Morphological study on dental caries induced in WBN/KobSlc rats (Rattus norvegicus) fed a standard laboratory diet

In our previous studies, WBN/KobSlc was characterized as a rat strain in which only males began to develop pancreatitis, and then presented with diabetic symptoms. In the course of studying their pancreatic inflammation, we detected molar caries in prediabetic males feeding on a standard diet (CRF-1) widely used for experimental animals. The purpose of this study is to confirm whether the WBN/KobSlc strain is caries-susceptible to the diet reported to be non-cariogenic, and to examine the effect of a prediabetic condition on their dental caries. For a morphological study, 25 male WBN/KobSlc rats aged 3.2–7.8 months and 24 females of the same strain aged 3.3–6.6 months were used, along with 10 males and 10 females of 8.2-month-old F344 rats. Marked dental caries were detected in the mandibular molars of male and female WBN/KobSlc rats regardless of pancreatitis, although no similar changes were observed in any teeth of the F344 strain fed the same diet. Soft X-ray examination revealed that the caries began in the crown and progressed horizontally and vertically, and that a severe radiolucent lesion extensively expanded to the entire crown, corresponding to a macroscopically deleted molar. The caries had gradually developed mainly in the second mandibular molar from more than 3.5 months of age, while none were seen in any rats before that time. The WBN/KobSlc rats were caries-susceptible even to the standard laboratory diet, and pancreatitis was not directly associated with the onset of dental caries in this strain.

Virulence of Streptococcus mutans: an antibiotic-suppressed rat model for studies of pathogenesis

This investigation describes a simple and effective method of antibiotic suppression of the total indigenous microbiol flora of rats. Specifically, the results of this study demonstrate that: (1) antibiotics which inhibit microbial growth of oral and fecal cultures from individual rats are effective in suppressing the indigenous flora of 95% of these rats when provided as dietary supplements; (2) S mutans 6715 colonized 95% of the antibiotic-suppressed animals while only 50% of the untreated rat pups yielded S mutans following challenge with a single inoculum of this micro-organism; and (3) significant smooth surface caries developed in S mutans-infected rats within 20 days when provided caries-promoting Diet 305, while noninfected, antibiotic-suppppressed offspring remained essentially caries-free.

Influence of experimental diets on carious lesions in the occlusal sulci and on the smooth surfaces of the molars of caries-susceptible rats

Three commonly used cariogenic diets were compared to determine why their abilities to support weight gain differed. The initiation and development of carious lesions in the occlusal sulci and on the smooth surfaces of rat molars also were evaluated. Relatively small changes in dietary composition tended to cause major changes in caries activity at one or both sites.

Patterns of dental caries in osborne-mendel and NIH black rats in relation to length of the caries test period

Both Osborne-Mendel and NIH Black rats developed carious lesions on the smooth surfaces and in the sulci during the first week on an intensive caries-test challenge. The number and size of lesions continued to increase throughout a ten week experiment. Progression on different surfaces varied with the strain, but final levels were not significantly different.

Comparison of the caries-producing properties of diets 2700, 2000, and modifications of 2000 in rats

Diet 2000 did not support as rapid growth as did diet 2700, even when supplemented simultaneously with protein, unsaturated fats, B-complex and fat-soluble vitamins, and minerals. With some strain variation, the mineral mixture as a supplement to diet 2000 caused reductions in caries activity in occlusal sulci and on smooth surfaces to about the same levels observed with diet 2700. Sucrose and confectioner's sugar fed alone alternating with laboratory meal were about equally capable of supporting caries.

Development of caries in the Hung-Hoppert caries-susceptible and caries-resistant rats under different experimental conditions

Rats of both Hunt-Hoppert lines, originally designated as caries-susceptible (Ca-S) and caries-resistant (Ca-R) lines, were highly susceptible to caries when subjected to a combination of diet and microflora that provided a challenge to the resistance of all surfaces of the teeth. Strain differences were indicated by the predominance of sulcal lesions in the Ca-S line and smooth-surface lesions in the Ca-R line.

Caries development in the African white-tailed rat (Mystromys albicaudatus) infected with a streptococcus of human origin

The African white-tailed rat (Mystromys albicaudatus) developed rampant dental caries when challenge was made with a combination of diet 2000 and a streptococcus of human origin (KI-R). The apparent lack of caries in certain species may result from the absence of a microbial and dietary challenge, rather than inherent resistance to the disease.