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.     

Observations of the periodontal ligament and cementum in cats with dental resorptive lesions

The etiology of feline dental resorptive lesions is unknown, but some evidence suggests that interactions between components of the periodontium may be initiating factors in the development of these lesions. In the present study, 22 clinically normal teeth were harvested from 7 cats. The teeth and periodontium were radiographed and examined histologically. In addition, 14 of the 22 teeth were examined histometrically. Two teeth were histologically normal with an open apical foramen and two were normal with a closed apical foramen. Histological evidence of periodontal ligament degeneration without cementum resorption was observed in 8 teeth, and varying degrees of cementum resorption were observed in 10 teeth. Mandibular molar and premolar teeth had distal drift, and mandibular canine teeth had mesial drift. Alterations in the periodontal ligament may represent a preclinical stage of dental resorption.     

Diagnostic value of the use of lateral and occlusal radiographic views in comparison with periodontal probing for the assessment of periodontal attachment of the canine teeth in dogs

OBJECTIVE: To determine the diagnostic value of 2 intraoral bisecting angle radiographic views in comparison with periodontal probing for the assessment of periodontal attachment of the canine teeth in dogs. STUDY POPULATION: 466 canine teeth from 117 dogs. PROCEDURE: Periodontal probing measurements were recorded, and clinical attachment levels (CAL) were calculated at the mesial, buccal, distal, and lingual (or palatal) surfaces on each canine tooth. Occlusal and lateral radiographs of the canine teeth were obtained. Alveolar margin height (AMH) was measured at the same 4 surfaces. Values for AMH and CAL were compared on the basis of tooth surface, dental arch, and radiographic view. RESULTS: The AMH at the mesial and distal surfaces of the mandibular canine teeth was measurable on the lateral view and was significantly correlated with CAL. Similar results were found for the mesial and distal surfaces of the maxillary canine teeth. Buccal and lingual AMH were measured on the mandibular occlusal radiographic view, and values were significantly correlated with CAL, but only the buccal AMH could be assessed on the occlusal radiographic view of the maxilla with values that correlated significantly with CAL. CONCLUSIONS AND CLINICAL RELEVANCE: The lateral radiographic view is suitable for evaluating periodontal attachment at the mesial and distal surfaces of the canine teeth in dogs. The occlusal radiographic view is suitable for assessing buccal surfaces as well as the lingual surface of mandibular canine teeth but not the palatal surface of maxillary canine teeth in dogs.     

Regional anesthesia of the infraorbital and inferior alveolar nerves during noninvasive tooth pulp stimulation in halothane-anesthetized cats

OBJECTIVE: To determine whether anesthesia of the infraorbital and inferior alveolar nerves abolishes reflex-evoked muscle action potentials (REMP) during tooth-pulp stimulation in halothane-anesthetized cats. ANIMALS: 8 healthy adult cats. PROCEDURE: In halothane-anesthetized cats, an anodal electrode was attached to the tooth to be stimulated and a platinum needle cathodal electrode was inserted in adjacent gingival mucosa. Cathodal and anodal electrodes were moved to the upper and lower canine, upper fourth premolar, and lower first molar teeth for stimulation; baseline REMP was recorded. A 25-gauge 1-cm needle was inserted 0.5 cm into the infraorbital canal. A 25-gauge 1-cm needle was inserted 1 cm rostral to the angular process of the ramus, and advanced 0.5 cm along the medial aspect. Chloroprocaine was injected at each site. Each tooth was stimulated every 10 minutes for 90 minutes. RESULTS: REMP was abolished within 10 minutes for all upper teeth, except for the upper canine tooth in 1 cat, and abolished within 10 minutes for lower teeth in 4 cats. In 1 cat, REMP was not abolished in the lower first molar tooth. In 3 cats, REMP was not abolished in the lower canine and first molar teeth. At 90 minutes, REMP was restored for all teeth except the lower canine tooth in 1 cat, for which REMP was restored at 120 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Regional anesthesia of the infraorbital and inferior alveolar nerves may provide dental analgesia in cats.     

Investigation into intraoral approach for nerve block injection at the mental foramen in the horse

Invasive dental procedures performed in the standing, sedated horse are facilitated by local and regional anaesthesia. The traditional transcutaneous approach to the mental foramen is used to desensitise the incisive region including the mandibular incisors, but is not well tolerated by many sedated patients. In this study, a new, intraoral needle insertion technique for nerve block at the mental foramen was investigated. In 15 equine cadaver heads and two live horses, computed tomography (CT) was used to verify Tuohy needle placement into each mental foramen using an intraoral technique. Varying volumes of contrast medium (3, 6, 10 mL) were injected into the mandibular canal with and without digital occlusion of the mental foramen. The distance of retrograde flow was measured. Additionally, measurements were taken to determine the position of the mental foramen within the interdental space. Correct placement of Tuohy needles and injection of contrast medium into the mandibular canal using an intraoral approach at the mental foramen was achieved in all injections. Retrograde flow of contrast medium was accomplished with all volumes, regardless of occlusion. Although not statistically significant, the 10 mL group appeared to have a greater distance of flow. The needle insertion technique described here appears to be a potential alternative to traditional transcutaneous approaches to mental nerve block for procedures involving the incisive region. In addition, it was found that 79% of the mandibular canals injected with 10 mL of contrast medium had retrograde flow to the position of PM4, suggesting this method may be a useful alternative technique for nerve block for the more rostrally located cheek teeth. The location of the mental foramen was consistently found in the distal third of the interdental space (approximately 60–80% of the distance between the distal aspect of the lateral corner incisor and the mesial aspect of the second premolar).     

Extraction techniques for equine incisor and canine teeth

Extraction of equine incisor and canine teeth is a vital part of equine dentistry. Although dental pathology involving the incisor and canine teeth is less common, the practitioner should be prepared to diagnose conditions and develop a treatment plan. Depending on the pathology revealed via oral examination and intraoral radiographs, the treatment plan may include either simple (nonsurgical) or surgical extraction of an incisor or canine tooth. Technique and instrumentation refinement over the last 20 years has led to more precise extraction procedures with reduced secondary trauma to healthy tissues. As a result, incisor and canine extraction procedures are more predictable in execution and quality, with minimal complications.     

The Inferior Alveolar Nerve of the Horse: Course and Anatomical Relationship with Mandibular Cheek Teeth

The precise location of neurovascular structures within the relatively long mandibular canal of the horse is of paramount importance in surgical procedures of the area. The inferior alveolar nerve (IAN) enters the mandibular canal on the medial (lingual) surface of the mandible and innervates all the mandibular teeth. During its course, the nerve moves laterally, crossing the roots of the inferior cheek teeth. However, the exact anatomical relationships occurring between the IAN and the roots of the equine mandibular cheek teeth have not been described in detail. In this study, the mandibles of 40 horses were examined with CT scans and then used for bilateral detailed anatomical dissection, to assess the path of the IAN and its relationship to the roots of the lower cheek teeth. The data obtained show that the equine IAN is located ventral to the apices of the molar teeth (311/411, 310/410, 309/409 according to the Triadan numerical system). At the level of PM₄ (308/408), the IAN is located on the lingual side of the roots and coronally to its apices. At the level of PM₃ (307/407), the IAN is then found on the lingual side of the roots but in proximity to the apices. In 2 of 40 horses (=5%), the IAN moves towards the lingual side between the mesial and the distal root of PM₄. Our observations are valuable for planning a surgical approach to the ventral side of the mandible in the horse and to avoid potential post‐operative complications.     

Furcation entrance anatomy of the fourth maxillary premolar in dogs

Tooth surface and interradicular area (furcation) measurements were determined for 20 fourth maxillary premolar teeth obtained randomly from canine cadavers. The palatal furcation entrance had a mean width of 1.2 +/- 0.1 mm. The coronal roof of the palatal furcation was located at the cementoenamal junction (CEJ). The buccal furcation entrance had a mean width of 0.9 +/- 0.2 mm. The horizontal attachment area between the CEJ and the coronal roof of the buccal furcation was 1.3 +/- 0.3 mm. The mesial furcation entrance had a mean width of 0.4 +/- 0.1 mm. The horizontal attachment area between the CEJ and the coronal roof of the mesial furcation entrance was 1.7 +/- 0.3 mm. The mean coefficient of variation for variables measured was 10.3%. Tooth size did not have a significant effect on furcation entrance measurement. All teeth had a fluted area between the CEJ and mesial furcation, a concavity coronal to the furcation area, a distal concavity of the mesial root trunk between the mesiopalatal and mesiobuccal roots, and a mesial furcation concavity of the distal root extending apically for a mean distance of 60% of the distal root length. The complexity of furcation entrance anatomy may be a factor in the manifestation of periodontal disease involving the furcation of the fourth maxillary premolar in dogs.     

Temperature changes in dental pulp associated with use of power grinding equipment on equine teeth

OBJECTIVE: To quantify the temperature changes in the dental pulp associated with equine dental procedures using power grinding equipment. DESIGN: A matrix experimental design with replication on the same sample was followed to allow the following independent variables to be assessed: horse age (young or old), tooth type (premolar or molar), powered grinding instrument (rotating disc or die grinder), grinding time (15 or 20 seconds) and the presence or absence of water coolant. PROCEDURE: Sound premolar and molar teeth from a 6-year-old horse and a 15-year-old horse, which had been removed postmortem, were sectioned parallel to the occlusal plane to allow placement of a miniature thermocouple at the level of the dental pulp. The maximum temperature increase, the time taken to reach this maximum and the cooling time were measured (n=10 in each study). The teeth were placed in a vice and the instrument used on the tooth as per clinical situation. RESULTS: Significant differences were recorded for horse age (P < 0.001), instrument type (P < 0.001), grinding time (P < 0.001) and presence or absence of coolant (P < 0.001). There was no significant difference for tooth type. CONCLUSION: Thermal insult to the dental pulp from the use of power instruments poses a significant risk to the tooth. This risk can be reduced or eliminated by appropriate selection of treatment time and by the use of water irrigation as a coolant. The increased dentine thickness in older horses appears to mitigate against thermal injury from frictional heat.     

A retrospective study of dental conditions of captive brown bears (Ursus arctos spp.) compared with free-ranging Alaskan grizzlies (Ursus arctos horribilis).

The teeth of 63 skulls of brown bears (Ursus arctos spp.) that had lived in the Bernese bear pit between 1850 and 1995 were examined and radiographed for occlusion, loss of teeth, calcified dental plaque and calculus, attrition, and caries. Dental pathology and periodontal status were evaluated with respect to age and location in the dentition. Further techniques such as computed tomography, microhardness testing, histologic sectioning, and scanning electron microscopy were used in selected cases to verify the macroscopic and radiographic diagnoses. Fourteen skulls originating from free-ranging wild Alaskan brown bears (Ursus arctos horribilis) were examined as a control group. For zoo bears over 10 yr old, severe enamel and dentinal attrition has been observed in canine teeth, with exposed pulp and proximal lesions in molar teeth. Deposits of calcified dental calculus were found in various locations and increased with age. A much lower degree of calculus deposition was found in the Alaskan grizzlies, whose average caries frequency was higher but with large individual variation and different locations in canine teeth and occlusal lesions in molar and premolar teeth. Radiographic evaluation of perialveolar osteolytic processes revealed a greater frequency of apical and combined apical-marginal lesions of the alveoli in zoo bears over 10 yr old. Stereotypical behavior like cage chewing is a suspected cause of canine tooth and secondary alveolar lesions, whereas a nutritionally inappropriate diet and inadequate opportunities for tooth-cleaning activities are responsible for the lack of natural cleaning and the extensive calculus formation that results. The methods used in this study are useful in assessing and comparing the dental health status of free-ranging bears, and those living in zoological gardens, by evaluating anesthetized bears or bear skull collections representing both groups.     

Dental and craniofacial findings in eight miniature schnauzer dogs affected by myotonia congenita: preliminary results

Myotonia is a clinical sign characterized by the delay of skeletal muscle relaxation following the cessation of a voluntary activity or the termination of an electrical or mechanical stimulus. Recently, Miniature Schnauzers with myotonia congenita associated with defective chloride ion conductance across the skeletal muscle membrane were identified. Congenital myotonia in these dogs appears to follow an autosomal recessive mode of inheritance. Craniofacial and dental findings of eight Miniature Schnauzer dogs with myotonia congenita are described in the present paper. These findings include: delayed dental eruption of both deciduous and permanent dentition: persistent deciduous dentition; unerupted or partially erupted permanent teeth: crowding and rotation of premolar and or incisor teeth: missing teeth: increased interproximal space between the maxillary fourth premolar and first molar teeth: decreased interproximal space between the maxillary canine and lateral incisor teeth: inability to fully close the mouth due to malocclusion: distoclusion: and, decreased mandibular range of motion. A long narrow skull with a flattened zygomatic arch and greater mandibular body curvature were also consistent findings in the affected dogs. The small number of dogs studied prevents conclusive statements about the origin of these abnormalities, however it is interesting that only 1 of 45 unaffected Miniature Schnauzer dogs showed similar traits.     

Extensive bilateral odontogenic cysts in the mandible of a dog

A 5-year-old female neutered Boxer dog was diagnosed with extensive odontogenic cysts that affected the left and right mandibles. Rostral mandibular swelling was detectable clinically, and bilateral cystic mandibular lesions were identified radiographically. The dog's owners elected for euthanasia. A full postmortem was performed. Cystic cavities were confirmed in the body of each mandible, extending from the incisor teeth to the mid premolar region. Incisor, canine, and premolar tooth roots indented each cavity. Histologic examination of the cystic cavities reflected an inner lining of attenuated stratified squamous epithelium overlying a fibrous layer infiltrated by a mixed, predominantly mononuclear, inflammatory infiltrate.     

Wolf teeth and their extraction

The equine first premolar or ‘wolf tooth’ (Triadan 05) is a normal vestigial tooth, which is often absent, but when present most commonly lies rostral to the second maxillary premolar (Triadan 06). The routine extraction of wolf teeth has been performed historically and is contentious, but clinically indicated in some instances. This review article aims to summarise concisely the limited peer reviewed literature on wolf teeth and to describe the practice of their extraction. Extraction is usually performed in the standing sedated horse, and complications are avoided with good surgical planning, analgesia and instrumentation.     

Tooth resorption in the Swedish Eurasion lynx (Lynx lynx)

The etiology of tooth resorption in the domestic cat remains unknown. The high prevalence and progressive nature of the disease complicates defining healthy control groups. In order to evaluate the possible influence of various life style changes on the prevalence of tooth resorption, healthy control groups are a prerequisite. This paper presents a prevalence study for tooth resorption in a free-ranging wild felidae population. Skulls from 46 free-ranging Eurasian lynx (Lynx lynx) were examined. The age of the animals had previously been estimated based on cementum annuli in the maxillary right canine tooth. The dental examination included both dental probing and radiographic imaging. Complicated fractures of the canine teeth were found in 9/46 (19.5%) skulls. In one fractured canine, apical root resorption and periapical lucency was detected. The root resorption was attributed to inflammatory resorption as a consequence of the initial dental trauma and necrotic pulp. No signs of tooth resorption were found in the remaining teeth. Supernumerary roots were detected in 18/46 skulls (39.1 %). Supernumerary "peg" teeth caudal to the mandibular first molar tooth were detected in 6/46 (13.0%) skulls. Although further studies on dental ultra-structure are needed, the Swedish Eurasian lynx may, in the future, be useful as a healthy comparative model for studies on the etiopathogenesis of tooth resorption in the domestic cat.     

In vitro study of heat production during power reduction of equine mandibular teeth

OBJECTIVE: To measure the amount of heat generated during 3 methods of equine dental reduction with power instruments. DESIGN: In vitro study. SAMPLE POPULATION: 30 premolar and molar teeth removed from mandibles of 8 equine heads collected at an abbatoir. PROCEDURE: 38-gauge copper-constantan thermocouples were inserted into the lingual side of each tooth 15 mm (proximal) and 25 mm (distal) from the occlusal surface, at a depth of 5 mm, which placed the tip close to the pulp chamber. Group-NC1 (n = 10) teeth were ground for 1 minute without coolant, group-NC2 (10) teeth were ground for 2 minutes without coolant, and group-C2 (10) teeth were ground for 2 minutes with water for coolant. RESULTS: Mean temperature increase was 1.2 degrees C at the distal thermocouple and 6.6 degrees C at the proximal thermocouple for group-NC1 teeth, 4.1 degrees C at the distal thermocouple and 24.3 degrees C at the proximal thermocouple for group-NC2 teeth, and 0.8 degrees C at the distal thermocouple and -0.1 degrees C at the proximal thermocouple for group-C2 teeth. CONCLUSIONS AND CLINICAL RELEVANCE: In general, an increase of 5 degrees C in human teeth is considered the maximum increase before there is permanent damage to tooth pulp. In group-NC2 teeth, temperature increased above this limit by several degrees, whereas in group-C2 teeth, there was little or no temperature increase. Our results suggest that major reduction of equine teeth by use of power instruments causes thermal changes that may cause irreversible pulp damage unless water cooling is used.     

Unilateral failure of development of mandibular premolars and molars in an Eastern Grey kangaroo (Macropus giganteus) and its effects on molar progression

An adult male Eastern Grey kangaroo from a wildlife reserve near Melbourne was submitted for necropsy examination and was discovered to have abnormal dentition. There was no evidence that any premolars or molars had ever been present on the right mandible, whilst the incisors were normal. The age of the kangaroo was estimated to be 1 year 9 months using the right maxillary molars and 2 years 4 months old using the contralateral side, presumably due to the asymmetry of the dental arcades. 'Lumpy jaw', a common periodontal disease of kangaroos, from which Bacteroides sp was cultured, was present on the base of the vertical ramus of the left mandible. Complete unilateral absence of premolar and molar teeth in the mandible of a kangaroo has not been described. This condition affected molar progression in both sets of maxillary molars.     

Prevalence of dental and mandibular disorders in culled sheep in Spain

At the slaughterhouse, 1465 culled sheep heads were studied in order to identify disorders of the mandibular cheek teeth. Of these, 227 (15.5%) had evidence of osteomyelitis. The lesional profile showed that the mandible was affected in a similar proportion on both sides (46.7% on the right side vs 50.7% on the left side), mainly in the middle region (55.3%) and with most of the lesions closed without fistulisation (89.4%). In addition, swelling was palpable, with an increase in thickness in the area of the affected body (2.65 ± 0.065 cm vs 1.74 ± 0.030 cm). In 78.6% of the animals, the regional lymph nodes were enlarged. Concerning the mandibular cheek teeth, more than half of the animals lacked at least one tooth (57.0%), with the first premolar being the most frequently missing tooth (34.8%) and the third molar the least (8.2%). The impaction of food around the teeth was very common with the posterior molars being more frequently affected. In the knowledge of the authors, this is the first study that analyses the prevalence of mandibular molar and premolar disorders in sheep, and these are revealed as an important condition affecting culled sheep.     

Epidemiological study on periodontal diseases and some other dental disorders in dogs

The prevalence of dental disorders in dogs was studied by applying index systems for human with some modifications. A total of 251 mongrel dogs including 143 stray dogs kept in the Animal Protection Offices in Tokyo and Hokkaido and 108 pet dogs visiting veterinary clinicians in Chiba Prefecture and Hokkaido were used. Periodontitis was prevalent among these dogs regardless of their sources and its incidence was increased with age. The lesion was more severe and more frequent in the premolar and molar regions than in the maxillary and mandibular incisor regions. Missing of teeth was observed at a high and increasing incidence with age. The tooth most commonly lost was the first premolar, followed by the other premolars and molars, where severe periodontitis was frequently found. Calculus was seen on many teeth, and aging agravated its prevalence and severity. Dental caries was observed in stray dogs, but neither to a serious degree nor at a significant level. These findings emphasize the necessity of dental hygiene, proper dental care and continuous periodical survey for dogs.