Solutions Containing a Statherin-Derived Peptide Reduce Enamel Erosion in vitro.

The effect of solutions containing a statherin-derived peptide (Stn15pSpS) on the protection against enamel erosion in vitro was evaluated. Bovine enamel specimens were divided into 4 groups (n = 15/group): (1) deionized water (negative control), (2) Elmex Erosion Protection™ (positive control), (3) 1.88 × 10-5 M Stn15pSpS, and (4) 3.76 × 10-5 M Stn15pSpS. The solutions were applied on the specimens for 1 min. Stimulated saliva was collected from 3 donors and used to form a 2-h acquired pellicle on the specimens. Then, the specimens were submitted to an erosive pH-cycling protocol 4 times/day, for 7 days (0.01 M HCl pH 2.0/45 s, artificial saliva/2 h, and artificial saliva overnight). The solutions were applied again during pH-cycling, 2 times/day for 1 min after the first and last erosive challenges. Enamel loss (µm) was assessed by contact profilometry. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05). The best protection against erosion was conferred by Elmex Erosion Protection that significantly differed from all the other treatments, followed by the solutions containing Stn15pSpS, regardless of the concentration. However, 3.76 × 10-5 M Stn15pSpS did not differ from the negative control. The solution containing the lower concentration of Stn15pSpS protected against erosion in vitro, which should be confirmed using protocols that more closely resemble the clinical condition.

Effect of experimental and commercial artificial saliva formulations on the activity and viability of microcosm biofilm and on enamel demineralization for irradiated patients with head and neck cancer (HNC).

The effect of different artificial saliva formulations on biofilm activity and viability, and on enamel demineralization for head and neck cancer (HNC) patients was evaluated. Irradiated enamel samples were treated (1 min) with BioXtra® or with experimental formulations containing carboxymethylcellulose plus inorganic constituents alone (AS) or containing 0.1 mg mL-1 CaneCPI-5 (AS + Cane), 1.0 mg mL-1 hemoglobin (AS + Hb) or combination of both (AS + Cane + Hb). Phosphate-buffered-saline and chlorhexidine (0.12%) were negative and positive control, respectively. Biofilm was produced from the saliva of five male HNC patients, under 0.2% sucrose exposure for 5 days, and daily treated with the formulations (1 min). No significant effects were observed for the different experimental treatments. BioXtra® significantly reduced lactobacilli, demonstrating antibacterial potential for this group. Chlorhexidine was an effective treatment to significantly reduce all parameters, being an important antimicrobial and anticaries agent. Future in vitro studies must be performed using a new approach for the design of the experimental formulations.

Effect of a sugarcane cystatin on the profile and viability of microcosm biofilm and on dentin demineralization.

To analyze the effect of a sugarcane cystatin (CaneCPI-5) on the microbial profile and viability, as well as on the prevention of dentin demineralization using a microcosm biofilm model. Ninety bovine dentine specimens were divided into five experimental groups according with the solution they were treated for 60 s: (1) PBS (negative control), (2) 0.12% chlorhexidine (positive control), (3) Fluoride (500 ppm F, as NaF), (4) 0.025 mg/ml CaneCPI-5, and (5) 0.05 mg/ml CaneCPI-5. Specimens were incubated with inoculum (McBain's saliva plus human saliva) in the first 8 h, and from then on, they were exposed to McBain saliva containing sucrose and daily treated (60 s) with the solutions for 5 days. Resazurin and colony-forming unit counting assays were performed. Dentin demineralization was measured by transverse micro-radiography (TMR). 0.12% chlorhexidine significantly reduced the metabolic activity of the microcosm biofilm in relation to the negative control and treated groups (p < 0.01). CHX and F significantly reduced the counts of total microorganisms, mutans group streptococci, and lactobacilli when compared with the negative control. None of the treatments was able to significantly reduce dentin demineralization in comparison with the negative control. In the model evaluated, CaneCPI-5 neither altered the microcosm biofilm profile and viability nor protected dentin against demineralization.