[...]... interprismatic enamel, which can form the basis for enamel classification Equine enamel is composed of two main types termed Equine Types 1 and 2 enamel, with small amounts of Equine Type 3 enamel.20 Equine Type 1 enamel is present on the medial aspect of the enamel folds, i.e at the amelodentinal Figure 3.6 Scanning electron micrograph of Equine Type 1 enamel showing interprismatic plates (IP) alternating... However, increased amounts of Equine Type 1 enamel are present in the upper cheek teeth, and almost equal amounts of Equine Type 1 and 2 occur in the lower cheek teeth, whereas incisor enamel is composed almost solely of Equine Type 2 enamel Equine Type 1 prisms are oriented at angles of approximately 45° to both the amelodentinal junction and the occlusal surface, but bundles of Equine Type 2 enamel prisms... satisfactory for equine incisors that form a true arch However, these terms are unsatisfactory for the equine cheek teeth, because they do not form part of a continuous dental arch as they are separated from the incisors by the inderdental space (‘bars of mouth’) The term cheek teeth row is a more appropriate term to describe the rows of six cheek teeth Equine dental evolution The evolution of equine dentition... his clients and the more rewarding his dentistry practice will be REFERENCES 1 Scoggins RD (2001) Bits, bitting and dentistry In: Proceedings of the 47th Annual Meeting of the American Association of Equine Practitioners, 47, pp 138–141 2 Bennett DG (2001) Bits and bitting: form and function In: Proceedings of the 47th Annual Meeting of the American Association of Equine Practitioners, 47, pp 130–137... electron micrograph of a section of an equine tooth showing dentin (D) enamel and cement (C) A thin layer of Equine Type 3 enamel is visible on the left (3) at the junction with dentin Adjacent to this area is a wider layer of Equine Type 1 enamel (1) showing interprismatic enamel (IP) (contiguous with Type 3 enamel and enamel prisms (P)) To the right is a wider layer of Equine Type 2 enamel (2) that in... American Association of Equine Practitioners, 48, pp 458–462 6 Engelke E and Gasse H (2003) An anatomical study of the rostral part of the equine oral cavity with respect to position and size of a snaffle bit Equine Veterinary Education, 15, 158–163 7 Clayton HM and Lee R (1984) A fluoroscopic study of the position and action of the jointed snaffle bit in the horse’s mouth Journal of Equine Veterinary Science,... (Fig 3.1) Additionally, in some equine teeth, invaginations of enamel epithelium, which will later become infundibula, develop from the convex aspect of the ‘bell’ into the papilla (one per incisor and two per upper cheek teeth) Equine cheek teeth have multiple cusps (raised occlusal areas) that arise from protrusions on the convex aspect of the bell The enamel organ in equine incisors and in all brachydont... bundles of enamel prisms) (Fig 3.10) In contrast, Equine Type 1 enamel contains no decussation Equine incisors are smaller and flatter than cheek teeth, have less support from adjacent teeth and yet undergo great mechanical stresses during prehension that could readily cause enamel cracks Therefore it is not surprising that they are largely composed of Equine Type 2 enamel prisms Cheek teeth primarily... 8:50 AM Page 32 Morphology 32 Section 1 MORPHOLOGY Figure 3.10 Scanning electron micrograph of a section of an equine incisor tooth, showing dentin (D), infundibular enamel (IE) and infundibular cement (IC) A thin layer of Equine Type 1 enamel is present on the left (1) The bulk of the enamel is Equine Type 2 (2) and this is oriented at a wide variety of angles including horizontal (h), obliquely (o) and... rows between flat plates of dense interprismatic enamel (Figs 3.5 and 3.6) Equine Type 2 enamel is present on the periphery of the enamel layer, i.e at the amelocemental (enamel to cement) junction, and is composed solely of enamel prisms ranging from horseshoe to keyhole in shape (Fig 3.7) with no interprismatic enamel present Equine Type 3 enamel is composed of prisms completely surrounded by large . Emeritus Equine Medicine and Surgery University of Illinois College of Veterinary Medicine IL 61802 USA Dwight G Bennett DVM PhD Professor Emeritus of Equine. Veterinary Centre Midlothian EH25 9RG UK Jack Easley DVM MS Diplomate ABVP (Equine) Equine Veterinary Practitioner Shelbyville KY 40065 USA Christine Gibbs