EFFECTS OF SUGAR RESTRICTION ON STREPTOCOCCUS-MUTANS AND STREPTOCOCCUS-SOBRINUS IN SALIVA AND DENTAL PLAQUE

The effect of sugar restriction on the oral levels of mutans streptoco cci was studied in 20 subjects fulfilling three criteria: (1) having m ore than 300,000 CFU mutans streptococci/ml saliva, (2) harbouring bot h Streptococcus mutans and Streptococcus sobrinus in saliva, and (3) e ating sugar frequently. The subjects were randomly divided into a test group (n = 12), who were asked to refrain from using sugar-containing foods between meals and to reduce sugar in main meals for 6 weeks, an d a control group (n = 8), who did not receive any dietary advice. Sal iva and plaque samples were collected at baseline and at 3, 6 and 12 w eeks. The results showed that the levels of S. mutans and S. sobrinus decreased in saliva and plaque during the 6-week sugar restriction per iod. The decrease in mutans streptococci was more pronounced on buccal than on approximal tooth surfaces. Both species seemed to react in a similar way to the sugar restriction in saliva as well as in dental pl aque. At the follow-up examination at 12 weeks, i.e. 6 weeks after com pleting the sugar restriction period, the numbers of S. mutans and S. sobrinus had increased again, but were still lower when compared to th e baseline values.