Use of the feed additive sodium hexametaphosphate to prevent dental calculus in squirrel monkeys (Saimiri spp.)

Dental calculus and associated periodontal disease are serious clinical problems in captive squirrel monkeys. Calculus begins to appear as early as 2 years of age, with subsequent development of periodontal disease, dental abscessation, tooth loss and other sequelae. When used as a feed additive, sodium hexametaphosphate (HMP) retards the growth of calculus on previously cleaned teeth in rhesus monkeys, lemurs, and other species. We wanted to determine whether HMP would reduce dental calculus in squirrel monkeys (Saimiri spp.) whose teeth had not been pre-cleaned. The study animals were divided into two groups. One received a standard diet; the other received an identical diet containing the HMP additive at a concentration effective in other primate and non-primate species that had received dental cleaning prior to treatment with HMP. Teeth were graded for extent of calculus formation at the start of the study and at 3 and 6 months during HMP treatment. We compared the results from the two groups both by total score per animal and according to tooth type (e.g., incisors versus incisors in test and control groups). At the end of 6 months, dental calculus did not differ significantly between the experimental groups. Therefore, we conclude that HMP is ineffective in squirrel monkeys with preexisting dental calculus.