Figure 1: Severe gingivitis and periodontal bone loss in a four-year-old saluki. Photo courtesy John Lewis I recently received a request to write a column about the role of nutrition in health and disease of the teeth of companion animals. Nutrition can play a role in proper formation of the immature teeth. During amelogenesis (development of the organic enamel matrix and its subsequent mineralization), lack of proper nutrition can result in enamel hypoplasia or hypomineralization. Poor nutrition is not the most common clinical cause of enamel hypoplasia or hypomineralization, but it can contribute. Enamel hypoplasia can also be due to hereditary causes, as described in the Samoyed.1 Other causes of enamel hypoplasia include premature birth, exposure to epitheliotropic (such as canine distemper virus), fever, trauma, and exposure to certain antibiotics during development of enamel in the young animal. Abnormalities Developmental abnormalities of the enamel include hypoplasia, hypomineralization, or both. Hypoplasia results in a defect in the thickness or presence of enamel, whereas hypomineralization can result in flaky, less strong enamel that can wear easily. Consider hypoplasia as a problem of quantity (or even lack of presence of enamel in specific areas of the tooth), whereas hypomineralization is a problem with the quality of the enamel due to incomplete or lacking maturation of the enamel. Once the enamel is formed, there is no further laydown of enamel throughout life. However, exchange of minerals through the surface of the enamel can occur to some degree. Perhaps the aspect of nutrition most significantly affecting the teeth after eruption is a diet’s ability, or inability, to reduce plaque and/or calculus accumulation on the teeth. Most veterinarians will share their intuition that clinical patients eating only canned food will tend to have more plaque, calculus, and gingivitis. Studies that support this popularly held belief are surprisingly limited. One review in the Australian Veterinary Journal concluded, “There is reasonable evidence that soft diets are associated with increased frequency and severity of periodontal disease.”2 However, a comprehensive study in the Journal of Veterinary Dentistry of 1,350 client-owned dogs showed few apparent differences of the association of calculus, gingival inflammation, and periodontal bone loss in dogs fed dry food only compared with those fed other than dry food only.3 Chewing materials In the same study, there was less accumulation of calculus, less gingival inflammation, and less periodontal bone loss in dogs given access to more types of chewing materials (rawhides, bones, biscuits, chew toys) compared with dogs given access to fewer or no chewing materials.3 The benefits and risks of access to certain chew items must be weighed by pet owners since chewing on certain rawhides and bones may result in more immediate concerns, such as gastrointestinal issues or broken teeth. Given chewing materials have been shown to decrease calculus and gingivitis, it makes sense the size of kibble and design of the kibble may play a role in preventing periodontal disease. If chewed upon, kibble can provide a cleansing effect on the teeth that do the chewing. Mechanical effects of a diet can be achieved by a larger kibble that decreases the chance of a pet swallowing the kibble whole, and when chewed, the kibble might be designed to not readily break into tiny pieces, encouraging additional chewing. Another strategy to prevent calculus accumulation is the addition of compounds, such as sodium hexametaphosphate to prevent mineralization of plaque. Plaque is a mixture of food particles, saliva, and bacteria that creates the “fuzzy” feeling on your teeth shortly after you drink a sugar-filled beverage or eat some food. When we brush our teeth, this fuzzy layer is removed before it has a chance to mineralize and become calculus. Though plaque is the “bad actor” that incites periodontal inflammation, calculus provides a rough surface on the teeth to allow for additional plaque accumulation. Sodium hexametaphosphate is a calcium sequestrant preventing plaque from becoming its mineralized form called calculus, also known by the lay term of “tartar.” One study in the American Journal of Veterinary Research found anticalculus effects attributable to sodium hexametaphosphate were only significant when it was used as a surface coating instead of being incorporated into the food.4 This same study found the feeding of a single daily snack of sodium hexametaphosphate-coated plain biscuits (0.6 percent HMP) decreased calculus formation by nearly 80 percent. Similar to the American Dental Association (ADA), the Veterinary Oral Health Council (VOHC) consists of a group of volunteer experts in veterinary dentistry who review available research to confirm whether products have the ability to decrease plaque and/or calculus formation. See www.vohc.org to find a list of products proven to decrease plaque and/or calculus accumulation in companion animals. In next month’s column, I will discuss whether diet plays a role in development of tooth resorption in cats. John Lewis, VMD, DAVDC, FF-OMFS practices and teaches at Veterinary Dentistry Specialists and Silo Academy Education Center, both located in Chadds Ford, Pa. References Pedersen NC, Shope B, Liu H. An autosomal recessive mutation in SCL24A4 causing enamel hypoplasia in Samoyed and its relationship to breed-wide genetic diversity. Canine Genet Epidemiol. 2017; Nov 22;4:11. Watson AD. Diet and periodontal disease in dogs and cats. Aust Vet J. 1994;71(10):313-318. Harvey CE, Shofer FS, Laster L. Correlation of diet, other chewing activities and periodontal disease in North American client-owned dogs. J Vet Dent. 1996;13(3):101-105. Stookey GK, Warrick JM, Miller LL. Effect of sodium hexametaphosphate on dental calculus formation in dogs. Am J Vet Res. 1995;56(7):913-918.
