[show abstract][hide abstract] ABSTRACT: The acquired enamel pellicle (AEP) is important for minimizing the abrasion caused by parafunctional conditions as they occur, for instance, during bruxism. It is a remarkable feature of the AEP that a protein/peptide film can provide enough protection in normofunction to prevent teeth from abrasion and wear. Despite its obvious critical role in the protection of tooth surfaces, the essential adhesion features of AEP proteins on the enamel surface are poorly characterized. The objective of this study was to measure the adhesion force between histatin 5, a primary AEP component, and hydroxyapatite (HA) surfaces. Both biotinylated histatin 5 and biotinylated human serum albumin were allowed to adsorb to streptavidin-coated silica microspheres attached to atomic force microscope (AFM) cantilevers. A multimode AFM with a Nanoscope IIIa controller was used to measure the adhesion force between protein-functionalized silica microspheres attached to cantilever tips and the HA surface. The imaging was performed in tapping mode with a Si3N4 AFM cantilever, while the adhesion forces were measured in AFM contact mode. A collection of force-distance curves (~3,000/replicate) was obtained to generate histograms from which the adhesion forces between histatin 5 or albumin and the HA surface were measured. We found that histatin 5 exhibited stronger adhesion forces (90% >1.830 nN) to the HA surface than did albumin (90% > 0.282 nN). This study presents an objective approach to adhesion force measurements between histatin 5 and HA, and provides the experimental basis for measuring the same parameters for other AEP constituents. Such knowledge will help in the design of synthetic proteins and peptides with preventive and therapeutic benefits for tooth enamel.
Journal of dental research 03/2014; · 3.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Dental erosion is a multifactorial condition that can result in the loss of tooth structure and function, potentially increasing tooth sensitivity. The exposure of enamel to acids from non-bacterial sources is responsible for the progression of erosion. These erosive challenges are counteracted by the anti-erosive properties of the acquired pellicle (AP), an integument formed in vivo as a result of selective adsorption of salivary proteins to the tooth surface, containing also lipids and glycoproteins. This review provides an in-depth discussion regarding how the physical structure of the AP, along with its composition contributes to AP anti-erosive properties. The physical properties that contribute to AP protective nature include pellicle thickness, maturation time and site of development. The pellicle contains salivary proteins embedded within its structure that demonstrate anti-erosive properties. However, rather than individual proteins, protein-protein interactions play a fundamental role in the protective nature of the AP. In addition, dietary and synthetic proteins can modify the pellicle, enhancing its protective efficiency against dental erosion. The salivary composition of the AP and its corresponding protein-profile may be employed as a diagnostic tool, since it likely contains salivary biomarkers for oral diseases that initiate at the enamel surface, including dental erosion. Finally, by modifying the composition and structure of the AP, this protein integument has the potential to be used as a target-specific treatment option for oral diseases related to tooth demineralization.
[show abstract][hide abstract] ABSTRACT: To quantify the proteome composition of the GCF in periodontal health (HH) and in sites with different clinical conditions in chronic periodontitis (CP) subjects.
5 subjects with HH and 5 with CP were submitted to full-mouth periodontal examination, and GCF sampling. Sites in the CP group were classified and sampled as periodontitis (P, probing depth, PD>4 mm), gingivitis (G, PD≤3mm with bleeding on probing, BOP), and healthy sites (H, PD≤3mm without BOP). GCF proteins were subjected to liquid chromatography electrospray ionization mass spectrometry for identification, characterization and quantification.
230 proteins were identified; 145 proteins were detected in HH, 214 in P, 154 in G, and 133 in H. Four proteins were exclusively detected at HH, 43 proteins at P, 7 proteins at G, and 1 protein at H. Compared to HH group, 35 and 6 proteins were more abundant in P and G (p<0.001), respectively; and 4, 15 and 37 proteins were less abundant in P, G and H (p≤0.01), respectively.
There are marked differences in the GCF proteome according to disease profile. Comprehension of the role of the identified proteins in the etiopathogenesis of periodontal disease may lead to biomarkers definition.
PLoS ONE 01/2013; 8(10):e75898. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Understanding the composition and structure of the acquired enamel pellicle (AEP) has been a major goal in oral biology. Our lab has conducted studies on the composition of AEP formed on permanent enamel. The exhaustive exploration has provided a comprehensive identification of more than 100 proteins from AEP formed on permanent enamel. The AEP formed on deciduous enamel has not been subjected to the same biochemical characterization scrutiny as that of permanent enamel, despite the fact that deciduous enamel is structurally different from permanent enamel. We hypothesized that the AEP proteome and peptidome formed on deciduous enamel may also be composed of unique proteins, some of which may not be common with AEP of permanent enamel explored previously. Pellicle material was collected from 10 children (aged 18-54 months) and subjected to mass spectrometry analysis. A total of 76 pellicle proteins were identified from the deciduous pellicle proteome. In addition, 38 natural occurring AEP peptides were identified from 10 proteins, suggesting that primary AEP proteome/peptidome presents a unique proteome composition. This is the first study to provide a comprehensive investigation of in vivo AEP formed on deciduous enamel.
International Journal of Molecular Sciences 01/2013; 14(1):920-34. · 2.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acquired enamel pellicle (AEP) is a protein film that forms on the enamel surface of teeth by selective adsorption of proteins and peptides present in the mouth. This protein film forms the interface between enamel and the damage oral biofilm, which modulates the attachment of bacteria found in oral biofilm. The overall goal of this study was to gain insight into the biological formation of the human in vivo AEP. This study hypothesized that AEP is created by the formation of successive protein layers, which consist of initial binding to enamel and subsequent protein-protein interactions. This hypothesis was examined by observing quantitative and qualitative changes in pellicle composition during the first two hours of AEP formation in the oral cavity. Quantitative mass spectrometry approaches were used to generate an AEP protein profile for each time-point studied. Relative proteomic quantification was carried out for the 50 proteins observed in all four time-points. Notably, the abundance of important salivary proteins, such as histatin 1, decrease with increasing of the AEP formation, while other essential proteins such as statherin showed constant relative abundance in all time-points. In summary, this is the first study that investigates the dynamic process to the AEP formation by using proteomic approaches. Our data demonstrated that there are significant qualitative and quantitative proteome changes during the AEP formation, which in turn will likely impact the development of oral biofilms.
PLoS ONE 01/2013; 8(7):e67919. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study aimed to determine whether dental calculus formation is really higher among patients with chronic kidney disease undergoing hemodialysis than among controls. Furthermore, the study evaluated correlations between dental calculus formation and dental plaque, variables that are related to renal disease and/or saliva composition.
The Renal Group was composed of 30 patients undergoing hemodialysis, whereas the Healthy Group had 30 clinically healthy patients. Stimulated whole saliva and parotid saliva were collected. Salivary flow rate and calcium and phosphate concentrations were determined. In the Renal Group the saliva collection was carried out before and after a hemodialysis session. Patients from both groups received intraoral exams, oral hygiene instructions, and dental scaling. Three months later, the dental calculus was measured by the Volpe-Manhold method to determine the rate of dental calculus formation.
The Renal Group presented a higher rate of dental calculus formation (p < 0.01). Correlation was observed between rate of dental calculus formation and whole saliva flow rate in the Renal Group after a hemodialysis session (r = 0.44, p < 0.05). The presence of dental calculus was associated with phosphate concentration in whole saliva from the Renal Group (p < 0.05).
In conclusion, patients undergoing hemodialysis presented accelerated dental calculus formation, probably due to salivary variables.
[show abstract][hide abstract] ABSTRACT: The acquired enamel pellicle (AEP) is a thin film formed by the selective adsorption of salivary proteins onto the enamel surface of teeth. The AEP forms a critical interface between the mineral phase of teeth (hydroxyapatite) and the oral microbial biofilm. This biofilm is the key feature responsible for the development of dental caries. Fluoride on enamel surface is well known to reduce caries by reducing the solubility of enamel to acid. Information on the effects of fluoride on AEP formation is limited. This study aimed to investigate the effects of fluoride treatment on hydroxyapatite on the subsequent formation of AEP. In addition, this study pioneered the use of label-free quantitative proteomics to better understand the composition of AEP proteins. Hydroxyapatite discs were randomly divided in 4 groups (n = 10 per group). Each disc was exposed to distilled water (control) or sodium fluoride solution (1, 2 or 5%) for 2 hours. Discs were then washed and immersed in human saliva for an additional 2 hours. AEP from each disc was collected and subjected to liquid chromatography electrospray ionization mass spectrometry for protein identification, characterization and quantification. A total of 45 proteins were present in all four groups, 12 proteins were exclusively present in the control group and another 19 proteins were only present in the discs treated with 5% sodium fluoride. Relative proteomic quantification was carried out for the 45 proteins observed in all four groups. Notably, the concentration of important salivary proteins, such as statherin and histatin 1, decrease with increasing levels of fluoride. It suggests that these proteins are repulsed when hydroxyapatite surface is coated with fluoride. Our data demonstrated that treatment of hydroxyapatite with fluoride (at high concentration) qualitatively and quantitatively modulates AEP formation, effects which in turn will likely impact the formation of oral biofilms.
PLoS ONE 01/2012; 7(8):e42204. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: We provide a brief overview of the salivary proteome but with an emphasis on the major challenges in protein identification and quantitation. Precautions are necessary to avoid proteolysis, deglycosylation and dephosphorylation of salivary proteins by microbial and host enzymes in saliva. Many proteins are differentially expressed in secretions from different salivary glands and their proportional contributions to saliva vary with the flow rate. The total protein concentration in the secretion from any one gland varies considerably, depending on factors such as flow rate, duration of stimulation, nature of the stimulus and circadian rhythms. Many plasma proteins enter saliva via gingival crevicular fluid, of which there are increased amounts in persons with gingivitis or periodontal disease. These factors must be taken into account in the identification of potential biomarkers for different oral or systemic diseases.
[show abstract][hide abstract] ABSTRACT: We will provide a translational view of using the recent technological advances in dental research for predicting, monitoring, and preventing the development of oral diseases by investigating the diagnostic and therapeutic role of salivary proteins. New analytical state-of-the-art technologies such as mass spectrometry and atomic force microscopy have revolutionized the field of oral biology. These novel technologies open avenues for a comprehensive characterization of the salivary proteins followed by the evaluation of the physiological functions which could make possible in a near future the development of a new series of synthetic protein for therapeutic propose able to prevent global oral diseases such as periodontal disease and dental caries, the two most prevalent oral diseases in the World.
Journal of Cell Communication and Signaling 09/2011; 5(4):271-5.
[show abstract][hide abstract] ABSTRACT: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated.
A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50%) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO₃ solution and the primary teeth in 5% or 50% AgNO₃ solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%).
The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000).
Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO₃ solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were capable of indicating loss of marginal seal in the composite restorations; the 3-step conventional adhesive system had better performance regarding microleakage in enamel on primary and permanent teeth.
Journal of applied oral science: revista FOB 06/2011; 19(3):254-9. · 0.39 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim was to compare the performance of different methods in detecting approximal caries lesions primary molars ex vivo.
One hundred thirty-one approximal surfaces were examined by 2 observers with visual inspection (VI) using the International Caries Detection and Assessment System, radiographic interpretation, and clinically using the Diagnodent pen (LFpen). To achieve a reference standard, surfaces were directly examined for the presence of white spots or cavitations, and lesion depth was determined after sectioning. The area under the receiver operating characteristic curve (A(z)), sensitivity, specificity, and accuracy were calculated, as well as the interexaminer reproducibility.
Using the cavitation threshold, all methods presented similar sensitivities. Higher A(z) values were achieved with VI at white spot threshold, and VI and LFpen had higher A(z) values at cavitation threshold. VI presented higher accuracy and A(z) than radiographic and LFpen at both enamel and dentin depth thresholds. Higher reliability values were achieved with VI.
VI performs better, but both radiographic and LFpen methods also show good performance in detecting more advanced approximal caries lesions.
[show abstract][hide abstract] ABSTRACT: We have described the oral status and salivary flow rate of 30 children and adolescents suffering from chronic renal failure (CRF) undergoing hemodialysis and compared the associated parameters with those of 30 clinically healthy subjects with no history of chronic disease. The subjects of the renal group (RG) and healthy group (HG) were paired by gender and age (7-19 years old). Anamneses and an interview consisting of questions on oral hygiene habits comprised the first step in the study, followed by whole and parotid saliva collection and intra-oral examination. No statistical significant difference was found between the RG and HG subjects in terms of the presence of gingival inflammation, dental history of caries, and enamel hypoplasia. However, statistical significant differences were found between the groups related to a sensation of dry mouth, salivary flow rate, delayed tooth eruption, dental staining by iron supplementation, presence of plaque, and dental calculus. Based on our results, we conclude that CRF children and adolescents undergoing hemodialysis present some oral manifestations related to their disease. These manifestations include a sensation of dry mouth, delayed tooth eruption, dental staining by iron supplementation, and dental calculus. A lower flow rate of whole and parotid saliva production just before hemodialysis was also observed.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to evaluate the effects of infrared diode laser phototherapy (LP) on tissues of the submandibular gland (SMG) and parotid gland (PG). Wistar rats were randomly divided into experimental (A and B) and control (C) groups. A diode laser, 808 nm wavelength, in continuous wave mode, was applied to the PG, SMG and sublingual gland in the experimental groups on two consecutive days. The doses were 4 J/cm(2) and 8 J/cm(2), and total energy was 7 J and 14 J, respectively. The power output (500 mW) and power density (277 mW/cm(2)) were the same for both experimental groups. In order to visualize the area irradiated by the infrared laser, we used a red pilot beam (650 nm) with 3 mW maximum power for the experimental groups. For the control group, the red pilot beam was the only device used. The SMG and PG were removed after 1 week of the first irradiation. Total protein concentration, amylase, peroxidase, catalase and lactate dehydrogenase assays were performed, as well as histological analysis. Statistical tests revealed significant increase in the total protein concentration for groups A and B in the parotid glands (P < 0.05). Based on the results of this study, LP altered the total protein concentration in rats' parotid glands.
Lasers in Medical Science 02/2008; 24(2):202-8. · 2.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the flow rate, amylase and peroxidase activities, and total protein and sialic acid concentrations in saliva of adolescents with cerebral palsy.
The saliva of 24 adolescents with cerebral palsy was compared with that of 18 adolescents without cerebral palsy, all aged around 12 years, 2 months. The whole saliva was collected under slight suction and frozen at -80 degrees C. Flow rate, amylase and peroxidase activities, and total protein and sialic acid concentrations were analyzed by standard methods.
The flow rate was low in the cerebral palsy group. The cerebral palsy group demonstrated low amylase and peroxidase activities. Boys and girls from the cerebral palsy group demonstrated higher total protein concentration than the boys and girls from the control group. Sialic acid, free and total, concentration was higher in the cerebral palsy group than in the control group.
The results suggest that adolescents with cerebral palsy present alterations in the salivary parameters studied that can increase the risk of oral disease in this population.
[show abstract][hide abstract] ABSTRACT: To analyze sodium, potassium, calcium, phosphorus, and magnesium concentrations in whole saliva of adolescents with cerebral palsy (CP) and compare them with those of normal individuals.
Thirty-six adolescents with CP aged 12.0 +/- 1.8 years were compared with 36 healthy age-matched individuals. Saliva was collected under slight suction. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry.
Significant differences were observed with matched and unmatched flow rates. Sodium concentrations were significantly decreased, whereas potassium levels were significantly increased in the CP group. No statistically significant differences were observed regarding phosphorus, magnesium, and calcium concentrations between adolescents with CP and controls.
Our results suggest that there is an alteration in the sodium and potassium concentration in whole saliva of individuals with CP.
Quintessence international 05/2007; 38(4):301-6. · 0.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this open-label, crossover study was to measure salivary pH after the oral administration of distilled water, a 10% sucrose solution, and valproic acid to a population of 10 children with cerebral palsy. Salivary pH was measured just prior to giving the solutions and then every five minutes for 60 minutes. The critical pH was defined at 5.5, below which dental demineralization occurs. In this population, valproic acid decreased salivary pH to below the critical pH for an extended period of time (mean = 4.32 at 20 minutes) when compared to mean salivary pH after administration of distilled water (7.11 at 20 minutes) and a 10% sucrose solution (5.96 at 20 minutes). Recovery from this low pH to above the critical level did not occur until after 50 minutes and furthermore did not recover to baseline, neutral levels, for the duration of this study (60 minutes). Our results suggest that children with cerebral palsy, a population with a tendency toward reduced salivary function, have a compromised ability to buffer the oral administration of an exogenous acid. This can result in an increased susceptibility to demineralization and caries of the teeth.
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to measure certain components in whole saliva from children with Down syndrome aged 12 months to 60 months. Twenty children with Down syndrome were compared with 18 children without Down syndrome. Whole saliva was collected under slight suction and the salivary pH was measured with a portable pH meter soon after collection. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. Sialic acid was determined by thiobarbituric acid assay. Amylase was assayed measuring the maltose produced by the breakdown of starch and peroxidase with ortho-dianisidine. No statistically significant differences were observed in sialic acid, calcium, phosphorus and magnesium concentrations between the group with Down syndrome and the control group. Protein and sodium concentration were higher in the group with Down syndrome compared to the control group. On the other hand, the flow rate, pH, amylase and peroxidase activities and potassium concentration were lower in those with Down syndrome compared to those children in the control group.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to analyze some standard parameters of the unstimulated and stimulated whole saliva of mouth-breathers and a control group to determine if these variables present any difference in mouth-breathers compared to control group, since these parameters of saliva can influence the oral health.
Saliva samples were collected from 61 adolescents aged 10-19 years; 30 were mouth-breathers and 31 were nose-breathers. The unstimulated salivary specimen was collected, followed by collection of the stimulated saliva. Soon after collecting the salivary sample, the flow rate and buffering capacity were determined. The samples were then stored at -80 degrees C until analysis was performed. The analysis consisted of the determination of protein content and total, free and bound sialic acid levels.
No statistically significant difference was observed in the flow rate, buffering capacity, protein content, total and bound sialic acid levels of unstimulated and stimulated saliva, nor in the free sialic acid of stimulated saliva. However, the levels of free sialic acid of the unstimulated saliva were significantly higher in the mouth-breather compared to the control group.
Since a higher level of free sialic acid is indicative of an increase in the number of bacteria in saliva, our findings suggest that mouth-breathers retain more bacteria in oral tissues.
International Journal of Pediatric Otorhinolaryngology 06/2006; 70(5):799-805. · 1.35 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study evaluated the flow rate and composition of whole saliva in patients with chronic renal failure undergoing hemodialysis. In the group on dialysis (RG) (n = 15), saliva was collected just prior to hemodialysis CT1) and at completion (T2), while in the healthy subjects (HG)(n = 15) saliva was collected at the same time of day as the pre-dialysis. Saliva samples were analyzed by inductively coupled argon plasma with atomic emission spectrometry. Significant differences were found in the flow rate, potassium, magnesium and phosphorus concentrations at the RG-T1 and HG (p < 0.05). Sodium concentration at RG-T1 and RG-T2 were higher than HG (p < 0.05). Total protein concentration was higher at RG-T1 than at the other two analyses. Salivary peroxidase activity at RG-T1 and RG-T2 was lower than at HG. Our findings suggest that in patients with chronic renal failure, the saliva is altered. Hemodialysis, however, seems to help control saliva composition and flow rate.