132
external inflammatory tooth resorption that is the consequence of orthodontic forces, luxation/avulsion or pulpitis (Heithersay 1999; Patel et al. 2009). Cervical tooth resorption is much more common in the cat (DeLaurier et al. 2009) and dog (Peralta et al. 2010). However, this pattern of tooth resorption is also seen clinically in the canine teeth of the horse. The pathogenesis of this form of tooth resorption may involve exposed dentin at the cemento-enamel junction (Patel et al. 2009) but in a retrospective study in man (Heithersay 1999), orthodontic treatment, intracoronal bleaching of endodontically-treated teeth and a history of trauma were the most frequently associated predisposing factors. One case series in man suggested an association between invasive cervical tooth resorption with feline herpes virus type 1 (von Arx et al. 2009). Invasive cervical tooth resorption rarely involves the pulp as the mantel layer of dentin appears to be resistant to clastic cells. Tooth resorption in man (Sch€
atzle et al. 2005) and in cats
(Reiter et al. 2005) has also been hypothesised to be secondary to endocrine and systemic conditions. However, a survey of 109 cats showed no correlation of serumvitamin D3 levels and feline tooth resorption (Girard et al. 2010). Preliminary investigation has shown no relationship of EORTH and thyroid hormones in the horse (Earley et al. 2011). The PDL is a unique soft tissue of mesenchymal
origin situated between two hard tissues (bone and cementum). There are resident stem cells within the PDL that can differentiate into both clastsic and blastic cells that actively produce or remove cementum and alveolar bone. The regenerative ability of the PDL is the basis for guided tissue regeneration in the treatment of selective types of periodontal disease in man (Villar and Cochran 2010) and dogs (Gingerich and Stepaniuk 2011). It would appear that the fibroblasts within the PDL secrete factors that inhibit ankylosis of alveolar bone to dentin (Nanci 2013). Replantation of luxated teeth predictably results in root resorption only if the PDL undergoes drying or if the PDL is removed from the root surface (Andreasen 1985). A recent case series reported the preliminary success of replanted equine cheek teeth that had undergone extracorporal endodontic therapy (Stoll 2014). The authors of the accompanying paper hypothesise that
the underlying cause of EOTRH may be due to the masticatory forces placed on the geriatric tooth of shorter root length (Schrock et al. 2013; Moore et al. 2016). This would be similar to the root resorption noted in people undergoing orthodontic treatment. With regards to hypercementosis, this appears to be a unique feature of equine periodontal disease. Generalised tooth resorption and hypercementosis has rarely been reported in man (Sch€
atzle
et al. 2005) and is not a common feature of tooth resorption in the cat or dog. Hypercementosis, as noted in the accompanying paper, is a variable component of EOTRH. Cementomas are not an infrequent finding in association with apically infected cheek teeth and at the site of previously extracted apically infected cheek teeth. Perhaps the unregulated regenerative response of the PDL, with excessive cementum formation, is a unique feature of the horse.
Authors’ declaration of interests No conflicts of interest have been declared.
© 2015 EVJ Ltd
EQUINE VETERINARY EDUCATION / AE / MARCH 2016
References
Andreasen, J.O. (1985) External root resorption: its implication in dental traumatology, paedodontics, periodontics, orthodontics and endodontics. Int. Endodontic J. 18, 109-118.
von Arx, T., Schawalder, P., Ackermann, M. and Bosshardt, D.D. (2009) Human and feline invasive cervical sesorptions: the missing link? - Presentation of four cases. J. Endod. 35, 904-913.
Baratt, R.M. (2007) Equine incisor resorptive lesions. In: Proceedings of the 21st Annual Veterinary Dental Forum, Minneapolis, USA, pp 23- 30.
Caldwell, L.A. (2007) Clinical features of chronic disease of the anterior dentition in horses. In: Proceedings of the 21st Annual Veterinary Dental Forum, Minneapolis, USA, pp 18-21.
Darcey, J. and Qualtrough, A. (2013) Resorption: Part 1. Pathology, classification and aetiology. Br. Dental J. 214, 441-451.
DeLaurier, A., Boyde, A., Jackson, B., Horton, M.A. and Price, J.S. (2009) Identifying early osteoclastic resorptive lesions in feline teeth: a model for understanding the origin of multiple idiopathic root resorption. J. Periodont. Res. 44, 248-257.
Earley, E.T., Smedley, R.M., Baratt, R.M., Galloway, S.S. and Rawlinson, E. (2011) Equine odontoclastic tooth resorption and hypercementosis: an in-depth evaluation of 15 cases to determine any possible causes or associations. In: Proceedings of AAEP Focus on Dentistry, Albuquerque, New Mexico.
Gingerich, W. and Stepaniuk, K. (2011) Guided tissue regeneration for infrabony pocket treatment in dogs. J. Vet. Dent. 28, 282-288.
Girard, N., Servet, E., Hennet, P. and Biourge, V. (2010) Tooth resorption and vitamin D3 status in cats fed premium dry foods. J. Vet. Dent. 27, 142-147.
Gregory, R.C., Fehr, J. and Bryant, J. (2006) Chronic incisor periodontal disease with cemental hyperplasia and hypoplasia in horses. Proceedings of the Focus on Dentistry, AAEP. 312-316. Available at:
www.aaep.org/focus_on_dentistry/310–314% 20Gregory%20formatted.pdf.
Heithersay, G.S. (1999) Clinical, radiologic and histopathologic features of invasive cervical resorption. Quintessence Int. 30, 27-37.
Jones, S.A. and Boyde, A. (1974) Coronal cementogenesis in the horse. Arch. Oral Biol. 19, 605-614.
Lorello, O., Foster, D.L., Levine, D.G., Boyle, A., Engiles, J. and Orsini, J.A. (2015) Clinical treatment and prognosis of equine odontoclastic tooth resorption and hypercementosis. Equine Vet. J. Epub ahead of print; doi: 10.1111/evj.12406.
Moore, N.T., Schroeder, W. and Staszyk, C. (2016) Equine odontoclastic tooth resorption and hypercementosis affecting all cheek teeth in 2 horses: clinical and histopathological findings. Equine Vet. Educ. 28, 123-130.
Nanci, A. (2013) Ten Cate’s Oral Histology, Elsevier, St. Louis. pp 205- 232, 239–244.
Ne, R.F., Witherspoon, D.E. and Gutmann, J.L. (1999) Tooth resorption. Quintessence Int. 30, 9-25.
Patel, S., Kanagasingam, S. and Pitt Ford, T. (2009) External cervical resorption: a review. J. Endod. 35, 616-625.
Reiter, A.M., Lyon, K.F., Nachreiner, R.F. and Shofer, F.S. (2005) Evaluation of calciotropic hormones in cats with odontoclastic resorptive lesions. Am. J. Vet. Res. 66, 1446-1452.
Peralta, S., Verstraete, F.J.M. and Kass, P.H. (2010) Radiographic evaluation of the types of tooth resorption in dogs. Am. J. Vet. Res. 71, 784-93.
Sahara, N. (2014) Development of coronal cementum in Hypsodont horse cheek teeth. Anat. Rec. 297, 716-730.
Sch€
atzle, M., Tanner, S.D. and Bosshardt, D.D. (2005) Progressive, generalized apical idiopathic root resorption and hypercementosis. J. Periodontol. 76, 2002-2011.
Schrock, P., L€ upke, M., Seifert, H. and Staszyk, C. (2013) Three-
dimensional anatomy of equine incisors: tooth length, enamel cover and age related changes. BMC Vet. Res. 9, 249 (Article URL
http://www.biomedcentral.com/1746-6148/9/249).
Continued on page 139
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88
