Acquired pellicle as a modulator for dental erosion

Acquired pellicle engineering: a fascinating approach to prevent demineralization

The acquired enamel pellicle (AEP) consists of an organic, acellular, and bacteria-free film, formed in vivo as a result of biomolecules adsorption onto the tooth surface. It is composed of proteins, glycoproteins, lipids, phospholipids, and other macromolecules, such as carbohydrates. The AEP formation process is complex and can be divided into three stages: initiation, development, and maturation. The pellicle has two main layers: the globular and basal layers. The basal layer offers the most protection against demineralization, as the subsequent globular layer is weaker and less tenacious. The formation of the AEP can be influenced by various factors, such as the physicochemical properties of the teeth, location in the oral cavity, pathologies, and even the oral microbiota. With the advancement of "omics" techniques, it has been possible to observe the presence of acid-resistant proteins in the AEP, which allowed the development of the "acquired pellicle engineering" strategy. This strategy involves enriching and modifying the basal layer with acid-resistant proteins. Among these proteins, hemoglobin, statherin-derived peptide, and a protein derived from sugarcane stand out. The objective of this literature review is to provide a comprehensive overview of the AEP, detailing its composition, formation process, and protective functions. Additionally, the review aims to explore recent advances in the field of "acquired pellicle engineering," highlighting the acid-resistant proteins of the AEP and their potential applications in dentistry. Finally, the review intends to highlight the clinical implications of these findings and how they may contribute to the development of new strategies for the prevention and treatment of dental pathologies according to published studies.

Chitosan nanoparticles suspension can minimize enamel loss after in vitro erosive challenge

BACKGROUND

Chitosan nanoparticles suspension (ChNPs) showed antimicrobial effects in the oral cavity, but its effects on enamel erosion prevention remain little explored.

OBJECTIVE

This study synthesized ChNPs and evaluated their effect on enamel after erosive challenge.

DESIGN

ChNPs were synthesized by ionic gelation and characterized using scanning electron microscopy (SEM), infrared spectrophotometry (FTIR), dynamic light scattering methods (DLS) and zeta potential (ZP). In total, 56 human enamel blocks were divided into four groups (n=14/group): (i) ChNPs suspension (4.4mg/mL); (ii) 0.05% sodium fluoride solution (NaF); (iii) chitosan solution (5.0 mg/mL); and (iv) distilled water. After incubation in freshly collected human saliva (3h), the samples were exposed to erosive challenge in 1% citric acid (90s) and remineralizing solution (2h) performed four times a day. After the 1st and 4th acid exposures, solutions were applied for 2 min. After 7 days, % Vickers surface hardness change (% SMH) was obtained using 300 g load applied for 15s. Enamel surface loss was evaluated using optical profilometer by subtracting the final profile values from baseline ones. Data were analyzed by ANOVA and post-hoc T tests (α=0.05). Surface topography was obtained by optical profilometer.

RESULTS

SEM revealed the formation of spherical nanoparticles. DLS showed nanoparticles with 85.7±10.5 nm diameter and ZP value of +45.5±5.4mV. Enamel surface loss was significantly lower in ChNPs and NaF groups, exhibiting a less rough surface in the treated areas. ChNPs, NaF and chitosan groups showed lower % SMH values.

CONCLUSIONS

ChNPs suspension minimized enamel loss after in vitro erosive challenge and appears to be a promising material for enamel erosion prevention.

Paving the way for the use of Statherin-Derived Peptide (StN15) to control caries through acquired pellicle and biofilm microbiome engineering: Proof-of-concept in vitro/in vivo studies

OBJECTIVE

This proof-of-concept sequence of in vivo/in vitro studies aimed to unveil the role of acquired enamel pellicle (AEP) engineering with statherin-derived peptide (StN15) on the AEP protein profile, enamel biofilm microbiome in vivo and on enamel demineralization in vitro.

DESIGN

In vivo studies, 10 volunteers, in 2 independent experiments (2 days each), rinsed (10 mL,1 min) with: deionized water (negative control) or 1.88 × 10-5 M StN15. The AEP, formed along 2 h and the biofilm, along 3 h, were collected. AEP was analyzed by quantitative shotgun-label-free proteomics. The enamel biofilm microbiome was evaluated using 16S-rRNA Next Generation Sequencing (NGS). An in vitro model with microcosm biofilm was employed. Bovine enamel samples (n = 72) were treated with 1) Phosphate-Buffer-Solution (PBS), 2) 0.12 %Chlorhexidine, 3) 500ppmNaF; 4) 1.88 × 10-5MStN15; 5) 3.76 × 10-5MStN15 and 6) 7.52 × 10-5MStN15. Biofilm was supplemented with human saliva and McBain saliva and cultivated for 5 days. Resazurin, colony forming units (CFU) and Transversal Microradiography Analysis-(TMR) were performed.

RESULTS

Proteomic results showed several proteins with acid-resistant, calcium-binding, and antimicrobial properties in the StN15 group. The microbiome corroborated these findings, reducing bacteria that are closely related to dental caries in the StN15 group, compared to the PBS. The microcosm biofilm showed that the lowest concentration of StN15 was the most efficient in reducing bacterial activity, CFU and enamel demineralization compared to PBS.

CONCLUSION

StN15 can effectively alter the AEP proteome to inhibit initial bacterial colonization, thereby mitigating enamel demineralization. Future research should explore clinical applications and elucidate the mechanisms underlying the protective effects of StN15.

Resveratrol alters oral biofilm in vitro and in vivo

OBJECTIVE

To evaluate the ability of resveratrol to reduce dental caries in vitro and in vivo.

METHODS

In part 1, a microcosm biofilm protocol was employed. One hundred twenty-six bovine enamel specimens were treated with: Resveratrol (50, 100, 200, 400 µg/mL), Phosphate buffered saline (negative control), Dimethyl sulfoxide (negative control) and 0.12% Chlorhexidine (positive control). The biofilm was produced from the saliva of 10 volunteers, under 0.2% sucrose exposure for 5 days, and daily treated with the solutions (1 min). At the end of the experimental period, resazurin and viable plate count assays were performed. Enamel demineralization was evaluated by transverse microrradiography (TMR). In part 2, 12 volunteers participated in a triple-blind crossover protocol for 7 weeks, according to the following treatments: 1) 100 mg/L resveratrol; 2) 0.05% NaF (226 mg/L F); 3) 100 mg/L resveratrol + 0.05% NaF; 4) Deionized water (negative control). Biofilm samples were collected from both sides of the mouth 12 h after the use of the solutions.

RESULTS

Resveratrol at 50 and 200 µg/mL significantly reduced biofilm metabolic activity and mutans streptococci, respectively. Chlorhexidine was an effective treatment to significantly reduce all parameters, being an important antimicrobial and anticaries agent in vitro. Resveratrol alone or associated with NaF modulated several caries-associated bacteria in vivo.

CONCLUSION

The present study represents the first step regarding the use of resveratrol within the concept of acquired enamel pellicle and biofilm engineering to prevent dental caries.

The preventive effect of silver diamine fluoride-modified salivary pellicle on dental erosion

OBJECTIVE

To investigate the preventive effect of silver diamine fluoride (SDF) modified salivary pellicle (SP) against dental erosion.

METHODS

Enamel and dentin blocks allocated into 4 groups (n = 30 each). Blocks in Group SDF+SP were treated with SDF and SP. Blocks in Group SDF were treated with SDF. Blocks in Group DW+SP were treated with deionized water (DW) and SP. Blocks in Group DW were treated with DW. The blocks were subjected to an erosive challenge at pH 3.2 for 2 mins, 5 times per day for 14 days. Salivary pellicle morphology was assessed by atomic force microscopy (AFM). Crystal characteristics, percentage microhardness loss (%SMHL), surface loss, and surface morphology were assessed by X-ray diffraction (XRD), microhardness test, profilometry, and scanning electron microscopy (SEM), respectively.

RESULTS

AFM revealed a modified pellicle morphology in Group SDF+SP. XRD of both blocks revealed hydroxyapatite, silver chloride, silver phosphate, and silver fluoride in Groups SDF+SP and SDF. Fluoroapatite was found in Group SDF+SP only. %SMHL ( ± Standard deviation in %) of Groups SDF+SP, SDF, DW+SP, and DW were 33.4 ± 2.2, 38.6 ± 2.2, 50.3 ± 2.2, and 58.3 ± 2.4 in enamel and 16.1 ± 2.2, 19.7 ± 2.1, 32.8 ± 2.1, and 39.0 ± 2.3 in dentin, respectively. The presence of SDF and SP reduced %SMHL in both blocks (p < 0.001). The surface loss ( ± Standard deviation in μm) of Groups SDF+SP, SDF, DW+SP, and DW were 3.6 ± 0.7, 4.1 ± 0.4, 5.3 ± 0.5, and 7.0 ± 0.6 in enamel and 5.4 ± 0.6, 6.1 ± 0.5, 9.1 ± 0.7, and 9.2 ± 0.5 in dentin, respectively. The presence of SDF and SP reduced surface loss in enamel and dentin blocks (p = 0.031 and p = 0.002, respectively). SEM showed enamel surface remained relatively smooth and partially dentinal tubule occlusion on dentin blocks in Groups SDF+SP and SDF.

CONCLUSION

SDF had a positively synergistic effect with SP. SDF-modified salivary pellicle provided a superior protective effect against dental erosion.

Proteome of the 2-h in vivo Formed Acquired Enamel Pellicle of Adolescents with Erosive Tooth Wear, Caries, or Sound

INTRODUCTION

Acquired pellicle (AP) acts as a membrane preventing acids from coming into direct contact with the tooth. Possibly, individuals with different dental health status present changes in its composition that could disrupt this function. Thus, the aim of this study was to compare the protein composition of the AP in adolescents with erosive tooth wear (ETW), caries, or sound.

METHODS

Calibrated examiners in BEWE index and ICDAS-merged Epi criteria assessed ETW and caries in a sample of 454 systemically healthy adolescents aged 12-15 years old. Thirty subjects from that sample were selected for this study: ETW group (n = 10; total BEWE ≥9 and absence of dentinal caries lesions); caries group (n = 10; total BEWE <9 and with at least one dentinal caries lesion), and sound group (n = 10; total BEWE <9 and absence of dentinal caries lesions). Two-hour-formation AP samples were taken from buccal, occlusal/incisal, palatal/lingual tooth surfaces. Protein composition was analysed by liquid chromatography-tandem mass spectrometry. Using mean reporter ion values, relative abundances of proteins were compared among the three groups to calculate for fold changes. Twofold protein increases or decreases were reported (t test, p < 0.05). Gene Ontology (GO) of included proteins was assigned.

RESULTS

Mean age of participants was 13.1 ± 1.14 years and 56.6% were females. The prevalence of ETW was of 66.6% and of dentinal caries of 33.3%. The GO analyses showed that the majority of detected proteins were stress response related. The ETW group disclosed upregulated relative abundance of antileukoprotease (2.85-fold in ETW vs. sound and 2.34-fold in ETW group vs. caries group); histatin (2.42-fold in ETW group vs. sound group and 2.20-fold in ETW group vs. caries group), and prolactin-induced protein (2.30-fold in ETW group vs. sound group and 2.06-fold in ETW group vs. caries group) (p < 0.05). Hemoglobin subunits alpha (HBA) and beta (HBB) showed decreased relative abundances in the ETW and caries groups when compared to the sound group (HBA: 0.42-fold in ETW group and 0.40-fold in caries group; HBB: 0.45-fold in ETW group and 0.38-fold in caries group; p < 0.05).

CONCLUSION

AP from individuals with ETW showed differences when compared to other dental conditions, with relative abundance increasing of some stress response-associated proteins in ETW and a decrease in proteins related to salivary protection against acid challenges.

Acquired pellicle and biofilm engineering with CaneCPI-5: Insights from proteomic and microbiomics analysis

OBJECTIVE

In this in vivo proof-of-concept study, acquired pellicle engineering was implemented to promote alterations in the protein composition of the acquired enamel pellicle (AEP) and the bacterial composition of the dental biofilm after treatment with Sugarcane cystatin (CaneCPI-5).

DESIGN

After prophylaxis, 10 volunteers rinsed (10 mL, 1 min) with the following solutions: 1) deionized water (H2O- negative control or 2) 0.1 mg/mL CaneCPI-5. The AEP and biofilm were formed along 2 or 3 h, respectively. The AEP was collected with electrode filter papers soaked in 3 % citric acid. After protein extraction, samples were analyzed by quantitative shotgun label-free proteomics. The biofilm microbiome was collected with a dental curette. The DNA was extracted, amplified, and analyzed by 16S-rRNA Next Generation Sequencing (NGS).

RESULTS

Treatment with CaneCPI-5 increased several proteins with antimicrobial, acid-resistance, affinity for hydroxyapatite, structural and calcium binding properties, such as Cysteine-rich-3 (6-fold-p = 0.03), Cystatin-B (5.5-fold-p < 0.01), Neutrophil-defensin 1 (4.7-fold-p < 0.01), Mucin (3.9-fold-p < 0.01), Immunoglobulin-heavy-constant (3.8-fold-p < 0.01) and Lactotransferrin (2.8-fold-p < 0.01). Microbiome revealed that several commensal bacteria had their abundance increased after rinsing with CaneCPI-5, such as Corynebacterium and Neisseria, while Streptococcus and Prevotella nigrescens were decreased. The results indicate the efficiency of CaneCPI-5 in promoting beneficial changes in the AEP and biofilm, making this phytocystatin a potential target for incorporation into dental products.

CONCLUSION

Cane demonstrated the capability to alter the protein composition of the acquired enamel pellicle (AEP) and the initial colonizers of the biofilm, enhancing the presence of proteins and bacteria crucial for dental protection.

Statherin-Derived Peptide Protects against Intrinsic Erosive Enamel Wear in situ

INTRODUCTION

This in situ study investigated the protective effect of a solution containing statherin-derived peptide (StatpSpS) against enamel intrinsic erosion (ERO).

METHODS

Fifteen volunteers wore appliances containing 2 bovine specimens. The samples were subjected to ERO with HCl, mimicking dental ERO by intrinsic acid. The volunteers participated in 3 phases (double-blind and crossover): (1) deionized water (negative control); (2) commercial solution containing SnCl2/NaF/AmF (800 ppm Sn+2, 500 ppm F-, pH 4.5) (positive control); (3) solution containing 1.88 × 10-5m StatpSpS. Four times a day, the volunteers administered one drop of the solutions (50 μL, 1 min) on each specimen. After the treatment, erosive challenges were performed extraorally with 0.01 m HCl (pH 2.0, 4 times/day, 1 min, 150 mL). Enamel wear was assessed by profilometry. Data were analyzed by one-way RM-ANOVA/Bonferroni's tests (p < 0.05).

RESULTS

In terms of the treatments, both the commercial solution (SnCl2/NaF/AmF) and StatpSpS significantly reduced the wear when compared to the negative control (p < 0.01), without significant differences between them (p > 0.05).

CONCLUSION

The solution containing StatpSpS demonstrated protection against enamel intrinsic erosive wear. This study marks a significant advancement in the prevention of intrinsic erosive wear, utilizing StatpSpS in acquired pellicle engineering procedures.

Salivary Proteins in Human Acquired Enamel Pellicle (AEP) on Eroded and Uneroded Teeth in Patients with Gastro-Oesophageal Reflux Disease (GORD)

The aim of this in vivo study was to compare total protein present in the salivary films (F) and acquired enamel pellicle (AEP) on eroded and non-eroded surfaces in patients suffering from GORD symptoms with and without GORD diagnosis (GORD, No-GORD). Thirty-nine patients suffering from GORD symptoms and erosive tooth wear on lower first molars and an unaffected posterior occlusal surface in the same quadrant were recruited from Guy's hospital, London. Salivary film and AEP were collected from the eroded and uneroded occlusal surfaces, using 0.5% sodium dodecyl sulphate (SDS)-soaked filter papers. Total protein concentration was analysed using bicinchoninic acid assay (BCA). Statistical analysis was conducted using Shapiro-Wilk, ANOVA, and Tukey's tests (p < 0.05), comparing four GDS sample types and GORD vs. No-GORD groups. The level of significance was set as p < 0.05. Data were compared between eroded and uneroded surfaces in the same patient with GORD symptoms, as well as between those with or without a GORD diagnosis (GORD, No-GORD). The AEP total protein concentration from the eroded [2.17 (0.49) mg/mL] and uneroded surfaces [2.24 (0.66) mg/mL] of the GORD group were statistically significantly lower than those on eroded [3.27 (1.01) mg/mL] and uneroded [3.33 (1.57) mg/mL] surfaces in the No-GORD group (p = 0.007) (p = 0.008), respectively. No statistically significant differences were observed for film and AEP between eroded and uneroded surfaces (p > 0.05).

Toothpaste containing TiF4 and chitosan against erosive tooth wear in situ

OBJECTIVE

This study compared the protective effect of an experimental TiF4/Chitosan toothpaste with a commercial toothpaste on the prevention of erosive tooth wear (ETW) in situ.

METHODS

Fifteen subjects took part in this crossover and double-blind study, in which they wore a palatal appliance containing 4 bovine enamel and 4 dentin in 3 phases (5 days each). Half of the samples were subjected to erosive challenges (90 s in 0.1 % citric acid, pH 2.5, 4 times/day), and the other half to erosive plus abrasive challenges (15 s plus 45 s of contact, 2 times/day). The phases corresponded to the application of the different toothpastes: 1) TiF4 (1400 ppm F-) plus Chitosan, 2) Elmex®, Erosion Protection (1400 ppm F-, Chitosan), and 3) Placebo (negative control). Tooth wear was measured using contact profilometry (μm) and submitted to two-way RM ANOVA/Tukey test (p < 0.05).

RESULTS

No significant differences were detected between the experimental and commercial toothpastes, regardless of the challenge on both tissues. Both significantly reduce ETW compared to negative control (p < 0.0006). Tooth wear was increased by brushing only on eroded enamel (p < 0.01), but not on dentin (p = 0.6085). TiF4/Chitosan [erosion 2.98 ± 1.12 μm vs. erosion and abrasion 3.12 ± 1.33 μm] and Elmex® toothpastes [erosion 2.35 ± 0.93 μm vs. erosion and abrasion 2.98 ± 1.0 μm] minimized the impact of brushing compared to placebo on enamel [erosion 4.62 ± 1.48 μm vs. erosion and abrasion 5.15 ± 1.50 μm].

CONCLUSIONS

TiF4 plus chitosan toothpastes showed to be effective in minimizing the ETW as the commercial toothpaste is in situ.

CLINICAL RELEVANCE

The experimental toothpaste has similar effect against ETW compared to the commercial toothpaste. Considering the increased ETW prevalence worldwide, this result supports clinical trials and a possible application of this experimental anti-erosive toothpaste in the future.

Preventive dental erosion with silver diamine fluoride: An in vitro study

OBJECTIVES

To evaluate the erosion preventive effect of 38 % silver diamine fluoride (SDF) solution in enamel and dentin of human permanent teeth.

METHODS

Ninety enamel and ninety dentin blocks were prepared from permanent molars and allocated into three groups. Gp-SDF received a one-off application of 38 % SDF solution. Gp-SNF received a one-off application of a solution containing 800 ppm stannous chloride and 500 ppm fluoride. Gp-DW received a one-off application of deionized water. The blocks were submitted to acid challenge at pH 3.2, 2 min, 5 times/day for 7 days. All blocks were immersed in human saliva between cycles for one hour. The crystal characteristics, percentage of surface microhardness loss (%SMHL), surface loss, and elemental analysis and surface morphology were examined by X-ray diffraction (XRD), microhardness test, non-contact profilometry, and energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. Data of%SMHL and surface loss were analyzed by one-way ANOVA.

RESULTS

XRD spectra revealed that fluorapatite and silver compounds formed in Gp-SDF, while fluorapatite and stannous compounds formed in Gp-SNF. Gp-DW presented only hydroxyapatite. The median (interquartile range) of%SMHL in Gp-SDF, Gp-SNF and Gp-DW were 27.86(3.66), 43.41(2.45), and 46.40(3.54) in enamel (p< 0.001), and 14.21(1.57), 27.99(1.95), and 33.18(1.73) in dentin, respectively (p < 0.001). The mean (standard deviation, μm) of surface loss of Gp-SDF, Gp-SNF, and Gp-DW were 2.81(0.59), 4.28(0.67), and 4.63(0.64) in enamel (p < 0.001) and 4.13(0.69), 6.04(0.61), and 7.72(0.66) in dentin, respectively (p < 0.001). SEM images exhibited less enamel corruption and more dentinal tubular occlusion in Gp-SDF compared to Gp-SNF and Gp-DW. EDS analysis showed silver was detected in Gp-SDF while stannous was detected in the dentin block of Gp-SNF.

CONCLUSION

38 % SDF yielded superior results in protecting enamel and dentin blocks from dental erosion compared to SNF and DW.

CLINICAL SIGNIFICANCE

Topical application of 38 % SDF is effective in preventing dental erosion in human enamel and dentin.

Carbon dots combined with phytosphingosine inhibit acid-induced demineralization of hydroxyapatite in vitro

OBJECTIVES

To study the effects of carbon dots (CDs), in combination with phytosphingosine (PHS), against acid-induced demineralization of hydroxyapatite in vitro.

METHODS

CDs were generated from citric acid and urea by microwave heating. Transmission electron microscope (TEM), FT-IR, and fluorescence intensity were used to characterize the CDs. A hydroxyapatite (HAp) model was used to investigate the protective effects of CDs, PHS, and their combinations with and without a salivary pellicle against acid-induced demineralization in vitro. Ca2+ release as a parameter to evaluate the inhibition of demineralization was measured by capillary electrophoresis. The interactions between CDs, PHS, and HAp discs were investigated using a fluorescence detector.

RESULTS

Uniform-sized CDs were synthesized, showing typical optical characteristics. CDs exhibited no inhibition of acid-induced demineralization in vitro, in contrast to PHS. Notably, a pre-coating of CDs increased the protective effects of PHS against acid-induced demineralization, which was not disturbed by the presence of a salivary pellicle and Tween 20. Scanning electron microscope (SEM) confirmed the binding and layers formed of both CDs and PHS to the HAp surfaces. Based on fluorescence spectra CDs binding to HAp seemed to be dependent on Ca2+ and PO43- interactions.

CONCLUSIONS

CDs combined with PHS showed protective effects against acid-induced demineralization of HAp discs in vitro.

Acquired Pellicle and Biofilm Engineering by Rinsing with Hemoglobin Solution

INTRODUCTION

The identification of acid-resistant proteins, including hemoglobin (Hb), within the acquired enamel pellicle (AEP) led to the proposition of the "acquired pellicle engineering" concept, which involves the modification of the AEP by incorporating specific proteins, presenting a novel strategy to prevent dental demineralization.

OBJECTIVE

Combining in vivo and in vitro proof-of-concept protocols, we sought to reveal the impact of AEP engineering with Hb protein on the biofilm microbiome and enamel demineralization.

METHODS

In the in vivo studies, 10 volunteers, in 2 independent experiments, rinsed (10 mL,1 min) with deionized water-negative control or 1.0 mg/mL Hb. The AEP and biofilm formed along 2 or 3 h, respectively, were collected. AEP was analyzed by quantitative shotgun-label-free proteomics and biofilm by 16S-rRNA next-generation sequencing (NGS). In in vitro study, a microcosm biofilm protocol was employed. Seventy-two bovine enamel specimens were treated with (1) phosphate-buffered solution (PBS), (2) 0.12% chlorhexidine, (3) 500 ppm NaF, (4) 1.0 mg/mL Hb, (5) 2.0 mg/mL Hb, and (6) 4.0 mg/mL Hb. The biofilm was cultivated for 5 days. Resazurin, colony forming units (CFU), and transversal microradiography were performed.

RESULTS

Proteomics and NGS analysis revealed that Hb increased proteins with antioxidant, antimicrobial, acid-resistance, hydroxyapatite-affinity, calcium-binding properties and showed a reduction in oral pathogenic bacteria. In vitro experiments demonstrated that the lowest Hb concentration was the most effective in reducing bacterial activity, CFU, and enamel demineralization compared to PBS.

CONCLUSION

These findings suggest that Hb could be incorporated into anticaries dental products to modify the oral microbiome and control caries, highlighting its potential for AEP and biofilm microbiome engineering.

Hemoglobin Protects Enamel against Intrinsic Enamel Erosive Demineralization

INTRODUCTION

This study investigated the changes in the acquired enamel pellicle (AEP) proteome when this integument is formed in vivo after treatment with sugarcane-derived cystatin (CaneCPI-5), hemoglobin (HB), and a statherin-derived peptide (StN15), or their combination and then exposed to an intrinsic acid challenge. The effectiveness of these treatments in preventing intrinsic erosion was also evaluated.

METHODS

Ten volunteers, after prophylaxis, in 5 crossover phases, rinsed with the following solutions (10 mL, 1 min): control (deionized water-H2O) - group 1, 0.1 mg/mL CaneCPI-5 - group 2, 1.0 mg/mL HB - group 3, 1.88 × 10-5M StN15 - group 4, or a blend of these - group 5. Following this, AEP formation occurred (2 h) and an enamel biopsy (10 µL, 0.01 m HCl, pH 2.0, 10 s) was conducted on one incisor. The biopsy acid was then analyzed for calcium (Arsenazo method). The vestibular surfaces of the other teeth were treated with the same acid. Acid-resistant proteins in the residual AEP were then collected and analyzed quantitatively via proteomics.

RESULTS

Compared to control, treatment with the proteins/peptide, mixed or isolated, markedly enhanced acid-resistant proteins in the AEP. Notable increases occurred in pyruvate kinase PKM (11-fold, CaneCPI-5), immunoglobulins and submaxillary gland androgen-regulated protein 3B (4-fold, StN15), Hb, and lysozyme C (2-fold, StN15). Additionally, a range of proteins not commonly identified in the AEP but known to bind calcium or other proteins were identified in groups treated with the tested proteins/peptide either in isolation or as a mixture. The mean (SD, mM) calcium concentrations released from enamel were 3.67 ± 1.48a, 3.11 ± 0.72a, 1.94 ± 0.57b, 2.37 ± 0.90a, and 2.38 ± 0.45a for groups 1-5, respectively (RM-ANOVA/Tukey, p < 0.05).

CONCLUSIONS

Our findings demonstrate that all treatments, whether using a combination of proteins/peptides or in isolation, enhanced acid-resistant proteins in the AEP. However, only HB showed effectiveness in protecting against intrinsic erosive demineralization. These results pave the way for innovative preventive methods against intrinsic erosion, using "acquired pellicle engineering" techniques.

Introspection of the Etiopathological Mechanisms Underlying Noncarious Cervical Lesions: Analysis of the Different Theories and Their Impact on the Mineralized Structures of the Tooth

The noncarious cervical lesions (NCCLs) recognize an etiological framework of onset very different from the carious processes with etiology whose bacteria aggregated in a biofilm play a predominant role, leading in this way to the loss of the mineralized structure of the tooth. The pathological picture of the NCCLs, which manifests itself with a clinical picture of dental wear, differs from caries because it mainly recognizes a series of pathological processes, such as erosion, through the action of generally acidic chemical agents and abrasion, which is basically expressed through repeated mechanical trauma characteristic of tooth brushing. However, in the literature, there is no unanimous agreement in identifying only these two mechanisms, but there are some who propose a more marked role of anomalous occlusal loads, which would be unloaded on some teeth which, in addition to both erosive and abrasive mechanisms, would give rise to abfraction. Therefore, the aim of this review was to collect literature etio-pathological information and discuss the mechanisms underlying NCCLs.

Incorporation of bioactive glass-ceramic into coconut oil for remineralization of incipient carious lesions

This study evaluated the efficacy of incorporating different concentrations of bioactive glass-ceramic (Biosilicate) into coconut oil on the remineralizing potential and surface roughness of white spot lesions. Fragments (6 x 6 x 2mm) of bovine teeth were sectioned and initial microhardness (KHN) and surface roughness (Ra) readings were obtained. The samples were submitted to cariogenic challenge to form white spot lesions and were separated into six groups (n=13): 1) Artificial Saliva (AS); 2) Coconut Oil (CO); 3) CO+2% Biosilicate (CO+2%Bio); 4) CO+5% Biosilicate (CO+5%Bio); 5) 2% Biosilicate Suspension (2% Bio) and 6) 5% Biosilicate Suspension (5% Bio). The treatments for 1 cycle/day were: immersion into the treatments for 5 minutes, rinsing in distilled water, and storage in artificial saliva at 37ºC. After 14 days, KHN and Ra readings were taken. The surface roughness alteration ((Ra) was analyzed (Kruskal-Wallis, Dunn's post-test, p<0.05). CO+2%Bio had higher (p = 0.0013) (Ra followed by CO+5%Bio (p = 0.0244) than AS. The relative KHN and remineralization potential were analyzed (ANOVA, Tukey, p<0.05), and 5% Bio treatment presented a higher relative microhardness than all other groups (p>0.05). The remineralizing potential of all the treatments was similar (p > .05). When Biosilicate was added, the pH of the suspensions increased and the alkaline pH remained during the analysis. Biosilicate suspension is more efficient than the incorporation of particles into coconut oil at white spot lesion treatment. In addition to the benefits that coconut oil and Biosilicate present separately, their association can enhance the remineralizing potential of Biosilicate.

Salivary pellicle modulates biofilm formation on titanium surfaces

OBJECTIVES

The present study aimed to evaluate the potential of the salivary pellicle (SP) formed on titanium (Ti) surfaces to modulate the formation of a biofilm composed of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis.

MATERIALS AND METHODS

Ti substrates were incubated for 2 h with a pool of saliva samples obtained from 10 systemically and periodontally healthy subjects. Enamel substrates were included as a biological reference. Scanning electron microscopy (SEM) and Raman spectroscopy analysis were used to analyze the formation of the salivary pellicle. After the SP formation, the surfaces were incubated for 12 h with a mix of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis. The number of bacterial cells attached to each surface was determined by the XTT assay while bacterial viability was analyzed by fluorescence microscopy using the LIVE/DEAD® BacLightTM kit.

RESULTS

The SEM and Raman spectroscopy analysis confirmed the presence of a salivary pellicle formed on the tested surfaces. Regarding the biofilm formation, the presence of the SP decreases the number of the bacterial cells detected in the test surfaces, compared with the uncover substrates. Even more, the SP-covered substrates showed similar bacterial counts in both Ti and enamel surfaces, meaning that the physicochemical differences of the substrates were less determinant than the presence of the SP. While on the SP-uncover substrates, differences in the bacterial adhesion patterns were directly related to the physicochemical nature of the substrates.

CONCLUSIONS

The salivary pellicle was the main modulator in the development of the biofilm consisting of representative oral bacteria on the Ti substrates.

CLINICAL RELEVANCE

The results of this study provide valuable information on the modulatory effect of the salivary pellicle on biofilm formation; such information allows us to understand better the events involved in the formation of oral biofilms on Ti dental implants.

Acquired enamel pellicle protects gastroesophageal reflux disease patients against erosive tooth wear

The objective of this study was to compare the protein profile of the acquired enamel pellicle (AEP) formed in vivo in patients with or without gastroesophageal reflux disease (GERD), and with or without erosive tooth wear (ETW). Twenty-four volunteers were divided into 3 groups: 1) GERD and ETW; 2) GERD without ETW; and 3) control (without GERD). The AEP formed 120 min after prophylaxis was collected from the lingual/palatal surfaces. The samples were subjected to mass spectrometry (nLC-ESI-MS/MS) and label-free quantification by Protein Lynx Global Service software. A total of 213 proteins were identified, or 119, 92 and 106 from each group, respectively. Group 2 showed a high number of phosphorylated and calcium-binding proteins. Twenty-three proteins were found in all the groups, including 14-3-3 protein zeta/delta and 1-phosphatidylinositol. Several intracellular proteins that join saliva after the exfoliation of oral mucosa cells might have the potential to bind hydroxyapatite, or participate in forming supramolecular aggregates that bind to precursor proteins in the AEP. Proteins might play a central role in protecting the dental surface against acid dissolution.

Different vehicles containing CaneCPI-5 reduce erosive dentin wear in situ

OBJECTIVE

This study evaluated the protective capacity of a sugarcane-derived cystatin (CaneCPI-5) in different vehicles (1-solution and 2-chitosan gel) against erosive dentin wear in situ.

METHODS

In part-1, 15 volunteers participated in a crossover protocol (solutions): Water; Elmex™ and CaneCPI-5. The volunteers wore an appliance with 4 dentin samples for 5 days. These samples were treated with a drop of the solutions for 1 min (4X/d), then the acquired pellicle (AP) was formed and the samples were subjected to erosive challenges (EROSION: citric acid, for 90 s, 4X/day). 2X/day, half of the samples were also abraded for 15 s (ABRASION). In part-2, 16 volunteers participated in a crossover protocol (gel): No gel, Chitosan gel, Chitosan gel + NaF and Chitosan gel + CaneCPI-5. The volunteers also wore an appliance. The samples were treated once/day with the gel or not for 4 min, then the AP was formed and the samples were subjected to erosive and abrasive challenges, as reported in part-1. Dentin wear was measured by profilometry. Data were analyzed by two-way RM-ANOVA and Sidak's tests (p < 0.05).

RESULTS

Part-1: Elmex™ and CaneCPI-5 significantly reduced dentin loss in comparison with Water for the EROSION/ABRASION conditions (p < 0.05). Part-2, all the treated groups significantly reduced the dentin loss in comparison to the No gel. The greatest reduction was found for the gel + CaneCPI-5 group for the EROSION/ABRASION (p < 0.05).

CONCLUSION

The solution and chitosan gel containing CaneCPI-5 protected against erosive dentin wear in situ.

CLINICAL RELEVANCE

These different vehicles are probably sufficient for protecting people with high risk of developing erosive dentin wear.

Phyllanthus emblica fruits: a polyphenol-rich fruit with potential benefits for oral management

The fruit of Phyllanthus emblica Linn., which mainly grows in tropical and subtropical regions, is well-known for its medicine and food homology properties. It has a distinctive flavor, great nutritional content, and potent antioxidant, anti-inflammatory, anti-cancer and immunoregulatory effects. According to an increasing amount of scientific and clinical evidence, this fruit shows significant potential for application and development in the field of oral health management. Through the supplementation of vitamins, superoxide dismutase (SOD) and other nutrients reduce virulence expression of various oral pathogens, prevent tissue and mucosal damage caused by oxidative stress, etc. Phyllanthus emblica fruit can promote saliva secretion, regulate the balance of the oral microecology, prevent and treat oral cancer early, promote alveolar bone remodeling and aid mucosal wound healing. Thus, it plays a specific role in the prevention and treatment of common oral disorders, producing surprising results. For instance, enhancing the effectiveness of scaling and root planing in the treatment of periodontitis, relieving mucosal inflammation caused by radiotherapy for oral cancer, and regulating the blood glucose metabolism to alleviate oral discomfort. Herein, we systematically review the latest research on the use of Phyllanthus emblica fruit in the management of oral health and examine the challenges and future research directions based on its chemical composition and characteristics.

Plant extracts have dual mechanism on the protection against dentine erosion: action on the dentine substrate and modification of the salivary pellicle

To investigate the effect of some polyphenol-rich plant extracts on the protection of dentine against demineralization, both acting on the dentine and on the salivary pellicle. Dentine specimens (n = 180) were randomly distributed into 6 experimental groups (n = 30/group): Control (deionized water), Açaí extract, Blueberry extract, Green tea extract, Grape seed extract, and Sn²⁺/F^- (mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the site of action of the substance: on the dentine surface (D) or on the salivary pellicle (P). The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (D), 2 min immersion in experimental substances, 60 min of incubation in saliva (P) or not (D), and 1 min erosive challenge. Dentine surface loss (DSL), amount of degraded collagen (dColl) and total calcium release were analyzed. Green tea, Grape seed and Sn²⁺/F^- showed significant protection, with least DSL and dColl. The Sn²⁺/F^- showed better protection on D than on P, whereas Green tea and Grape seed showed a dual mode of action, with good results on D, and even better on P. Sn²⁺/F^- showed the lowest values of calcium release, not differing only from Grape seed. Sn²⁺/F^- is more effective when acting directly on the dentine surface, while Green tea and Grape seed have a dual mode of action: with a positive effect on the dentine surface itself, but an improved efficacy in the presence of the salivary pellicle. We further elucidate the mechanism of action of different active ingredients on dentine erosion, where Sn²⁺/F^- acts better on the dentine surface, but plant extracts have a dual mode of action, acting on the dentine itself as well as on the salivary pellicle, improving the protection against acid demineralization.

Olive Oil as a Transport Medium for Bioactive Molecules of Plants?-An In Situ Study

(1) Caries and erosions still remain a challenge for preventive dentistry. Certain plant extracts have shown beneficial effects in preventive dentistry. The aim of this study was to evaluate the antibacterial, anti-adherent and erosion-protective properties of ellagic acid (EA) as a polyphenolic agent. The combination with olive oil was investigated additionally to verify a possible improved bioactive effect of EA. (2) An in situ study was carried out with six subjects. Individual splints were prepared with bovine enamel specimens. The splints were worn for 1 min (pellicle formation time). Thereafter, 10 min rinses were performed with EA in water/in oil. Bacterial adherence was evaluated by fluorescence microscopy (DAPI, ConA, BacLight) after an 8 h oral exposition time. Additionally, the splints were worn for 30 min to quantify demineralization processes. The ultrastructure of the pellicle was investigated after an oral exposure time of 2 h under a transmission electron microscope. Statistical analysis was performed by Kruskal-Wallis tests, Mann-Whitney U tests and Bonferroni-Holm correction. (3) Rinsing with EA led to a significant reduction of adherent vital and dead bacteria. The combination with olive oil did not improve these outcomes. The assessment of glucan structures after rinsing with EA in water showed significant effects. Significant differences were observed for both rinses in calcium release at pH 3.0. After rinsing with EA in oil, significantly less calcium was released compared to rinsing with EA in water (pH = 3.0). (4) Olive oil is not suitable as a transport medium for lipophilic polyphenols. EA has anti-adherent and antibacterial properties in situ. EA also shows erosion-protective effects, which can be enhanced in combination with olive oil depending on the pH value. Ellagic acid has a neutral pH and could be an opportunity in the treatment of specific patient groups (xerostomia or mucositis).

New insights into the protective effect of statherin-derived peptide for different acquired enamel pellicle formation times on the native human enamel surfaces

OBJECTIVES

This study evaluated the protective impact of acquired enamel pellicle (AEP) engineering with statherin-derived peptide (StatpSpS), considering different AEP formation times.

DESIGN

A total of 120 native human enamel specimens were divided into 2 main groups: 1) No AEP engineering and 2) AEP engineering with StatpSpS (pretreatment for 1 min; 37 °C, under agitation). Each group was further divided into 4 subgroups: No pellicle, or 1, 60-and-120 min AEP formation times (human saliva; 37 °C). The specimens were then subjected to an erosive challenge (1% citric acid; pH 3.6; 1 min; 25 °C). This procedure was repeated for 5 cycles. Relative surface reflection intensity (%SRI) was measured and scanning electron microscopy (SEM) of the enamel surface was done.

RESULTS

All AEP engineering groups protected against initial dental erosion in comparison with No pellicle (p < 0.001), likewise all groups with AEP, independent of engineering or formation times (p 0.001). Furthermore, engineering with StatpSpS even without the presence of AEP protected the enamel when compared to the No engineering/No pellicle group (p < 0.0001). No difference was observed regarding the protection from the different AEP formation times (p > 0.05). Regarding the SEM analysis, in the "No AEP engineering & No AEP" group, a more severe effect of citric acid was observed, with more enamel prism heads and scratches on the surface when compared with the other groups.

CONCLUSIONS

AEP provides almost instant protection at formation times even as short as 1 min, protecting the native enamel against erosion. Treatment with StatpSpS by itself provides similar protection as the AEP.

Gels containing statherin-derived peptide protect against enamel and dentin erosive tooth wear in vitro

The effect of gels containing a statherin-derived peptide (Stn) on the protection against enamel and dentin erosive tooth wear (ETW) in vitro was evaluated. Bovine enamel and dentin specimens were divided into 2 groups (n = 15 and 18/group for enamel and dentin, respectively) that were treated with Chitosan or Carboxymethylcellulose (CMC) gels containing Stn15pSpS at 1.88 × 10-5 M or 3.76 × 10-5 M. Chitosan or CMC gels without active ingredients served as negative controls, while chitosan gel containing 1.23% F (as NaF) and acidulated phosphate fluoride gel (1.23% F) served as positive controls. The gels were applied on the specimens for 4 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 gels were applied again during pH cycling, 2 times/day for 4 min after the first and last erosive challenges. Enamel and dentin loss (μm) were assessed by contact profilometry. Scanning electron microscopy (SEM) was analyzed using a cold field emission. Data were analyzed by two-way ANOVA (for chitosan and CMC gels, separately) and Tukey's multiple comparison test. SEM images showed changes to enamel topography after application oft the gels containing Stn or F. Regarding CMC-based gels, for enamel, none of the treatments significantly reduced ETW in comparison with placebo; for dentin, however, gels containing Stn, regardless the concentration, significantly reduced the ETW. Moreover, Chitosan-based gels, regardless the Stn concentration, were able to protect enamel and dentin against ETW. Gels containing Stn might be a new approach to protect against ETW.

Caries Management-The Role of Surface Interactions in De- and Remineralization-Processes

BACKGROUND

Bioadhesion and surface interactions on enamel are of essential relevance for initiation, progression and prevention of caries and erosions. Salivary proteins on and within initial carious and erosive lesions can facilitate or aggravate de- and remineralization. This applies for the pellicle layer, the subsurface pellicle and for proteins within initial carious lesions. Little is known about these proteinaceous structures related to initial caries and erosion. Accordingly, there is a considerable demand for an understanding of the underlying processes occurring at the interface between the tooth surface and the oral cavity in order to develop novel agents that limit and modulate caries and erosion. Objectives and findings: The present paper depicts the current knowledge of the processes occurring at the interface of the tooth surface and the oral fluids. Proteinaceous layers on dental hard tissues can prevent or aggravate demineralization processes, whereas proteins within initial erosive or carious lesions might hinder remineralization considerably and restrict the entry of ions into lesions.

CONCLUSIONS

Despite the fact that organic-inorganic surface interactions are of essential relevance for de- and remineralization processes at the tooth surface, there is limited knowledge on these clinically relevant phenomena. Accordingly, intensive research is necessary to develop new approaches in preventive dentistry.

Synergistic effect between plant extracts and fluoride to protect against enamel erosion: An in vitro study

Polyphenol-rich solutions, such as plant extracts and teas, can modify the salivary pellicle and improve the protection against dental erosion. In this study, we further explored how these polyphenol-rich plant extracts solutions behave in the presence of fluoride. We distributed enamel specimens into 9 groups (n = 15): Control_No_F- (Deionized water); Control_F- (500 ppm F-), Grape_Seed_No_F- (Grape seed extract), Grape_Seed_F- (Grape seed extract + 500 ppm F-), Grapefruit_Seed_No_F- (Grapefruit seed extract), Grapefruit_Seed_F- (Grapefruit seed extract + 500 ppm F-), Blueberry_No_F- (Blueberry extract), Blueberry_F- (Blueberry extract + 500 ppm F-), and Sn2+/F-_Rinse (commercial solution containing 800 ppm Sn2+ and 500 ppm F-). The specimens were submitted to 5 cycles (1 cycle per day), and each cycle consisted of: salivary pellicle formation (human saliva, 30 min, 37°C), modification of the pellicle (2 min, 25°C), pellicle formation (60 min, 37°C), and an erosive challenge (1 min, citric acid). Between cycles, the specimens were kept in a humid chamber. Relative surface hardness (rSH), relative surface reflection intensity (rSRI) and calcium released to the acid were analysed, using general linear models, and Kruskal-Wallis with post-hoc Dunn's tests. We observed that the presence of fluoride in synergy with the extract solutions provided better protection than the groups containing extract or fluoride only. For rSH, we observed a significant main effect of extracts (F(4,117) = 9.20; p<0.001) and fluoride (F(1,117) = 511.55; p<0.001), with a significant interaction (F(3,117) = 6.71; p<0.001). Grape_Seed_F- showed the best protection, better than fluoride, and Sn2+/F-_Rinse. Calcium results also showed greater protection for the groups containing fluoride, whereas for rSRI, despite a significant interaction between extract and fluoride (F(3,117) = 226.05; p<0.001), the differences between the groups were not as clearly observed. We conclude that polyphenols from plant extracts, when combined with fluoride, improve the protective effect of salivary pellicles against enamel erosion.

Film-Forming Polymers for Tooth Erosion Prevention

Different agents have been proposed to prevent the progression of acid induced dental substance losses, which are called erosive tooth wear (ETW), such as fluorides, calcium, and phosphate-based products; however, there is a need for a further increase in efficacy. Recently, the ability of polymers to interact with the tooth surface, forming acid resistant films, has come into the focus of research; nevertheless, there is still the need for a better understanding of their mode of action. Thus, this article provides an overview of the chemical structure of polymers, their mode of action, as well as the effect of their incorporation into oral care products, acid beverages, and antacid formulations, targeting the prevention of ETW. Recent evidence indicates that this may be a promising approach, however, additional studies are needed to confirm their efficacy under more relevant clinical conditions that consider salivary parameters such as flow rate, composition, and clearance. The standardization of methodological procedures such as acid challenge, treatment duration, and combination with fluorides is necessary to allow further comparisons between studies. In conclusion, film-forming polymers may be a promising cost-effective approach to prevent and control erosive demineralization of the dental hard tissue.

New insights into the anti-erosive property of a sugarcane-derived cystatin: different vehicle of application and potential mechanism of action

A new sugarcane-derived cystatin (CaneCPI-5) showed anti-erosive properties when included in solutions and strong binding force to enamel, but the performance of this protein when added to gel formulations and its effect on surface free energy (SFE) requires further studies.

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.

Protein-based engineering of the initial acquired enamel pellicle in vivo: Proteomic evaluation

OBJECTIVE

To study the proteomic alterations in the initial AEP after rinsing with CaneCPI-5, StN15 or Hb or their combination.

MATERIALS AND METHODS

In five crossover phases, after prophylaxis, 10 volunteers in 5 consecutive days, rinsed (10 mL, 1 min) with the following solutions: deionized water (H₂O- negative control- 1), 0.1 mg/mL CaneCPI-5 (2), 1.88×10^-5 M StN15 (3), 1.0 mg/mL Hb (4) or their combination (5). The AEP formed after 3 min was collected with electrode filter papers soaked in 3% citric acid. After protein extraction, samples were analyzed by quantitative shotgun label-free proteomics.

RESULTS

Rinsing with the proteins/peptide increased the amounts of proteins in the AEP. The total numbers of proteins identified after rinsing with CaneCPI-5, StN15, Hb or their combination versus water, were 131, 167, 148 and 142, respectively. The treatment with the proteins/peptide or their combination increased proteins that bind calcium, phosphate and interact with distinct proteins, as well as proteins with antimicrobial and acid-resistant properties, such as, Cornifin-B (7.7, 12.6, and 4.3-fold for CaneCPI-5, StN15 and Hb, respectively), isoforms of Cystatin (2.2-2.4-fold for CaneCPI-5 and StN15), Proline-rich-protein 4 (4.3-fold; StN15), Histatin-1 (2.8-fold; StN15) and Hemoglobin (7.7-25-fold for Hb and Combination). Immunoglobulin, Keratin and Histone were exclusively identified upon treatment with the proteins/peptide, alone or combined.

CONCLUSION

Rinsing with proteins/peptide, alone or combined, increased protective proteins in the initial AEP.

CLINICAL RELEVANCE

Our results suggest that rinsing with the proteins/peptide or their combination increases the proteins capable of enhancing the protective function of the basal layer of AEP.

Solutions and Gels Containing a Sugarcane-Derived Cystatin (CaneCPI-5) Reduce Enamel and Dentin Erosion in vitro

The effect of solutions and gels containing a sugarcane-derived cystatin (CaneCPI-5) on the protection against enamel and dentin erosion in vitro was evaluated. Bovine enamel and dentin specimens were divided into 2 groups (n = 135 and 153/group for enamel and dentin, respectively) that were treated with solutions or chitosan gels containing 0.1 or 0.25 mg/mL CaneCPI-5. The positive controls for solutions and gels were Elmex Erosion Protection™ solution and NaF gel (12,300 ppm F), respectively. Deionized water and chitosan gel served as controls, respectively. The solutions were first applied on the specimens for 1 min and the gels for 4 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 (0.1% citric acid pH 2.5/90 s, artificial saliva/2 h, and artificial saliva overnight). The solutions and gels were applied again during pH cycling, 2 times/day for 1 min and 4 min, respectively, after the first and last erosive challenges. Enamel and dentin losses (µm) were assessed by contact profilometry. Data were analyzed by 2-way ANOVA and Tukey's test (p < 0.05). All the treatments significantly reduced enamel and dentin loss in comparison with controls. Both CaneCPI-5 concentrations had a similar protective effect against enamel erosion, but only the higher concentration was as effective against dentin erosion as the positive control. Regarding the vehicles, only the 0.1 mg/mL gel performed worse than the positive control for dentin. CaneCPI-5 reduced enamel and dentin erosion to a similar extent as the fluoride-containing vehicles. However, dentin requires higher CaneCPI-5 concentrations, in the case of gels. Solutions or gels containing CaneCPI-5 might be a new approach to protect against dental erosion.

Functional biomedical materials derived from proteins in the acquired salivary pellicle

In the oral environment, the acquired salivary pellicle (ASP) on the tooth surface comprises proteins, glycoproteins, carbohydrates, and lipids. The ASP can specifically and rapidly adsorb on the enamel surface to provide effective lubrication, protection, hydration, and remineralisation, as well as be recognised by various bacteria to form a microbial biofilm (plaque). The involved proteins, particularly various phosphoproteins such as statherins, histatins, and proline-rich proteins, are vital to their specific functions. This review first describes the relationship between the biological functions of these proteins and their structures. Subsequently, recent advances in functional biomedical materials derived from these proteins are reviewed in terms of dental/bone therapeutic materials, antibacterial materials, tissue engineering materials, and coatings for medical devices. Finally, perspectives and challenges regarding the rational design and biomedical applications of ASP-derived materials are discussed.

Rinsing with Statherin-Derived Peptide Alters the Proteome of the Acquired Enamel Pellicle

Changes in the proteomic profile of the acquired enamel pellicle (AEP) formed for 3 min or 2 h after rinsing with a peptide containing the 15 N-terminal residues of statherin, with serines 2 and 3 phosphorylated (StatpSpS), were evaluated. Nine volunteers participated in 2 consecutive days. Each day, after professional tooth cleaning, they rinsed for 1 min with 10 mL of phosphate buffer containing 1.88 × 10-5 M StatpSpS or phosphate buffer only (control). The acquired pellicle formed on enamel after 3 min or 2 h was collected with electrode filter papers soaked in 3% citric acid. After protein extraction, samples were analyzed by quantitative shotgun label-free proteomics. In the 3-min AEP, 19 and 131 proteins were uniquely identified in the StatpSpS and control groups, respectively. Proteins typically found in the AEP were only found in the latter. Only 2 proteins (neutrophil defensins) were increased upon treatment with StatpSpS, while 65 proteins (among which are several typical AEP proteins) were decreased. In the 2-h AEP, 50 and 108 proteins were uniquely found in StatpSpS and control groups, respectively. Hemoglobin subunits and isoforms of keratin were only found in the StatpSpS group, while cystatin-C, cathepsin D, and cathepsin G, isoforms of heat shock 70 and protocadherin were exclusively found in the control group. In addition, 23 proteins were increased upon treatment with StatpSpS, among which are histatin-1, serum albumin, and isoforms of neutrophil defensin and keratin, while 77 were decreased, most of them were typical AEP proteins. In both evaluated periods, rinsing with StatpSpS profoundly changed the proteomic profile of the AEP, which might impact the protective role of this integument against carious or erosive demineralization. This study provides important insights on the dynamics of the protein composition of the AEP along time, after rinsing with a solution containing StatpSpS.

Is there difference in the comparative and quantitative salivary proteome between stimulated and unstimulated saliva in head and neck cancer patients treated by radiotherapy?

Stimulation of saliva production is an alternative to improve the quality of life of patients treated by radiotherapy. However, there is no information about changes in the salivary proteome of stimulated and unstimulated saliva in these patients.

OBJECTIVES

Thus, we evaluated the difference in the proteomic profile of stimulated and unstimulated saliva in patients with head and neck cancer (HNC) treated by radiotherapy.

METHODS

Stimulated and unstimulated saliva were collected from 9 patients with HNC before (BRT), during (DRT; 2-5 weeks) and after (ART; 3-4 months) treatment. Healthy patients paired by age and gender also had their saliva collected (C; control group). The stimulated and unstimulated salivary flow were evaluated (p < 0.05). Salivary proteins were extracted and processed for shotgun proteomic analysis.

RESULTS

Significant differences were observed between stimulated and unstimulated salivary flows for C and BRT (p greater than 0.001), but not for DRT and ART. Proteins involved with apoptosis, antibacterial and acid-resistance were decreased in stimulated saliva in comparison to unstimulated saliva DRT and ART. Isoforms of keratins were not identified in control and BRT.

CONCLUSION

there is a marked difference in the protein profile of stimulated and unstimulated salivary flows in HNC patients treated by radiotherapy. In addition, saliva stimulation in patients with HNC decreases important proteins involved with dental protection. The unstimulated salivary flow seems to be the best alternative to search for biomarkers. Our results contribute in an unprecedented way to understand the changes in the salivary proteome of different flows in HNC patients undergoing radiotherapy treatment.

The salivary pellicle on dental biomaterials

The salivary pellicle, an adlayer formed by adsorption of salivary components on teeth and dental biomaterials, has direct consequences on basic outcomes of dentistry. Here, we provide an overview of salivary pellicle formation processes with a critical focus on dental biomaterials. We describe and critique the array of salivary pellicle measurement techniques. We also discuss factors that may affect salivary pellicle formation and the heterogeneity of the published literature describing salivary pellicle formation on dental biomaterials. Finally, we survey the many effects salivary pellicles have on dental biomaterials and highlight its implications on design criteria for dental biomaterials. Future investigations may lead to rationally designed dental biomaterials to control the salivary pellicle and enhance material function and patient outcomes.

Proteomic profile of the acquired enamel pellicle of professional wine tasters with erosive tooth wear

The aim of this study was to compare the acquired enamel pellicle protein profile of professional wine tasters with mild and moderate erosive tooth wear. Twelve professional wine tasters participated (3 from a low tooth wear group; 9 from a high tooth wear group). Acquired enamel pellicle samples were collected and processed for proteomic analysis (nLC-ESI-MS/MS). The acquired enamel pellicle proteomic profile was different between the groups. The proteins found exclusively in the low tooth wear group were histatins 1 and 3 and mucins 7 and 21. When comparing the wear groups, proteins with higher levels in the low tooth wear group included neutrophil defensins (1 and 3), lysozyme C, lysozyme, myeloperoxidase, and squalene monooxygenase. In conclusion, the findings indicate that the proteins found at higher levels in the low tooth wear group and proteins exclusively found in the low tooth wear group might be protective and, therefore, could be good candidates for further studies regarding their potential to be added to dental products to protect professional wine tasters from extrinsic erosive tooth wear.

Radiotherapy changes acquired enamel pellicle proteome in head and neck cancer patients

OBJECTIVES

To evaluate in vivo the proteomic profile of the acquired enamel pellicle (AEP) in patients with head and neck cancer (HNC) before, during and after radiotherapy.

METHODS

Nine patients, after prophylaxis, had their AEPs collected before (BRT), during (DRT; 2-5 weeks) and after (ART; 3-4 months) radiotherapy. AEP was also collected from nine healthy patients (Control). The proteins were extracted in biological triplicate and processed by label-free proteomics.

RESULTS

Statherin was increased more than 9-fold and several hemoglobin subunits were increased more than 5-fold DRT compared to BRT, while lactotransferrin, proline-rich proteins, cystatins, neutrophil defensins 1 and 3 and histatin-1 were decreased. ART, there was an increase in lactotransferrin and several isoforms of histones, while statherin and alpha-amylase proteins were decreased. MOAP-1 was exclusively found ART in comparison to BRT. When compared to Control, AEP of patients BRT showed an increase in proteins related to the perception of bitter taste, mucin-7 and alpha-amylases, while cystatin-S was decreased.

CONCLUSIONS

HNC and radiotherapy remarkably altered the proteome of the AEP. Antibacterial and acid-resistant proteins were decreased during radiotherapy.

CLINICAL SIGNIFICANCE

Our results provide important information for designing more effective dental products for these patients, in addition to contributing to a better understanding of the differential protective roles of the AEP proteins during radiotherapy. Moreover, some proteins identified in the AEP after radiotherapy may serve as prognostic markers for survival of HNC patients.

Acquired pellicle engineering with proteins/peptides: Mechanism of action on native human enamel surface

OBJECTIVE

This study investigated the mechanism of action of different proteins/peptides (separately or in combination), focusing on how they act directly on the native enamel surface and on modifying the salivary pellicle.

METHODS

A total of 170 native human enamel specimens were prepared and submitted to different treatments (2 h; 37 °C): with deionized water, CaneCPI-5, Hemoglobin, Statherin, or a combination of all three proteins/peptides. The groups were subdivided into treatment acting on the enamel surface (NoP - absence of salivary pellicle), and treatment modifying the salivary pellicle (P). Treatment was made (2 h; 37 °C) in all specimens, and later, for P, the specimens were incubated in human saliva (2 h; 37 °C). In both cases, the specimens were immersed in 1% citric acid (pH 3.6; 2 min; 25 °C). Calcium released from enamel (CaR) and its relative surface reflection intensity (%SRI) was measured after 5 cycles. Between-group differences were verified with two-way ANOVA, with "presence of pellicle" and "treatment" as factors (α = 0.05).

RESULTS

The presence of pellicle provided better protection regarding %SRI (p < 0.01), but not regarding CaR (p = 0.201). In relation to treatment, when compared to the control group, all proteins/peptides provided significantly better protection (p < 0.01 for %SRI and Car). The combination of all three proteins/peptides demonstrated the best protective effect (p < 0.01 for %SRI).

CONCLUSION

Depending on the protein or peptide, its erosion-inhibiting effect derives from their interaction with the enamel surface or from modifying the pellicle, so a combination of proteins and peptides provides the best protection.

CLINICAL SIGNIFICANCE

The present study opens a new direction for a possible treatment with a combination of proteins for native human enamel, which can act directly on the enamel surface as well on the modification of the salivary pellicle, for the prevention of dental erosion.

The effect of red wine in modifying the salivary pellicle and modulating dental erosion kinetics

This study investigated the potential of red wine in modulating dental erosion kinetics in the presence or absence of salivary pellicle. Polished human enamel specimens were used in two conditions; presence or absence of acquired enamel pellicle; and subdivided according to exposure: red wine, orange juice, apple juice, or citric acid. The specimens were incubated in clarified whole human saliva (presence of acquired enamel pellicle) or in a humid chamber (absence of acquired enamel pellicle) for 2 h at 37°C, then in the test substances for 1 min, at 25°C, under shaking. This was repeated four times. Surface hardness was measured initially and after each cycle and surface reflection intensity was measured initially and after all cycles. In the presence of acquired enamel pellicle, red wine caused the least surface hardness loss, followed by orange juice, apple juice, and citric acid. Statistically significantly less surface reflection intensity loss was observed for red wine and orange juice than for apple juice and citric acid. In the absence of acquired enamel pellicle, red wine and orange juice caused less surface hardness loss than apple juice and citric acid. Orange juice showed the least surface reflection intensity loss, followed by red wine, citric acid, and apple juice. The polyphenol composition of these drinks can notably modulate the erosion kinetics.

Salivary pellicle modification with polyphenol-rich teas and natural extracts to improve protection against dental erosion

OBJECTIVE

To investigate the modification of the salivary pellicle with different polyphenol-rich teas and natural extracts for the protection against dental erosion.

METHODS

We performed two experiments: one with teas (Green tea, Black tea, Peppermint tea, Rosehip tea, negative control [NC]) and other with natural extracts (Grape seed, Grapefruit seed, Cranberry, Propolis, NC), where NC was deionized water. A total of 150 enamel specimens were used (n = 15/group). Both experiments followed the same design, consisting of 5 cycles of: salivary pellicle formation (30 min, 37 °C), modification with the solutions (30 min, 25 °C), further salivary pellicle formation (60 min, 37 °C) and erosive challenge (1 min, 1% citric acid, pH 3.6). Relative surface microhardness (rSMH), relative surface reflection intensity (rSRI) and amount of calcium release (CaR) were evaluated. Data were analysed with Kruskal-Wallis and Wilcoxon rank sum tests with Bonferroni correction (α = 0.05).

RESULTS

Regarding teas, Black and Green teas showed the best protection against dental erosion, presenting higher rSMH and lower CaR than NC. Peppermint tea was not different to NC and Rosehip tea caused erosion, showing the highest CaR and greatest loss of SMH and SRI. Regarding natural extracts, Grape seed and Grapefruit seed extracts presented the best protective effect, with significantly higher rSMH and lower CaR. Cranberry caused significantly more demineralization; and Propolis did not differ from NC.

CONCLUSION

Green tea, Black tea, Grape seed extract and Grapefruit seed extract were able to modify the salivary pellicle and improve its protective effect against enamel erosion, but Rosehip tea and Cranberry extract caused erosion.

CLINICAL RELEVANCE

Some some bio-products, such as teas and natural extracts, improve the protective effect of the salivary pellicle against enamel erosion. More studies should be performed in order to test the viability of their use as active ingredients for oral care products.

Acquired salivary pellicle and oral diseases: A literature review

As soon as saliva contacts the teeth surface, salivary proteins adhere to the tooth surface to form acquired salivary pellicle. The formation of this acquired salivary pellicle is a dynamic and selective process of macromolecular adsorption and desorption. Although acquired salivary pellicle contains proteins and peptides, it also contains lipids, and other macro-molecules, all of which contribute to its protective properties. Acquired salivary pellicle is related to the development of common oral diseases, such as erosion, dental caries, and periodontal disease. Acquired salivary pellicle acts as a natural barrier to prevent a tooth's surface from making direct contact with acids and to protect it from erosive demineralization. It contributes to the control of dental erosion by modulating calcium and phosphate concentrations on the tooth surface. It also influences the initial colonizer of oral biofilm and affects the transportation pathway of the acidic products of cariogenic bacteria, which affects the development of dental caries. In addition, it influences periodontal disease by acting on the colonization of periodontal pathogens. This paper's aim is to provide an overview of the acquired salivary pellicle, highlighting its composition, structure, function, role in common oral diseases, and modification for the prevention of oral diseases.

Dentifrices or gels containing MMP inhibitors prevent dentine loss: in situ studies

OBJECTIVES

Evaluate the effect of dentifrices or gels containing MMP inhibitors on dentine loss in situ.

MATERIALS AND METHODS

Acrylic palatal appliances containing bovine dentine blocks were divided into two rows, corresponding to the groups erosion (ERO) and erosion associated with abrasion (ERO+ABR). For ERO, the appliances were immersed in a cola drink for 5 min, 4 times/day, while for ERO+ABR, the blocks were brushed for 15 sec with a dentifrice slurry after the second and third erosive challenges. Ten volunteers took part in study 1 (S1), where the dentifrices evaluated contained 1100 ppm fluoride as NaF, 0.61% green tea extract, or 0.012% chlorhexidine digluconate. Thirteen volunteers participated in study 2 (S2), in which the treatment was performed only once (1 min) with gels containing 400 μM EGCG (EGCG400), 0.012% chlorhexidine, 1 mM FeSO₄, 1.23% F (NaF), placebo, or received no treatment. Dentine loss was analyzed by profilometry (μm).

RESULTS

Regarding S1, ERO+ABR induced significantly higher dentine loss compared with ERO and all dentifrices tested led to significantly lower dentine loss when compared with placebo. For S2, regardless of the conditions or times of evaluation, gels containing EGCG, CHX, or FeSO₄ led to significantly less wear compared with the other groups.

CONCLUSION

Both dentifrices and gels containing MMP inhibitors significantly reduced dentine loss.

CLINICAL RELEVANCE

Dentifrices and gels containing MMP inhibitors are able to increase the protection against dentine wear, although gels have a better effect when compared with fluoride gel, lasting up to 10 days after a single application.

Optimizing the formation of the acquired enamel pellicle in vitro for proteomic analysis

Saliva is the major contributor for the protein composition of the acquired enamel pellicle (AEP), a bacteria-free organic layer formed by the selective adsorption of salivary proteins on the surface of the enamel. However, the amount of proteins that can be recovered is even smaller under in vitro condition, due to the absence of continuous salivary flow.