Resumo O objetivo deste estudo in vitro foi determinar a concentração de fluoreto nos produtos de diamino fluoreto de prata (DFP) e sua biodisponibilidade com dentina desmineralizada. Os produtos avaliados (concentrações esperadas de flúor) foram: I: Saforide 38% (45.283 ppm F); II: Advantage Arrest 38,3 a 43,2% (45.283 a 51.013 ppm F); III: Ancárie 12% (14.100 ppm F); IV: Ancárie 30% (35.400 ppm F), V: Cariestop 12% (14.100 ppm F) e VI: Cariestop 30% (35.400 ppm F). A concentração de fluoreto foi avaliada utilizando um eletrodo íon-específico (EIE) por técnica direta, que foi confirmada após microdifusão. O pH dos produtos foi determinado com uma tira de teste de pH. Para o teste de biodisponibilidade, blocos de dentina desmineralizada foram tratados com um dos produtos por 1 min. Fluoreto fracamente (tipo CaF2) e firmemente ligado (FAp) foram determinados. A concentração de fluoreto encontrada nos produtos (média±DP; ppm F) pela técnica direta com EIE foi: I: 53.491±554; II: 57.249±1.851; III: 4.814±268; IV: 5.726±43; V: 10.145±468; VI: 11.858±575; esses valores foram confirmados após microdifusão (teste t; p>0,05) e discordam dos declarados pelos fabricantes. O pH do Ancárie 12 e 30% foi de 6,0 e 4,5, respectivamente, em desacordo com o pH alcalino esperado para a solução de DFP e encontrado nos demais produtos avaliados. Não houve correlação entre CaF2 (r=0,221; p=0,337) ou FAp (r=-0,144; p=0,830) formados na dentina desmineralizada e concentração de fluoreto encontrada nos produtos. Os problemas de pH e concentração de fluoreto encontrados nos produtos comerciais profissionais disponíveis de DFP sugerem que eles não estão sob vigilância sanitária.

Abstract The aim of this in vitro study was to determine the fluoride concentration in silver diamine fluoride (SDF) products and their bioavailability with demineralized dentine. The products evaluated (expected fluoride concentrations) were: I: Saforide 38% (45,283 ppm F); II: Advantage Arrest 38.3 to 43.2% (45,283 to 51,013 ppm F); III: Ancárie 12% (14,100 ppm F); IV: Ancárie 30% (35,400 ppm F), V: Cariestop 12% (14,100 ppm F) and VI: Cariestop 30% (35,400 ppm F). The fluoride concentration was evaluated using an ion-specific electrode (ISE) by direct technique, which was confirmed after microdiffusion. The pH of the products was determined with a pH test strip. For the bioavailability test, demineralized dentine slabs were treated with one of the products for 1 min. Loosely (CaF2-like) and firmly-bound fluoride (FAp) were determined. The fluoride concentration found in the products (mean±SD; ppm F) by the ISE direct technique was: I:53,491±554; II:57,249±1,851; III:4,814±268; IV:5,726±43; V:10,145±468; VI:11,858±575; these values were confirmed after microdiffusion (t-test; p>0.05) and disagree with the declared by the manufacturers. The pH of Ancárie 12 and 30% was 6.0 and 4.5, respectively, in disagreement with the alkaline pH expected for SDF solution and found in the other products evaluated. There was no correlation between either CaF2-like (r=0.221; p=0.337) or FAp (r=-0.144; p=0.830) formed in demineralized dentine and fluoride concentration found in the products. The problems of pH and fluoride concentration found in available professional commercial SDF products suggest that they are not under sanitary surveillance.

Abstract Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Abstract: Iontophoresis is a noninvasive technique, based on the application of a constant low-intensity electric current to facilitate the release of a variety of drugs, whether ionized or not, through biological membranes. The objective of this research was to evaluate the effect of iontophoresis using different electric current intensities on the uptake of fluoride in dental enamel with artificial caries lesions. In this in vitro operator-blind experiment, bovine enamel blocks (n = 10/group) with caries-like lesions and predetermined surface hardness were randomized into 6 groups: placebo gel without fluoride applied with a current of 0.8 mA (negative control), 2% NaF gel without application of any current, and 2% NaF gel applied with currents of 0.1, 0.2, 0.4 and 0.8 mA. Cathodic iontophoresis was applied for 4 min. The concentration of loosely bound fluoride (calcium fluoride) and firmly bound fluoride (fluorapatite) was determined. The results were analyzed by the nonparametric Kruskal-Wallis and Dunn tests. Iontophoresis at 0.8 mA, combined with the application of fluoridated gel (2% NaF), increased fluoride uptake in enamel with caries-like lesions, as either calcium fluoride or fluorapatite.

Resumo O fluoreto presente em dentifrícios de 1,100 µg/g é considerado efetivo no controle de cárie dental. No entanto, sob alto desafio cariogênico devido ao aumento da exposição ao açúcar, maior concentração de fluoreto (5.000 µg/g) poderia ser necessária para compensar o desequilíbrio no processo de cárie. Isso foi testado em um modelo de ciclagens de pH, que avaliou o efeito da concentração do fluoreto, relacionada ao dentifrício, na redução da desmineralização do esmalte dental sob condição de dois níveis de desafio cariogênico. Blocos de esmalte (n=20) foram submetidos a dois regimes de ciclagens de pH, simulando 8 e 16 exposições diárias ao açúcar, e foram tratados com soluções contendo: 0 (sem flúor), 275 ou 1.250 µg F/mL, resultando em 6 grupos de tratamento: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1.250-F e 8-h/1.250-F. As concentrações de 275 e 1.250 µg F/mL simularam uma diluição salivar na cavidade bucal quando dentifrícios de 1100 e 5000 µg F/g são usados. A desmineralização do esmalte foi avaliada na superfície (%PDS) e dureza em corte. Fluoreto incorporado pelo esmalte também foi determinado. Os dados foram analisados por Análise de Variância e teste de Tukey. O tratamento com 1.250 µg F/mL reduziu significativamente %PDS comparado ao de 275 µg F/mL (p<0,05), independente do nível do desafio cariogênico (comparações 4-h/1,250-F x 4-h/275-F e 8-h/1,250-F x 8-h/275-F, respectivamente). Esses resultados foram suportados pela concentração de fluoreto encontrada no esmalte. Os resultados sugerem que maior concentração de fluoreto pode parcialmente compensar um maior risco de cárie sob um maior desafio cariogênico provocado pelo aumento de exposição ao açúcar.

Abstract Fluoride present in toothpaste at 1,100 µg/g is considered effective on caries control. However, under high cariogenic challenge due to increasing sugar exposure, higher fluoride concentration (5,000 µg/g) could be necessary to compensate the unbalance on caries process. This was tested in a pH-cycling regimen, which evaluated the effect of fluoride concentration relative to toothpaste on reduction of enamel demineralization under conditions of two levels of cariogenic challenge. Enamel slabs (n=20) were subjected to two pH-cycling regimens, simulating 8x and 16x/day sugar exposure and were treated with solutions containing: 0 (no fluoride), 275 or 1,250 µg F/mL, resulting in 6 treatment groups: 4-h/0-F; 8-h/0-F; 4-h/275-F; 8-h/275-F; 4-h/1,250-F and 8-h/1,250-F. The 275 and 1,250 µg F/mL concentrations simulate mouth salivary dilution when 1,100 and 5,000 µg/g toothpastes are used. Enamel demineralization was assessed by surface (%SHL) and cross-sectional hardness. Fluoride taken up by enamel was also evaluated. Data were analyzed by ANOVA one-way and Tukey's test. The treatment with 1,250 µg F/mL significantly reduced %SHL compared with 275 µg F/mL (p<0.05), irrespective the level of cariogenic challenge (4-h/1,250-F vs. 4-h/275-F and 8-h/1,250-F vs 8-h/275-F comparisons, respectively). These data were supported by fluoride concentration found in enamel. These findings suggest that higher fluoride concentrations could partly compensate the greater caries risk under higher cariogenic challenge due to increasing sugar exposure.

Resumo Dentifrícios de baixa concentração de fluoreto (F) (< 600 µg F/g) estão amplamente disponíveis no mundo, mas ainda não há evidência para recomendar seu uso, quer seja em formulações regulares ou melhoradas. Assim, o objetivo deste estudo foi avaliar o potencial anticárie de dentifrícios de baixa concentração de fluoreto encontrados no mercado brasileiro, utilizando um modelo de ciclagens de pH validado e testado. Blocos de esmalte bovinos foram selecionados pela dureza de superfície e randomizados em quatro grupos (n=12): dentifrício sem fluoreto (controle negativo), dentifrício de baixa concentração de fluoreto (500 μg F/g), dentifrício acidulado de baixa concentração de fluoreto (550 μg F/g) e dentifrício de 1100 μg F/g (controle positivo). Os blocos foram submetidos ao regime de ciclagem de pH por 8 dias e tratados 2 x/dia com suspensões aquosas dos dentifrícios (1:3 p/v). O pH das suspensões foi checado, e apenas o acidulado tinha baixo pH. Após a ciclagem de pH, a dureza de superfície foi novamente determinada e a porcentagem de perda de dureza foi calculada como indicador de demineralização. As concentrações de fluoreto fracamente e firmemente ligado ao esmalte também foram determinadas. O dentifrício de 1.100 μg F/g foi mais efetivo do que os de baixa concentração na redução da desmineralização do esmalte e foi o único que diferiu significativamente do não fluoretado (p<0,05). Todos os dentifrícios fluoretados foram capazes de formar maiores concentrações de fluoreto fracamente ligado ao esmalte do que o não fluoretado (p<0,05), mas o de 1.100 μg F/g foi o único que diferiu do não fluoretado na capacidade de formar fluoreto firmemente ligado ao esmalte. Os resultados sugerem que dentifrícios de baixa concentração de fluoreto disponíveis no mercado brasileiro, independentemente da formulação, não têm potencial anticárie.

Abstract Low-fluoride (F) dentifrices (<600 µg F/g) are widely available worldwide, but evidence to recommend the use of such dentifrices, with either regular or improved formulations, is still lacking. Therefore, the aim of this study was to evaluate the anticaries potential of low-F dentifrices found in the Brazilian market, using a validated and tested pH-cycling model. Enamel blocks were selected by surface hardness (SH) and randomized into four treatment groups (n=12): non-F dentifrice (negative control), low-F dentifrice (500 μg F/g), low-F acidulated dentifrice (550 μg F/g) and 1,100 μg F/g dentifrice (positive control). The blocks were subjected to pH-cycling regimen for 8 days and were treated 2x/day with dentifrice slurries prepared in water (1:3, w/v). The pH of the slurries was checked, and only the acidulated one had low pH. After the pH cycling, SH was again determined and the percentage of surface hardness loss was calculated as indicator of demineralization. Loosely- and firmly-bound F concentrations in enamel were also determined. The 1,100 μg F/g dentifrice was more effective than the low-F ones to reduce enamel demineralization and was the only one that differed from the non-F (p<0.05). All F dentifrices formed higher concentration of loosely-bound F on enamel than the non-F (p<0.05), but the 1,100 μg F/g was the only one that differed from the non-F in the ability to form firmly-bound F. The findings suggest that the low-F dentifrices available in the Brazilian market, irrespective of their formulation, do not have anticaries potential.

Abstract Calcium fluoride-like materials (“CaF2”) formed on dental surfaces after professional fluoride application are unstable in the oral environment but can be retained longer with a daily NaF mouthrinse. We tested the effect of twice daily 0.05% NaF rinses on the retention of “CaF2” formed on enamel and dentine after applying acidulated phosphate fluoride (APF). “CaF2” formed on enamel/dentine by APF application significantly decreased after exposure to artificial saliva and the 0.05% NaF rinse was ineffective to avoid this reduction. These findings suggest that the combination of APF and 0.05% NaF is not clinically relevant, either for caries or dental hypersensitivity.

Knowledge of factors related to caries and the possible consequences in controlling the disease may show the use of education as a relevant tool for achieving success in terms of dental health maintenance. Therefore, the aim of the present study was to investigate the relationship between acquired knowledge and salivary factors related to dental caries for freshmen students (n = 44) and trainees (n = 32) of the Piracicaba Dental School. Knowledge about dental caries was evaluated by a discursive questionnaire analyzed by the content analysis technique. Salivary flow and pH, buffer capacity, salivary sucrase activity, microbiological counts (total microorganisms, mutans, and lactobacilli) and inorganic concentration of calcium, phosphorus, and fluoride in saliva were evaluated and compared between groups using the Mann–Whitney test, with a significance of 5%. Trainees demonstrated knowledge of the disease, whereas freshmen showed unspecific and confusing concepts. Among the factors analyzed, statistically significant differences were observed for pH, buffer capacity, sucrase activity, total microorganisms, and calcium and fluoride concentrations in saliva. Knowledge about the disease increases and improves over time during the undergraduate program (highest among trainees); although the students from the final year of the program consume more sugar than those from the previous one, they try to balance this activity with greater exposure to fluorides.

Streptococcus mutans é especificamente suprimido pelo tratamento intensivo com clorexidina em gel, mas o tempo de recolonização e o efeito em outras bactérias orais não está totalmente claro. Nesse estudo, a recolonização de estreptococos do grupo mutans foi avaliado em nove voluntários adultos saudáveis, os quais eram altamente colonizados por esse microrganismo. Saliva estimulada foi coletada antes (baseline) e 1, 7, 14, 21 e 28 dias após a aplicação de clorexidina em gel a 1% nos dentes dos voluntários por dois dias consecutivos. Em cada dia, o gel foi aplicado utilizando moldeiras descartáveis por 3 x 5 min com intervalos de 5 min entre cada aplicação. A saliva foi inoculada em ágar sangue para determinação dos microrganismos totais (MT); em mitis salivarius ágar para determinação dos estreptococos totais (ET) e em meio mitis salivarius com bacitracina para determinar a contagem de estreptococos do grupo mutans (EGM). O tratamento com clorexidina foi capaz de reduzir as contagens de EGM e a proporção de EGM em relação aos microrganismos totais (%EGM/MT) (p<0,05), mas esses valores não diferiram estatisticamente do baseline (p>0,05) após 14 dias para EGM e 21 dias para %EGM/MT. As contagens de MT e ET e a proporção de EGM em relação a estreptococos totais não difereriram estatisticamente do baseline (p>0,05) após o tratamento com clorexidina. Os resultados sugerem que o efeito do tratamento com clorexidina em gel na supressão de estreptococos do grupo mutans é limitado a menos de um mês em indivíduos altamente colonizados.

Streptococcus mutans is specifically suppressed by intensive treatment with chlorhexidine gel, but the time for recolonization and the effect on other oral bacteria are not totally clear. In this study, recolonization of mutans streptococci was evaluated in nine healthy adult volunteers, who were highly colonized with this microorganism. Stimulated saliva was collected before (baseline) and at 1, 7, 14, 21 and 28 days after application of 1% chlorhexidine gel on volunteers' teeth for two consecutive days. On each day, the gel was applied using disposable trays for 3 x 5 min with intervals of 5 min between each application. Saliva was plated on blood agar to determine total microorganisms (TM); on mitis salivarius agar to determine total streptococci (TS) and on mitis salivarius agar plus bacitracin to determine mutans streptococci (MS). Chlorhexidine was capable of reducing the counts of MS and the proportion of MS with regard to total microorganisms (%MS/TM) (p<0.05), but these values did not differ statistically from baseline (p>0.05) after 14 days for MS and 21 days for %MS/TM. The counts of TM and TS and the proportion of MS to total streptococci did not differ statistically from baseline (p>0.05) after chlorhexidine treatment. The results suggest that the effect of chlorhexidine gel treatment on suppression of mutans streptococci is limited to less than a month in highly colonized individuals.

AIM: To evaluate the effects of three hydrogen peroxide (HP) concentrations on enamel mineral content (MC), following three peroxide applications and using three methods to measure the MC. METHODS : Forty samples were obtained from bovine incisors and randomly divided into 4 groups (n=10). The control group remained untreated, while the experimental groups were tested for three HP concentrations (10%, 35% and 50%). The HP gel was applied 3 times on the enamel surface for 30 min per application and the samples were analyzed after each application. The MC of the enamel was determined before and after bleaching using Fourier transform (FT-Raman) spectroscopy and micro energy-dispersive x-ray fluorescence spectrometry (µEDXRF). The calcium (Ca) lost from the bleached enamel was quantified with an atomic absorption spectrometer (AAS). The data were analyzed statistically by ANOVA, Tukey and Dunnett´s tests (p<0.05). RESULTS: The FT-Raman showed a decrease in MC for all bleaching treatments, without influence of the different HP concentrations or the number of applications. µEDXRF did not detect any changes in MC. CONCLUSIONS: Ca loss was observed by the AAS, with no difference among the three HP concentrations. The FT-Raman and AAS analyses detected MC reduction and Ca loss after HP bleaching.

Enhancement filters are potentially supposed to improve the diagnostic performance of digital images. Thus, the aim of this study was to compare the performance of digital radiography with and without enhancement filters for the detection of induced proximal caries lesions. The total sample consisted of 120 sound human teeth (40 premolars, 80 molars). Enamel subsurface demineralization was induced in one of the proximal surfaces of 60 teeth. Standardized radiographs of all teeth were acquired after the demineralization phase using the Digora-Optime® system. Four radiologists examined the digital radiographs and applied the following filters provided by the Digora® for Windows 2.6 package: Negative, Sharpen and both (Negative plus Sharpen). Validation of radiographic diagnosis was carried out by Knoop cross-sectional micro-hardness profiling on the proximal surfaces. Intraobserver agreement was estimated using Kappa statistics (k). Sensitivity, specificity and over-all accuracy were compared using ANOVA/Tukey test (α = 5%). Intraobserver agreement ranged from good to very good/optimal (k: 0.65–0.83). Although not statistically significant, the highest sensitivity (0.68 ± 0.22) and accuracy (0.76 ± 0.16) values were observed using the Sharpen filter as opposed to the Negative filter, which presented the lowest performance indices (0.57 ± 0.13 and 0.70 ± 0.10, respectively). Specificity ranged from 0.84 to 0.85, considering all imaging modalities (p > 0.05). Insofar as the Sharpen filter had the highest performance indices, it may be considered a useful adjunct for detecting subtle proximal caries lesions.

A cavidade oral apresenta vários genótipos de Streptococcus mutans, que podem possuir diferentes capacidades de virulência. Entretanto, pouco se sabe sobre a diversidade e virulência de genótipos de S. mutans isolados in vivo sob uma condição controlada de alto desafio cariogênico. Este estudo avaliou a diversidade genotípica de S. mutans identificados no biofilme dental formado in vivo na presença de sacarose, assim como a acidogenicidade e aciduricidade desses genótipos. Para possibilitar formação de biofilme, voluntários bochecharam com água destilada ou solução de sacarose 8x/dia durante 3 dias. S. mutans isolados da saliva e do biofilme dental foram genotipados por PCR com primers-arbitrários. Genótipos isolados do biofilme foram avaliados em relação à habilidade de reduzir o pH da suspensão devido à glicólise, em relação à susceptibilidade a ácidos e também atividade F-ATPase. A maioria dos voluntários apresentou apenas 1 genótipo na saliva, que foram detectados em quase todas as amostras de biofilme em altas proporções. Genótipos isolados somente na presença de sacarose apresentaram maior acidogenicidade do que aqueles genótipos isolados apenas na presença de água. Genótipos de biofilmes formados na presença de sacarose foram mais acidúricos após 30 e 60 min de incubação em pH 2,8 e 5,0, respectivamente. Os resultados do presente estudo sugerem que biofilmes formados sob condição de alto desafio cariogênico podem apresentar genótipos de S. mutans mais acidúricos e mais acidogênicos.

The oral cavity harbors several Streptococcus mutans genotypes, which could present distinct virulence properties. However, little is known about the diversity and virulence traits of S. mutans genotypes isolated in vivo under controlled conditions of high cariogenic challenge. This study evaluated the genotypic diversity of S. mutans isolated from dental biofilms formed in vivo under sucrose exposure, as well as their acidogenicity and aciduricity. To form biofilms, subjects rinsed their mouths with distilled water or sucrose solution 8 times/day for 3 days. S. mutans collected from saliva and biofilms were genotyped by arbitrarily-primed PCR. Genotypes identified in the biofilms were evaluated regarding their ability to lower the suspension pH through glycolysis and their acid susceptibility and F-ATPase activity. Most subjects harbored only one genotype in saliva, which was detected in almost all biofilm samples at high proportions. Genotypes isolated only in the presence of sucrose had higher acidogenicity than those isolated only in the presence of water. Genotypes from biofilms formed with sucrose were more aciduric after 30 and 60 min of incubation at pH 2.8 and 5.0, respectively. The present results suggest that biofilms formed under high cariogenic conditions may harbor more aciduric and acidogenic S. mutans genotypes.

Streptococcus mutans has been considered one of the main etiological agents of dental caries and the genotypic diversity rather than its salivary counts may be considered as a virulence factor of this bacterium. For genotyping with polymerase chain reaction (PCR) with arbitrary primers, several primers have been used in order to improve complexity and specificity of amplicon patterns. Thus, the aim of this study was to evaluate the degree of agreement of genotypic identification among AP-PCR reactions performed with 5 distinct arbitrary primers of S. mutans isolated from saliva. Stimulated saliva was collected from 11 adult volunteers for isolation of S. mutans, and a total of 88 isolates were genotyped with arbitrary primers OPA 02, 03, 05, 13 and 18. Fourteen distinct genotypes were identified in the saliva samples. Most volunteers (9 out of 11) presented only one genotype. The results of the present study suggest that primers OPA 02, 03, 05 and 13 were suitable for genotypic identification of S. mutans isolates of saliva from adult volunteers.

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 mm² 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 (Pi) and calcium (Ca) concentrations. Microhardness data were evaluated using two-way ANOVA (p<0.05) and Tukey's test. Pi 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 Pi 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 (Az = 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.

A composição do biofilme dental in situ exposto a açúcares é bem conhecida, mas o efeito dos açúcares na diversidade genotípica de S. mutans no biofilme dental ainda não foi explorada. Este estudo avaliou a diversidade genotípica de S. mutans no biofilme dental formado in situ sob frequente exposição à sacarose e seus monossacarídeos constituintes (glicose e frutose). Primeiramente, saliva de voluntários foi coletada para isolamento de S. mutans e os mesmos voluntários usaram um dispositivo intraoral palatino, contendo blocos de esmalte, que foram submetidos 8x/dia aos seguintes tratamentos: água destilada e deionizada (controle negativo), solução de glicose 10% + frutose 10% (carboidratos fermentáveis) e solução de sacarose 20% (fermentável e indutor de PEC). Após 3, 7 e 14 dias, os biofilmes foram coletados e colônias de S. mutans foram isoladas. A técnica de reação em cadeia de polimerase usando primers arbitrários (AP-PCR) demonstrou que o genótipo salivar foi detectado em quase todas as amostras de biofilme, independente do tratamento, e parece refletir aqueles genótipos presentes em maiores proporções no biofilme. Além do genótipo salivar, outros foram encontrados nos biofilmes, mas em uma menor proporção e foram distintos entre os tratamentos. Os dados sugerem que o modelo in situ é útil para a avaliação da diversidade genotípica de S. mutans. Porém, nas condições do presente estudo, não foi possível demonstrar que genótipos específicos foram detectados no biofilme devido ao estresse induzido pelo metabolismo da sacarose ou fermentação de seus monossacarídeos.

In situ dental biofilm composition under sugar exposure is well known, but sugar effect on the genotypic diversity of S. mutans in dental biofilm has not been explored. This study evaluated S. mutans genotypic diversity in dental biofilm formed in situ under frequent exposure to sucrose and its monosaccharide constituents (glucose and fructose). Saliva of 7 volunteers was collected for isolation of S. mutans and the same volunteers wore intraoral palatal appliances, containing enamel slabs, which were submitted to the following treatments: distilled and deionized water (negative control), 10% glucose + 10% fructose (fermentable carbohydrates) solution or 20% sucrose (fermentable and EPS inductor) solution, 8x/day. After 3, 7 and 14 days, the biofilms were colleted and S. mutans colonies were isolated. Arbitrarily primed polymerase chain reaction (AP-PCR) of S. mutans showed that salivary genotypes were also detected in almost all biofilm samples, independently of the treatment, and seemed to reflect those genotypes present at higher proportion in biofilms. In addition to the salivary genotypes, others were found in biofilms but in lower proportions and were distinct among treatment. The data suggest that the in situ model seems to be useful to evaluate genotypic diversity of S. mutans, but, under the tested conditions, it was not possible to clearly show that specific genotypes were selected in the biofilm due to the stress induced by sucrose metabolism or simple fermentation of its monosaccharides.