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.

Hydrated Calcium Silicate in Resin Composites for Prevention of Secondary Caries.

INTRODUCTION AND AIMS: The gaps at the margins of restorative composite resin can increase as the carious process occurs underneath the materials, causing further demineralization along the tooth cavity wall. The aim of this study was to evaluate the effects of restorative resin composite containing hydrated calcium silicate (hCS) filler on enamel protection against demineralization by simulating microleakage between the test material and teeth in a cariogenic environment. METHODS: The experimental resin composites were composed of 70 wt.% filler, which was mixed with a glass filler and hCS in a weight ratio of 70.0% glass (hCS 0), 17.5% hCS + 52.5% glass (hCS 17.5), 35.0% hCS + 35.0% glass (hCS 35.0), and 52.5% hCS + 17.5% glass (hCS 52.5). A light-cured experimental resin composite disk was positioned over a polished bovine enamel disk, separated by a 30-µm gap, and immersed in artificial saliva with pH 4.0 for 15, 30, and 60 days. After the immersion period, the enamel disk was separated from the resin composite disk and evaluated using a microhardness tester, atomic force microscopy, and polarized light microscopy. The opposing sides of the enamel and resin composite disks were observed using scanning electron microscopy/energy dispersive X-ray spectrometry. RESULTS: The enamel surface showed a significant increase in microhardness, decreased roughness, and remineralization layer as the proportion of hCS increased (P < .05). In the scanning electron microscopy image, the enamel surface with hCS 35.0 and 52.5 after all experimental immersion periods, showed a pattern similar to that of a sound tooth. CONCLUSIONS: The results demonstrated that increasing the hCS filler level of restorative resin composites significantly decreased enamel demineralization. CLINICAL RELEVANCE: Hydrated calcium silicate laced restorative resin composites may be a promising dental biomaterial for protecting teeth against demineralization and preventing secondary caries around restorations.

Development of an Artificial White Spot Lesion Creation Protocol: A Preliminary Study.

BACKGROUND AND OBJECTIVES: Protocols that determine the lesion depth of specific demineralization solutions are lacking. This in vitro study aimed to evaluate various lesion depths of artificial white spot lesions (WSLs) at different exposure times.  Materials and methods: Artificial WSLs were created by placing 30 extracted human premolar teeth into 0.05M acetate buffer solution with a controlled environment of pH 4.4 at 37ºC, which were then exposed in the solution for various durations of 4, 5, 6, 8, 10, and 12 days. The specimens were visually examined using the Ekstrand-Ricketts-Kidd (ERK) system to confirm the WSL, followed by buccolingual sectioning, and evaluated under a scanning electron microscope (SEM) to measure the lesion depth. RESULTS: The SEM showed that the mean lesion depths of representative specimens were 101.33 µm (day 4), 124 µm (day 5), 159 µm (day 6), 187 µm (day 8), 202 µm (day 10), and 212 µm (day 12). The artificial WSL was visually demonstrated in grades 1 and 2 of the ERK system. CONCLUSIONS: The depths of the lesions increased as the duration increased from day 4 to day 12, indicating that the lesion depths increased with the more prolonged exposure to the acetate buffer solution.

Assessment of Remineralization Ability of Different Fluoride Varnishes on Artificial Enamel Lesion of Primary Teeth - A Comparative Study.

Aim: The current study's aim was to evaluate the potential of various fluoride varnishes to remineralize artificial enamel lesions on primary teeth. Materials and Methods: For the study, 90 deciduous molar teeth that were implicated for extraction were taken. A window region with a size of 3 × 3 mm was located in the middle of the tooth's coronal surface. The remaining portion was given a coat of nail polish and given time to dry. A demineralizing solution was used to create the artificial enamel lesion. The samples were randomized into three experimental groups at random, with 30 samples in each group. Group 1: Application of Clinpro White Varnish, Group 2: Application of Duraphat Varnish, and Group 3: Application of MI Varnish. After 14 days, samples from each group were examined under scanning electron microscopy at a magnification of 1000× to determine whether remineralization had occurred. Microhardness was also determined using a microhardness tester. Result: Before the intervention, the mean demineralized enamel lesion in the Clinpro White Varnish group was 134.44 ± 0.04, in the Duraphat Varnish group was 133.76 ± 0.12, and in the MI Varnish group was 133.89 ± 0.08. After intervention, the maximum remineralized area was found in the MI Varnish group (82.74 ± 0.18) followed by the Clinpro White Varnish group (101.43 ± 0.16) and the Duraphat Varnish group (104.11 ± 0.10). After the intervention, there was a statistically significant difference found between the groups. After the intervention, the maximum microhardness mean value improved in the MI Varnish group (257.03 ± 1.09 to 261.18 ± 1.20) followed by Clinpro White Varnish (258.78 ± 1.64 to 260.10 ± 1.22) and Duraphat Varnish group (255.24 ± 1.51 to 258.02 ± 0.89). Conclusion: According to the findings of the current investigation, all of the varnishes utilized in this in vitro experiment are capable of correcting early enamel defects on primary teeth. However, MI Varnish group was very effective compared to the Clinpro White Varnish group and the Duraphat Varnish group.

Examining enamel-surface demineralization upon exposure to acidic solutions and the remineralization potential of milk and artificial saliva.

The enamel surface may undergo demineralization due to exposure to acidic substances and the remineralization of the etched enamel is crucial to regain or maintain integrity. This study aimed to investigate the erosive effect of 10 acidic solutions on tooth enamel and the remineralization capacity of milk and artificial saliva by measuring surface roughness (Ra), enamel depth, and microhardness. A total of 80 bovine incisor enamel specimens were immersed in 10 different acidic solutions, including four different acidic drinks, three different citric acid solutions, and three different citric acid buffer solutions, for 1 h. After demineralization, the specimens were immersed in milk and artificial saliva for 3 h. Surface roughness, enamel abraded depth, and microhardness were measured before demineralization, in-between time intervals and after remineralization. Data were analyzed using Friedman and Kruskal-Wallis tests (p < 0.05). The results indicate a significant difference in surface roughness between the measurements taken at different time intervals, particularly between the baseline and after 1 h demineralization. Also, the specimens immersed in CAB1 exhibited greatest increase in Ra among other acidic solutions (Δ: 0.18 ± 0.07). Moreover, only the microhardness increased after remineralization (p < 0.05). Enamel demineralization using various acidic solutions revealed increased Ra and enamel abraded depth, and decreased microhardness. The use of remineralization agents, milk and artificial saliva, demonstrated an increase in microhardness. This study provides insights into the effects of different acidic solutions and potential remineralization agents on tooth enamel.

Remineralization potential of varying concentrations of two plant-based extracts of Cocos nucifera on white spot lesions using SEM and EDAX analysis: An in vitro study.

Aim: To evaluate the remineralization potential of varying concentrations of two plant-based extracts of Cocos nucifera on white spot lesions using SEM and EDAX in vitro testing methods. Materials and Methods: The pulp was freshly obtained from coconut and divided into two. Then, coconut milk was obtained by blending, while the next portion was freeze-dried and lyophilized. Third molar teeth were processed into tooth slabs (N = 40) and split equally into five groups by block randomization. After demineralization, one tooth slab was taken from each, and SEM analysis was done. Remineralization was then performed among the various groups that included Group 1, which acted as a control and consisted of the remineralization solution. Groups 2 and 3 comprised 1:1 and 2:1 concentrations of the coconut milk, whereas Groups 4 and 5 consisted of 1:1 and 2:1 concentrations of the lyophilized extract. SEM and EDAX testing were done post-remineralization. Ca and phosphate values were tabulated, and statistical significance was determined for the obtained values using ANOVA. Results: Among the control and treatment groups, surface remineralization was better observed in 1:1 coconut milk and 2:1 coconut milk than in the 2:1 lyophilized coconut, control, and 1:1 lyophilized coconut. Between the control and treatment groups, Ca and phosphate percentages (P < 0.001) showed statistical differences. The lowest value of 2.3% was noted in the 2:1 lyophilized coconut group. Conclusion: Coconut extracts exhibit remineralization potential on the artificial carious lesion. Coconut milk exhibited significant improvement in the surface properties than lyophilized coconut.

Comparative Analysis of the Effectiveness of Four Distinct Remineralizing Agents in Artificial White Spot Lesions Following Chitosan Nanoparticle Pretreatment: An In Vitro Study.

Aim The aim of the study was to compare the effectiveness of chitosan nanoparticle pretreatment with four different remineralizing agents in artificial white spot lesions. Methods  A total of 100 human maxillary first premolars were selected and divided into five groups of 20 samples in each group. Artificial white spot lesions were created by immersing the samples in the demineralizing solution for 96 hours. Chitosan pretreatment was done for all samples followed by subjecting Group I samples to artificial saliva (control), Group II samples to 3M Clinpro, Group III samples to GC Tooth Mousse, Group IV samples to SHY-NM, and Group V samples with Aclaim using a cotton applicator tip. Each group was divided into two subgroups of 10 samples, which were subjected to hardness testing and mineral content analysis. Surface microhardness and the calcium phosphorous ratio were recorded using a Vickers microhardness tester and energy-dispersive X-ray (EDAX) analysis at three levels i.e., baseline, after demineralization, and after remineralization and tabulated. Statistical analysis was conducted by analyzing data using ANOVA and post hoc followed by Dunnett's t-test using IBM SPSS Statistics for Windows, Version 16 (Released 2007; IBM Corp., Armonk, New York, United States). Results Vickers surface hardness testing and EDAX analysis showed statistically significant values for all the groups. Among them, maximum remineralization potential was seen in samples treated with Chitosan and 3M Clinpro combination, and minimum remineralization potential was seen in Chitosan and artificial saliva combination. Conclusion The addition of chitosan nanoparticles with various remineralizing agents showed a significant synergistic effect on remineralization activity. Also, chitosan and Clinpro combination showed the maximum surface hardness and EDAX analysis values when compared to other groups.

Dual-species biofilm of Streptococcus mutans and Candida albicans produces subsurface caries lesions on bovine enamel.

OBJECTIVES: To develop a protocol for forming subsurface caries lesions on bovine enamel by dual-species biofilms of Streptococcus mutans and Candida albicans in vitro. DESIGN: Biofilms were grown on bovine enamel specimens in artificial saliva (AS) for seven days. After 24 h of formation, the AS was supplemented or not with fluoride (F) using sodium fluoride (0.005 or 0.008 ppm F), and the biofilms were exposed or not to a 20 % sucrose solution (reproducing a cariogenic challenge) once/day. On the seventh day, the biofilms were harvested and had their extracellular polysaccharides (EPS) and inorganic components analyzed. The specimens were subjected to computed X-ray microtomography analysis to determine their mineral concentration. Data were compared using two-way analyses of variance, followed by Fisher's LSD or Student-Newman-Keuls tests (p < 0.05). RESULTS: Biofilms exposed to the cariogenic challenge had significantly higher EPS concentrations than those not exposed, regardless of the presence of F. For biofilms grown with 0.008 ppm F, those exposed to the cariogenic challenge had lower F levels than those not exposed. For biofilms exposed to the cariogenic challenge, those grown with 0.008 ppm F had lower lesion depths and integrated mineral loss, and higher outer layers than those grown without F. CONCLUSIONS: The dual biofilm model assessed was able to create subsurface caries lesions in bovine enamel in vitro, which was influenced by the presence of F in the culture medium and exposure to sucrose.

In Vitro Effect of Streptococcus mutans Biofilm Produced in Sugar-Free Coca-Cola on Enamel.

OBJECTIVE: Sugary drinks such as Coca-Cola may expedite dental caries. For this reason, sugar-free drinks like Coca-Cola Zero Sugar (CZ) may be considered advantageous. This research aims to evaluate in vitro the CZ effect in the presence of Streptococcus mutans (S. mutans) biofilm on enamel demineralization. METHODS: Ninety-six human enamel slabs (4 × 4 mm) were used. S. mutans UA-159 72-hour biofilm was created over enamel surfaces. The specimens were soaked in CZ, HCl, or 10% sucrose in PBS solution, 3 times a day for 15 minutes over the course of 4 days. Viable counts (CFU/mL) and biofilm biomass (Crystal Violet staining) were evaluated. pH was measured after each exposure. After 4 days, Demineralization was evaluated clinically and by Vickers microhardness tests. Slabs were photographed using a stereomicroscope before and after exposure to caries-promoting conditions. RESULTS: Slabs that were soaked in CZ showed an increase in viable counts compared to control and almost similar counts with 10% sucrose in PBS solution exposures (1010and109CFUmL, respectivly). Biofilm biomass tests showed a 25% higher bacterial growth in the CZ group. CZ pH measures were the lowest and the only group to show a decrease in pH over time (pH ∼3). Enamel slabs that were evaluated clinically in the stereomicroscope postexposures had a chalky and matt appearance as opposed to their shiny appearance in the baseline evaluation. CONCLUSIONS: CZ creates a favourable environment for the growth of S. mutans. It may be suggested that even though CZ is sugar free it has a cariogenic effect on enamel. CLINICAL SIGNIFICANCE: Clinicians need to educate patients that sugar-free carbonated drinks may be just as harmful as regular carbonated drinks, and hence avoided. This research emphasizes the harmful effect sugar-free carbonated drinks on teeth and sheds new light on their cariogenic potential.

Resin infiltration versus fluoride varnish for visual improvement of white spot lesions during multibracket treatment. A randomized-controlled clinical trial.

AIMS: This study aimed to evaluate the visual improvement of resin infiltration of white spot lesions (WSL) during orthodontic treatment with the multibracket appliance (MBA) compared to fluoride varnish. METHODS: Patients aged 12-17 years with at least one WSL with an International Caries Detection and Assessment System (ICDAS) score of 1-2 during an active MBA treatment were included and randomized to receive either resin infiltration (Icon) or fluoride application (Flairesse). Standardized digital images were obtained before, one-day, one-week, one-month, three-months and six-months after treatment using a DSLR camera and a matching polarization filter. A grey reference card was used for color standardization. A Matlab routine was used to measure the color difference between adjacent healthy enamel and treated WSL. The independent-samples t-test was used for intergroup and paired-samples t-test for intragroup comparison. RESULTS: Images of 116 teeth from 36 patients were analyzed. The ΔE for the "Icon" treated WSL was smaller (T1ICON = 5.0 ± 1.4) than in the fluoride group (T1Fluoride = 8.4 ± 3.2). Caries infiltration significantly improved the aesthetic appearance of WSL (p < 0.001), which remained satisfactory at six months (T5ICON = 5.2 ± 1.6). CONCLUSION: WSL infiltration management during orthodontic treatment was superior to topical fluoridation in not only arresting the enamel lesions but also significantly improving the aesthetic appearance of demineralized regions around the brackets. CLINICAL RELEVANCE: WSL treatment in orthodontic patients is usually initiated after debonding. Research has shown that the earlier WSL is treated, the better the aesthetic outcome. There is limited data on the efficacy of resin infiltration of WSL during orthodontic treatment.

An In Vitro Study on the Effects of Hydrogen Peroxide-Based Bleaching Agents on Enamel: Field Emission Scanning Electron Microscopy (FESEM) With Energy Dispersive Spectroscopy (EDS) Evaluation.

Aim and objective The aim of the present in vitro study is to evaluate the morphological and elemental alterations in enamel following bleaching with hydrogen peroxide-based bleaching agents of different concentrations and pH values when exposed to different treatment times. Materials and method Twenty extracted maxillary central incisors were selected for the study. Tooth samples were prepared by sectioning the tooth cervico-incisally into two halves. The teeth were divided into different groups based on the bleaching protocol and bleaching agent applied: Group IA, Group IB, Group IIA, and Group IIB. Group IA received a 35% hydrogen peroxide-based bleaching agent of pH 6 for 10 minutes with light application. Group IB received a 35% hydrogen peroxide-based bleaching agent of pH 6 for 30 minutes with light activation. Group IIA received a 40% hydrogen peroxide-based bleaching agent of pH 8.5 for 10 minutes with chemical activation. Group IIB received a 40% hydrogen peroxide-based bleaching agent of pH 8.5 for 30 minutes with chemical activation. The morphology of the enamel before and after the application of the bleaching agent was evaluated using field emission scanning electron microscopy. The elemental analysis of enamel between the control and test samples was done with the help of energy dispersive spectroscopy. Results Paired t-test was used to analyze the data obtained from the study. The test samples showed erosive alterations in enamel surface morphology and also a decrease in the concentration of minerals when compared to the corresponding control groups. Conclusions The present study evidences the erosive potential of hydrogen peroxide-based bleaching agents. It can be concluded that bleaching agents containing high concentrations of hydrogen peroxide with acidic pH can cause mineral loss and surface erosion of enamel which is extremely detrimental to the tooth integrity.

Chemical kinetics of silver diammine fluoride in demineralization and remineralization solutions-an in vitro study.

Introduction: Silver Diammine Fluoride (SDF) is a clinical minimal intervention to manage dentin caries. Its chemistry in demineralization conditions has been investigated widely, but far less in remineralization conditions. The aim was to investigate and compare the chemical reactions when SDF is added to remineralization and demineralization solutions. Methods: 0.01 ml SDF (Riva Star) was added to deionized water (DW); demineralization (DS = pH4) and remineralization (RS = pH7.0) solutions. The time sequence of concentrations of NH4+, F-, and Ag+ were measured using ion selective electrodes (ISEs) every 2 min. The pH was also measured. Precipitates were characterized using x-ray Diffraction (XRD) and, 31P and 19F nuclear magnetic resonance spectroscopy (NMR). Results: The concentrations of NH4+ and Ag+ showed decreasing trends in DW (-0.12 and -0.08 mM/h respectively), and in DS (-1.06 and -0.5 mM/h respectively); with corresponding increase in F- concentration (0.04 and 0.7 mM/h respectively). However, in RS, NH4+ concentration showed little change (0.001 mM/h), and Ag+ and F- concentrations were negligible. XRD results showed that precipitates (in RS only) contained AgCl, and metallic Ag. NMR showed that fluorapatite/carbonated fluorapatite (FAP/CFAP) were formed. The pH increased after SDF addition in all three solutions. Discussion: SDF dissolved to release NH4+, F- and Ag + . In DW and DS, NH4+ combined with Ag+ to form diamminesilver, causing an increase of F- and pH. In RS, F- reacted with Ca2+ and (PO)43- to form FAP/CFAP, and Ag+ reacted with Cl- to form AgCl/Ag. These suggests why SDF is effective in managing dentin caries.

Efficacy of the Probiotic L. brevis in Counteracting the Demineralizing Process of the Tooth Enamel Surface: Results from an In Vitro Study.

BACKGROUND: Enamel plays an essential role in protecting the underlying layers of the human tooth; therefore, preserving it is vital. This experimental study aimed to evaluate the potential ability of L. brevis to counteract the action of a demineralizing agent on dental enamel morphology and mineral composition in vitro. METHODS: The sample consisted of 12 healthy human posterior teeth. The coronal portion of each tooth was subdivided into two equal parts longitudinally. The specimens were randomly divided into four groups: artificial saliva, L. brevis suspension, demineralizing agent (DA), and DA plus L. brevis. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to evaluate the surface micromorphology and the mineral content, respectively. The statistical analysis was conducted using a one-way ANOVA, followed by Tukey's post hoc test. RESULTS: SEM analysis did not highlight significant changes in the enamel microstructure of L. brevis-treated specimens compared to the control. DA-induced damage to the enamel structure was drastically reduced when the specimens were contextually exposed to the probiotic. The treatment with DA substantially reduced the weight % of crucial enamel minerals, i.e., Ca and P. Notably, the probiotic was able to reverse the demineralization process, bringing Ca and P weight % back to basal levels, including the Ca/P ratio. CONCLUSIONS: The findings indicate that L. brevis is able to efficiently protect the dental enamel surface from the damage caused by DA and increase the enamel resistance to demineralization. Overall, L. brevis confirms its efficacy in preventing or counteracting the action of carious lesions through a novel mechanism that protects the tooth surface under a chemical challenge that mimics the caries process.

White spot lesions in fixed orthodontic treatment: Etiology, pathophysiology, diagnosis, treatment, and future research perspectives.

White spot lesions (WSLs) refer to localized areas of hypo-mineralization limited to the enamel of the teeth surface, which is noticeable clinically to the naked eye on drying of the teeth. During fixed orthodontic treatment, it is very hard for the patient to maintain excellent oral hygiene as the brackets, bands, wires, elastics, and other appliances and attachments worn intra-orally provide a platform for food retention, plaque formation, and then colonization by acidogenic bacteria like Streptococcus mutans and Lactobacillus. This review aims to elaborate and focus on etiology, pathophysiology, diagnosis, treatment aspect, and future scope for research about the WSLs occurring due to fixed orthodontic treatment.

Effectiveness of fluoride mouthrinse in prevention of demineralization during fixed orthodontic treatment: A systematic review and meta-analysis.

Enamel demineralization is a very common occurrence around bonded brackets in an orthodontic practice. Fluoride (FLR) applications have been used to prevent decalcification and further progression of white spot lesions. The purpose of this systematic review and meta-analysis was to systematically appraise available literature on the effectiveness of fluoride mouthrinse in the prevention of demineralization around fixed orthodontic appliances. A search was conducted for randomized controlled clinical trials among four electronic databases (MEDLINE, Google Scholar, PubMed, and Cochrane Review) through MeSH terms and keywords. Studies were excluded if random allocation was not conducted, or if they were animal or in vitro studies. About 146 articles were screened and 5 studies were selected for the present review. Only two studies were selected for MA due to variations in the measurement of outcomes among studies. This review concluded that rinsing with FLR in the course of the fixed orthodontic treatment lessens demineralization around the bracket. Using FLR mouthrinse to inhibit the formation of white spot lesions or dental caries in patients with multiple cavities or restoration can be considered in clinical practice.

Extrafibrillar demineralization: Yes or no?

OBJECTIVE: Extrafibrillar demineralization is considered to be an ideal solution for addressing the durability of resin-dentin bonding interfaces. However, its theoretical basis is contradictory to ionization equilibrium of hydroxyapatite dissolution. In this study, various calcium chelators were selected as dentin conditioners to explore the essence of dentin demineralization with chelators and its effect on resin-dentin adhesion. METHODS: Polyethyleneimine grafted with EDTA and polyacrylic acid sodium (PAAN450k) larger than 40 kDa, as well as PAAN (PAAN3k) and EDTA smaller than 6 kDa, were prepared as dentin conditioners. The dentin powder was designed to characterize whether it would demineralize without contact with PAAN450k. Dentin demineralization effect with four conditioners was evaluated with field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy and quantification of hydroxyproline concentration after enzymatic degradation. Micro-tensile bond strength (µTBS) test and failure mode analysis were employed to assess the bonding effect of the four chelators in both wet and dry bonding, with H3PO4 wet bonding serving as the control group. RESULTS: Demineralization occurs when PAAN450k was not in direct contact with the dentin powder. The extrafibrillar demineralization cannot be induced by any chelator regardless of its molecular weight. Complete demineralization including extrafibrillar and intrafibrillar demineralization would occur with sufficient interaction time. Moreover, chelators could not provide a reliable dentin bonding effect under a short interaction time. SIGNIFICANCE: From the perspective of theory and application, extrafibrillar demineralization is not a reliable strategy, which provides a reminder for exploring new strategies in the future.

Chitosan Phytate Nanoparticles: A Synergistic Strategy for Effective Dental Caries Prevention.

Dental caries is a widespread oral disease that poses a significant medical challenge. Traditional caries prevention methods, primarily the application of fluoride, often fall short in effectively destroying biofilms and preventing enamel demineralization, thereby providing limited efficacy in halting the progression of caries over time. To address this issue, we have developed a green and cost-effective synergistic strategy for the prevention of dental caries. By combining natural sodium phytate and chitosan, we have created chitosan-sodium phytate nanoparticles that offer both the antimicrobial properties of chitosan and the enamel demineralization-inhibiting capabilities of sodium phytate. In an ex vivo biofilm model of human teeth, we found that these nanoparticles effectively prevent biofilm buildup and acid damage to the mineralized tissue. Additionally, topical treatment of dental caries in rodent models has shown that these nanoparticles effectively suppress disease progression without negatively impacting oral microbiota diversity or causing harm to the gingival-mucosal tissues, unlike traditional prevention methods.

Formulation of arginine-loaded mesoporous silica nanoparticles (Arg@MSNs) modified orthodontic adhesive.

OBJECTIVES: The objective of this study was to synthesize arginine loaded mesoporous silica nanoparticles (Arg@MSNs), develop a novel orthodontic adhesive using Arg@MSNs as modifiers, and investigate the adhesive performance, antibacterial activity, and biocompatibility. METHODS: Arg@MSNs were synthesized by immobilizing arginine into MSNs and characterized using transmission electron microscope (TEM), dynamic light scattering (DLS), and Fourier Transform Infrared Spectrometer (FT-IR). Arg@MSNs were incorporated into Transbond XT adhesive with different mass fraction to form functional adhesives. The degree of conversion (DC), arginine release behavior, adhesive performance, antibacterial activity against Streptococcus mutans biofilm, and cytotoxicity were comprehensively evaluated. RESULTS: TEM, DLS, and FT-IR characterizations confirmed the successful preparation of Arg@MSNs. The incorporation of Arg@MSNs did not significantly affect DC and exhibited clinically acceptable bonding strength. Compared to the commercial control, the Arg@MSNs modified adhesives greatly suppressed the metabolic activity and polysaccharide production while increased the biofilm pH values. The cell counting kit (CCK)-8 test indicated no cytotoxicity. CONCLUSIONS: The novel orthodontic adhesive containing Arg@MSNs exhibited significantly enhanced antibacterial activities and inhibitory effects on acid production compared to the commercial adhesive without compromising their bonding strength or biocompatibility. CLINICAL SIGNIFICANCE: The novel orthodontic adhesive containing Arg@MSNs exhibits potential clinical benefits in preventing demineralization of enamel surfaces around or beneath orthodontic brackets due to its enhanced antibacterial activities and acid-producing inhibitory effects.

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.

Evaluation Study of Ammonium Removal from Groundwater by Electrodialysis: Case Study of Real Groundwater from the City of Kenitra in Morocco.

In this work, we investigated the feasibility of ammonium removal by electrodialysis (ED), a well-known electro-membrane process, based on the selective migration of anions and cations through anion exchange membranes (AEMs) and cation exchange membranes (CEMs). ED experiments are performed using a laboratory pilot. The ion exchange membranes (IEMs) pair used is AXE/CMX, AXE as an AEMs and CMX as a CEMs. The first tests are performed with real groundwater solutions from Kenitra city (Morocco), spiked with an initial concentration of 3 mg/L NH4Cl. The results gave a specific demineralization (SD) to NH4 + ions of 84.60 %; for a demineralization rate (DR) of 80 % and a time of 60 min. The multivariate principal component analysis (PCA) presents a total inertia of 99.23 %, the majority of the variables of which are positively correlated on the C1 axis with a variance of 95.5 % than that of C2 of 3.78 %. The quality of the diluted water determined by the Legrand-Poirier method showed that the water was aggressive and that the addition of 4.54 mg/L Ca2+ was necessary to balance the water and make it fit for human consumption.