Effect of Sweeteners on Root Dentine Demineralization Using a Microcosm Biofilm Model / Efecto de los Edulcorantes en la Desmineralización de la Dentina Radicular Utilizando un Modelo de Biofilm Microcosmo

ABSTRACT: The aim of the present study was to evaluate the effect of commercial sweeteners on root dentin demineralization using a microcosm biofilm model. Bovine dentin specimens with pre-determined surface hardness were randomized into six groups according to the studied sweeteners: sucralose, stevia, saccharin, aspartame. Sucrose was used as a positive control and an untreated group as a negative control. The specimens were submitted to biofilm development from one saliva donor and the cariogenic challenge occurred on subsequent five days, twice a day. At the end, the percentage of surface hardness loss (%SHL) and biomass was determined and submitted to ANOVA followed by Tukey's test. Sucrose presented the highest rate of demineralization, however, all sweeteners tested lead to a statistically higher root demineralization compared to the negative control (p <0.05). Sucrose caused greater demineralization in root dentin, however, the sweeteners were also able to induce it under this biofilm model.

RESUMEN: El objetivo del presente estudio fue evaluar el efecto de los edulcorantes comerciales en la desmineralización de la dentina radicular utilizando un modelo de biofilm microcosmo. Se asignaron al azar muestras de dentina bovina con una dureza de la superficie predeterminada de acuerdo con los edulcorantes estudiados: sucralosa, estevia, sacarina, aspartame. La sacarosa se utilizó como control positivo y un grupo no tratado como control negativo. Las muestras se enviaron al desarrollo de biopelículas de un donante de saliva y el desafío cariogénico se produjo en los siguientes cinco días, dos veces al día. Al final, se determinó el porcentaje de pérdida de dureza de la superficie (% PDS) y biomasa y se aplicó un estudio estadístico de ANOVA seguido de la prueba de Tukey. La sacarosa presentó la mayor tasa de desmineralización; sin embargo, todos los endulzantes probados condujeron a una desmineralización de la raíz estadísticamente mayor en comparación con el control negativo (p<0,05). La sacarosa causó una mayor desmineralización en la dentina de raíz, sin embargo, los edulcorantes también fueron capaces de inducirla bajo este modelo de biofilm.

Is the fluoride intake by diet and toothpaste in children living in tropical semi-arid city safe?

Abstract: Data about total fluoride intake in children living in a tropical semi-arid climate city is scarce, thus we conducted this study. Fifty-eight children aged two to five years, living in a Brazilian tropical city with optimally fluoridated water were selected. Dietary samples were collected using the duplicate diet method on two non-consecutive days in the children's home toothpaste was determined by subtracting the amount of fluoride recovered after brushing from the amount placed on the toothbrush. The mean total dose (SD) of fluoride intake was 0.043(0.016) mg F·kg-1·d-1, with the major (60.6%) contribution from water. The factors associated with the ingestion of fluoride from toothpaste were fluoride concentration of the toothpaste (p = 0.03) and the use of kids toothpaste (p = 0.02). The findings suggest that children have a low fluoride intake, measured by at-home meals and use of fluoride toothpaste; drinking water is the main source of fluoride ingestion.

Sucrose induced dentin demineralization in a microcosm biofilm model / Desmineralización de la dentina inducida por sacarosa en un modelo de biofilm microcosmo

The aim of this in vitro study was to assess the root dentin demineralization caused by a microcosm biofilm model that has been exposed to sucrose in different ways. Materials and Methods: Saliva of two volunteers was inoculated into an artificial medium for biofilm growth and dentin blocks were immersed into these media. Dentin specimens were randomly exposed to one of the five experimental conditions: C (control group - no saliva inoculum or sucrose), 0S (saliva inoculum without sucrose, negative control), 3S (three daily one-minute immersions in 20 % sucrose), 6S (six daily one-minute immersions in 20 % sucrose), and CS (continuously immersed in 5 % sucrose). After five days, biofilm was collected to determine the concentration of intracellular and extracellular polysaccharides and the dentin surface hardness loss (SHL) was measured. The experiment was carried out in triplicate. Results: The dentin SHL was higher in groups that were exposed to sucrose (3S, 6S and CS) and there was a statistically significant difference between all groups (p<0.001). CS had higher concentrations of polysaccharides (p>0.001) and there was no statistically significant difference between the other groups (0S, 3S and 6S) (p>0.005). Conclusion: The microcosm biofilm model developed has the potential to produce root dentin demineralization at different exposures to sucrose.

El objetivo de esta investigación in vitro fue evaluar la desmineralización de la dentina radicular causada por un modelo de biofilm microcosmo que fue expuesto de diferentes maneras a la sacarosa. La saliva de dos voluntarios fue colocada en un medio artificial para crecimiento del biofilm y los bloques de dentina fueron sumergidos en estos medios. Al aza rlos bloques fueron expuestos a una de las cinco condiciones experimentales: C (grupo control ­ sin inoculación de saliva o sacarosa), 0S (inoculación de saliva sin sacarosa, control negativo), 3S (tres inmersiones diarias de un minuto en sacarosa a 20 %), 6S (seis inmersiones diarias de un minuto en sacarosa a 20 %), y CS (sumergidos continuamente en 5 % de sacarosa). Después de cinco días, el biofilm fue recogido para determinar la concentración de polisacáridos intracelulares y extracelulares y fue medida la pérdida de dureza superficial de la dentina (SHL). El experimento se repitió en tres ocasiones. La dentina SHL era mayor en los grupos que fueron expuestos a la sacarosa (3S, 6S E CS) y hubo diferencia estadísticamente significativa entre todos los grupos (P<0,001). CS presentó mayor concentración de polisacáridos (p<0,001) y no hubo diferencia estadísticamente significativa entre los demás grupos (0S, 3S E 6S) (p>0,005). El modelo del biofilm desarrollado tiene potencial para producir desmineralización de la dentina radicular en diferentes exposiciones a la sacarosa.

Candida spp. in complete dentures of institutionalized elderly individuals / Candida spp. en prótesis dentales totales de personas mayores institucionalizadas

The objective of this study was to evaluate the prevalence of Candida spp. in complete dentures of institucionalized elderly, aged 60 or more, in a city of northeast of Brazil. A survey was conducted of the health profile and quantification of Candida spp. from isolation in Sabouraud agar. Our results showed that from 181 institutionalized elderlies, only 17 (66-84 years) met the inclusion criteria. 47.1 % were totally dependent, and 58.8 % needed help with hygiene. The most commonly used drugs were antihypertensive. The results showed a high prevalence of Candida spp. (64.5 %) in the dentures of institutionalized elderly and this may be a reflection of poor oral hygiene.

El objetivo fue asociar el uso de prótesis dentales totales y la prevalencia de Candida spp. en ancianos institucionalizados con 60 o más años de edad, en una ciudad del Nordeste de Brasil. Se llevó a cabo un estudio del perfil de salud y cuantificación de Candida spp. por aislamiento con agar Sabouraud. A partir de 181 ancianos institucionalizados, sólo 17 (66­84 años) cumplieron los criterios de inclusión. 47,1 % eran totalmente dependientes y 58,8 % necesitó ayuda con la higiene. Los fármacos más utilizados fueron antihipertensivos. Los resultados mostraron una alta prevalencia de Candida spp. (64,5 %) en las prótesis dentales totales de los ancianos institucionalizados y esto tal vez sea un reflejo de la deficiente higiene oral.

Association of chlorhexidine and high fluoride dentifrice on Streptococcus mutans viability using an in vitro biofilm model / Associação de clorexidina e dentifricio com alta concentração de flúor na viabilidade de Streptococcus mutans em um modelo de biofilmes in vitro

Objective: this in vitro study investigated the effect of high-fluoride dentifrice, Chlorhexidine (CHX), and their association on the viability of Streptococcus mutans using a biofilm model. Material and Method: biofilms were anaerobically grown on glass slides that were vertically suspended in 24-well plates for 5 days. After 48 h of initial growth, biofilms were treated for the next 72 h, 2x/day with 0.12% CHX and 2%, F as 0.08% and 0.4% NaF and their association. Results: CHX treatment decreased the bacteria counts either alone or in association with both F concentrations, when compared with control group and the F treatments alone (p < 0.05). Conclusion: no additional effect was observed when CHX and F were used in combination, when compared with CHX used alone.

Objetivo: este estudo avaliou, o efeito do dentifrício com alta concentração de fluor (F), da clorexidina (CHX) e da associação destes na viabilidade de Streptococcus Mutans (SM) utilizando um modelo de biofilme in vitro. Materiais e Métodos: biofilme cresceram anaerobicamente em lamínulas de vidro suspensas, verticalmente, em placas de 24 poços por 5 dias. Após 48h do crescimento inicial, o biofilme formado foi submetido a um tratamento por 72h, 2x/ dia com CHX 0.12%, F na forma de NaF a 0.08% e 0.4%, suas associações, CHX 2% (controle positivo) e solução salina (controle negativo). Os dados obtidos foram transformados e submetidos ao ANOVA e teste de Tukey e em seguida analisados por meio do SAS, com significância fixada em 5%. Resultados: isolada ou em associação com as diferentes concentrações de F, a CHX demonstrou maior potencial em reduzir os níveis de SM quando comparada ao uso isolado de F em ambas concentrações ou com o controle negativo (p < 0,05). Conclusão: o uso da combinação de F e CHX não apresentou efeito adicional na redução dos níveis de SM quando comparado ao uso isolado de CHX.

Recolonization of Mutans Streptococci after Application of Chlorhexidine Gel

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.

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. .

Genotypic and phenotypic analysis of S. mutans isolated from dental biofilms formed in vivo under high cariogenic conditions

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.

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.

Polarization of dental caries among individuals aged 15 to 18 years

OBJECTIVE: To evaluate the role of socioeconomic variables and self-perceived oral health in the polarization of caries among adolescents in Santa Bárbara D'Oeste, Brazil. MATERIAL AND METHODS: Cross-sectional study. Sampling was randomized and sample size was defined according to WHO criteria. Two hundred and seventy seven adolescents (15 to 18 year-old) were examined by five trained examiners that assessed DMFT index according to WHO criteria. Self-perceived oral health, access to dental services and socio-demographic variables were self-reported. Student's t tests, chi-square tests, and multivariate logistic regression (with significant caries index (SiC) as the outcome), were performed. RESULTS: Mean DMFT was 5.48 (±4.22) and the proportion of "caries free" subjects was 15.5 percent. Mean DMFT (9.71±2.85) and mean D (1.67±2.18) of SiC positive subjects were significantly higher than mean DMFT (2.88±2.17) and mean D (0.45±0.87) of SiC negative subjects (p<0.0001). Mean D of white (0.76±1.51) was significantly smaller than mean D of non-white subjects (1.32±2.01). The only variable independently associated with the "SiC positive" outcome was "report of toothache within six months prior to the study" [OR=1.83 (95 percentCI 1.08 to 3.12)], p<0.001. CONCLUSION: SiC was associated with "report of toothache" but not with socio-demographic variables in the studied population.

Genotypic diversity of S. mutans in dental biofilm formed in situ under sugar stress exposure

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 percent glucose + 10 percent fructose (fermentable carbohydrates) solution or 20 percent 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.

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 por cento + frutose 10 por cento (carboidratos fermentáveis) e solução de sacarose 20 por cento (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.