Abstract
How experimental caries should respond to animal bodies with or without thymus was examined by using mice and nude mice. The animals were given antibiotics for a period of three days in order to depress the oral micro flora. One day after depression with antibiotics, the animals were administered Streptococcus mutans PS-14 and 6715 once every two days until the establishment of the infected bacteria. All the animals were bred for 105 days and fed a cariogenic diet (2000)during the experimental period. After being injected with Nembutal, mouse blood was collected by means of cardiac puncture. Serum was separated and serum immunoglobulins were measured by means of the single radial immunodiffusion method. No differences between the control groups and the infectious groups in both mice and nude mice were detected in serum IgG, IgA and IgM concentrations.
In the nude mice, particulaly, plaque samples taken after sacrifice were cultured for measuring the mount of viable S. mutans. The upper and lower jaws were cleaned and then stained, and caries were scored using the Keyes method. Extensive carious lesions were produced in nude mice, but no differences during serotypes were detected in the caries score and in the mount of viable S. mutans at the time of sacrifice.
