Success of Occlusal Aperture Access for Endodontic Therapy of Canine Teeth in Dogs.

The objective of this study was to determine the success of the natural crowns of endodontically treated canine teeth in pet dogs, instrumented and obturated using rotary driven non-taper nickel titanium files, through an occlusal access preparation, without the placement of a prosthetic cast metal crown. A search of medical records at a private veterinary dental referral practice was conducted to identify pet dogs having had endodontic treatment of one or more canine teeth over an eleven-year period (2007-2018). Follow up, performed by the same veterinary dental specialist, included a complete oral health assessment under general anesthesia and included intraoral radiography thereby allowing close visual examination of the crown and restoration as well as assessing endodontic success. Time to follow up was between two and nine years after treatment with a mean of 4.5 years. Analysis revealed that 29/29 (100%) of the treated crowns maintained their stability and did not require extraction. 5/29 (17.2%) of the treated teeth had an enamel fracture requiring additional treatment to the crown after the initial treatment; 1/29 (3.4%) had additional abrasion but did not require treatment and 23/29 (79.3%) were found to have sustained no additional damage. This study supports endodontic treatment without the placement of a prosthetic crown in canine teeth in pet dogs when an occlusal access site is used as described in this paper. Further study is required on the increased risk of fracture of the remaining unaltered canine teeth.

Radiographic Outcome of the Endodontic Treatment of 55 Fractured Canine Teeth in 43 Dogs (2013-2018).

Medical records from 4 private practice veterinary dentistry specialty clinics were reviewed for a 5-year period (2013-2018) to identify dogs that had a fractured canine tooth treated by root canal therapy and returned for subsequent follow-up evaluation. Evaluation criteria included the presence of complete medical records with diagnostic quality intraoral radiographs for each procedure visit with a minimum of 6 months between visits. Forty-three dogs with a total of 55 endodontically treated canine teeth were identified and evaluated. Root canal treatment outcome was defined as successful, no evidence of failure (NEF), or failure based on radiographic findings. Patient age, time from initial treatment to follow-up, obturation material used, radiographic quality of obturation (including voids, overfill, and retention of fractured endodontic files), radiographic evidence of periapical disease and/or presence of external inflammatory root resorption (EIRR), and the presence or absence of a full coverage metal crown were evaluated. Treatment was classified as successful in 51 (92.73%) teeth, NEF in 3 (5.45%) teeth, and failure in 1 (1.82%) tooth. The results suggest that endodontic treatment of fractured canine teeth in dogs is a successful treatment option that allows for retention of this functionally important tooth.

Tooth chipping prevalence and patterns in extant primates.

OBJECTIVES: A tooth chip occurs when a hard object forcefully contacts the surface of the tooth, typically removing enamel from the occlusal edge. In this study, chipping patterns in extant primates were compared, and hard-object-feeding assessed alongside other factors (e.g., grit mastication and dental properties), to elucidate dietary and behavioral inferences in archeological and paleontological samples. MATERIALS AND METHODS: Thirteen species of extant primates were studied, including eight species within the Cercopithecidae, two within the Ceboidea, and three within the Hominoidea. Four additional species were also incorporated from the literature for some of the analyses. The severity (Grade 1-3), position (buccal, lingual, mesial, and distal) and number of tooth fractures were recorded for each specimen. RESULTS: Species considered hard-object-feeding specialists presented higher rates of chipping, with sakis, mandrills, sooty mangabeys and Raffles' banded langurs having high chipping rates (28.3%, 36.7%, 48.4%, and 34.7% of teeth, respectively). Species that seasonally eat harder foods had intermediate chipping frequencies (e.g., brown woolly monkeys: 18.5%), and those that less commonly consume hard food items had the lowest chipping frequencies (e.g., Kloss gibbon: 7.3%; chimpanzees: 4.4%). DISCUSSION: The results suggest hard food mastication influences differences in chipping prevalence among the species studied. Although Homo fossil samples show high rates of chipping comparable to hard-object-feeding extant primates, they display a different pattern of chipping, supporting the hypothesis that these fractures are mostly non-food related (e.g., grit mastication in Homo naledi; non-masticatory tooth use in Neanderthals).

Anatomy of a dinosaur-Clarification of vertebrae in vertebrate anatomy.

The flat-end surfaces of dinosaur vertebral centra led to the presumption that intervertebral discs occupied the space between their vertebrae. A set of fused hadrosaur vertebrae allowed that hypothesis to be tested. The Tyrannosaurus rex responsible for this pathology did not escape unscathed. It left behind a tooth crown that had fractured. Fragments of that tooth were scattered through the intervertebral space, evidencing that there was no solid structure to impede its movement. That eliminates the possibility of an intervertebral disc and instead proves the presence of an articular space, similar to that in modern reptiles, but at variance to what is noted in birds. While avian cervical vertebral centra appear to be separated by diarthrodial joints, the preponderance of their thoracic vertebral centra is not separated by synovial joints.

Tooth fracture frequency in gray wolves reflects prey availability.

Exceptionally high rates of tooth fracture in large Pleistocene carnivorans imply intensified interspecific competition, given that tooth fracture rises with increased bone consumption, a behavior that likely occurs when prey are difficult to acquire. To assess the link between prey availability and dental attrition, we documented dental fracture rates over decades among three well-studied populations of extant gray wolves that differed in prey:predator ratio and levels of carcass utilization. When prey:predator ratios declined, kills were more fully consumed, and rates of tooth fracture more than doubled. This supports tooth fracture frequency as a relative measure of the difficulty of acquiring prey, and reveals a rapid response to diminished food levels in large carnivores despite risks of infection and reduced fitness due to dental injuries. More broadly, large carnivore tooth fracture frequency likely reflects energetic stress, an aspect of predator success that is challenging to quantify in wild populations.

Treatment of Canine Tooth Fractures in the Northern Elephant Seal ( Mirounga angustirostris): Three Cases.

The Marine Mammal Center (TMMC) in Sausalito, California, rescues, rehabilitates, and releases hundreds of stranded northern elephant seals ( Mirounga angustirostris) each year. Common causes for stranding include maternal separation, malnutrition, and trauma. Causes of trauma include shark bites, conspecific interactions, and anthropogenic factors. Several cases of fractured teeth, secondary to presumed trauma, are presented to the center each year. This case series describes surgical approach and treatment of 3 young northern elephant seals that were admitted to TMMC for rehabilitation with tooth fractures with pulp exposure of maxillary or mandibular canine teeth. All 3 seals were successfully released into their natural environment.

Dental Pathology of the Iberian Lynx ( Lynx pardinus), Part I: Congenital, Developmental, and Traumatic Abnormalities.

The Iberian lynx is an endangered felid that has been subject to an intensive ongoing conservation program in an attempt to save it from extinction. Identification of dental pathologies could play an important role in the survival of this endangered species. The objective of this study is to evaluate the dental pathologies (congenital, developmental, and traumatic abnormalities) of this species of felid. Skulls of 88 adult specimens of the Iberian lynx ( Lynx pardinus) from the Doñana Biological Station [Estación Biológica de Doñana-Consejo Superior de Investigaciones Científicas] (EBD-CSIC), Seville, Spain, were examined macroscopically, and full-mouth dental radiographs of all specimens were performed. Presence, absence, form of teeth, number of roots, supernumerary teeth, and persistent deciduous teeth were evaluated. The presence of attrition/abrasion, tooth fractures, enamel hypoplasia/hypomineralization, endodontic disease, intrinsically stained teeth, and other traumatic findings were also evaluated. Abnormal grooves and dilacerations were the most common abnormalities seen in the roots of teeth. Two hundred and fifteen fractured teeth (11.3% of evaluated teeth) were detected, and mainly complicated fractures were noted in maxillary canine teeth (24.2% of fractured teeth) and mandibular canine teeth (16.7% of fractured teeth). Endodontic disease was present in 3.9% of the teeth examined. Intrinsic tooth staining was assessed in 8.5% of evaluated teeth. Of all teeth examined, 831 teeth (43.7% of evaluated teeth) exhibited some type of attrition/abrasion. Our study concluded that there is a high prevalence of dental fractures and attrition/abrasion with associated endodontic disease that could lead to impaired hunting ability as well as a threat to overall health and subsequent survival of this endangered species.

Successful Treatment of a Persistent Oroantral Fistula via Transbuccal and Transnasal Endoscopic Debridement in a Horse.

We report an unusual case of a young Quarter Horse with a large dental fracture fragment displaced into the maxillary sinus, leaving an oroantral communication that caused food impaction and metaplastic calcification in the sinus and facial deformation with cutaneous fistulation. Oral extraction of a remaining tooth fragment from its alveolus was succeeded by a maxillary sinusotomy for removal of the abnormal sinus contents. Since the oroantral fistula did not heal spontaneously following the placement of a silicone dental prosthesis, minimally invasive transbuccal and transnasal endoscopic approaches were used to encourage closure of the oroantral fistula by alveolar granulation. The clinical, diagnostic, and therapeutic features of this case may be helpful to clinicians when dealing with similar cases.

Radiographic outcome of root canal treatment of canine teeth in cats: 32 cases (1998-2016).

OBJECTIVE To describe the radiographic outcome of root canal treatment (RCT) of canine teeth of cats. DESIGN Retrospective case series. ANIMALS 32 cats with 37 canine teeth with complicated crown fractures that underwent RCT. PROCEDURES Medical record databases of 5 referral veterinary hospitals were searched to identify cats that underwent RCT between 1998 and 2016. Only cats that had at least 1 follow-up examination during which radiographs were obtained of the treated canine tooth or teeth were included in the study. Dental radiographs obtained before and immediately after RCT and during all follow-up examinations were reviewed. Treatment was considered successful if the periodontal ligament space was within reference limits and preoperative external inflammatory root resorption (EIRR), if present, had stabilized. Treatment was considered to have no evidence of failure if preoperative EIRR had stabilized and preexisting periapical lucency was stable or decreased in size but had not resolved. Treatment was considered to have failed if periapical lucency or EIRR developed subsequent to RCT or preexisting periapical lucency increased in size or preoperative EIRR progressed following RCT. RESULTS Follow-up time after RCT ranged from 3 to 72 months. The RCT was successful for 18 (49%) of the 37 treated teeth, had no evidence of failure for 12 (32%), and failed for 7 (19%). Preexisting EIRR and patient age ≥ 5 years significantly increased the rate of RCT failure. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that RCT was a viable treatment option to salvage endodontically diseased canine teeth in cats.

USE OF COMPOSITE MATERIALS AS A COMPONENT OF TUSK FRACTURE MANAGEMENT IN AN ASIAN ELEPHANT (ELEPHAS MAXIMUS) AND AN AFRICAN ELEPHANT (LOXODONTA AFRICANA).

Tusk fractures in Asian (Elephas maximus) and African elephants (Loxodonta africana) can result in damage to the distal end or to longitudinal cracks, potentially progressing to pulpitis. With pulp exposure, endodontic therapy is the treatment of choice, but conservative therapy has sufficed for some elephants. This manuscript describes the use of composite materials as a component of tusk fracture management. A 7-yr-old male Asian elephant fractured the distal end of both tusks with pulp exposure in one. Capping of each tusk with a Kevlar/fiberglass composite prevented further damage, and a modification allowed care of the exposed pulp tissue. A 34-yr-old male African elephant with a longitudinal crack received a carbon fiber/fiberglass composite circumferential wrap to potentially stabilize the crack. Compression of the crack was achieved, but follow-up was truncated due to bacterial pulpitis. Both cases show that composite material allows for lightweight, durable management of tusk fractures with continued radiographic monitoring.

Diagnoses and Treatment of Dental Disorders in a Research Colony of Macaca fascicularis: A Case Series.

During daily routine oral examinations in a research colony of nonhuman primates (NHPs, Macaca fascicularis), a variety of oral-dental lesions were identified. A dental care program was established based on these findings. Based on the presence of dental clinical signs and their severity, 31 animals were triaged to be examined and treated by a veterinarian. Clinical examination consisted of visual inspection using a periodontal probe/explorer and full or partial mouth dental radiographs. Treatment was performed during the same procedure. Some animals had a follow-up examination including radiographs months later. Four common dental diseases were diagnosed: periodontal disease, caries, tooth fracture, and tooth attrition. Less frequent were dental abscess, enamel hypomineralization, gingival hyperplasia, hypercementosis, tooth luxation, tooth dysplasia, root resorption, abrasion. Less severe periodontal disease was treated conservatively. If severely affected, teeth were extracted. Well-circumscribed caries without endodontic involvement were treated by composite restoration. Teeth with extensive caries and pulp involvement were extracted. Teeth with exposed pulp were treated via extraction or orthograde root canal treatment. In this case series, 27 (87%) of 31 NHPs exhibited at least 1 moderate to severe dental lesion that required treatment. The presumable improvement in welfare and weight of oral/dental lesions for the overall health status in research NHPs encourages us to continue this program prospectively.

The Influence of Force Direction on the Fracture Pattern and Fracture Resistance of Canine Teeth in Dogs.

Biomechanical studies of the elongated canine tooth of animals are few, and thus our understanding of mechanical and physical properties of animal teeth is limited. The objective of the present study was to evaluate the influence of force direction on fracture resistance and fracture pattern of canine teeth in an ex vivo dog cadaver model. Forty-five extracted canine teeth from laboratory beagle dogs were standardized by hard tissue volume and randomly distributed among 3 force direction groups. The teeth were secured within a universal testing machine and a load was applied at different directions based on testing group. The maximum force to fracture and the fracture pattern classification were recorded for each tooth. After correcting for hard tissue cross-sectional area in a multivariate analysis, no significant difference in the amount of force required for fracture was apparent between the different force direction groups. However, the influence of force direction on fracture pattern was significant. The results of this study may allow the clinician to educate clients on possible causal force directions in clinically fractured teeth and, thus, help prevent any contributing behavior in the future.

Dental disorders in brown howler monkeys (Alouatta guariba clamitans) maintained in captivity.

BACKGROUND: The aim of this study was to investigate dental disorders of brown howler monkeys maintained in captivity. The hypothesis is that the identification and diagnosis of the lesions may contribute to control and prevention. METHODS: Sixteen intact brown howler monkeys (Alouatta guariba clamitans), eight females and eight males, weighing from 3.9 to 6.8 kg, were studied. Under general anesthesia, the teeth were evaluated by visual inspection, probing, palpation, and intra-oral radiographic exam. The findings were registered on a dental chart specific for primates. RESULT: Of the 16 monkeys evaluated in the present study, 94% (n = 15) had some type of dental disorder. The lesions observed were dental calculus (88%), dental wear (81%), missing teeth (38%), gingivitis (19%), gingival recession (6%), dental fracture (19%), pulp exposure (19%), and dental staining (25%). CONCLUSIONS: Alouatta guariba clamitans maintained in captivity have a high rate of dental problems.

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.

The Influence of Crown Height to Diameter Ratio on the Force to Fracture of Canine Teeth in Dogs.

Previous work suggests that the tooth height to diameter ratio (H/D) may have an influence on the fracture resistance of dog canine teeth. Thus, it can be hypothesized that canine teeth with distal abrasion or teeth already requiring pulpal manipulation may benefit from a reduction in height and that an ideal H/D exists that balances tooth fracture resistance and tooth function. Therefore, a study was performed to investigate the influence of H/D on force to fracture and probability of fracture of canine teeth in dogs. Thirty extracted canine teeth from laboratory Beagle dogs were standardized by hard tissue volume and evenly distributed among three groups; unaltered H/D (group A), 10% reduction in H/D (group B), and 20% reduction in H/D (group C). The teeth were potted in clear autopolymerizing orthodontic acrylic and then secured within a universal materials testing machine. A displacement was applied at a speed of 1-mm/min to the distoocclusal line angle at an angle of 45 degrees to the long axis of the crown. The maximum measured force at the time of fracture represented the maximum force to fracture. A linear regression model showed a significant inverse relationship between H/D and force to fracture (p = 0.043; 95% CI-55.2 to -0.09). A margin of safety (MoS) analysis was performed to determine the probability of fracture by comparing normal force distributions of the measured force at fracture to that reported in a previous study, representative of normal biting-pulling loads on canine teeth. When 100% of the load was applied to a single unaltered canine tooth the probability of fracture was 36.7%. Decreases in H/D of 10% and 20% resulted in a decreased probability of fracture by 24.1% and 60.4%, respectively. A paired MoS analysis was conducted wherein the applied loads were distributed across 2 maxillary canine teeth according to their relative heights. Within the pair, a 20% decrease in H/D decreased the probability of fracture of that tooth by 86.5%, but increased the probability of fracture of the unaltered contralateral canine tooth by 54.4%. The findings of this study support the hypothesis that teeth with a lower H/D are more resistant to fracture. However, given the potential impact of crown reduction of a single canine tooth on the load redistribution to the remaining unaltered canine teeth, further investigation is needed to determine what H/D would be ideal. In addition, future studies could elucidate in which clinical scenarios the concept of H/D reduction could be implemented. The results of this study may have implications on the successful long-term management of traumatized canine teeth in dogs.

Classification and Epidemiology of Traumatic Dentoalveolar Injuries in Dogs and Cats: 959 Injuries in 660 Patient Visits (2004-2012).

The objective of this study was to determine the epidemiology of traumatic dentoalveolar injuries (TDI) in dogs and cats and to evaluate the applicability of a human classification system for TDI in dogs and cats. All patients diagnosed with a TDI were identified from the University of Wisconsin-Madison School of Veterinary Medicine Dentistry and Oral Surgery Service case log and the hospital patient processing software. The study population consisted of 621 dogs and cats, in a total of 660 patient visits from 2004 to 2012, admitted for oral treatment and subsequently diagnosed with at least one TDI Medical records including diagnostic imaging studies were reviewed to group the injury according to a classification system used in humans for TDI. Patient signalment, tooth injured, and number of injuries per patient were recorded and tabulated. The overall prevalence of TDI was 26.2%. The mean +/- SD number of TDI per patient was 1.45 +/- 0.85. All 14 classes of TDI recognized by the classification system utilized in humans were identified, and all (100%) TDI identified in this study were classifiable using this system. Enamel-dentin-pulp fracture was the most common TDI (49.6%). The most commonly injured teeth were the mandibular or maxillary canine teeth (35.5%). The most common age for dogs and cats with TDI were 3-6 years (33.0%) and 7-10 years (31.3%). With a frequency of 1 in 4 animals, TDI are common and represent a significant pet health concern. Most TDI are considered severe and require timely, and sometimes immediate, treatment. The adoption and utilization of a complete classification system, such as the one used in this study, is recommended in order to improve future epidemiological study of TDI in animals.

Consequences of crown shortening canine teeth in Greenland sled dogs.

OBJECTIVES: To evaluate the consequences of crown shortening, focusing on the prevalence of pulp exposure and periapical pathology in Greenland sled dogs that had had their canine crowns shortened at an early age. METHODS: Five cadaver heads and 54 sled dogs underwent an oral examination for dental fractures and pulp exposure of canines. All canines were radiographed and evaluated for periapical pathology. RESULTS: The prevalence of canine pulp exposure in 12 (5 heads and 7 dogs) crown shortened dogs was 91 · 7%, and 21 · 3% in 47 not-crown shortened dogs. A significant (P < 0 · 001) risk of pulp exposure of the canines in the crown shortened group compared to the not-crown shortened group was seen with a relative risk of 4 · 3 on a dog basis and a relative risk of 12 · 2 on a tooth basis. In dogs with pulp exposure of canines (n = 51) the prevalence of periapical pathology was 82 · 4%, but only 0 · 8% in dogs without pulp exposure (n = 133) resulting in a significant (relative risk, 109 · 5; P < 0 · 001) risk of periapical pathology in teeth with pulp exposure compared to teeth without pulp exposure. CLINICAL SIGNIFICANCE: The high risk of periapical pathology observed in teeth with pulp exposure confirms that these teeth should not be neglected in affected dogs.