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 use of oral endoscopy for detection of cheek teeth abnormalities in 300 horses

The main objective of this study was to evaluate an endoscopic examination protocol for routine dental examination in horses. The oral cavities of 300 standing, sedated horses were examined under field and hospital conditions with a rigid endoscope using a standardised technique that included examination of the occlusal, lingual (palatal) and buccal surfaces of all cheek teeth rows. The most common cheek teeth abnormalities detected were sharp enamel edges (present in 96.3% of horses), focal overgrowths (64.3%), fissure fractures (54.3%), diastemata (24.3%) and infundibular hypoplasia/caries (48.3%). Rigid endoscopy of the equine oral cavity was found to be a safe non-invasive diagnostic technique that appeared to be superior to clinical oral examination for detecting subtle cheek teeth changes.     

Standing oral extraction of cheek teeth in 100 horses (1998--2003)

REASONS FOR PERFORMING STUDY: Extraction of cheek teeth (CT) by the conventional repulsion technique requires general anaesthesia and carries a high rate of post operative complications. Consequently, an alternative method of extraction, i.e. orally in standing horses, was evaluated. HYPOTHESIS: The need for and risks of general anaesthesia could be avoided and post extraction sequelae reduced by performing extractions orally in standing horses. METHODS: One hundred mainly younger horses (median age 8, range 2-18 years) with firmly attached CT that required extraction because of apical infections, displacements, diastemata, idiopathic fractures and the presence of supernumerary CT had the affected teeth (n = 111) extracted orally under standing sedation. Follow-up information was obtained for all cases, a median of 16 months later. RESULTS: Oral extraction was successful in 89 horses and unsuccessful in 11 due to damage to the CT clinical crown (n = 9) during extraction, for behavioural reasons (n = 1) and because the apex of a partly extracted CT fell back into the alveolus following sectioning (n = 1). Predispositions to extraction-related CT fractures were present in 5 of the 9 cases, i.e. advanced dental caries (n = 2) and pre-existing 'idiopathic' fractures (n = 3). The iatrogenically fractured CT were later repulsed under standing sedation (n = 3) and under general anaesthesia (n = 6). Eighty-one of the remaining 89 horses had successful oral CT extraction with no or minimal intra- or post operative complications occurring. Post operative complications in the other 8 cases included post extraction alveolar sequestration (n = 3), alveolar sequestration and localised osteomyelitis (n = 1), localised osteomyelitis (n = 1), incorporation of alveolar packing material into alveolar granulation tissue (n = 1), and nasal discharge due to continued intranasal presence of purulent food material (n = 1) and to ongoing sinusitis (n = 1). The above sequelae were treated successfully in all cases, with general anaesthesia required in just one case. Following oral extraction, significantly (P<0.001) fewer post operative problems developed in 54 horses with apically infected CT in comparison with 71 previous cases that had repulsion of apically infected CT at our clinic. CONCLUSIONS AND POTENTIAL RELEVANCE: Oral extraction of cheek teeth is a successful technique in the majority of younger horses with firmly attached CT and greatly reduces the post operative sequelae, compared with CT repulsion. Additionally, the costs and risks of general anaesthesia are avoided. Further experience and refinement in the described protocol could potentially increase the success of this procedure and also reduce the incidence of post operative sequelae.     

Equine idiopathic cheek teeth fractures. Part 1: Pathological studies on 35 fractured cheek teeth

REASONS FOR PERFORMING STUDY: There is little published information on the pathology of idiopathic fractures of cheek teeth (CT). OBJECTIVES: To perform pathological examinations on equine CT with idiopathic fractures in order to establish fracture patterns and to gain information on their aetiopathogenesis. HYPOTHESIS: Gross and histological examination of CT with idiopathic fractures, including measurements of dentinal thickness, will provide information on fracture patterns, and on the duration and aetiopathogenesis of these fractures. METHODS: Of 35 CT with idiopathic fractures that were examined to determine their fracture patterns, 20 underwent gross, histological and ultrastructural examinations, including dentinal thickness measurements, with the latter compared to dentinal measurements of dental age and Triadan position matched control CT, to help determine the duration of any pre-existing endodontic disease. RESULTS: The fracture planes involved the pulp chambers in 30 out of 35 CT examined, and ran through coalesced, carious infundibula in the other 5 (maxillary) CT. The maxillary CT, particularly the Triadan 09 position were preferentially affected. The most common fracture plane, which was termed a maxillary buccal slab fracture, occurred through the 2 lateral (1st and 2nd) pulp chambers of maxillary CT and usually involved only the clinical crown. Buccal slab fractures of mandibular CT (through 4th and 5th pulp chambers) and midline sagittal fractures through the infundibula (of maxillary CT) were the next most common fracture patterns. Reduced dentinal thickness (probably indicating prior pathological changes in the fractured CT) was present in 25% of fractured CT. CONCLUSIONS: Most idiopathic equine CT fractures involve the pulp chambers, especially those on the buccal aspect of both upper and lower CT. No predisposition to fracture was found in the majority of affected CT that appeared to have a normal endodontic appearance prior to development of fractures through their pulp chambers. The remaining idiopathic CT fractures were caused by advanced infundibular caries. POTENTIAL RELEVANCE: All CT with idiopathic fractures are all at risk of pulpar or even apical infection.     

Occlusal angles of cheek teeth in normal horses and horses with dental disease

The angle between the occlusal surface of the tooth and the horizontal plane of 687 cheek teeth from the skulls of 22 horses without gross dental disorders and 11 horses with dental disorders were measured by using stiff malleable wire as an imprint. Each measurement was repeated five times and the mean angle was recorded. In the normal skulls, the mean occlusal angles of the mandibular cheek teeth ranged from 19.2 degrees at the Triadan 06 position to 30 degrees at the 11 position, and these angles were significantly greater than the occlusal angles of the opposing maxillary cheek teeth (range 12.5 degrees to 18 degrees) at all the positions except the 06. The rostral mandibular cheek teeth had significantly lower occlusal angles than the caudal mandibular cheek teeth, but the converse was true for the maxillary teeth. In the skulls with dental disorders the occlusal angles of the mandibular cheek teeth ranged from 15.6 degrees to 28.5 degrees , and of the maxillary cheek teeth from 9.2 degrees to 16.4 degrees. They were not significantly different from the angles of the teeth from the normal skulls, except at the 06 position, where they were smaller.     

Extraction of cheek teeth using a lateral buccotomy approach in 114 horses (1999-2009)

Reason for performing the study: There are few published data regarding the success rates of cheek tooth (CT) removal by lateral buccotomy in the horse. Objectives: A retrospective study of 114 horses admitted to 2 private equine referral hospitals over a 10 year period (1999–2009), which underwent CT removal via a lateral buccotomy. Methods: Hospital records were analysed and details including case details, presenting complaint and results of all diagnostic tests and surgical reports were documented. Information obtained during post operative reassessment was also available for analysis. Long‐term follow‐up information (>2 months) was obtained for 112 horses. Results: Short‐term complications (<2 months) occurred in 24/77 horses (31%) undergoing exodontia of the maxillary CT and 10/37 horses (27%) involving mandibular CT, with the majority arising from partial wound dehiscence and infection following 16 extractions (47%). All healed well by second intention. Other complications included both temporary (n = 6) and permanent (n = 3) facial nerve paralysis, myositis (n = 4) and the inadvertent establishment of an oroantral fistula (n = 4). One myositis case was subjected to euthanasia 24 h post operatively. Five horses had persistent sinusitis following surgery due to dental remnants (n = 2) and excessive packing material (n = 1) found in the sinuses. No inciting cause could be found in the remaining 2 horses. One further horse suffered a fatal cardiac arrest at induction of anaesthesia. Of all horses, 92% operated on had returned to their previous level of work after >2 months with no complications. Conclusion: Horses with CT removal by a lateral buccotomy have a reasonable prognosis for long‐term outcome. Potential relevance: Performing a lateral buccotomy is a justified treatment alternative for the surgical removal of equine CT following unsuccessful attempts by standing oral extraction, offering advantages over alternatives such as retropulsion, endodontic therapy and periapical curettage.     

Periapical curettage: an alternative surgical approach to infected mandibular cheek teeth in horses

OBJECTIVE: To evaluate an alternative surgical method for treating periapical infection of the mandibular cheek teeth of horses. DESIGN: Retrospective study. ANIMALS: Eleven horses (3-13 years) with periapical mandibular tooth infection. METHODS: Hospital records (1992-2002) of horses that had periapical curettage for the treatment of mandibular cheek tooth root infection were retrieved. Clinical signs, radiographic, and surgical reports were reviewed. Outcome was obtained by telephone questionnaire for 7 horses and by physical examination in 2. RESULTS: Eleven horses (14 infected mandibular molariform teeth) had periapical curettage. Two horses were lost to follow-up. Mean follow-up was 41 months; 2 horses had subsequent tooth repulsion, 7 (78%) horses healed completely although 2 horses still had some local mandibular swelling. CONCLUSION: Periapical curettage, which allows alveolar drainage, appears to be a viable treatment option for periapical infections of equine mandibular cheek teeth. CLINICAL RELEVANCE: Periapical curettage can be performed simply, without expensive imaging or surgical equipment, and thus is useful for both referral and first opinion practice.     

Computed tomography of the upper cheek teeth in horses with infundibular changes and apical infection

Reasons for performing study: Infundibular changes are frequently encountered computed tomographic studies of the equine maxillary cheek teeth but the possible importance of this finding is not known. Infundibular caries is a possible cause for pulpitis and apical infection in some horses. Objectives: To study the relationship between the 2 pathologies and the frequency of changes. Methods: The maxillary cheek teeth 108‐ 208 , 109–209 and 110–210 of 25 horses were evaluated using computed tomography and both the prevalence of infundibular and apical infection changes as the possible link with apical infection evaluated statistically. Results: The prevalence of infundibular changes was high in both normal and diseased teeth. Both apical infection and the occurrence of infundibular changes were more prevalent in 109–209 and 110–210. In spite of this, the 2 processes could not be linked to one another. No differences were noted between the left and right sides. Conclusions: A direct relationship between the 2 processes was not established statistically and other underlying causes for the high occurrence of both apical infection and infundibular changes in diseased and normal 108‐ 208 , 109–209 and 110210 are considered.     

Dental diastemata and periodontal disease secondary to axially rotated maxillary cheek teeth in three horses

Malerupted axially rotated maxillary cheek teeth (CT) were identified as the primary cause of diastemata and severe periodontitis in 3 horses. Diastema widening and periodontal debridement was performed initially in one case but did not resolve clinical signs. Subsequently, all 3 cases underwent extraction of the axially rotated teeth per os without complication. Follow‐up indicated remission of periodontitis and signs of oral pain. In these cases, maxillary CT had erupted in a manner that resulted in axial rotation of CT with undulating buccal and palatal surfaces aligned with the interproximal surfaces of adjacent normally orientated teeth. This resulted in poor interproximal compression and diastemata causing severe periodontitis. Axially rotated maxillary CT and the severe periodontitis that they precipitate, have not been previously described as a discrete dental disease entity.     

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.     

A study of the thickness of cheek teeth subocclusal secondary dentine in horses of different ages

Reasons for performing study: There is limited knowledge on the thickness of subocclusal secondary dentine in equine cheek teeth (CT). Hypotheses: Subocclusal secondary dentine is of consistent thickness above different pulp horns in individual horses and its thickness increases with age. Methods: 408 permanent CT were extracted post mortem from 17 horses aged 4–30 years, with no history of dental disease. The CT were sectioned longitudinally in the medio‐lateral (bucco‐palatal/lingual) plane through each pulp horn, and the thickness of the secondary dentine overlying each pulp horn was measured directly. Results: The subocclusal thickness of secondary dentine above the pulp horns of CT varied from a mean thickness (above all pulp horns) of 12.8 mm (range 5–33 mm) in a 4‐year‐old to 7.5 mm (range 2–24 mm) in a 16‐year‐old horse. There was wide variation in the depth of subocclusal secondary dentine above different pulp horns, even within the same CT. In contrast to expectations, occlusal secondary dentine thickness did not increase with age. There were no significant differences in occlusal secondary dentine thickness between rostral and caudal, or medial and lateral aspects of the CT, or between contralateral CT. Mandibular CT had significantly thicker subocclusal secondary dentine than maxillary CT. Pink coloured secondary dentine was sometimes found 1–3 mm occlusal to the pulp horn in sectioned CT and this was likely caused by artefactual blood staining from the underlying pulp during sectioning. Conclusions: The thickness of subocclusal secondary dentine varies greatly between individual pulp horns, teeth and individual horses and can be as low as 2 mm over individual pulp horns. Potential relevance: Due to the great variation in the thickness of subocclusal secondary dentine between horses, and even between pulp horns in individual CT, there is a risk of exposure or thermal damage to pulp and thus of apical infection, even with modest therapeutic reductions of CT occlusal overgrowths. In the light of these findings, great care should be taken when reducing equine CT overgrowths and larger dental overgrowths should be reduced in stages.     

Treatment of equine cheek teeth by mechanical widening of diastemata in 60 horses (2000-2006)

REASON FOR PERFORMING STUDY: Cheek teeth (CT) diastemata are a significant cause of painful dental disease in horses and limited factual information is available on the treatment of this disorder. OBJECTIVE: To assess the response to mechanical widening in the treatment of diastema. METHOD: Details of the presenting signs and treatment of cases of CT diastema by widening were recorded and the response to treatment of these cases assessed by re-examinations and by obtaining follow-up information from owners. RESULTS: Sixty horses of various breeds, median age 9 years, with clinically significant CT diastemata were classified as having primary (inadequate rostro-caudal CT compression: n = 29) and secondary (to other dental abnormalities: n = 31) diastemata. Quidding was present in 82% of cases, weight loss in 35%, halitosis in 17% and bitting disorders in 12%; 85% of the identified CT diastemata involved mandibular CT and 15% maxillary CT, with caudal CT more commonly affected. Of 273 identified diastemata in the 60 horses, 207 were deemed to have significantly associated periodontal food pocketing and were widened to 4.5-5.5 mm diameter on their occlusal surface using a mechanical burr. The 29 horses with primary diastemata received a median of 1.3 treatments each and at 10 months following their last treatment 72% showed complete remission of signs and 28% showed good improvement. The 31 horses with secondary diastemata received a median of 2.2 treatments each and, at mean 9 months following their last treatment, 48% showed full improvement, 42% good improvement, 6% slight improvement and 3% no improvement. Inappropriate areas of the clinical crown were removed from 4 CT without causing pulpar exposure; one case was reported to have a transient oral infection post treatment and another developed an apical infection in a treated tooth that was unrelated to the diastema widening. CONCLUSION: Diastema widening is an effective treatment of periodontal pocketing in CT diastemata. POTENTIAL RELEVANCE: The described treatment of CT diastema widening by trained personnel is an effective and safe treatment, but repeated treatments are often necessary, especially with secondary diastemata.     

Equine odontoclastic tooth resorption and hypercementosis affecting all cheek teeth in two horses: Clinical and histopathological findings

This report describes the clinical presentation and histopathological findings of two horses with equine odontoclastic tooth resorption and hypercementosis (EOTRH) affecting all cheek teeth. Equine odontoclastic tooth resorption and hypercementosis is a well documented condition known to affect the incisors, canines and occasionally the premolars in horses. At this time there have been no documented cases of EORTH affecting all cheek teeth described in the peer reviewed literature. This paper documents the first reported cases of EOTRH affecting the cheek teeth in one horse in the United States and one from Germany.     

The prevalence of secondary dentinal lesions in cheek teeth from horses with clinical signs of pulpitis compared to controls

Reasons for performing study: With the advent of detailed oral examination in horses using dental mirrors and rigid endoscopy, secondary dentinal lesions are observed more frequently. More information regarding the association of secondary dentinal defects with apical dental disease would improve the sensitivity of oral examination as a diagnostic aid for pulpitis. Objectives: To assess prevalence and severity of secondary dentinal defects observed on examination of occlusal surfaces of cheek teeth (CT) from horses showing clinical signs of pulpitis compared to asymptomatic controls. Methods: Records from all cases of equine CT exodontia at the University of Bristol over a 4 year period were examined. Case selection criteria included the presence of clinical signs of pulpitis, an intact extracted tooth and availability of a complete history and follow up. Cases where coronal fracture or periodontal pocketing featured were excluded. CT from cadavers with no history of dental disease served as normal controls. Triadan positions and eruption ages of control teeth were matched with those of teeth extracted from cases. CT from selected cases and control teeth were examined occlusally. Secondary dentinal defects were identified and graded. Prevalence of occlusal lesions in CT with pulpitis and controls was compared. Results: From the records of 120 horses where exodontia was performed, 40 cases matched selection criteria. Twenty‐three mandibular and 21 maxillary CT were extracted from cases. The controls consisted of 60 mandibular and 60 maxillary CT from 7 cadaver skulls. Secondary dentinal defects were significantly over‐represented in CT extracted from cases of pulpitis (P<0.001). Of diseased mandibular CT, 56.5% had defects compared to none of the controls. Of diseased maxillary CT, 57% had defects compared with 1.6% of controls. Multiple defective secondary dentinal areas and severe lesions were more prevalent in diseased mandibular CT compared with diseased maxillary CT. Conclusions and practical significance: Careful examination of occlusal secondary dentine is an essential component in investigation of suspected pulpitis in equine CT.