Anticaries effect of an antioxidant-rich apple concentrate on enamel in an experimental biofilm-demineralization model.

AIMS: To assess the anticaries activity of an antioxidant-rich apple concentrate (ARAC) in an experimental biofilm caries model on enamel. METHODS AND RESULTS: A validated caries model with Streptococcus mutans UA159 biofilms was used. Biofilms were formed on enamel slabs during 5 days. To mimic cariogenic challenges, triplicate slabs were exposed three times per day for 5 min to 10% sucrose followed by five additional minutes of exposure to serial dilutions of ARAC in 0·9% NaCl. A triplicate slab exposed to 10% sucrose followed by 0·9% NaCl served as caries-positive control. Acidogenicity was estimated by medium pH twice per day. After the experimental phase, biofilms were recovered to determine biomass, viable bacteria and intra- and extracellular polysaccharides. Slabs were used to estimate demineralization by the percentage of surface microhardness loss (%SHL). Differences among treatments were analysed by anova and Bonferroni test (P < 0·05). Streptococcus mutans biofilms were exposed to ARAC after a cariogenic challenge with sucrose-induced lower enamel demineralization than the positive control. The highest dilution of ARAC at 1 : 100 000 (v/v) showed the most marked reduction in demineralization of about 57%. Although no differences were observed in the number of bacterial cells, the intracellular polysaccharides or in the biomass (P > 0·05), the highest dilution of the apple concentrate induced significantly lower extracellular polysaccharide formation by the biofilm. CONCLUSIONS: An apple concentrate in low concentrations appears to have a potential anticaries activity on enamel. Data suggest a metabolic rather than an antimicrobial mechanism, but further research is needed. SIGNIFICANCE AND IMPACT OF THE STUDY: Phenolic compounds contained in apple concentrates seem to have anticaries properties that may be effective even in the presence of sucrose and in very low doses. Nutritional interventions that do not require rescinding from sucrose might be derived from these findings.

Cuantificación de bacterias relacionadas con la caries dental en saliva de adultos y adultos mayores / Quantification of caries-associated bacteria from saliva of adults and older adults

Introducción: Se considera que Streptococcus mutans (S. mutans) y Lactobacillus spp. se asocian con la caries. Otras especies del biofilm oral, como Streptococcus sanguinis (S. sanguinis) han sido sindicadas como protectoras, pero principalmente en niños. Existe escasa evidencia sobre el nivel de estas bacterias en adultos mayores. Objetivo: Determinar si existen diferencias en los recuentos microbianos de tres especies relacionadas con la caries en pacientes adultos y adultos mayores. Materiales y Métodos: Una muestra de pacientes por conveniencia compuesta de 63 pacientes (18 a 79 años) proporcionó saliva estimulada con la que se sembraron placas de agar MSB, MM10 SB y Agar Rogosa para el cultivo de S. mutans, S. sanguinis y Lactobacillus spp., respectivamente. Los recuentos bacterianos fueron expresados como UFC/mL. Resultados: Los recuentos de S. mutans y Lactobacillus spp. no mostraron variaciones relacionadas con la edad (p>0.05). Los adultos mostraron mayores recuentos de S. sanguinis que los adultos mayores, 3.7 x 105 +/- 3.8 x 105 UFC/mL y 5.9 x 104 +/- 9.4 x 104 UFC/mL, respectivamente (p<0.05). Conclusiones: La edad no parece afectar los niveles de especies tradicionalmente consideradas como cariogénicas. Estos resultados sugieren que la edad puede relacionarse con los patrones de colonización de S. sanguinis en el biofilm oral.

Introduction: Streptococcus mutans (S. mutans) and Lactobacillus spp. have been traditionally associated with caries, regardless of the subject’s age. Other oral biofilm species have been linked as caries protective, including Streptococcus sanguinis (S. sanguinis), but mainly in children. Scarce evidence exists on the levels of these bacteria in older adults. Aim: To determine whether there are differences in the microbial counts of three caries-associated bacterial species in adults and older adults. Methodology: A convenience sample of sixty three patients, aged 18 to 79 years, participated in the study. Stimulated saliva samples were obtained and in MSB, MM10 and Rogosa agar plates for the culture of S. mutans, S. sanguinis and Lactobacillus spp., respectively. Bacterial counts were obtained by microscopic observation (10x) of the colonies and expressed in CFU/mL. Results: Bacterial counts of S. mutans and Lactobacillus spp. did not reveal age-related differences (p>0.05). Adults showed higher S. sanguinis counts than older adults with 3.7 x 105 +/- 3.8 x 105 CFU/mL and 5.9 x 104 +/- 9.4 x 104 CFU/mL, respectively (p<0.05). Conclusions: Age does not seem to affect the levels of bacterial species traditionally associated with caries. The results suggest that age may be related to colonization patterns of S. sanguinis in the oral biofilm.

Effect of fluoridated milk on enamel and root dentin demineralization evaluated by a biofilm caries model.

Although some studies suggest an anticaries effect of fluoridated bovine milk (F-milk) on enamel, evidence is still considered weak. Even more uncertain, the effect of F-milk on root caries remains largely unknown. This study evaluated the effect of F-milk on enamel and on root dentin demineralization using a validated Streptococcus mutans biofilm model, simulating a high cariogenic challenge. S. mutans (UA159) biofilms were formed on bovine enamel and root dentin saliva-coated slabs after measuring initial surface microhardness (SH). Biofilms were exposed to 10% sucrose 8×/day and treated 2×/day with either: (1) 0.9% NaCl (negative control), (2) bovine milk, (3) F-milk (5.0 ppm F as NaF) or (4) NaF 0.05% (anticaries-positive control). Medium pH was monitored twice/day, as a biofilm acidogenicity indicator. After 5 days for enamel and 4 days for dentin, biofilms were recovered to analyze: biomass, soluble proteins, viable microorganisms, and extra- and intracellular polysaccharides. Enamel and dentin demineralization were estimated by percentage of SH loss. Results were compared by ANOVA and Tukey's test. Neither acidogenicity nor biofilm composition differed among treatment groups in biofilms formed on enamel or dentin (p > 0.05). F-milk, however, significantly reduced enamel and dentin demineralization when compared with the negative control (p < 0.05). Also, F-milk was as efficient as 0.05% NaF to reduce enamel (p > 0.05), but not dentin demineralization (p < 0.05). These findings suggest that milk containing 5.0 ppm of fluoride is effective to control enamel caries and that it may be effective on root dentin caries prevention.