The role of computed tomography in the assessment of dental disease in 66 guinea pigs

Computed Tomographic Findings of Dental Disease and Secondary Diseases of the Head Area in Client-Owned Domestic Rabbits (Oryctolagus cuniculus): 90 Cases

Domestic rabbits have teeth that grow throughout the animal's life and are prone to disease. Clinical signs of dental disease in domestic rabbits are non-specific, and, therefore, a definitive diagnosis usually requires additional methods. This study was carried out on a group of 105 domestic rabbits aged 3 to 9 years. In total, 90 domestic rabbits with dental disease visible on CT images and other secondary diseases of the head area qualified for this study. Malocclusion was found in 57 (63.3%). Retrograde elongation of the tooth apices in the mandible was present in 39 (43.3%), and it was present in the maxilla in 48 (53%). Clinical tooth crowns were overgrown in 39 (43%). Dental abscesses were present in 54 (63%). Secondary to the presence of a dental abscess, osteomyelitis was found in 43 (79% of the animals with a dental abscess). Dental inflammatory resorption was found in 36 (40%). Secondary to dental disease, nasal cavity inflammation was found in 18 (20%). Otitis media was present in six (6.7%). The most common dental disease found in this study's animals was malocclusion secondary to abnormal clinical crown abrasion and abnormal tooth growth. In domestic rabbits, osteomyelitis is a common complication of dental abscesses. Computed tomography is an invaluable diagnostic method in the diagnosis of dental disease and secondary diseases of the head area, such as inflammation of the nasal cavities or otitis media, in pet rabbits.

Computed Tomographic Findings Secondary to Dental Pathologies: Comparison between Rabbits and Guinea Pigs

(1) Background: dental pathologies are the most frequent reason for requesting a CT scan of the head in rabbits and guinea pigs. The study aimed to review head CT exams of both species to identify and characterize lesions secondary to dental disease. (2) Methods: head CT studies of 48 rabbits and 52 guinea pigs with dental pathologies were reviewed. (3) Results: dental abnormalities of mandibular teeth were the most represented, both in rabbits (81.2%) and guinea pigs (98%). The aggressive bone lesion associated with teeth was the more frequently observed bone lesion in rabbits' mandible and maxilla; in guinea pigs, the more frequent bone lesions were bulging around the roots of the teeth with focal lysis in the maxilla, and without focal lysis in the mandible. In the maxilla, the increased attenuation of nasal cavities (rhinitis) was the most frequently observed abnormality both in rabbits (60%) and guinea pigs (83.3%); the exophthalmos was more represented in rabbits (53.3%). In the mandible, the cavernous space-occupying lesion was more represented both in rabbits (92.3%) and guinea pigs (73.3%). (4) Conclusions: lesions secondary to dental pathologies were often observed both in rabbits and guinea pigs; CT examination has proven to be valuable in detecting secondary alterations in both species.

Incidental Findings in Computed Tomography Examination of the Head in Rabbits and Guinea Pigs

(1) Background: Rabbits and guinea pigs are popular pet animals and often undergo computed tomography (CT) examination for assessment of pathologies of the head. The goal of the study was to review CT examinations of the heads of rabbits and guinea pigs to identify and classify incidental findings. (2) Methods: 60 CT studies of the heads of rabbits and 65 of guinea pigs presented at 2 Institutions were reviewed and the indications for the study recorded. (3) Results: The presence of CT findings not directly related to the reason for the CT examination was present in 40/60 (66.7%) studies of rabbits and in 42/65 (64.4%) studies of guinea pigs. Most commonly, the incidental findings involved the ears, in 24/60 studies in rabbits and in 29/65 studies in guinea pigs. Incidental findings involved the nasal cavities, respectively, in 9 and 7 rabbits and guinea pigs. Soft tissue mineralization was present in 11 rabbits and 17 guinea pigs. (4) Conclusions: Based on the present study, incidental findings detected on CT studies are often present in rabbits and guinea pigs. Veterinarians should be aware of the possible clinical impact of these findings.

Histological characteristics of macrodontic cheek teeth of guinea pigs

Macrodontia is the enlargement of tooth dimensions of different ethologies. This work aims to show a histological evaluation of macrodontic teeth in guinea pigs. The material was obtained from animals postmortem. Ninety structural changes derived from 24 guinea pigs were evaluated. All teeth used in the study showed macrodontic changes. The samples were decalcified, dehydrated and embedded in paraffin. Material was cut in the transverse and longitudinal planes in relation to the alveolar bone. Histological evaluation included apical bud cells, pulp cavity cells, periodontium, dentin, enamel, cementum and alveolar bone tissue. Individual elements were evaluated with respect to their morphology and distribution. Moreover, the arrangement of the individual hard tooth structures was assessed on the teeth. No atypia was found among the cells that make up the apical bud, pulp or periodontal cavity. Displacement of periodontal cells or odontoblasts towards the pulp cavity as well as disorganization of the cell system in the pulp cavity were observed. Changes in the dentine ligaments and the reconstruction of the alveolar bone were also observed in areas where dentine and cement systems were affected. Dental slides were observed and showed that the enamel is also involved in structural remodelling of the pulp cavity. The histological assessment revealed that structural changes in macrodontic teeth involve the rearrangement of typical tooth tissues.

Management of Dental Disease in Aardvarks (Orycteropus afer) and Potential Use of Cone-Beam Computed Tomography

Oral disease involving teeth is a common cause of morbidity in aardvarks (Orycteropus afer) under managed care. Cases can be challenging due to the species’ unique skull and dental anatomy and limited veterinary literature. A retrospective evaluation was performed on dental examinations in nine aardvarks housed at a single zoological institution in the United States between 1995 and 2021. The prevalence of dental disease in this population was 88%, with most cases categorized as mild (4/8). Clinical signs were only seen in three cases. Facial swelling prior to surgery was the most common clinical sign (3/8). Dental pathology was more common in the mandibular teeth (27/38) compared to the maxillary teeth (11/38). Dental abnormalities found upon intraoral examination included the presence of dental points (7/8), crown elongation (3/8), purulent material within the oral cavity (4/8), loose teeth (2/8), periodontal pockets (2/8), and oronasal fistula (1/8). Three patients required dental extractions with a lateral buccostomy approach. Diagnostic imaging was performed in most cases (7/8), with two cases undergoing cone-beam computed tomography (CBCT) to characterize dental pathology that was difficult to fully evaluate with standard radiography. Tomographic findings are described in both cases. CBCT was found to be a helpful tool for diagnosing and characterizing dental disease in aardvarks.

Correlation between computed tomography, magnetic resonance imaging and cross-sectional anatomy of the head of the guinea pig (Cavia porcellus, Linnaeus 1758)

The current work aimed to study the anatomical features of the guinea pig's head by two medical imaging techniques: computed tomography (CT) and magnetic resonance imaging (MRI), and their correlation with the anatomical cross-sectional images. Six adult healthy guinea pigs were used in the present study. Two heads were imaged by CT scanner and then by MRI. The examined heads were cut sagittally and transversely, and two skulls were macerated. The anatomical features were identified on the anatomical sections and compared with the tomographic and MRI images obtained. Data were presented as three-dimensional reconstructed images of the head. In addition, representative combinations of the sagittal and transverse anatomical sections and the corresponding CT scans and MRI images were also presented. Reconstruction of CT images enabled the visualization of different bony structures and airways of the guinea pig head. In addition, skull bones were easily visualized on CT scans, while different parts of the brain were identified on MRI images. Air cavities could be identified by their different contrast on the CT scans and their low intensity on MRI images. The study showed that guinea pig had poorly developed paranasal sinus system represented by rostral and caudal maxillary sinuses. On the contrary, the guinea pig had two tympanic bullae: a small dorsal and a large ventral bulla. In conclusion, this study provides one of the first investigations that uses the multislice CT scans and MRI to study the guinea pig's head and their correlation with the corresponding anatomical sections.

[Extraction of diseased mandibular incisors in the guinea pig (Cavia porcellus) via ventral mandibular trepanation]

OBJECTIVE

This retrospective study describes the use of ventral mandibular trepanation for extraction of diseased mandibular incisors in guinea pigs and evaluates the clinical outcome.

MATERIAL AND METHODS

In 40 guinea pigs with abnormal feed intake, at least one mandibular incisor was extracted via ventral mandibular trepanation. The diagnosis of primary mandibular incisor disease was based on the findings of the clinical general examination and intraoral and radiographic examination under general anesthesia. Following the procedure radiographs were taken and the patients were monitored and cared for as inpatients until discharge. Regular re-examinations were undertaken in order to assess and treat the surgical sites.

RESULTS

A total of 42 altered mandibular incisors were extracted via ventral mandibular trepanation. Macrodonts (25/42) and periapical and alveolar changes (8/42) were the main reasons for extraction. Tooth residuals of unknown etiology (4/42) as well as such resulting from failed conventional extraction attempt using luxators (3/42) and traumatically loosened incisors (2/42) were also extracted. Tooth-associated jaw abscesses were found in 40 % of the guinea pigs. In addition, 40 % of the animals presented secondary elongation of the molars requiring occlusal equilibration. In all patients, it was possible to completely remove the altered incisors or residuals. On average, independent feed intake was observed 2 days after surgery and the animals were discharged. Complete healing of the surgical site was observed on average after 39 days (minimum 9 days, maximum 98 days). A total of 22 animals were evaluated 6 months following surgery and showed no further tooth-associated complaints.

CONCLUSION AND CLINICAL RELEVANCE

Ventral mandibular trepanation allows diseased mandibular incisors in guinea pigs to be removed entirely within one surgery and thus represents a curative procedure. Unlike the conventional extraction with luxators, it does not bear the risk of tooth fractures resulting in tooth fragments remaining in the alveolus.

Computed tomographic findings of dental disease in domestic rabbits (Oryctolagus cuniculus): 100 cases (2009-2017)

OBJECTIVE

To characterize the CT findings and epidemiological features of acquired dental disease in rabbits.

ANIMALS

100 client-owned rabbits (Oryctolagus cuniculus).

PROCEDURES

Medical records were searched to identify rabbits that underwent skull CT for any reason from 2009 to 2017. History, signalment, and physical examination findings were recorded. The CT images were reevaluated retrospectively for evidence of dental disease and graded according to a previously described system (from 1 [no evidence of disease] to 5 [severe dental disease]) for acquired dental disease in rabbits, and an overall (mean) grade was assigned. Descriptive analyses were performed. Factors were assessed for associations between dental disease grade and malocclusion stage.

RESULTS

Common findings included premolar or molar tooth curvature in transverse (n = 100 rabbits) and sagittal (95) planes, apical elongation of premolar or molar teeth (99), sharp dental points (93), deformation of the mandibular canal (82), and periodontal ligament space widening (76). Acquired dental disease was classified as grade 1 (n = 2 rabbits), 2 (60), 3 (14), 4 (4), or 5 (20). Most CT findings were significantly correlated with each other. Agreement of grades was fair between left- and right-sided quadrants and between maxillary and mandibular quadrants. Age was associated with increasing dental disease grade and malocclusion stage (proportional ORs, 1.21 and 1.32/y, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE

Fair agreement in disease grades between dental quadrant pairs indicated a degree of asynchrony in the development of dental disease. Findings suggested premolar or molar tooth curvature in a sagittal plane, subtle elongation at premolar or molar tooth apices, and mandibular canal deformation should be added to the grading system.

Evidence-Based Advances in Rodent Medicine

The number of exotic companion pet rodents seen in veterinary practices is growing very rapidly. According to the American Veterinary Medical Association's surveys, more than 2,093,000 pet rodents were kept in US households in 2007 and in 2012 it was more than 2,349,000 animals. This article summarizes the most important evidence-based knowledge in exotic pet rodents (diagnostics of the hyperadrenocorticism in guinea pigs, pituitary tumors in rats, urolithiasis in guinea pigs, use of itopride as prokinetics, use of deslorelin acetate in rodents, cause of dental disease, and prevention of mammary gland tumors in rats).

An Investigation into the Relationship between Owner Knowledge, Diet, and Dental Disease in Guinea Pigs (Cavia porcellus)

Simple Summary

Dental disease is a serious problem in small mammals, with cases in rabbits well documented. Guinea pigs also suffer from this condition, yet the literature investigating the underlying causes in guinea pigs is limited. Owners of guinea pigs were surveyed to investigate what they fed their animals. It was discovered that there was no relationship between the overall diet of the animals and whether or not they had been diagnosed with dental disease or displayed clinical signs of the disease. However, the environment was important, with animals that had access to the outside, including the use of runs on both concrete and grass, less likely to display clinical signs of disease. Some of the clinical signs of dental disease in guinea pigs, including difficulty eating, were related to dental problems. These findings are important, as many guinea pigs may not have continuous access to the outdoors. Dental disease is a serious welfare concern, as many owners may not pick up on the clinical signs, leaving animals susceptible to pain, dysphagia, malnutrition, and secondary infection. It is important that owners are aware of key clinical signs, particularly in multi-animal households where monitoring food consumption may be challenging.

Abstract

Recent studies have highlighted a high prevalence of dental disease in domestic guinea pigs, yet the aetiology of this multi-factorial disease is still unclear. Factors that have been associated with dental disease include feeding a diet that is high in energy but low in fibre, feeding an insufficiently abrasive diet, a lack of dietary calcium, and genetics. As many of these factors relate to the husbandry requirements of guinea pigs, owner awareness of dietary requirements is of the utmost importance. An online questionnaire was created based on previous research into the husbandry and feeding of rabbits. Guinea pig owners were asked to answer questions on the clinical history of their animals and their diet and management. In total, 150 surveys were completed for 344 guinea pigs, where owners of multiple animals could complete the survey for individuals. According to the owners, 6.7% of guinea pigs had been clinically diagnosed with dental disease, but 16.6% had signs consistent with dental disease. The specific clinical signs of having difficulty eating (Exp(B) = 33.927, Nagelkerke R² = 0.301, p < 0.05) and producing fewer or smaller faecal droppings (Exp(B) = 13.733, Nagelkerke R² = 0.149, p < 0.05) were predictive for the presence of dental disease. Having access to an outside environment, including the use of runs on both concrete and grass, was significantly related to not displaying clinical signs of dental disease (Exp(B) = 1.894, Nagelkerke R² = 0.021, p < 0.05). There was no significant relationship between owner knowledge, guinea pig diet, and dental disease in the study population. This study highlights the importance of access to the outdoors for the health and welfare of guinea pigs in addition to the need for owners to be alert to key clinical signs. A relationship between diet and dental disease was not identified in this study; however, the underlying aetiological causes of this condition require further investigation.

Extraction of an incisor embedded within the nasal cavity in two guinea pigs

Oral examination of two guinea pigs revealed that the unilateral incisor was absent. On radiographic examination, the incisor was identified within the nasal cavity in both patients. Under anesthesia in both patients, the skin was incised from the nostril to 1.5 cm proximal, and the premaxilla and part of the maxilla were exposed. The bone was removed using a surgical drill, and the incisor was exposed in the nasal cavity. The root was grasped with forceps and carefully extracted as it was degraded and very fragile. Diagnosis was easy using oral and radiographic examination. In guinea pig patients where an incisor is absent on oral examination, this condition should be considered.