Effect of fluoridated dentifrice and acidulated phosphate fluoride application on early artificial carious lesions

Purpose : To evaluate the effect of a combination of fluoride dentifrice and acidulated phosphate fluoride (APF) on enamel with incipient caries lesions. Materials and Methods: Bovine dental enamel blocks with artificial caries lesions were divided into four treatment groups and submitted to a pH-cycling model: (1) Placebo non-fluoridated dentifrice (PD); (2) Fluoridated dentifrice (171)), 1,100 ppm F; (3) APF (12,300 ppm F, pH 3.5) + PD; 4) APF + FD. APF was applied to enamel blocks of groups APF+PD and APF+FD before the pH-cycling regimen and all of them were exposed to dentifrice during the cycling. Results: The results showed that 61-81% of the fluoride previously deposited in enamel by APF was released to the media during the pH-cycling. The final concentration of fluoride in enamel in the group APF+PD was lower than that before the cycling (P 0.05). FD treatment was significantly more efficient than PD in rehardening the enamel surface and increasing the hardness of the caries lesions. APF+PD treatment was not more efficient than PD in increasing enamel hardness and an additive effect of APF+FD was not observed.162919

In vitro induction of enamel subsurface demineralization for evaluation of diagnostic imaging methods

The aim of this study was to investigate a model of inducing enamel subsurface demineralization for evaluating diagnostic imaging methods. Fifty sound teeth had their crowns coated with acid-resistant varnish, leaving a 7 mm(2) circular window of exposed enamel in one of the proximal surfaces. The specimens were assigned to 5 groups (4 experimental and the control) and were kept immersed in a buffer solution at pH 4.8, 50% saturated in relation to enamel, for 60, 75, 90 and 120 days, or were not exposed to the solution. Digital radiographs were taken, prior to and after each immersion period, and interpreted by a radiologist. For validation, the enamel was submitted to microhardness profiling. In addition, the solutions were analyzed for phosphorus (P-i) and calcium (Ca) concentrations. Microhardness data were evaluated using two-way ANOVA (p<0.05) and Tukey's test. P-i and Ca concentrations were compared using one-way ANOVA (alpha = 0.05). The performance of radiography was assessed by ROC analysis. The microhardness values for the control group ranged from 405 to 432 KHN. Of the 4 experimental groups, the 60-day group demonstrated the highest values (179-379 KHN) and the 120-day group, the lowest values (103-277 KHN). The lowest total concentrations of P-i and Ca (1.74 mM and 2.63 mM, respectively) were found in the solutions of the 60-day group, indicating the lowest rate of mineral loss, however, there was no significant difference among the other experimental groups. The performance for detecting images consistent with caries lesions was high (A(z) = 0.89). Therefore, this in vitro model of inducing demineralization may be considered suitable for research intended to evaluate imaging methods for the diagnosis of proximal caries lesions.15539239

Linear and logarithmic subtraction for detecting enamel subsurface demineralization

Objective: To compare the diagnostic performance of linear and logarithmically contrast-enhanced subtraction images, acquired with digital and digitized radiographs, in detecting approximal enamel subsurface demineralization. Methods: Fifty caries-free human third molars were immersed in a demineralizing solution for 60, 75, 90, and 120 days, in order to induce artificial enamel subsurface demineralization. The teeth were coated with nail varnish, leaving only a circular window of approximately 7 mm(2) in one of the approximal surfaces, allowing contact with the solution. Standardized radiographs of the teeth were taken prior to and after the demineralization period with three digital systems, CygnusRay MPS (R), DenOptix (R) and DIGORA (R), and InSight (R) film. Conventional, digital and digitized radiographs were assessed by three experienced radiologists. Linear and logarithmically contrast-enhanced subtraction images were acquired and then examined by a fourth independent radiologist. For the validation of the radiographic diagnosis, the enamel test areas were submitted to Knoop microhardness profiling. Radiographic interpretation data was evaluated using ROC analysis. The areas under the ROC curves (A(z)) were compared by the chi-squared test. The level of significance was set at P = 0.05. Results: No significant differences were found between linear and logarithmically contrast-enhanced subtraction images, acquired with the four studied modalities: CygnusRay MPS (R)(linear) (A(z) = 0.95), CygnusRay MPSlog(R) (A(z) = 0.98), DenOptix(linear)(R) (A(z) = 0.97), DenOptixe(log)(R)(A(z) = 0.99), DIGORA(linear)(R) inem (A(z) = 0.98), DIGORA(log)(R) (A(z) = 0.98), digitized radiography(linear) (A(z) = 0.99), digitized radiography(linear) (A(z) = 0.99). Conclusion: Linear and logarithmically contrast-enhanced subtraction images, acquired with digital and digitized radiographs, were diagnostically comparable for assessing enamel subsurface demineralization.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.34313313

Relationship between stressful situations, salivary flow rate and oral volatile sulfur-containing compounds

The relationship between stress, salivary flow rate and oral volatile sulfur-containing compounds (VSCs) is not clearly established. Two stressful situations were studied: psychological stress caused by a biochemistry examination (Study I) and psychophysiological stress caused by premenstrual syndrome (PMS) (Study II). Seventy-one undergraduate dental students took part in Study I and VSCs were measured 1 wk before the examination, on the day of examination and I wk after. In Study II, 50 women were selected (23 with and 27 without PMS) and the measurements were made during non-menstrual, premenstrual and menstrual stages. Unstimulated salivary flow was determined in the subjects of both studies. On the day of the biochemistry examination, VSCs significantly increased and salivary flow decreased compared with baseline values. Women with PMS showed higher VSC concentrations during the premenstrual stage than those without PMS (P < 0.05), but the salivary flow was not statistically different. A change in VSCs was observed during different stages of the menstrual cycle for the groups of women, but the salivary flow did not change. The results suggest that a stressful situation can be a predisposing factor for the increase of VSCs in the mouth air, but the mechanism cannot be simply explained by reduction of the salivary flow.110533734

Effect of a calcium carbonate-based dentifrice on enamel demineralization in situ

Since the effect of calcium carbonate (CaCO3) based dentifrice on enamel demineralization is not clearly established, it was evaluated using the IEDT model described by Zero's group in 1992. This study had a crossover design and 10 volunteers were submitted to 3 treatment groups: a negative control, brushing without dentifrice; an active control, brushing with silica-based dentifrice (SiO2/MFP group), and the experimental group, brushing with CaCO3-based dentifrice (CaCO3/MFP). Both dentifrices contained 1,500 mug F/g (w/w) as sodium monofluorophosphate (MFP). Enamel surface microhardness was determined in the dental blocks and the percentage change in relation to baseline was calculated. Fluoride uptake in enamel and its concentration in 'test plaque' were determined. The results showed that the dentifrice containing CaCO3/MFP was more effective than SiO2/MFP in reducing enamel demineralization (p < 0.05). A higher concentration of fluoride ion was found in 'test plaque' treated with CaCO3/MFP than in the negative control (p < 0.05). The results suggest that CaCO3 abrasive may enhance the effect of fluoride present in dentifrice on dental caries control. Copyright (C) 2003 S. Karger AG, Basel.37319419

Effect of sucrose concentration on dental diofilm formed in situ and on enamel demineralization

The relationship between sucrose concentration and cariogenic potential was studied in situ. Adult volunteers wore intraoral palatal appliances containing human dental enamel blocks, which were extraorally submitted 8 times a day for 14 days, to the treatments: deionized distilled water and sucrose solutions from 1 to 40%. The biofilm formed was analyzed with respect to acidogenicity and biochemical composition; enamel demineralization was evaluated by microhardness. The results showed that 1% sucrose is less cariogenic than 5% or higher concentrations, although sucrose solution at 40% was still able to increase the concentration of insoluble polysaccharide in the biofilm formed. The findings suggest that the threshold of sucrose solution concentration for the formation of a cariogenic biofilm is 5%, which provided the same cariogenic potential as that observed for 10 and 20% sucrose solution. Copyright (C) 2006 S. Karger AG, Basel.401283

Low-fluoride toothpaste and deciduous enamel demineralization under biofilm accumulation and sucrose exposure

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Because low-fluoride toothpaste (500 p.p.m. F) has not clearly been shown to be effective for controlling caries in caries-active children, this experimental in situ study was conducted to evaluate whether its effect, when compared with a conventional toothpaste (1,000-1,500 p.p.m. F), would depend on the cariogenic challenge. During four phases of 14 d each, 14 volunteers used 500 or 1,100 p.p.m. F toothpaste and wore palatal appliances containing deciduous enamel slabs, on which biofilm was accumulated and exposed to 20% sucrose solution at frequencies increasing from two to eight times per day. The F concentration was determined in the biofilm formed, and enamel demineralization was assessed by surface hardness loss (%SHL) and integrated area of hardness x lesion depth (Delta S). The F uptake by enamel was also determined. Fluoride in biofilm fluid and solids was statistically higher when conventional F toothpaste was used. The toothpastes did not differ statistically in terms of %SHL, Delta S, and F in enamel, but only the conventional F toothpaste significantly reduced caries-lesion progression according to the frequency of sucrose exposure. The findings suggest that the high-F availability in biofilm, resulting from the use of conventional toothpaste compared with low-F toothpaste, may be important for reducing caries-lesion progression in conjunction with a high frequency of sucrose exposure.1184370375Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2007/05994-3