Intermittent sucrose feeding and caries in hamsters.

SEVERAL studies have compared the effects of sucrose and other carbohydrates on caries activity in rats receiving modifications of cariogenic diet 2000 of KEY= and JORDAN (1964) and it has been concluded that complete or intermittent replacement of dietary sucrose with other carbohydrates results in greater inhibition of caries on the molar smooth surfaces of rats than in the deep molar fissures (LARJE and LARSON 1970; FROSTELL, KEYES and LARSON, 1967; GUGGENHEIM et al., 1966). In the hamsters, where the predominant type of caries observed resembles smooth surface caries in rats, major reductions in caries have also resulted when sucrose was completely re-Because of the implied relationship between dietary sucrose and smooth surface caries activity in these test systems, it was desirable to determine the effects of intermittent substitution of sucrose with other carbohydrates on caries activity in the hamster since evidence of this particular aspect of the sucrose caries relationship in hamsters was not available. In the present study, glucose or corn starch was used as the sucrose substitute according to the schedule shown in Table 1. Theexperimentalfeeding programmes were started 7 days after weanling hamsters, 19-21 days of age, were infected orally with Streptococcus mutans strain Kl-R and provided with Diet 2000, which contained 56 per cent powdered sucrose, to facilitate implantation of Strep. mutans and initiation of plaque formation. One week prior to the termination of the experiment, oral swabs of 3 animals in each group were incubated overnight at 37°C in Todd-Hewitt broth and the cultures were examined by the fluorescent antibody technique (JABLON and ZINNER, 1966) for the detection of the following serotypes : Strep. mutans strains AHT, BHT and GS-5, which correspond to serologic groups a, b, and c of BRATTHALL (1970); Streptococcus sdivarius strain HHT and Actinomyces viscosus strain T-6. The study was terminated after 6 weeks of the experimental dietary programme and the defleshed jaws were stained with 5 per cent aqueous (w/v) Procion Brilliant Red 3 BNS (I.C.I. Organics, Providence, Rhode Island) according to ZINNER, DUANY and GOLAND (1971). Plaque extent was expressed as the number of molar surface units (KEYES, 1959) containing adherent deposits; caries was scored by the method of KEYES (1959). Table 1 shows that complete replacement of sucrose by glucose or corn starch after the first week of the experiment resulted in drastic reductions in caries scores in the 215 216 DOROTHEA B. FITZGERALD AND R. J. …