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May/June 2014 Today's Veterinary Practice 97 PracTical DenTisTry Peer reviewed tvpjournal.com M any types of hard tissue pathol- ogy affect small animal veteri- nary patients. Many of these are caused by a form of trauma, but acidic degradation, infection, and genetics also play a role. ENAMEL HYPOCALCIFICATION/ HYPOPLASIA 1-4 Enamel is a very thin (< 1 mm) mate- rial on the surface of the tooth crown. Ameloblast cells initiate enamel forma- tion, and are only present during this process. 5,6 Enamel is created prior to tooth eruption and cannot be natu- rally repaired after teeth erupt. Causes & Development Hypoplasia/hypocalcification results from disruption of normal enamel development. 7,8 • Enamel hypocalcification occurs when normal amounts of enamel are produced, but are hypomineral- ized, making the enamel softer than normal. • Enamel hypoplasia occurs when the enamel produced is hard, but thin and deficient in amount. Enamel hypocalcification can result from trauma to an unerupted tooth, which can affect one or several adjacent teeth, and is the most common acquired cause. While this defect may originate from external trauma, it is often as- sociated with extraction of deciduous teeth. Enamel hypoplasia may result from a hereditary condi- tion known as amelogenesis imperfecta, 9 which results when a decreased amount of enamel matrix is applied to teeth during development. In these cases, nearly all teeth, and all surfaces, are involved. A severe systemic infectious (for example, canine distem- per virus infection that occurs in puppies before the teeth have erupted) or nutritional condition may also result in improper enamel production. 9 Clinical Signs & Diagnosis Common signs of enamel hypocalcification/hypoplasia are listed in Table 1. These signs emphasize that prompt therapy is critical to the health of the patient. Prior to therapy, dental radiographs must be exposed to evaluate whether tooth nonvitality or root malformation (Figure 1) is present. Treatment Options Treatment goals include: • Removing sensitivity • Avoiding endodontic infection by occluding the dentinal tubules • Smoothing the tooth to decrease plaque accumulation. disorders of Dental HarD tissues in dogs Brook A. Niemiec, DVM, FAVD, Diplomate AVDC Southern California Veterinary Dental Specialties, San Diego, California Figure 1. Dental radiographs of (A) left maxillary fourth premolar (208) of dog with generalized enamel hypocalcification—the tooth is nonvital as evidenced by the periapical lucencies (red arrows) and wider endodontic system in the distal root (blue arrow) compared to the palatine root of first molar (green arrow), and (B) mandibular second and third premolars (306 and 307), dem- onstrating significant root hypoplasia—note the short roots of the second and third premolars (red arrows), that the canine root only extends to the first pre- molar (second premolar root is normal), and the normal first premolar. A B Table 1. clinical signs of enamel Defects • Affected areas stained tan to dark brown; may appear pitted and rough (Figure 2, page 98) 10 • Hard tooth surface , not soft or sticky (characteristics of caries lesions) • Exposed dentin as areas of malformed enamel exfoliate; this exposure results in significant patient discomfort 11,12 • Stained dentin , since it is porous • Increased plaque retention due to tooth roughness (results in early periodontal disease) 13-15 • Potential infection via the dentinal tubules TVP_2014_0506_PD_HardTissue-Periodontal.indd 97 5/23/2014 6:35:49 PM