Effect of Starch and Sucrose on Dental Biofilm Formation and on Root Dentine Demineralization

Abstract

The cariogenicity of starch alone or in combination with sucrose is controversial and the effect on dentine demineralization and on the dental biofilm formed has not been explored under controlled conditions. A crossover, single-blind study was conducted in four steps of 14 days each, during which 11 volunteers wore palatal appliance containing 10 slabs of root dentine to which the following treatments were applied extraorally: 2% starch gel-like solution (starch group); 10% sucrose solution (sucrose group); a solution containing 2% starch and 10% sucrose (starch + sucrose group), or 2% starch solution followed by 10% sucrose solution (starch → sucrose group). On the 14th day of each phase the biofilms were collected for biochemical and microbiological analyses, and dentine demineralization was assessed by hardness. A higher demineralization was found in dentine exposed to sucrose and starch sucrose combinations than to starch alone (p < 0.01), but the sucrose-containing groups did not differ significantly from each other (p > 0.05). The concentrations of soluble and insoluble extracellular polysaccharides (EPS), and the proportion of insoluble EPS, were lower in the biofilm formed in presence of starch (p < 0.01) than in those formed in the presence of sucrose or sucrose/starch combinations; however, no significant difference was observed among the groups containing sucrose (p > 0.05). RNA was successfully isolated and purified from in situ biofilms and only biofilms formed in response to sucrose and starch/sucrose combinations showed detectable levels of gtfB and gtfC mRNA. The findings suggest that the combination of starch with sucrose may not be more cariogenic to dentine than sucrose alone.

Calcium binding to S. mutans grown in the presence or absence of sucrose

“…In this regard, it is noteworthy that IEPS concentration represents approximately 5% of the total biofilm wet weight, in agreement with previous in situ studies. 2,13,14,[24][25][26] This low percentage, supposedly relevant to induce differences between the bacterial pellets on residual Cabinding capacity, might not be able to significantly affect bound Ca concentration once the bacteria are treated with Ca-containing solutions (i.e., 1 or 10 mM). Furthermore, the results suggest that the EPS concentration is not the reason for the low concentration of inorganic ions (Ca, inorganic phosphorus, and fluoride) found in dental biofilms formed under exposure to sugars, 2,3,[12][13][14]24,26 suggesting that further research should be done to explain this biological phenomenon.…”

“…The precipitate was treated with a hot alkaline solution to extract bacterial proteins, 13 whose concentration was determined by the Lowry method. 17 …”

S. mutans biofilm model to evaluate antimicrobial substances and enamel demineralization

“…The tubes were sonicated at 7 W for 30 s (Branson, Sonifier 50, Danbury, CT USA) to detach the biofilms formed on the slabs. 20 The slabs were carefully removed from the suspension and stored to determine enamel demineralization. Aliquots of the suspension were used to determine biofilm bacterial viability, biomass (dry weight and total soluble proteins) and polysaccharides.…”

Knowledge of dental caries and salivary factors related to the disease: influence of the teaching-learning process

“…13,14 Microbiological counts of total microorganisms, mutans streptococci, and lactobacilli were performed after dilutions of the saliva, which were inoculated in petri dishes containing blood agar, mitis salivarius agar plus bacitracin, and rogosa agar, respectively, and subsequently incubated at 37°C, 10% CO 2 , for 48 h. The results were expressed as colony-forming units (CFU)/mL saliva. 15 For the determination of fluoride concentration in saliva, the samples were diluted in TISAB II at a ratio of 1:1. Standard fluoride solutions were used to construct the calibration curve.…”