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dc.contributor.advisorDixon, Padraic M.en
dc.contributor.advisorKempson, Sue A.en
dc.contributor.authordu Toit, Nicoleen
dc.date.accessioned2010-11-22T12:42:20Z
dc.date.available2010-11-22T12:42:20Z
dc.date.issued2009
dc.identifier.urihttp://hdl.handle.net/1842/4385
dc.description.abstractEighty normal cheek teeth and 26 normal incisors extracted from 14 donkeys (median age 19 years) at post mortem were anatomically examined including grossly and by computerised axial tomography (CAT) imaging. Decalcified histology was performed on 54 sections from 18 teeth (8 donkeys), undeclacified histology on 16 sections from 7 donkeys and scanning electron microscopy on 10 sections from 10 teeth (3 donkeys). The dental formulae and tooth number was found to be the same as in horses with a higher prevalence (17 %) of canine teeth in female donkeys. A decrease in tooth length, pulp horn length and pulp horn width with age was illustrated, as was an increase in occlusal secondary dentine depth with age, although not all these age changes were statistically significant. Normal histological and ultrastructural features of donkey teeth were identified and found to be similar to equine findings. Enamel was found to be thicker buccally in both maxillary and mandibular cheek teeth. Quantitative measurements of transverse dentine thickness around pulp cavities, dentinal tubule diameters and densities, and enamel prism diameters were made. Left lower incisors (301) were extracted from 7 donkeys and 6 horses for micro-hardness determination of enamel, primary and secondary dentine using a Knoop Hardness indenter. No significant difference between donkey and horse incisor microhardness was demonstrated. Examination of 19 donkey skulls at post mortem examination showed donkeys to have a higher degree of anisognathia (27%) compared to horses (23%). Post mortem dental examination of 349 donkeys (median age 31) demonstrated a high prevalence of dental disease (93%) and in particular cheek teeth diastemata (85%). Furthermore, age was associated with increasing prevalence of dental disease and diastemata. Diastemata were also associated with the presence of other dental disorders and with colic-related death in affected donkeys. Quantitative measurements of 45 diastemata from 16 donkeys showed no difference in the medial and lateral width of diastemata but periodontal pockets were deeper laterally. The definition of valve and open diastemata were confirmed. Pulp exposure, dental caries and periodontal disease were examined in detail (54 skulls) at post mortem. A total of 19 teeth were extracted for further detailed examination as performed in normal anatomy. Clinical dental examinations were performed on 357 donkeys in the U.K. that were selected for age distribution, and the prevalence of dental disease in different age groups was found to increase from 28% in the youngest group (age 0-10 years) to 98% in the oldest group (age > 35 years). An increased prevalence of most dental disorders with age was demonstrated as was an association between dental disease and weight loss, poor body condition score, supplemental feeding and previous episodes of colic. Clinical dental examination of 203 working donkeys in Mexico showed similar types of dental disorders as found in the U.K. study, with dental disease present in 62%, of which 18% required urgent dental treatment. There was a significant association between age groups and dental disease, and age groups and body condition score, but there was no association between dental disease and body condition score. However, body condition score was not associated with supplemental feeding or faecal egg counts either.en
dc.contributor.sponsorThe Donkey Sanctuaryen
dc.language.isoen
dc.publisherThe University of Edinburghen
dc.relation.hasversiondu Toit, N., Kempson, S.A., Dixon, P.M. (2008) Donkey dental anatomy. Part 1: Gross and computed axial tomography examinations. The Veterinary Journal 176, 338 -344.en
dc.relation.hasversiondu Toit, N., Kempson, S.A., Dixon, P.M. (2008) Donkey dental anatomy. Part 1: Histological and scanning electron microscopy examinations. The Veterinary Journal 176, 345 -353.en
dc.relation.hasversiondu Toit, N., Bezensek, B., Dixon, P.M. (2008) Comparison of the microhardness of enamel, primary and regular secondary dentine of the incisors of donkeys and horses. The Veterinary Record 162, 272 - 275en
dc.relation.hasversiondu Toit, N., Gallagher, J., Burden, F.A, Dixon, P.M. (2008) Post mortem survey of 349 donkeys from an aged population (2005-2006). Part 1: Prevalence of specific dental disorders. Equine Veterinary Journal 40 (3), 204 – 208.en
dc.relation.hasversiondu Toit, N., Gallagher, J., Burden, F.A, Dixon, P.M. (2008) Post mortem survey of 349 donkeys from an aged population (2005-2006). Part 2: Epidemiological studies. Equine Veterinary Journal 40 (3), 209 - 213.en
dc.relation.hasversiondu Toit, N., Burden, F.A., Dixon, P.M. (2008) Detailed investigation of dental caries and pulpar exposure in donkey cheek teeth using CAT, histology and SEM, The Veterinary Journal, 178 (3), 387 - 395.en
dc.subjectdonkey teethen
dc.subjecthistologyen
dc.subjectultrastructureen
dc.subjectclinical examinationen
dc.titleAnatomical, pathological and clinical study of donkey teethen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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