EXPER IMENTAL ROOT SURFACE CARIES IN HAMSTERS THE DEVELOPMENT OF THE DISEASE AFTER INOCULATIONS OF TWO .f YPES OF CARIOGENIC BACTERIA

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The aim of this study was to investigate the development of root surface caries in hamsters fed a high-sucrose diet over a 24-week period after inoculations of two types of cariogenic bacteria. Twenty-one-day old male golden hamsters (n= 103) were divided into 5 groups. Four groups were given diet 2000, and one group was given a stock diet CE 2. Of the groups given diet 2000, three groups were infected with Actinomyces viscosus ATCC 15987 and Streptocοccus mutans NTCC 10449 separately (AV and SM groups) or in combination (AVSM g1oup), and one group remained uninfected. A grid method was used to evaluate the plaque accumulation, alveolar bone loss, and root surface caries. After 12 weeks, root surface caries developed mainly on the first mandibular molars in the three infected groups. At 24 weeks, the prevalence of root surface caries was highest in the AV group, but root caries scores were not significantly different among the three infected groups. In the groups SM and AVSM, the molar crowns were extensively destroyed by caries, while in the AV group the crowns were almost intact. It was concluded that challenge with Actinomyces viscosus may be appropriate to stud y root surface caries in hamsters.