Caries Development In Rats Research Articles

The effect of different doses of octenidine hexafluorosilicate on the development of dental caries in rats

At present, ammonium hexafluorosilicate and hexafluorosilicates of organic amonium cations are actively studied as potential anticaries agents, which demonstrate certain advantages over traditional compounds of fluorine. Previously, it was shown that hexafluorosilicates with bactericidal cations of chlorhexidine, polyhexamethyleneguanidine and cetylpyridinium effectively reduce the number and depth of carious lesions of teeth in rats and at the same time significantly improve the biochemical parameters of the pulp of the teeth.
 The aim of the work – to study the effect of different doses of octenidine hexafluorosilicate (OHFS) on the incidence of dental caries in rats fed a cariogenic diet (CD).
 OHFC preparations were applied to the teeth and gums of rats in the composition of phytogels based on Na-salt of carboxymethylcellulose. In the incisor pulp, the activity of alkaline (ALP) and acidic (ACP) phosphatases, elastase, lysozyme was determined, and the mineralizing index (MI) was calculated. The number and depth of dental caries lesions were calculated and caries prophylactic efficacy (CPE) was calculated. The activity of elastase, catalase, lysozyme and urease was determined in the gums, and the degree of atrophy of the alveolar process was determined.
 Determination of dental caries lesions shows that CD does not increase the number of carious lesions, and after the application of gels with OHFS, their number significantly decreases. The most effective was the concentration of the OHFS gel, equal to 2 mg/ml, although the concentration of the OHFS gel 1 mg/ml showed a decrease by 33.3%. The calculated CPE is 33.3% for a gel with 1 mg/ml OHFS, 36.4% for a gel with 2 mg/ml and 24.2% for a gel with 4 mg/ml. It has been shown that in rats receiving CD, the ALP activity significantly decreases and the ACP activity significantly increases, which gives a significant decrease in MI from 43.9 to 28.9. Application of gels with OHFS returns the activity of both phosphatases to the control level and almost completely normalizes MI, and the concentration of OHFS gel of 2 mg/ml turned out to be the most effective. Application of gels with 1 mg/ml and 2 mg/ml OHFS reduced elastase activity by 6% and 12%, respectively, whereas application of a gel with 4 mg/ml OHFS did not result in a decrease in elastase activity. From the results of determining the degree of dysbiosis in the blood serum of rats, it can be seen that CD causes the development of generalized dysbiosis. Application of gels with OHFS significantly reduce the degree of dysbiosis, especially gels with OHFS concentrations of 1 and 2 mg/ml.
 Oral application of gels containing OHFS reduces the incidence of caries on the teeth, increases the mineralizing activity of the pulp and reduces the degree of generalized dysbiosis. The most effective concentration of the OHFS gel is 2 mg/ml, which corresponds to a dose of 2.2 mg/kg.

Antimicrobial peptide GH12 targets Streptococcus mutans to arrest caries development in rats

ABSTRACTBackground:Targeting Streptococcus mutans, the principle cariogenic bacterium, could prove to be an effective means of preventing dental caries. A de novo designed antimicrobial peptide, GH12, has shown bactericidal effects on S. mutans and inhibitory effects on virulence and regulatory systems of S. mutans. However, the effects of GH12 on caries remain to be elucidated.Objectives: The objectives of this study were to evaluate the direct effects of GH12 on caries and numbers of S. mutansin vivo.Design: The Keyes score was evaluated in a rodent model and in vivo S. mutans was quantified by qPCR. To further interpret the in vivo anticaries efficacy, an in vitro biofilm model using short-term treatments with GH12 mimicked treatments in vivo was adopted. Results: In vivo data showed that GH12 at 8 mg/L reduced the incidence and severity of caries. Furthermore, GH12-treated animals had less S. mutans infection. In vitro data revealed that GH12 reduced the number of S. mutans within the biofilm, as well as reducing lactic acid and water-insoluble EPS synthesis of S. mutans biofilms. Afterwards, all rats showed no significant difference in weight gain, and no sign of harm to the mucosa, indicating that GH12 possessed good biocompatibility in vivo.Conclusion: Due to the combined inhibitory effects of GH12 on the biomass and cariogenic properties of S. mutans biofilms, the population of S. mutans in vivo was reduced, residual S. mutans biofilms were less acidic and compact, and thereby the onset and development of caries were arrested. Such findings collectively certified the clinical prospects for GH12.

Effects of Wi-Fi (2.45 GHz) and Lactic Acid Bacteria on Oral Pathogens and Caries Development in Rats.

To evaluate the effects of Wi-Fi and lactic acid bacteria on salivary mutans streptococci and caries formation. Wistar rats and their offspring were equally divided into two main groups and seven subgroups. Experimental groups were exposed to Wi-Fi during pregnancy and lactation. Subgroups were divided according the administration of the beneficial bacteria L. plantarum 167.P6.5 and L. rhamnosus M17-10.2. In the 8-week experimental period after weaning at 21 days, Mutans streptococci counts and the number of carious lesions were determined. The MS count ratios at the end of 8 weeks were statistically significantly lower than those at the end of 4 weeks in all groups given L. rhamnosus (p < 0.05). A strong correlation was found between the total MS count and sulcal caries scores (r = 0.507). No statistically significant difference was observed between groups exposed to Wi-Fi and other groups in terms of microorganism count and caries scores (p < 0.05). These results suggest that lactic acid bacteria, especially those originating from an oral source, may be of benefit as probiotics for the prevention of oral pathogens and dental caries. Perinatal and lactational exposure to Wi-Fi does not predispose to caries development in rats.

Effect of emodin on the cariogenic properties of Streptococcus mutans and the development of caries in rats.

Emodin is an active herbal component traditionally used in East Asian countries for treating a variety of diseases. The present study investigated the effects of emodin on specific virulence factors of Streptococcus mutans (S. mutans) in vitro and on caries development in vivo. The growth and acid production of S. mutans were significantly inhibited by emodin (0.5–2 mg/ml). Emodin also significantly suppressed the synthesis of insoluble glucans by S. mutans. Furthermore, the topical application of emodin reduced the incidence and severity of carious lesions in rats. These results suggest that the natural compound emodin may be a novel pharmacological agent for the prevention and treatment of dental caries.

The effect of eugenol on the cariogenic properties of Streptococcus mutans and dental caries development in rats

Eugenol has been widely used in medicine due to its antibacterial, anti-inflammatory, antioxidant, anticancer and analgesic properties. The present study was designed to investigate the effects of eugenol on the cariogenic properties of Streptococcus mutans and dental caries development in rats. Eugenol demonstrated significant inhibitory effects against acid production by S. mutans. The synthesis of water-insoluble glucans by glucosyltransferases was reduced by eugenol. Eugenol also markedly suppressed the adherence of S. mutans to saliva-coated hydroxyapatite beads. Furthermore, topical application of eugenol reduced the incidence and severity of carious lesions in rats. These results suggest that the natural compound eugenol may be a useful therapeutic agent for dental caries.

Inhibitive effect of photodynamic therapy with different parameters on caries development in rats

Objective To evaluate the inhibitive effect of Photodynamic therapy (PDT) with different parameters on dental caries formation in rats.Methods Wistar rats were infected with S.mutans to establish the rat caries mode 1.The rat's teeth were treated with 0.9% NS and 0.2% NaF as controls;laser,photosensitizer and laser plus photosensitizer,respectively as treated groups.Hematoporyrin monomethyl ether(HM ME) was used as photosensitizer and laser as the light source.The rats were sacrificed after five weeks.Keyes count was used to measure the inhibitory effect of PDT on dental caries.The surface morphology of the teeth was evaluated by scan electronic microscopy(SEM).Results The PDT-treated group and NaF-treated group showed significantly reduced Keyes scores compared with the negative controls (P＜0.05).The laser-treated group,photosensitizer-treated group and NS-treated group showed no significantly reduced Keyes scores compared with the negative controls (P＜0.05).The differences of Keyes scores between various parameter PDT treated groups were significant (P＜0.05).Additionally,Keyes scores reduced gradually with the increasing of laser power.The outcome of SEM showed that the teeth treated with different laser powers exhibited different changes in morphology.Conclusion HMMEPDT had significant inhibitive efficacy on caries development in rats and its inhibitory effect presented close correlation with the power of laser,which indicates that it is important to apply appropriate power in clinical treatment. Key words: Photodynamie therapy; Hematoporyrin monomethyl ether; Animal caries model

Protective efficacy of Psidium cattleianum and Myracrodruon urundeuva aqueous extracts against caries development in rats

This study evaluated the influence of Psidium cattleianum Sabine (Myrtaceae) and Myracrodruon urundeuva Allemão (Anacardiaceae) aqueous extracts on S. mutans counts and dental enamel micro-hardness of rats submitted to a cariogenic challenge. Sixty Wistar rats were distributed in three groups and received water (control) or aqueous extracts of Psidium cattleianum or Myracrodruon urundeuva as hydration solution. Initially the animals had their sublingual and submandibular salivary glands surgically removed and the parotid ducts ligated. Then the rats were inoculated with 106 CFU of Streptococcus mutans ATCC 35668 and were fed with a cariogenic diet. To detect and quantify the presence of S. mutans, oral biofilms were sampled and microbial DNA was extracted and submitted to amplification by means of real-time PCR (Polymerase Chain Reaction). After seven weeks the animals were sacrificed and enamel demineralization was analyzed by cross-sectional micro-hardness. Both extracts produced a significant reduction on S. mutans counts and decreased the enamel demineralization. It can be concluded that the extracts tested had a significant effect on S. mutans in oral biofilm of the rats, decreasing S. mutans accumulation and enamel demineralization.

Apigenin andtt-Farnesol with Fluoride Effects onS. mutansBiofilms and Dental Caries

Apigenin (Api) and tt-farnesol (Far) are two naturally occurring agents that affect the development of cariogenic biofilms. Fluoride (F) interferes physicochemically with caries development and also exhibits antibacterial activity. We examined whether the association of Api and Far enhance the anti-caries properties of F by acting cooperatively on the expression of virulence of Streptococcus mutans. The biological effects of each of the agents were greatly enhanced when used in combination with F. In general, biofilms treated with Api and/or Far in combination with F displayed less biomass and fewer insoluble glucans and iodophilic polysaccharides than did those treated with the test agents alone (P < 0.05). The combination of the test agents with F was highly effective in preventing caries development in rats, especially Api+Far+F, and results were comparable with those observed with chlorhexidine + F (positive control). Results from these studies showed that apigenin and tt-farnesol may enhance the cariostatic effectiveness of fluoride.

Effects of caffeine and theophylline on the development of dental caries in rats.

The purpose of this study was to evaluate the influence of caffeine and theophylline on the development of dental caries in rats. Six Wistar dams (spf), mutans streptococci free, were obtained, each with six male pups. The dams were infected by Streptococcus sobrinus 6715 and divided into three groups which received during the lactating period: (1) diet 2000; (2) diet 2000 plus caffeine (2 mg/100 g) and (3) diet 2000 plus theophylline (0.57 mg/100 g). After weaning, the pups were infected by S. sobrinus, placed in a König-Höfer programmed feeder machine, and received 17 meals daily at hourly intervals, for five weeks. During this time the pups were fed with the same diet that their dams were. The percentage of S. sobrinus relative to total flora was significantly higher in the theophylline group. The results for slight (Ds) and moderate (Dm) dentine lesions, for smooth-surface and sulcal scores were statistically higher for the theophylline group than the other groups. Salivary assays did not demonstrate significant inorganic alterations in salivary composition. Caffeine and theophylline groups showed the highest ulcer score. It is concluded that caffeine does not affect the cariogenic potential of the diet, however theophylline can increase the development of dental caries, and this effect may be related to organic alterations of salivary composition.

Litter Effects on Caries in Rats and Implications for Experimental Design

The purpose of this study was to obtain quantitative estimates of litter effects on caries development in rats and to examine the implications for design of rat caries experiments. Twelve female Sprague–Dawley rats, aged 60 days, were bred with 4 male rats. Nine of the 12 dams had litters in close proximity. The litters were culled to 10 pups. One pup from each litter was placed with each of the other dams for nursing, leaving 2 pups from each litter with the birth dam. This design allowed the litter effect to be separated into a prenatal component, reflecting the shared genetic makeup and in utero environment of littermates, and a postnatal component reflecting a shared environment from shortly after birth to weaning. Pups were infected with Streptococcus sobrinus and fed Diet 2000 and 10% (w/v) sucrose water for 5 weeks. There was no significant evidence of a postnatal litter effect for smooth surface caries (p = 0.37) or sulcal caries (p = 0.43). The prenatal litter effect was significant for both smooth surface caries and sulcal caries (p<0.01). When litter effects are present, the statistical power of caries studies is improved if animals from the same litter are divided evenly among experimental groups. In addition, if litter effects are present but not allowed for in data analysis, incorrect statistical inferences may be drawn. Based on our results and other reports of litter effects, we recommend planning for litter effects in the design and analysis of rat caries studies.

Effects of a hydrogenated isomaltooligosaccharide mixture on glucan synthesis and on caries development in rats.

The caries inhibitory effect of the hydrogenated derivative of an isomaltooligosaccharides mixture (IMO-H) was examined in vitro and in vivo experiments. IMO-H could not be used as a substrate for the crude glucosyltransferases (GTases) of Streptococcus sobrinus 6715 to synthesize water-insoluble glucan. Moreover, it not only significantly inhibited the synthesis of water-insoluble glucan from sucrose, but also the sucrose-dependent adherence of these growing cells the glass surfaces. In the in vivo experiment, the addition of IMO-H to a sucrose-containing diet resulted in significant reduction of caries development in specific-pathogen-free (SPF) rats infected with S. sobrinus 6715.

Development of Preventive Measures Based on the Aetiology of Dental Caries: A Review

Mutans streptococci including Streptococcus mutans and Streptococcus sobrinus are aetiologically associated with the development of dental caries in humans and experimental animals. These organisms produce glucosyltransferases (GTases), which catalyse the synthesis of adherent glucan from sucrose, promoting the adherence of the organisms to the tooth surface. In addition, they release large quantities of acids from various dietary sugars. These are the essential virulence factors of mutans streptococci. We found that structural isomers of sucrose such as palatinose and trehalulose were not utilised by the organisms and no significant glucans or acids were produced. Another interesting sucrose substitute would be sugar alcohol; maltitol and palatinit are good examples. Other unique compounds developed recently are oligosaccharides rich in isomaltose and panose, which contain α (1→6) glucosidic linkage. They strongly inhibit glucan synthesis from sucrose by GTases, and cannot be degraded by most oral streptococci. These sucrose substitutes are now manufactured on an industrial scale. Enzymatic inhibition of GTases is an alternative measure to suppress caries development. Polymeric polyphenol compounds from oolong tea and hen egg yolk IgG specific for cell-associated GTase of mutans streptococci have been shown to exhibit marked GTase inhibition and decrease in caries development in rats. Keywords: dental caries, mutans streptococci, glucosyltransferase, palatinose, polyphenol, maltitol, passive immunity.

Composition and Flow Rate of Saliva and Caries Development in Young Rats following Administration of Lithium

Lithium carbonate (Li2CO3), an antipsychotic medication, was investigated to determine the effects on the stimulated flow and composition of saliva and on caries development in rats. Lithium carbonate was delivered via osmotic pumps at 10, 15 and 60 mg/kg/day. All animals were infected with Streptococcus sobrinus 6715 and fed a cariogenic diet. Lithium administration exerted a caries-protective effect on sulcal surfaces, though the reduction in caries scores was statistically significant only for the groups receiving Li2CO3 at 10 and 60 mg/kg/day compared to control animals (p +/- 0.05, ANOVA). There were no detectable alterations in protein concentration, electrophoretic profiles, or flow rates of stimulated parotid and submandibular saliva associated with the decreased sulcal caries incidence. Weight gain, water consumption and the populations of total cultivable flora recovered were not influenced by the administration of lithium. Investigation into the mechanisms of the sulcal caries reduction will require further exploration of changes caused by lithium on salivary gland function.

Trehalulose Does Not Induce Dental Caries in Rats Infected with Mutans Streptococci

The effects of trehalulose, a structural isomer of sucrose, and a syrup (TP syrup) rich in trehalulose and palatinose on caries development were examined in specific pathogen-free Sprague-Dawley rats. Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 fermented the syrup which resulted in acid production, while both strains were found not to utilize trehalulose. Furthermore, trehalulose did not serve as a substrate for glucosyltransferases of these mutans streptococci to synthesize water-insoluble glucan, and it inhibited the sucrose-dependent adherence of mutans streptococci to a glass surface. Although trehalulose induced no significant dental caries in specific pathogen-free rats infected with either MT8148R or 6715, TP syrup was found to induce significant but low dental caries. Furthermore, replacement of the dietary sucrose content with trehalulose resulted in a significant reduction of caries development in rats infected with strain 6715.

Non-cariogenicity of the disaccharide palatinose in experimental dental caries of rats.

The caries-inducing activity of palatinose (isomaltulose, alpha-D-glucopyranosyl-1,6-fructose) was examined in in vitro and in vivo experiments, comparing it with other carbohydrates. When Streptococcus mutans was successively subcultured in a broth medium containing 1% palatinose, the strains belonging to serotype a, d, or g did not ferment palatinose, whereas the strains belonging to serotype b, c, e, or f did ferment palatinose. Furthermore, palatinose significantly inhibited the synthesis of insoluble glucan from sucrose by S. mutans. Specific-pathogen-free rats which had been infected with S. mutans 6715 and fed a diet containing 56% palatinose did not develop significant dental caries. However, rats infected similarly, but fed a diet containing sucrose, glucose, fructose, or a glucose-fructose mixture manifested significant caries when compared with the noninfected, sucrose-fed control rats. Furthermore, it was found that replacement of half of the sucrose content with palatinose resulted in decreased caries development compared with caries development in rats fed the sucrose diet.

An effect of zinc deficiency on dental caries

Rat pups suckled by dams fed a zinc-deficient diet developed higher levels of dental caries following a caries-test challenge than pups suckled by dams fed a zinc-adequate diet. The zinc deficient treatment was administered during the mineralization stage of tooth development before the molars erupted. The data shows that suboptimal zinc nutriture was associated with an increase in dental caries. Fluoride, a trace element, is recognized as a factor in preventing dental caries and its use has had a significant impact on dental health in this country. However, the possible roles of other trace elements have not been closely examined. Zinc is a trace element important to bone mineralization as well as in general nutrition. The effects on dental caries produced by the addition of zinc to rat diets have been reported (1, 2, 3). In those investigations, however, zinc supplements were added to diets that were adequate in zinc. Moreover, zinc supplements were fed after the teeth had appeared in the oral cavity. Because the critical period of tooth maturation occurs before eruption (4), post-eruptive zinc supplements probably should not markedly influence the development and, specifically, the mineralization of the tooth. Therefore, we investigated the influence of pre-eruptive zinc deficiency on caries development in rats.

Action of melatonin on caries development in rats.

Action of melatonin on caries development in rats.

Action of lactose and calcium on caries development in rats.

Action of lactose and calcium on caries development in rats.

The Effect of Phosphate Structure on Dental Caries Development in Rats

The Effect of Phosphate Structure on Dental Caries Development in Rats

Caries development in rats of different ages with controlled flora

Sprague-Dawley rats were subjected to a 56-day caries test regimen on cariogenic Diet 580 started when they were 18, 21, 25, 30, 35 or 40 days of age. Comparisons of caries activity were made in three experimental groups: A—Controls; B—Animals “infected” by being housed with an older caries-active animal the first week on the test regimen; C—Animals pretreated for 5 days with erythromycin and then “infected” as in Group B. All animals were maintained on a noncariogenic laboratory chow prior to the beginning of the caries-test period. Animals sacrificed at 40 days of age without having been on the test regimen were caries-free. The “noninfected” animals of Group A showed so much variation that no valid correlation of caries activity with age could be demonstrated. Both groups of “infected” animals (B and C). whether or not pretreated with an antibiotic, showed comparable high levels of activity, which was consistently less for the older animals. The buccal and lingual surfaces, which tend to become more self cleansing in the older animals, showed a greater decrease in caries activity than the proximal and sulcal surfaces, whose anatomical features favor food and microbial plaque accumulation. While the results are in general consistent with the opinion that resistance to the carious process increases with age it appeared that the age of the tooth is not the sole determinant.