Comparison of age determination techniques for known-age Cape fur seals

Known-age teeth were used to validate age determination techniques for the Cape fur seal (Arctocephalus pusillus pusillus). Thin sectioning and staining of decalcified teeth produced the poorest age estimates. For etched half canines, only upper canines could be used to estimate age with good results, and coating improved the accuracy. Scanning electron microscopy produced poor accuracy in age estimation. External ridges reflected age accurately only in younger age classes and should only be used to verify counts of internal growth layer groups, or when rapid, preliminary estimates of age are necessary. This study has highlighted the importance of comparing different age determination techniques and validating such techniques with known-age animals. The reliability with which age can be estimated for the Cape fur seal has also been improved.     

Scanning electron microscopic study of the dentinal tubules in dog canine teeth

Dentin adhesive restorative techniques are regularly used in veterinary dentistry. Knowledge of the microanatomic structure and properties of dentin is essential to ensure success in restorative procedures. The aim of this study was to describe the density and diameter of dentinal tubules in dog canine teeth using recently described standardized scanning electron microscopy techniques. The results showed dentin of dog canine teeth to be more oval-shaped with a higher tubular density and slightly larger tubular diameters compared with human teeth. These features suggest dog canine teeth have less intertubular dentin compared with human teeth, which may theoretically result in lower resin-dentin shear bond strengths.     

Treatment of maxillary cheek teeth apical infection caused by patent infundibula in six horses (2007–2013)

Six young horses presented with clinical signs of maxillary cheek teeth apical infection (bilateral in 2 horses) that included the presence of rostral maxillary swellings with discharging sinus tracts and were unexpectedly found to have no evidence of endodontic infection in 7 affected teeth. The apical infection of these teeth was attributed to infundibular dysplasia that allowed inoculation of the periapical tissue with contaminated oral contents. Treatment was by debridement and obturation of affected infundibula from their occlusal aspect using techniques normally used for endodontic therapy. Five out of 6 cases showed resolution of clinical signs over a mean follow‐up period of 19 months (range 6–48 months). These cases demonstrate that patency of the infundibular apex is a potential cause of cheek teeth apical infection in young horses, which can be successfully treated by debridement and subsequent infundibular restoration.     

Is your practice diagnosing cheek teeth diastemata?

Diastema (pleural diastemata) is the most common disorder predisposing the horse to periodontal disease. These can affect the incisors or cheek teeth but pose more significant problems in the cheek teeth. Cheek teeth diastema can be congenital or develop secondary to other pathology. This condition is underdiagnosed in clinical practice due to lack of awareness of its seriousness and also due to poor dental examination techniques. A thorough dental examination requires both digital palpation and visual inspection of the oral cavity. Proper patient restraint and the use of a mouth speculum, bright light source, dental mirror or oral endoscope are required to fully inspect the equine oral cavity. Diastemata diagnosed early and managed properly can prevent the progression of periodontal disease and allow affected horses to preserve their dentition into old age.     

Description of a technique for orthograde endodontic treatment of equine cheek teeth with apical infections

An orthograde endodontic method, similar to that used in human dentistry, is described for use on endodontically diseased permanent cheek teeth in horses. The technique has been adapted to meet the anatomical and physiological differences between hypsodont and brachyodont teeth and is performed in sedated horses. The techniques of debriding the pulp cavity and use of dental materials which fulfil the requirements for equine teeth are presented here. The results of this technique appear to be promising but have yet to be evaluated in a peer‐reviewed study. By using orthograde endodontic therapy on sedated horses it is now possible to save endodontically diseased permanent cheek teeth.     

Endodontic Instruments for Root Canal Therapy

This article on endodontic instrumentation includes endodontic instruments and techniques of root-canal preparation of teeth in veterinary patients. Familiarity with instruments covered in this article and with advances in veterinary endodontics has become necessary for the veterinary dental practitioner who wishes to practice dentistry using current techniques. Veterinary endodontic techniques that help to retain the teeth longer are increasing in demand as an option to extracting damaged teeth. Endodontic treatment involves removal of the irreversibly damaged pulp, followed by cleaning and shaping of the root canal space using endodontic instruments and subsequent filling, or obturation, with a semisolid material and a sealer.     

Oral surgery. Basic techniques

Some of the clinical problems most frequently seen in veterinary dentistry and their surgical solutions are discussed. Extraction of teeth, surgical repositioning of teeth, tooth transplant, oral abscesses of tooth origin, impaction of teeth, repair of maxillary canine oronasal fistula, and simple techniques for oral wiring are among the issues considered.     

A review of equine dental disorders

Equine dentistry is a very important but until recently rather neglected area of equine practice, with many horses suffering from undiagnosed, painful dental disorders. A thorough clinical examination using a full mouth speculum is a pre-requisite to performing any equine dental procedure. Common incisor disorders include: prolonged retention of deciduous incisors, supernumerary incisors and overjet--the latter usually accompanied by cheek teeth (CT) overgrowths. Overjet can be surgically corrected, but perhaps should not be in breeding animals. In younger horses, traumatically fractured incisors with pulpar exposure may survive by laying down tertiary dentine. Loss or maleruption of incisors can cause uneven occlusal wear that can affect mastication. Idiopathic fractures and apical infection of incisors are rare. The main disorder of canine teeth is the development of calculus of the lower canines, and occasionally, developmental displacements and traumatic fractures. The main indications for extraction of "wolf teeth" (Triadan 05s) are the presence of displaced or enlarged wolf teeth, or their presence in the mandible. Developmental abnormalities of the CT include; rostral positioning of the upper CT rows in relation to the lower CT rows--with resultant development of focal overgrowths on the upper 06s and the lower 11s. Displaced CT develop overgrowths on unopposed aspects of the teeth and also develop periodontal disease in the inevitable abnormal spaces (diastemata) that are present between displaced and normal teeth. Diastemata of the CT due to excessive developmental spacing between the CT or to inadequate compression of the CT rows is a common but under diagnosed problem in many horses and causes very painful periodontal disease and quidding. Supernumerary CT mainly occur at the caudal aspect of the CT rows and periodontal disease commonly occurs around these teeth. Eruption disorders of CT include prolonged retention of remnants of deciduous CT ("caps") and vertical impaction of erupting CT that may lead to large eruption cysts and possibly then to apical infections. Disorders of wear, especially enamel overgrowths ("enamel points"), are the main equine dental disorder and are believed to be largely due to the dietary alterations associated with domestication. If untreated, such disorders will eventually lead to more severe CT disorders such as shearmouth and also to widespread periodontal disease. More focal dental overgrowths will develop opposite any CT not in full opposition to their counterpart, e.g., following maleruption of or loss of a CT. Because of the great length of reserve crown in young (hypsodont) CT, apical infections usually cause infection of the supporting bones and depending on the CT involved, cause facial swellings and fistulae and possibly sinusitis. Diagnosis of apical infection requires radiography, and possibly scintigraphy and other advanced imaging techniques in some early cases. When possible, oral extraction of affected CT is advocated, because it reduces the costs and risks of general anaesthesia and has much less post-extraction sequelae than CT repulsion or buccotomy.     

Iatrogenic fracture of the premaxilla during standing exodontia

This case report describes a 17‐year‐old horse that presented with a history of oral dysphagia secondary to buccal slab fractures and apical infection in two cheek teeth. During standing surgery to remove the diseased cheek teeth, the horse sustained a bilateral comminuted fracture of the premaxilla. An audible crack was followed by bilateral epistaxis. Subsequent radiography revealed minimal displacement at the fracture sites and the horse responded well to conservative management without the need for additional fixation techniques. One year later, the fracture appeared completely healed on repeat radiography. This is an uncommon complication of standing dental procedures necessitating the use of a speculum but is noteworthy and may be important to consider and inform owners in such aged cases.     

A long-term study of apicoectomy and endodontic treatment of apically infected cheek teeth in 12 horses

The aim of this study was to evaluate the long-term results of apicoectomy and retrograde endodontic treatment in 12 horses with apical cheek teeth infections. The affected apices were removed using a diamond bur mounted on a dental drill, and after pulp removal the root canals were filed with Hedstrøm files and then alternately flushed with sodium hypochlorite, hydrogen peroxide and alcohol. The pulp canals were dried and filled with endodontic cement and gutta-percha points. An undercut was made in the apical aspect of the root canals that were then sealed with self-curing glass ionomer cement.Follow up information was obtained 38–67 months following treatment and indicated that the treatment had been successful in 7/12 horses (58%), partially successful in 2 horses (17%) and unsuccessful in 3 (25%). With good case selection, apicoectomy can preserve a proportion of apically infected cheek teeth. The use of advanced imaging techniques and improved surgical techniques could increase the success rate.     

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.     

Computed tomography and scintigraphy for evaluation of dental disease in the horse

Computed tomography (CT) uses x‐ray beams and reconstructive computer technology to create tomographic slices (sections) of the area being imaged. Computed tomography has higher contrast resolution than conventional radiography allowing for more accurate differentiation of soft tissues and fluids. This form of 3D imaging removes problems caused by superimposition of multiple anatomical structures, which is a major impediment when viewing radiographs of the equine head. Once the images are acquired, multi‐planar and 3D reconstructions can be performed to view different teeth or associated structures in an optimal way. Anatomical and pathological changes in the dental tissues, periodontal tissues, alveolar bone and adjacent sinuses can then be assessed. Scintigraphy with 99^m technetium methyl‐diphosphate (methylene‐diphosphonate) can detect changes in bone that precede radiographic changes, and this makes it a very useful imaging modality for diagnosis of early periapical infection of the equine cheek teeth. Additionally, it is invaluable for imaging suspected infections of supernumerary or dysplastic teeth where the results of radiography or even CT may be equivocal. Periapical infections of the cheek teeth typically result in focal and intense increased radionuclide uptake located over the apical region of the affected tooth.     

Bovine dental fluorosis: histologic and physical characteristics

Incisor teeth from 5- to 6-year-old Holstein-Friesian cattle maintained on a ration averaging 40 ppm F annually from 4 months of age were analyzed by a variety of histologic techniques. These techniques included photomicroscopy, microradiography, protein staining, and microhardness testing. The features of fluorotic enamel that were noted were: hypomineralized outer enamel, coronal cementum hyperplasia, disrupted subsurface pigment band, hypoplastic pits, puckered incremental lines, periodic radiolucent regions, positive protein staining, and decreased microhardness of the outer enamel. These results were similar to the lesions of dental fluorosis observed in other species, and explain the external appearance of fluorotic bovine teeth observed under field conditions.     

MAGNETIC RESONANCE IMAGING OF PULP IN NORMAL AND DISEASED EQUINE CHEEK TEETH

A retrospective analysis of 619 upper and lower cheek teeth from 62 horses was performed. Based on clinical findings, as well as radiographic and magnetic resonance (MR) imaging findings, the teeth were classified into five groups. There were 20 teeth with abnormal MR imaging signals as well as clinical alterations and 599 healthy teeth. Using MR imaging, the appearance of pulp in diseased and disease‐free teeth was compared, and the appearance of abnormal pulp was studied. Subsequently, the ability of MR imaging to diagnose pulpitis and pulp necrosis in teeth with normal external appearance was investigated. In horses with clinically verified dental disease, abnormal MR imaging findings were confirmed in the pulp of all affected teeth. An enlarged blurred pulp image with a lower signal intensity was observed only in clinically diseased teeth and was a reliable criterion for diagnosing dental disease on MR imaging. On the other hand, partial or complete absence of pulp in all MR imaging sequences was observed in both diseased and nondiseased teeth. These data demonstrate that pulp changes in equine cheek teeth can be evaluated using MR imaging.     

Recent developments in equine dentistry

ABSTRACT

Equine dentistry is a rapidly developing clinical specialty. It has benefitted from key advances in anatomical and physiological research, development of equipment and instrumentation, utilisation of standing sedation and anaesthesia protocols, a change towards minimally invasive surgical techniques, and the introduction of restorative and endodontic techniques translated from techniques used in human and canine dentistry. Anatomical research has provided further insight into the endodontic system of incisors and cheek teeth and how it changes throughout development with age. Studies of the periodontium have demonstrated a rich vascular supply and repair capacity. Routine dental visits are increasingly being performed utilising sedation and clinical instruments for routine examinations. Equipment has become more efficient, battery-operated and miniaturised giving benefits to both equine dental maintenance work and advanced techniques, assisting the transition to minimally invasive techniques, and the development of endodontic and restorative dentistry. Diagnosis has also benefitted from advances in equipment such as patient-side digital radiography systems, high definition oroscopy, and small diameter flexible fibrescopes that are capable of visualising inside a pulp canal. Dental units combining endodontic high- and low-speed drills, suction and air or water flush are becoming increasingly used and adapted for equine use. Sedative combinations and standing anaesthesia protocols have meant that revisions of traditional techniques, as well as novel techniques, can be performed with almost no requirement for general anaesthesia. Equine dentistry can only continue to advance in this way if there is early identification of dental disease through clinical oral examinations, leading to a system based on prophylaxis, as in human dentistry. This necessitates a change in attitude of the public and industry in general to a proactive approach, with early intervention based on examination and diagnostic findings of practitioners and not necessarily based on the clinical signs displayed by the patient.     

Assessment of vital pulp therapy for nine complicated crown fractures and fifty-four crown reductions in dogs and cats

Subjective owner assessment of the success of vital pulp therapy was performed for complicated crown fracture (n = 9) and crown reduction (n = 54) of canine teeth in dogs and cats. Our results documented that owners are not able to accurately determine the outcome of vital pulp therapy. Objective assessment of vital pulp therapy for teeth receiving crown reduction indicated maintenance of vitality in 28 of 28 (100%) teeth. Subjective and objective assessments of vital pulp therapy performed > 7-days following complicated crown fracture indicated 9 of 9 (100%) teeth were non-vital. A poor prognosis for maintenance of tooth vitality is warranted for vital pulp therapy of complicated crown fractures with prolonged pulp exposure regardless of the age of the patient. Whereas, an excellent prognosis can be provided for vital pulp therapy following crown reduction. Semiannual, postoperative oral and radiographic examinations are recommended for a minimum of 2-years to assess vitality in all teeth receiving vital pulp therapy.     

Polyodontia in donkeys

Polyodontia is defined as the presence of teeth in excess of the normal dental formula. In equids, supernumerary teeth are uncommon but, when present, are usually located mainly in the caudal aspects of the cheek teeth rows (distomolars), also being found adjacent to normal cheek teeth or even in an ectopic location. It is believed that this disorder is a result of an inappropriate differentiation of dental germinal tissue during gestational development, with external trauma also acting as an initiating factor, when teeth germs are affected. The presence of these abnormal teeth can lead to axial displacement, dental overgrowths, dental‐related soft tissue damage, diastemata formation, periodontal disease and development of secondary sinusitis. A large prospective, cross‐sectional study was performed in 800 donkeys, with the aim to investigate the prevalence and aetiopathogenesis of clinically diagnosed oral and dental disorders. Polyodontia was recorded in 2.25% of the donkeys, presenting 36 supernumerary teeth, with 2.80% being incisors and 97.20% cheek teeth, with prevalence increasing with age. The caudal aspects of the maxillary cheek teeth rows were the most common locations for supernumerary teeth development (distomolars). The mandible was far less commonly affected than the maxilla. Although polyodontia is uncommon in donkeys, it should be considered in the differential diagnosis of dental disease. A methodical oral examination and a complete radiographic survey of the entire dental arcades are crucial for a correct early diagnosis and treatment plan implementation. The increasing prevalence of fully erupted supernumerary teeth recorded in older groups suggested a late onset eruption process, and therefore, in donkeys undergoing regular dental prophylaxis, the presence of previously unnoticed supernumerary teeth should always be sought.     

Radiology of deciduous teeth resorption and definitive teeth eruption in the dog

The formation of the crown of definitive teeth, the development of the definitive roots with the accompanying resorption of the deciduous roots, and the eruption of the definitive teeth, were individually analysed in 18 Dachshunds.
Weekly radiographs were made from all dogs between the sixth and twentieth weeks of life, using techniques applied in the human dental clinic. From this data a table has been drawn representing the radiological evolution of the entire dentition in young Dachshunds.     

Area of desensitization following mental nerve block in dogs

Regional nerve blocks are commonly used to provide analgesia for dental and oral surgical procedures. The purpose of this study was to demarcate the areas of the mandible that would be desensitized by application of the mental nerve block. Seven healthy mixed-breed dogs were anesthetized for an annual dental examination and professional teeth cleaning procedure. Bupivacaine HCl (0.4 ml/ m2) was administered at one middle mental foramen based on previously described techniques for the mental nerve block. A noxious stimulus was applied at 23 predetermined ipsilateral mandibular locations using pressure from a mosquito hemostat on the mucocutaneous junction (MCJ) and a dental curette on the vestibular mucogingival line (MGL) at the incisor canine, and premolar teeth; and, the mesial and distal aspects of the first molar tooth. A thermal stimulus using a refrigerant spray on a cotton ball was applied to the ipsilateral canine, third premolar and fourth premolar teeth; and, the mesial and distal aspects of the first molar tooth. Demonstration of nociception or anesthesia was noted and the responses tabulated. The area of desensitized tissues was smaller than expected and highly variable within the study group. In conclusion, the unilateral mental nerve block does not reliably provide generalized desensitization to tissues of the incisive and rostral regions of the mandible. Although the mental nerve block is recommended, other modes of analgesia should be emphasized for surgical and dental procedures involving these areas.     

Commissurotomy for improving access to the oral cavity of the wombat

Wombats are a grazing marsupial with a diet rich in silicates, which is highly abrasive and results in a higher rate of tooth attrition than in other grazing marsupials such as kangaroos. Any interference in the natural wear process, such as malocclusion or loss of teeth, causes overgrowth of teeth. The small mouth opening of the wombat makes access to the caudal mouth difficult and overgrowth of cheek teeth can be difficult to treat effectively. This case report describes a technique that greatly improves access to allow dental treatment of all overgrown teeth with minimal complications.