the present study was to determine the prevalence of tooth resorption and to report other dental problems in a population of wild felidae. Observations of dental disorders and anomalies were made in skulls from 73 wild felidae (cheetahs, leopards, caracals, African wildcats, and lions) originating from Namibia. In addition, radiographs were taken in 43 cases to determine signs of bone and root pathology. Radiographs showed varying stages of tooth resorption in 16.0% of the specimens. Other dental anomalies found included fused teeth, supernumerary roots, or missing teeth. The prevalence of dental resorption in wild felidae was lower than reported in the domestic cat.

Evaluation of calciotropic hormones in cats with odontoclastic resorptive lesions.

OBJECTIVE: To assess associations between epidemiologic and laboratory variables and calciotropic hormones in cats with odontoclastic resorptive lesions (ORLs). ANIMALS: 182 client-owned cats older than 1 year of age with oral disease. PROCEDURE: Information on medical history, behavior, living environment, and feeding management was assessed by use of a questionnaire. After induction of general anesthesia, oral examination was performed following standardized protocols and included dental probing and full-mouth radiography. Laboratory analyses included evaluation of FeLV-FIV status, serum biochemical analyses, CBC, urinalysis, and serum concentrations of intact parathyroid hormone (iPTH), parathyroid hormone-related peptide (PTHrP), 25-hydroxyvitamin D (25-OHD), free thyroxine (fT4), and ionized calcium (iCa). RESULTS: ORLs were identified in 72.5% of cats. Mandibular third premolars were the most commonly affected teeth. Cats with ORLs were significantly older (mean, 9.2 years) than cats without ORLs (mean, 6.6 years). Multivariate logistic regression analysis revealed that 25-OHD, urine specific gravity, jaw-opening reflex on probing, and missing teeth were significant variables, even after accounting for age. Cats with ORLs had significantly higher mean serum concentration of 25-OHD (112.4 nmol/L) and significantly lower mean urine specific gravity (1.0263), compared with cats without ORLs (89.8 nmol/L and 1.0366, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Results did not indicate associations between iPTH, PTHrP, or fT4 and development of ORLs. In affected cats, the importance of high serum 25-OHD and low urine specific gravity has not been determined.

Bilateral maxillary periodontal ligament hamartoma in a dog.

A 12.5-year-old dog was presented for severe periodontal disease and bilateral maxillary enlargement. Radiographs of the maxilla showedgeneralized root resorption, ankylosis, and rarefaction of bone with focal radiodense areas. Surgical tooth extraction of multiple maxillary teeth and bilateral incisional biopsies of the periodontal tissue and maxilla in the region of the maxillary fourth premolars were performed. Histopathologic examination showed features typical of fully differentiated periodontal ligament with abundant cementum/alveolar lining bone and sparce odontogenic epithelial cell rests. Histopathology in conjunction with radiographic and clinical signs suggested a diagnosis of bilateral periodontal ligament hamartoma. Examination 3-months postoperatively indicated uncomplicated healing of the extraction and biopsy sites with no resolution of the maxillary enlargement.

Prevalence of dental resorptive lesions in Swedish cats.

Ninety-six, randomly selected Swedish cats were evaluated for the presence of dental resorptive lesions. All cats were examined while receiving general anesthesia. Diagnosis was based on oral examination and full-mouth, intraoral dental radiographs. Information concerning age, sex, vaccination status, eating habits, food type, environment (indoor or outdoor housing), oral, discomfort, dental care, and medical treatment was recorded. Hematologic samples included analysis for FeLV, FIV, and calcivirus. Of the cats examined in this study, 32% had gross or radiographic signs of dental resorptive lesions. There was a positive relationship between the occurrence of dental resorptive lesions and increasing age.

Feline odontoclastic resorptive lesions an unsolved enigma in veterinary dentistry.

This article presents a comprehensive review of the literature on feline odontoclastic resorptive lesions (FORLs), including etiopathogenesis, prevalence and predisposition, classification, histopathologic appearance, diagnosis, and treatment. Approximately one-third of all domestic cats may develop FORLs during their life span, and the risk of developing FORLs increases with age. Sophisticated dental treatments promise neither cure nor permanent improvement of affected teeth. Extraction is the current treatment of choice. Research on the etiology of FORLs has not been rewarding in recent years, and the causative factors contributing to the development of FORLs are still unknown.

The dental pathology of feral cats on Marion Island, part II: periodontitis, external odontoclastic resorption lesions and mandibular thickening.

Skulls (n = 301) of adult feral cats from Marion Island were examined macroscopically. Dental calculus was found infrequently (9.0% of cats, 0.76% of teeth), unlike the hard tissue lesions of moderate and advanced periodontitis and tooth loss (presumably due to periodontitis), which were commonly seen (61.8% of cats, 14.8% of teeth). Relatively few of these abnormalities were associated with external odontoclastic resorption lesions, which affected 14.3% of cats and 1.2% of teeth-less than in most recent surveys in domestic cats. Abnormal thickening of the mandibula, found in 39.5% of specimens, was most commonly bilateral (83.3%). The lesions ranged from a focal periosteal reaction, to localized exostosis, to generalized swelling and loss of density, to grossly enlarged mandibles with increased bone density. Mandibular swelling was significantly associated with other abnormalities (periodontitis, dental fractures, external odontoclastic resorption lesions and periapical lesions), but many cases of mandibular swelling were accompanied by only minor dental defects.

Feline dental resorptive lesions.

Resorptive lesions in feline teeth are frustrating. Despite a number of studies, there is as yet no satisfactory, clear-cut explanation for the cause, high prevalence, and recent emergence of this lesion, and experience with treatment has identified more problems, rather than indicated a successful management regime.