Alexander M. Reiter

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.

Association of periodontal disease with systemic health indices in dogs and the systemic response to treatment of periodontal disease

OBJECTIVE To determine whether severity of periodontal disease (PD) was associated with systemic health indices in dogs and whether treatment of PD altered systemic health indices. DESIGN Prospective cohort study. ANIMALS 38 dogs. PROCEDURES Healthy dogs with clinical signs of PD were included in the study. Physical examination, serum biochemical analysis, a CBC, urine evaluation, measurement of serum C-reactive protein (CRP) concentration, and a microalbuminuria test were performed prior to treatment of PD. All tooth roots were scored for gingivitis and attachment loss, and appropriate treatment of PD was performed. Laboratory data were obtained 4 weeks after treatment. The Spearman rank correlation and Wilcoxon signed rank test were used for statistical analysis. RESULTS Analyses of the correlation of several variables with attachment loss or gingivitis or of differences before and after treatment revealed significant results for several variables. After applying Bonferroni corrections for family-wise error rate, significant rank correlations were found between attachment loss and platelet number (r = 0.54), creatinine concentration (r = -0.49), and the within-dog difference in CRP concentrations before and after treatment (r = 0.40). The BUN concentration was significantly higher after treatment than before treatment. CONCLUSIONS AND CLINICAL RELEVANCE Increasing severity of attachment loss was associated with changes in systemic inflammatory variables and renal indices. A decrease in CRP concentration after treatment was correlated with the severity of PD. The BUN concentration increased significantly after treatment of PD. There is a need for continued research into the systemic impact of PD.

Use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats: six cases (2005-2007)

OBJECTIVE To determine outcome associated with use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats. DESIGN Retrospective case series. ANIMALS 3 dogs and 3 cats. PROCEDURES All 6 animals had severe inspiratory stertor at initial examination. Two animals had no orifice present at the stenosis. Nasopharyngeal stenosis was diagnosed and stent size determined by use of computed tomography. A percutaneous transluminal angioplasty balloon premounted with a balloon-expandable metallic stent was placed over a guidewire, advanced through the stenotic lesion under fluoroscopic and rhinoscopic guidance, and dilated to restore patency. RESULTS All animals had immediate resolution of clinical signs after stent placement. The procedure took a median of 38 minutes (range, 22 to 70 minutes). One animal with a stenosis located far caudally needed the tip of the stent resected because of hairball entrapment and exaggerated swallowing. Both animals without an orifice in the stenosis had tissue in-growth requiring a covered stent. All animals were reexamined 6 to 12 weeks after treatment via rhinoscopy, radiography, computed tomography, or a combination of techniques. All animals lacked signs of discomfort; 5 of 6 were breathing normally 12 to 28 months after the procedure. CONCLUSIONS AND CLINICAL RELEVANCE Transnasal balloon-expandable metallic stent placement may represent a rapid, safe, noninvasive, and effective treatment in animals with nasopharyngeal stenosis. If the stenosis is extremely caudal in the nasopharynx, serial balloon dilatation might be considered prior to stent placement. A covered stent should be considered initially if the stenosis is completely closed.

Symphysiotomy, Symphysiectomy, and Intermandibular Arthrodesis in a Cat with Open-Mouth Jaw Locking — Case Report and Literature Review

A Persian cat was presented with open-mouth jaw locking. It was suspected that abnormal extrusion of the maxillary canine teeth caused contact with the mandibular canine teeth on closure of the mouth, resulting in levering forces that may have led to increased symphyseal mobility, temporomandibular joint laxity, rotational movement of the left mandibular body and locking of the left coronoid process lateral to the zygomatic arch. Symphysiotomy, symphysiectomy, circumferential and interdental wiring, and intraoral resin-based splint application were performed to achieve intermandibular arthrodesis. Following removal of all devices, no further jaw locking episodes were reported during a 33-month follow-up period.

Protein tyrosine phosphatase 1B is a key regulator of IFNAR1 endocytosis and a target for antiviral therapies

Type 1 interferons (IFN1) elicit antiviral defenses by activating the cognate receptor composed of IFN-α/β receptor chain 1 (IFNAR1) and IFNAR2. Down-regulation of this receptor occurs through IFN1-stimulated IFNAR1 ubiquitination, which exposes a Y466-based linear endocytic motif within IFNAR1 to recruitment of the adaptin protein-2 complex (AP2) and ensuing receptor endocytosis. Paradoxically, IFN1-induced Janus kinase-mediated phosphorylation of Y466 is expected to decrease its affinity for AP2 and to inhibit the endocytic rate. To explain how IFN1 promotes Y466 phosphorylation yet stimulates IFNAR1 internalization, we proposed that the activity of a protein tyrosine phosphatase (PTP) is required to enable both events by dephosphorylating Y466. An RNAi-based screen identified PTP1B as a specific regulator of IFNAR1 endocytosis stimulated by IFN1, but not by ligand-independent inducers of IFNAR1 ubiquitination. PTP1B is a promising target for treatment of obesity and diabetes; numerous research programs are aimed at identification and characterization of clinically relevant inhibitors of PTP1B. PTP1B is capable of binding and dephosphorylating IFNAR1. Genetic or pharmacologic modulation of PTP1B activity regulated IFN1 signaling in a manner dependent on the integrity of Y466 within IFNAR1 in human cells. These effects were less evident in mouse cells whose IFNAR1 lacks an analogous motif. PTP1B inhibitors robustly augmented the antiviral effects of IFN1 against vesicular stomatitis and hepatitis C viruses in human cells and proved beneficial in feline stomatitis patients. The clinical significance of these findings in the context of using PTP1B inhibitors to increase the therapeutic efficacy of IFN against viral infections is discussed.

Mandibular reconstruction after gunshot trauma in a dog by use of recombinant human bone morphogenetic protein-2

CASE DESCRIPTION A 6-year-old German Shorthaired Pointer was evaluated for possible reconstruction of a mandibular defect resulting from gunshot trauma. CLINICAL FINDINGS A 5-cm defect of the right mandibular body was evident. A segment of the mandibular body was removed 9 weeks earlier because of severe contamination and comminution associated with gunshot trauma. Subsequent right-sided mandibular drift resulted in malocclusion in which the left mandibular canine tooth caused trauma to mucosa of the hard palate medial to the left maxillary canine tooth. The right maxillary canine tooth caused trauma to gingiva lingual to the right mandibular canine tooth. TREATMENT AND OUTCOME The right mandible was stabilized with a 2.0-mm maxillofacial miniplate positioned along the lateral alveolar margin and a 2.4-mm locking mandibular reconstruction plate placed along the ventrolateral mandible. An absorbable compression-resistant matrix containing collagen, hydroxyapatite, and tricalcium phosphate was soaked in recombinant human bone morphogenetic protein-2 (rhBMP-2; 7.2 mL of a 0.5 mg/mL solution for a dose of 3.6 mg) and placed in the defect. By 4 weeks after surgery, an exuberant callus was evident at the site of the defect. By 7 months after surgery, the callus had remodeled, resulting in normal appearance, normal occlusion, and excellent function of the jaw. CLINICAL RELEVANCE Mandibular defects resulting from gunshot trauma can be treated by removal of contaminated tissue and comminuted bone fragments, followed by staged reconstruction. The combination of rhBMP-2 and compression-resistant matrix was effective in a staged mandibular reconstruction in a dog with a severe traumatic mandibular defect.

Significant Association between Tooth Extrusion and Tooth Resorption in Domestic Cats

Abnormal extrusion of canine teeth is often noted in middle-aged and geriatric domestic cats. The same age group of cats also is commonly affected by tooth resorption (TR). This study explored the relationship between these two phenomena of unknown etiology. Using digital radiography, the distance between the alveolar margin (AM) and cementoenamel junction (CEJ), referred to as the AM-CEJ distance, was measured in clinically and radiographically healthy maxillary canine teeth of 24 TR-affected and 29 TR-free cats. The mean AM-CEJ distance of maxillary canine teeth of cats with and cats without TR was 2.68-mm and 2.22-mm, respectively. An analysis of covariance adjusting for age revealed a significant correlation (p = 0.02) between tooth extrusion and TR. Extrusion of the maxillary canine teeth became clinically apparent when an AM-CEJ distance of 2.5-mm or greater was evident in the absence of horizontal or vertical alveolar bone loss. Based on this criterion, 15 of 24 cats with TR (63.0 %) exhibited extrusion of maxillary canine teeth, compared to 9 of 29 cats without TR (31.0 %). Four extruded and five non-extruded maxillary canine teeth were evaluated histologically. Cementum of extruded teeth was significantly thicker compared to that of non-extruded teeth. Four of 4 canine teeth with extrusion (100 %) showed histological evidence of resorption, compared to 1 of 5 canine teeth without extrusion (20.0 %). These results suggest that tooth extrusion is linked to or may be caused by similar factors responsible for the development of TR.

Orofacial Manifestations of High-Rise Syndrome in Cats: A Retrospective Study of 84 Cases

Medical records of cats with high-rise trauma were reviewed to document the prevalence and clinical manifestations of orofacial injury. Cats were presented over a 10-year period from January 2000 to December 2009. Signalment, weight, number of stories fallen, and survival data were recorded in 84 cats and physical examination findings were obtained from 83 cats. Fourteen of these cats were examined by veterinarians of the Dentistry and Oral Surgery Service. Mean age was 37-months. Mean distance fallen was 2.65 stories, and in the majority of cases the substrate the cat fell on was not recorded. Overall, survival was 94.0 % when including euthanasia as a cause of death and 98.8 % when excluding euthanized patients. Orofacial findings included bilateral epistaxis, hard palate fracture +/− tear of palatal soft tissue, palatal soft tissue bruising, mandibular fracture, mandibular symphyseal separation, tongue injury, facial soft tissue injury, dental trauma, and other oral soft tissue injury. Sixty-six percent of cats suffered some degree of orofacial injury. The population was analyzed for the prevalence of each type of injury. An oronasal fistula was seen in one cat as a complication of an untreated hard palate fracture. Possible etiology of the injuries and treatment options are discussed.

Management of generalized gingival enlargement in a dog--case report and literature review.

The present report describes treatment of a dog with generalized gingival enlargement and serves as a review of etiology and treatment options for this condition. The combined use of scalpel blade, electrosurgical equipment, and a 12-fluted bur on a high-speed handpiece with water irrigation allowed for accurate excision of excess gingival tissue and contouring of remaining gingiva. Surgery coupled with professional dental cleaning periodontal therapy can decrease the recurrence of this condition. In addition, home oral hygiene is an important component of the treatment plan. The history of patients with gingival enlargement should be reviewed carefully, including drug history and previous medical conditions, in an attempt to elucidate a specific cause and thus allow for greater long-term success.

Results of surgical excision and evaluation of factors associated with survival time in dogs with lingual neoplasia: 97 cases (1995-2008)

OBJECTIVE To describe the clinical characteristics, treatments, outcomes, and factors associated with survival time in a cohort of dogs with lingual neoplasia that underwent surgical excision. DESIGN Retrospective case series. Animals-97 client-owned dogs. PROCEDURES Medical records of dogs with a lingual tumor examined between 1995 and 2008 were reviewed. Records were included if a lingual tumor was confirmed by histologic examination and surgical excision of the mass was attempted. Data were recorded and analyzed to identify prognostic factors. RESULTS Clinical signs were mostly related to the oral cavity. For 93 dogs, marginal excision, subtotal glossectomy, and near-total glossectomy were performed in 35 (38%), 55 (59%), and 3 (3%), respectively. Surgery-related complications were rare, but 27 (28%) dogs had tumor recurrence. The most common histopathologic diagnoses for the 97 dogs were squamous cell carcinoma (31 [32%]) and malignant melanoma (29 [30%]). Eighteen (19%) dogs developed metastatic disease, and the overall median survival time was 483 days. Median survival time was 216 days for dogs with squamous cell carcinoma and 241 days for dogs with malignant melanoma. Dogs with lingual tumors ≥ 2 cm in diameter at diagnosis had a significantly shorter survival time than did dogs with tumors < 2 cm. CONCLUSIONS AND CLINICAL RELEVANCE Similar to previous studies, results indicated that lingual tumors are most commonly malignant, and squamous cell carcinoma and malignant melanoma predominate. A thorough physical examination to identify lingual tumors at an early stage and surgical treatment after tumor identification are recommended because tumor size significantly affected survival time.