Effect of mutacin administration on Streptococcus mutans-induced dental caries in rats

A bacteriocin from serotype c Streptococcus mutans strain C3603 was examined for its inhibitory effect on experimental dental caries in rats infected with S. mutans MT8148R (serotype c). Significant reduction in the incidence of dental caries was found only when bacteriocin was incorporated both in the drinking water and in the diet at a high concentration. However, caries reduction was not as great as expected and the addition of bacteriocin to drinking water alone had no effect on the recovery of S. mutans, plaque deposition or caries incidence. The bacteriocin activity must have been reduced in the oral cavity of rats, and the reasons were examined. Bacteriocin-resistant mutants were not detected and the bacteriocin was not inactivated by saliva. Whereas the bacteriocin did not kill the S. mutans cells grown in a sucrose-containing medium, it completely killed the cells grown in a sucrose-free medium.     

L-gulono-gamma-lactone oxidase deficiency in rats with osteogenic disorder: enzymological and immunochemical studies

A strain of Wistar rats with L-gulono-gamma-lactone oxidase deficiency has recently been established. The activity of L-gulono-gamma-lactone oxidase in hepatic microsomes of the mutant rats was not detectable, while that of heterozygous rats was about half that of normal rats. These results were confirmed by immunological quantitation using antibody directed against this enzyme. Thus, it appears that these mutant rats either possess no enzyme at all or a very aberrant form of the enzyme in the liver. Aldonolactonase, another enzyme participating in the biosynthesis of L-ascorbic acid, was found to be present in normal amount in the mutant strain.     

Maternal transmission and dental caries induction in Sprague-Dawley rats infected with Streptococcus mutans

Thirty-four female rats (18 days old) were infected with Streptococcus mutans MT8148R (serotype c) or 6715 (g). Diets containing different proportions of sucrose were used to prepare the dams which harbored various levels of S. mutans in their oral cavity. Around 66 days of age, the female rats were bred and 34 dams subsequently bore 322 offspring. The dams were killed upon weaning (20 days of age) of their respective litters. There were positive correlations between the recovery of inoculated S. mutans and the caries incidence in the dams. Transmission of S. mutans from a dam to her offspring was studied in 10-, 15-, 20-, 27-, 34-, 41-, 48-, and 55-day-old rats by evaluating the recover of S. mutans from the offspring. Positive correlation between the magnitudes of recovered S. mutans MT8148R from dams and their offspring was found in all ages of young rats examined. Furthermore, caries incidence in young rats was found to be positively correlated with the recovery of both strains of S. mutans as well as with incidence of caries in their respective dams.     

Diabetes enhances dental caries and apical periodontitis in caries-susceptible WBN/KobSlc rats

Many epidemiologic studies have suggested that diabetes may be an important risk factor for periodontal disease. To determine whether diabetes induces or enhances periodontal disease or dental caries, dental tissue from diabetic male and nondiabetic female WBN/KobSlc rats and male and female age-matched nondiabetic F344 rats was analyzed morphologically and morphometrically for these 2 types of lesions. Soft X-ray examination revealed that the incidence and severity of both molar caries and alveolar bone resorption were much higher in male WBN/KobSlc rats with chronic diabetes than in nondiabetic female rats of the same strain. Histopathologic examination showed that dental caries progressed from acute to subacute inflammation due to bacterial infections and necrosis in the pulp when the caries penetrated the dentin. In the most advanced stage of dental caries, inflammatory changes caused root abscess and subsequent apical periodontitis, with the formation of granulation tissue around the dental root. Inflammatory changes resulted in resorption of alveolar bone and correlated well with the severity of molar caries. Our results suggest that diabetic conditions enhance dental caries in WBN/KobSlc rats and that periodontal lesions may result from the apical periodontitis that is secondary to dental caries.     

Alloxan-induced hyperglycemia causes rapid-onset and progressive dental caries and periodontitis in F344 rats

We have previously shown that diabetes increases dental caries, and periodontitis might be a secondary change resulting from dental caries in spontaneous diabetic rodent models. However, the lesions in these models were slow to manifest, and the intensity and frequency were mild and varied among individuals. The goal of this study was to confirm the reproducibility of caries development in chemically induced diabetic rats and investigate whether alloxan, which induces immediate and severe hyperglycemia in experimental animals, increases the lesions. Female F344 rats were examined 13 and 26 weeks after dosing of alloxan. Alloxan injection induced severe hyperglycemia in two-thirds of the rats. Progressive molar caries and periodontitis were already induced in all diabetic rats 13 weeks after dosing of alloxan, although the lesions were not observed in nondiabetic rats. Histopathologically, dental caries initially developed in the crown, then spread into the dental root, entered the periodontal connective tissue via the apical foramen, and progressed to periodontitis. In conclusion, alloxan-induced severe hyperglycemia is capable of causing rapid-onset and progressive dental caries and periodontitis in rats.     

Secretor status and dental caries in Iceland

The proportion of non-secretors of ABH blood-group substances among Icelanders is one of the highest recorded for European countries. Dental caries prevalence is also very high. In this study of dental caries in young adults mean number of decayed, missing and filled teeth for secretors were 17.4 and for non-secretors 19.9 (P less than 0.05). A majority of patients seeking free dental treatment in the Dental School were non-secretors (62.7%) significantly more than the proportion of non-secretors in the general population (36%; P less than 0.01). It is postulated that blood group substances may interfere with the adherence of Streptococcus mutans to teeth.     

Lactobacilli in human dental caries and saliva

Samples (98 plaque and 72 saliva) from 93 patients with dental caries were investigated for Lactobacillus species which comprised 65 (62.5%) of 104 isolates. Yeasts (20.1%), Streptococcus spp. (8.7%), Staphylococcus spp. (2.9%) and a few unidentified species (5.8%), were also found. The Lactobacillus isolates were L. brevis (24.6%) L. fermentum (18.5%) L. casei (16.9%), L. delbrueckii (15.4%), L. plantarum (9.23%), L. acidophilus (7.69%), L. jensenii (4.62%), L. salivarius (1.54%) and L. gasseri (1.54%). The most common species was L. brevis (24.6%). The strains tested for beta-lactamase production showed 75.4% positive. All the Lactobacillus strains were tested for bacteriocin production against Escherichia coli, Salmonella spp., Shigella dysenteriae, S. sonnei, Klebsiella spp. and Campylobacter sp. All the lactobacilli except L. jensenii produced bacteriocin against at least one of the indicator organisms. The involvement of Lactobacillus in dental caries was established, although its role and mechanism is not well understood. The ability of Lactobacillus spp. to protect their host against certain diseases by inhibiting the growth of potential pathogens was evident.     

Secretor status and dental caries in Iceland

Abstract The proportion of non-secretors of ABH blood-group substances among Icelanders is one of the highest recorded for European countries. Dental caries prevalence is also very high. In this study of dental caries in young adults mean number of decayed, missing and filled teeth for secretors were 17.4 and for non-secretors 19.9 ( P < 0.05). A majority of patients seeking free dental treatment in the Dental School were non-secretors (62.7%) significantly more than the proportion of non-secretors in the general population (36%; P < 0.01). It is postulated that blood group substances may interfere with the adherence of Streptococcus mutants to teeth.