Effect of Processing Methods of Human Saliva on the Proteomic Profile and Protein-Mediated Biological Processes.

The use of saliva as a protein source prior to microbiological and biological assays requires previous processing. However, the effect of these processing methods on the proteomic profile of saliva has not been tested. Stimulated human saliva was collected from eight healthy volunteers. Non-processed saliva was compared with 0.22 µm filtered, 0.45 µm filtered, and pasteurized saliva, by liquid chromatography-mass spectrometry. Data are available via ProteomeXchange with identifier PXD039248. The effect of processed saliva on microbial adhesion was tested using bacterial and fungus species and in biological cell behavior using HaCaT immortalized human keratinocytes. Two hundred and seventy-eight proteins were identified in non-processed saliva, of which 54 proteins (≈19%) were exclusive. Saliva processing reduced identified proteins to 222 (≈80%) for the 0.22 µm group, 219 (≈79%) for the 0.45 µm group, and 201 (≈72%) for the pasteurized saliva, compared to non-processed saliva. The proteomic profile showed similar molecular functions and biological processes. The different saliva processing methods did not alter microbial adhesion (ANOVA, p > 0.05). Interestingly, pasteurized saliva reduced keratinocyte cell viability. Saliva processing methods tested reduced the proteomic profile diversity of saliva but maintained similar molecular functions and biological processes, not interfering with microbial adhesion and cell viability, except for pasteurization, which reduced cell viability.

Optimizing citric acid protocol to control implant-related infections: An in vitro and in situ study.

OBJECTIVE: The present study aimed to establish an optimized protocol for biofilm removal from titanium (Ti) surfaces using citric acid (CA) solutions. BACKGROUND: Biofilm accumulation is the main factor to trigger peri-implant infections and to increase the risk of treatment failures. Although CA has been suggested as the anti-infective agent with highest potential for biofilm removal on Ti, there is no consensus that CA could improve the anti-infective treatment and its effect. METHODS: Physical and chemical alterations, electrochemical behavior, cytotoxicity, and antimicrobial effect of CA on Ti discs were evaluated using four concentrations (1, 10, 20, and 40%) and two application methods (immersion and rubbing). Negative control using 0.9% NaCl was used in all experiments. To evaluate whether different application times can have similar response, polymicrobial biofilm (microcosm model) was formed on Ti and treated with CA for 1, 2, 4, and 8 min. An in situ study was conducted to verify whether the established protocol is equally effective in biofilms formed on machined and sandblasted, large-grit, and acid-etched (SLA) Ti surfaces. RESULTS: CA 40% induced significantly higher surface alterations observed by confocal images and profilometry. In general, rubbing protocol decreased the surface roughness and increased the wettability (p < 0.05), exhibiting better surface cleaning by biofilm removal. CA 10% presented no indirect cytotoxicity and, when applied by rubbing for 8 min, presented proper in vitro antibacterial action and potential corrosion inhibition. When CA 10% was rubbed on Ti surfaces for 4 min, it displayed optimum cleaning ability as 8 min, working equally to remove in situ biofilm on machined and SLA surfaces. CONCLUSIONS: The application of CA 10% by rubbing for at least 4 min demonstrated to be a promising protocol to eliminate biofilms formed in smooth and rougher surfaces, which could improve implant-related infection therapies.

Fluoride Increase in Saliva and Dental Biofilm due to a Meal Prepared with Fluoridated Water or Salt: A Crossover Clinical Study.

Knowledge about fluoride delivery to oral fluids from foods cooked with fluoridated water and salt is scarce, and no study has evaluated fluoride concentrations in saliva or biofilm during meal consumption. In this randomized double-blind crossover study, 12 volunteers ingested meals (rice, beans, meat, and legumes) prepared with nonfluoridated water and salt (control group), fluoridated water (0.70 mg F/L; water group), and fluoridated salt (183.7 mg F/kg; salt group). Whole saliva was collected before meal ingestion, during mastication, and up to 2 h after meal ingestion. Dental biofilm was collected before and immediately after meal ingestion. Fluoride concentrations in saliva and dental biofilm were determined by an ion-specific electrode. The mean (±standard deviation; n = 4) fluoride concentrations in meals prepared for the control, water, and salt groups were 0.039 ± 0.01, 0.43 ± 0.04, and 1.71 ± 0.32 µg F/g, respectively. The three groups had significantly different fluoride concentrations in saliva collected during mastication (p < 0.0001) and after meal ingestion (p < 0.04; salt > water > control). The fluoride concentration in saliva returned to baseline 30 min after meal ingestion in the water group but remained high for up to 2 h in the salt group (p = 0.002). The fluoride concentration in biofilm fluid differed only between the salt and control groups (p = 0.008). The mastication of foods cooked with fluoridated water and salt increases fluoride concentrations in oral fluids and may contribute to the local effect of these community-based fluoride interventions on caries control.

Citric acid reduces oral biofilm and influences the electrochemical behavior of titanium: An in situ and in vitro study.

BACKGROUND: Citric acid (CA) has been suggested as an effective antimicrobial agent against biofilms formed on titanium. However, the antimicrobial effect of CA in biofilms formed in the oral environment and its effects on the physical properties of titanium surface remain unknown. Therefore, this study evaluated the antimicrobial effect of CA on in situ biofilm, whether this treatment favors the bacteria recolonization and its effect on the electrochemical properties of titanium. METHODS: In the in situ test, volunteers wore a palatal appliance containing titanium discs. After 7 days, the discs (N = 21) were exposed in vitro to the following treatments: immersion in 0.9% sodium chloride (control); 40% CA immersion; and 40% CA rubbing. Afterwards, these discs (N = 18) were exposed in vitro to new bacterial adhesion with Streptococcus sanguinis. New discs (N = 18) without biofilm were exposed to the treatments and subjected to electrochemical tests and surface characterization. Data were analyzed by one-way ANOVA followed by Tukey's HSD test. RESULTS: The CA groups showed a significant reduction (≈ 5-log reduction) in the biofilm formed in situ compared with the control group (p < 0.05), but no difference was found between CA application methods (p = 0.680). The acid treatment did not favor the recolonization of bacteria (p = 0.629). CA treatment did not influence the polarization resistance and capacitance of the oxide film, but statistically enhanced the electrochemical stability of titanium. CONCLUSION: Citric acid appears to be an effective clinical alternative for treatment of the main etiologic factor in dental implant failure, biofilm formation, enhancing electrochemical behavior of titanium.

Total Fluoride Intake by Children from a Tropical Brazilian City.

The main sources of fluoride intake by children are fluoridated water and toothpaste. Little has been studied regarding fluoride intake from these sources in regions with tropical climates and high temperatures throughout the year. This study aimed to determine the amount of fluoride ingested from diet and tooth brushing by children who live in a city with a tropical climate. Sixty-seven children from Teresina, Piauí, Brazil, took part in this study. The city's water supply was optimally fluoridated. The duplicate-diet method was used to determine the fluoride intake from diet. The intake of fluoride from dentifrice was determined by subtracting the amount of fluoride placed on the toothbrush and that recovered after brushing. The concentration of fluoride was measured using an ion-specific electrode and is expressed as milligrams/kilogram of body weight/day. The mean (±SD) total amount was 0.071 ± 0.036 mg F/kg body weight/day, and the relative contributions of diet and toothpaste were 0.025 ± 0.010 and 0.046 ± 0.035, respectively. The factors associated with fluoride intake from toothpaste were: use of children's toothpaste (p = 0.003), use of large amounts of toothpaste (p < 0.001), and a high frequency of tooth brushing (p = 0.003). Sixty-four percent of children had an intake of less than 0.07 mg F/kg body weight/day, which is considered the upper limit for an aesthetically tolerable fluorosis risk. The results suggest that the amount of fluoride ingested by most children who live in a Brazilian city with a tropical climate is considered safe in terms of the risk of dental fluorosis.