Impact of pelleted diets with different mineral compositions on the crown size of mandibular cheek teeth and mandibular relative density in degus (Octodon degus)

The impact of pelleted diets with different mineral compositions on the crown size of the mandibular cheek teeth, as well as the mandibular bone and cheek teeth density, in degus (Octodon degus) was investigated. A total of 28 animals were randomly divided into four groups and fed different calcium or phosphorous dietary content, in the presence or absence of UV light, for 14 months. Dental radiographs and CT images of the head were taken, and the crown size of premolar and molar teeth was recorded. Apical and coronal crown elongation of all cheek teeth and significantly smaller relative cheek teeth and mandibular densities were recorded in degus fed a high-phosphorus diet with an improper calcium:phosphorus ratio. A diet with a calcium:phosphorus ratio of 1:1 was also responsible for the rapid development of dental disease with subsequent severe health impairment.     

Hematologic and serum protein reference values of the Octodon degus

Blood and serum from normal degus (Octodon degus) that ranged in age from 3 to 48 months were analyzed to determine reference hematologic and serum protein values. Both sexes were evaluated and were similar. The hematologic and serum protein values for males were: erythrocytes, 8.69 +/- 0.19 X 10(6) /microliter; packed cell volume, 42.1% +/- 0.59%; hemoglobin, 12.0 +/- 0.15 g/dl; leukocytes, 8.50 +/- 0.39 X 10(3)/microliter; neutrophil-to-lymphocyte ration, 40:60; and total protein, 5.70 +/- 0.20 g/dl. The hematologic and serum protein values for females were: erythrocytes, 8.94 +/- 0.16 X 10(6)/microliter; packed cell volume, 40.0% +/- 0.61%; hemoglobin, 11.7 +/- 0.17 g/dl; leukocytes, 8.20 +/- 0.36 X 10(3)/microliter; neutrophil-to-lymphocyte ratio, 40:60; and total protein, 5.62 +/- 0.18 g/dl. The hematologic and serum protein values for the degu were similar in some respects to values reported for guinea pigs and rats.     

Observations of the cheek tooth occlusal angle in the horse

The angle of occlusion was evaluated in 230 mandibular cheek teeth from 21 horses. There was no significant relationship between horse condition (sedated, anesthetized, dead) and measurement of mean cheek tooth occlusal angle. Cheek tooth occlusal angle was not significantly affected by the position of the tooth in the mandibular arcade or tooth age. The measurement of individual mandibular cheek tooth occlusal angles was predictive for occlusal angle of the entire mouth. Multiple variations of the incisor separation angle technique were predictive of cheek tooth molar occlusal angle for the measured arcade and the entire mouth but was significantly different contralaterally, suggesting that the single tooth method may be preferred. However, despite the limitations of the relatively simple incisor separation angle technique, it may provide the equine veterinary dentist a rapid method of assessing cheek tooth occlusal angle to ensure proper dental floating methods and outcomes.     

Mandible and mandibular first molar tooth measurements in dogs: relationship of radiographic height to body weight

Height measurements of the mandible and the mandibular first molar tooth were obtained from 234 dogs. Statistical analysis was performed to determine possible associations between these measurements and body weight, sex, age, and body condition. There was a statistically significant association between the mandible: mandibular first molar tooth height measurement ratio and body weight (p < 0.0001) in all body weight groups. Small dogs had proportionally larger mandibular first molar teeth relative to mandibular height compared with larger dogs. This relationship may contribute to an increased susceptibility in small dogs for periodontitis and subsequent tooth loss. There was no statistically significant association between the mandible: mandibular first molar tooth height measurement ratio and other parameters evaluated in this study.     

Oral fractures in dogs of Brazil--a retrospective study

A retrospective study was performed in 100 dogs with 121 mandibular and 21 maxillary fractures. Dog fight (43.0%) and automobile (12.0%) trauma were the most common etiologies for fracture. The cause of fracture was unknown in 23.0% of the cases, while pathologic fractures occurred in 13.0% of cases. Young dogs (< 1-year-old) and dogs > 8-years of age were most affected. Mandibular fractures occurred in 90 dogs (90.0%), with two dogs (2.2%) having concurrent maxillary fractures. Maxillary fractures only were diagnosed in 10 dogs (10.0%). The molar region (47.1%) was the most commonly affected location for mandibular fracture, followed by fractures of the symphysis and parasymphysis (30.6%), premolar region (17.4%), angular process (4.1%) and vertical ramus (0.8%). In fractures of the mandibular region, the mandibular first molar tooth was often (85.9%) involved while the canine teeth were involved in 67.5% of symphyseal and parasymphyseal fractures. The most common fracture of the maxilla was the maxillary bone (52.4%), followed by the incisive (33.3%), palatine (9.5%), and nasal (4.8%) bones.     

Mandibular canine tooth impaction in a young dog--treatment and subsequent eruption: a case report

Extraction of an embedded supranumerary incisor tooth and surgical exposure of the crown of an impacted left mandibular canine tooth were performed in a 5 month-old Doberman Pinscher dog. Six months following surgery, the canine tooth was fully erupted and in normal occlusion. A review of tooth eruption in the dog is provided.     

Selected haematological and plasma chemistry parameters in juvenile and adult degus (Octodon degus)

Thirty-five juvenile (mean age 6.3 weeks) and 35 adult (mean age 2.0 years) healthy degus (Octodon degus) were studied to investigate selected haematological and plasma biochemistry parameters. Animals were anaesthetised with isoflurane, and blood was withdrawn from the cranial vena cava. Erythrocyte, haematocrit and neutrophil counts (including the percentage of neutrophils) were significantly higher in the adult degus than in the juveniles. In contrast, the reticulocyte count, mean corpuscular volume, mean corpuscular haemoglobin, number of platelets and percentage of lymphocytes were significantly lower in the adult animals. Total protein and globulin levels were significantly higher in the adult degus. The albumin:globulin ratio and plasma levels of urea nitrogen, cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, potassium, total calcium and inorganic phosphorus were significantly lower in adults than in juveniles.     

Mandibular cheek tooth eruption and development in Hereford cross Friesian steers as a means of age determination

Summary

The development of the mandibular cheek teeth was examined, both visually and by radiograph, in a group of 76 Hereford cross Friesian steers, of which all but one were slaughtered at the same weight ‐ 464 kg (1020 lb).

The age of the youngest animal was 1 year 0.3 months whereas the slaughter ages of the others ranged from I year 3 months to I year 8 months. The first molar was fully erupted and crown and root formation complete in all but the youngest steer. In the other five cheek teeth there were one or more siginificant differences between the mean ages of tooth development stages as assessed by radiograph. Cattle of 1 year 3 months could not be absolutely distinguished from those of 1 year 8 months by intra‐oral second molar eruption. Examination of stages of development seen radiographically gave a maximum age range of 4 months before differentiation. In this study, development bf the first two molars was in advance of the three permanent premolars and in these latter teeth the second premolar was the most developed.     

Immunohistochemical identification of lymphatic vessels in the periodontium of equine cheek teeth

Immunohistochemical detection of lymphatic capillaries was performed in the periodontium of maxillary and mandibular cheek teeth from 6 horses (aged 3-23 years). Tissue sections of the periodontium were taken at 4 different horizontal levels along the long axis of the tooth. The specimens were processed for immunoreaction with anti-Prox1, in order to distinguish lymphatic endothelium from blood vascular endothelium. Lymphatic vessels were detected in all periodontal tissues except for the dental cementum. Lymphatic capillaries were most densely distributed in the gingiva compared to other tissues of the periodontium. Lymphatic capillaries were found most consistently in samples taken from the gingival and subgingival regions in all horses examined. Within these levels, the gingiva as well as the spongiosa of the maxillary and mandibular bone had the greatest incidence of lymphatic vessels. Considering the distinct distribution of the lymphatic capillaries in the periodontium of the maxillary and mandibular cheek teeth, two complementary lymphatic drainage pathways are proposed: (1) superficial lymph drainage via the gingiva, emptying into the mandibular lymph nodes; (2) deep lymph drainage via the mandibular and maxillary spongiosa, emptying into the mandibular and retropharyngeal lymph nodes, respectively.     

Branching patterns of the adrenal arteries in the degu (Octodon degus)

The degu has drawn increasing attention for use as an experimental animal in stress response studies due to its physiological features, such as diurnality and seasonal breeding, which differ from conventional laboratory rodents. Stress response is elicited by steroid hormones secreted by the adrenal gland, whose functions are controlled by pituitary hormones reaching through the adrenal arteries. However, knowledge of the arterial anatomy of the degu adrenal gland remains insufficient. To address this issue, we observed adrenal arteries in 20 male degus injected with red-colored latex. Adrenal arterial branching patterns were classified into Types 1–4, which respectively have 1 to 4 parent arteries that give rise to the adrenal arteries. Based on the combination of the parent arteries, Types 2 and 3 were categorized into subtypes a to c, while Type 4 was categorized into subtypes a and b. On the left side, Type 2 (45%) and Type 3 (45%) were predominant, whereas Type 1 (5%) and Type 4 (5%) were infrequent. On the right side, Type 2 (50%) and Type 3 (45%) were predominant, whereas Type 4 (5%) was infrequent. Type 1 was not present. There were 0 to 4 cranial, 1 to 4 middle and 1 to 4 caudal adrenal arteries, with the total number varying from 2 to 9. The present observation provides knowledge of comparative anatomical features of the degu adrenal arteries, which can serve as an anatomical basis for comparative endocrinological studies.     

Timing of apical closure of the maxillary canine and mandibular first molar teeth of cats

Stage of apical closure was determined by radiographing the jaws of 15 cats at intervals from 5-11 months of age. The apices of the left mandibular first molar tooth were closed in all 15 cats by seven months of age and the apices of the left maxillary canine teeth were all closed by 11 months of age. The implications of the age of closure on endodontic pathology and treatment are discussed.     

Mapping of the radiographic central point of feline dental resorptive lesions

Intraoral dental radiographs of 217 cats presented for dental treatment were examined. Radiographic signs of dental resorptive lesions were identified in 107 cats, and the apparent central point of each lesion was mapped on a diagram of the tooth. Mapping was only possible on maxillary and mandibular canine teeth and on mandibular third premolar, fourth premolar, and first molar teeth. Resorptive lesions were most common on the molar teeth (n = 103) and maxillary canine teeth (n = 96), and least common on fourth premolar teeth (n = 56). Resorptive lesions on premolar and molar teeth were widely scattered, noted more commonly in the coronal portions of the root. Resorptive lesions in canine teeth had a tendency to be located more apically on the roots.     

Evaluation of a laryngoscope and a rigid endoscope for the examination of the oral cavity of small mammals

The oral cavities of 65 rabbits, 35 chinchillas, 38 guinea pigs, 19 degus and 13 prairie dogs suffering from a lack of appetite, hypersalivation, moist dermatitis, swelling of the lower jaw or mild exophthalmos were examined with a paediatric laryngoscope and rigid endoscope. The laryngoscope was safe and satisfactory for a preliminary examination, but changes in the less accessible caudal parts of the cavity could not be identified precisely. A rigid endoscope with 30 degrees optics made it possible to examine all parts of the oral cavity and oropharynx, and make detailed observations of surface lesions on the premolar and molar teeth and the mucosal surface of the gingiva, tongue and hard palate; endoscopy with 70 degrees optics provided an excellent view of the occlusal tooth surfaces, tooth crowns, and buccal mucosa. The collection of biopsy samples, the removal of foreign objects and the correction of malocclusions were greatly simplified by the use of the endoscope owing to the clear visualisation of the procedures, and the risk of injury was minimised. The examinations with a laryngoscope were made effectively on animals that were manually restrained, but a thorough examination with a rigid endoscope required the animals to be anaesthetised.     

Repulsion of maxillary and mandibular cheek teeth in standing horses

Objective: To report the technique and results of cheek teeth repulsion in standing, sedated horses. Study Design: Case series. Animals: Horses (n=12), ponies (6). Methods: Medical records (2006–2009) of horses that had cheek tooth repulsion while standing were reviewed. Inclusion criteria included: maxillary or mandibular cheek tooth disease diagnosed by clinical and radiographic examination where attempted oral extraction failed necessitating repulsion. Horses were sedated and a local nerve block performed. Intraoperative radiographs facilitated instrument positioning and ensured repulsion of all dental remnants. Alveolar cavities were packed postoperatively and secondary dental sinusitis treated with lavage. Results: Median horse age was 7 years (range, 1–30 years). Maxillary (n=15) and mandibular (5) cheek teeth were removed successfully. One horse was euthanatized 1 week after tooth removal because of concurrent liver disease and 10 horses (59%) had resolution of discharge after the 1st treatment; 41% of extractions required follow‐up medical or surgical treatment to resolve signs [6/12 maxillary sinusitis and 1/5 persistent mandibular drainage]. Conclusions: Standing repulsion of diseased and fractured cheek teeth is an effective means of resolving clinical signs of dental disease when oral extraction fails. Chronic sinus involvement increased the risk of postextraction surgical treatment for sinusitis.     

The pathogenesis of excessive wear in the permanent teeth of sheep

The two central pairs of permanent incisor teeth (l1P, I2P) were compared post mortem in sheep from two flocks, one of which showed excessive wear. Sheep were usually killed in groups of six. Excessive wear occurred during the winter and spring after the eruption of l1P. When l1P erupted at an early age it was also subject to that season;s wear but when it erupted at a later age, it was subject to less wear according to the amount of time it was in apposition with the dental pad during the high wear season. A small amount of compensatory growth at the root of the tooth occurred in some sheep when cementum was deposited on the apex. Apparent eruption of the crown of the tooth was actually due to gum recession. Normal reparative dentine was laid down in the pulp cavity of the crown of the tooth in anticipation of wear, but where wear was excessive unstructured dentine was deposited. In two cases the rate of wear was so great that the reparative dentine could not keep up and infection was able to gain access to the pulp cavity. There was no evidence of difference in the rate of wear of the molar teeth between the two flocks.     

Anterior crossbite correction in a dog using a lingual bar, a labial bow, lingual buttons, and elastic threads.

Anterior crossbite occurs as a result of several conditions. These conditions include retained deciduous teeth, over-crowding, trauma to developing permanent tooth buds, and trauma to erupted teeth. Treatment includes the use of orthodontic appliances and materials to correct the occlusal relationship. This case illustrates the use of a maxillary labial bow, a mandibular lingual bar and lingual buttons to correct an anterior crossbite in a dog.     

Hemisection and partial retention of carnassial teeth in client-owned dogs

Nine client-owned dogs presented with periodontally and/or endodontically involved mandibular or maxillary carnassial teeth that were either individually affected or adjacent to a jaw fracture. A total of 10 teeth were hemisected (8 mandibular first molar teeth and 2 maxillary fourth premolar teeth), and one crown-root segment was extracted for each tooth. Gingival tissues were approximated and sutured over the extraction sites, and the retained tooth portions were treated by means of standard root canal therapy or vital pulp therapy followed by standard root canal therapy. Retained crown-root segments of 2 of the 10 hemisected teeth were extracted following short- and long-term postoperative examinations due to continued periodontal complications. It was concluded that resection of a portion of a tooth can be a useful treatment for periodontally and/or endodontically involved carnassial teeth that are affected individually or located adjacent to a jaw fracture in dogs.     

Variability in the eruption of the permanent incisor teeth in sheep

The incisor teeth of 176 sheep of six breeds were inspected every two to three months for a year to record the shedding of the deciduous teeth and the eruption of the permanent teeth. In all the breeds the permanent central incisors erupted at between 12 and 18 months of age. In 96 per cent of the sheep the permanent middle incisors erupted at between 18 and 26 months; and in 92 per cent the permanent lateral incisors erupted at between 24 and 36 months of age. The permanent corner teeth erupted at between 32 and 44 months in 96 per cent of the sheep. The gingival redness and swelling accompanying the eruption of a permanent tooth disappeared within two months. In 14 cases two pairs of incisors erupted during the year, in 18 cases the incisors erupted asymmetrically, and in 22 cases no incisors erupted. Rotation of one incisor was observed in five sheep and was combined with dental deviation in one.     

Gingival thickness in dogs: association with age, gender, and dental arch location

Reduced gingival thickness is one of many factors that might predispose humans to periodontal disease and subsequent gingival recession. Gingival thickness differs between individuals, and is associated with age, gender, and location on the dental arch. Different gingival phenotypes exist in the human population according to the thickness of gingiva. Similar information on gingival phenotypes in dogs is unknown. The aim of this study was to investigate the thickness of the gingiva in dogs and its relation to age, gender and location on the dental arch. For this study, 48 dogs of comparable size (40-cm at withers) were divided into three groups according to their age as follows: < 2-years of age; 2 to 8-years of age; > 8-years of age. Gingival thickness was measured in both the mandible and maxilla using a transgingival probing technique. The graded probe was inserted midway into the attached gingiva at the level of each tooth class region. Young and middle aged dogs had significantly thicker gingiva (1.67 +/- 0.17 mm and 1.68 +/- 0.18 mm, respectively) compared with older dogs (1.54 +/- 0.16 mm). There was no significant difference in gingival thickness based on location or gender Generally, the gingiva was thicker at the level of large teeth such as canine and carnassial teeth. Regions of thinner gingiva at the level of incisor and premolar teeth correlated with the regions of highest prevalence of periodontal disease found in previous studies.