Inhibition Of Enamel Demineralization Research Articles

The combination of arginine and fluoride-containing bioactive glass acted synergistically in inhibiting enamel demineralization in permanent teeth

ObjectivesTo evaluate the in-vitro efficacy of inhibiting enamel demineralization using arginine in combination with fluoride-containing bioactive glass (FBG). MethodsIn this study, the healthy enamel blocks were first demineralized in acetic acid for 24 h, then soaked in anti-demineralization treatment solutions containing either arginine or FBG or both for 96 h.The specimens treated in acetic acid were applied as the control group. The pH, calcium and phosphorus ion concentrations of the solutions were measured before and after treatment. Changes in enamel mineral weight, microhardness, and composition were also analyzed. ResultsThe present of arginine facilitated fluorine release from treatment solutions with the presence of FBG. Both arginine and FBG significantly increased the pH of treatment solutions and prevented the further mineral weight loss compared to the control group. All anti-demineralization treatment groups showed significant increases in microhardness, but there was no statistical difference among the treatment groups. The SEM analysis showed enamel restoration in the arginine and FBG groups upon treatment, while the combined groups showing a superior anti-demineralization efficacy. 19F NMR showed the formation of fluorapatite in samples treated with solutions containing FBG. ConclusionsBoth arginine and FBG could inhibit enamel demineralization to some extent, and their combination demonstrated an enhanced anti-demineralization efficacy. The low-concentration combination group exhibited anti-demineralization effects comparable to those of high-concentration ones. Clinical SignificanceThis study introduces a new approach for caries prevention by combining the application of arginine and FBG. The release of fluorine promoted by the presented arginine along with calcium and phosphorus ions from FBG facilitated FAP formation. Additionally, the increment of pH resulting from arginine and FBG degradation further prevents enamel demineralization.

Efficacy of pit and fissure sealant containing S-PRG filler on inhibition of enamel demineralization

The aim of this in-vitro study was evaluating the effectiveness of an S-PRG filler containing fissure sealant (Beautisealant) to inhibit enamel demineralization and to compare it with two different fluoride-containing (Helioseal-F) and non-fluoride-based (Helioseal) conventional fissure sealants, using enamel microhardness tester. Material and Methods: In this study 30 caries-free 3rd molar teeth were used. Helioseal, Helioseal-F or Beautisealant fissure sealant was applied to the buccal surfaces of the teeth and subjected to a 14-day pH cycle. Lingual surfaces were the control group. Sections were taken in the bucco-lingual direction and cross-sectional microhardness values were measured at different depths. The significance of the mean difference between the groups was examined by One Way Analysis of Variance, the significance of the difference between buccal and lingual surfaces at different depths within the groups by Dependent t-test (p

The use of mouthwash containing trimetaphosphate as an adjunct therapy to fluoridated toothpaste reduces enamel demineralization

IntroductionThe decline in dental caries has been attributed to the widespread use of fluoride (F). Two forms of presentation are fluoridated toothpaste (FT) and mouthwash (MW), widely used by the population. Materials and methodsThis study aimed to evaluate in vitro the effects of combining FT and MW, whether supplemented with sodium trimetaphosphate (TMP) or not, on dental enamel demineralization. Bovine enamel blocks (n = 60) were selected based on initial surface hardness (SHi) and divided into 5 experimental groups (n = 12 each): I) Placebo Toothpaste (without F/TMP); II) 1100 ppm F Toothpaste (FT); III) 1100F associated with a MW at 100 ppm F (FT + MW 100F); IV) 1100F associated with a MW at 225 ppm F (FT + MW 250F); and V) 1100F associated with a MW at 100 ppm F supplemented with 0.4 % TMP (FT + MW 100F-TMP). The blocks were treated twice a day, undergoing 5 pH cycles over 7 days. Thus, the percentage change in surface hardness (%SH), integrated subsurface hardness loss (ΔKHN), and the concentration of F, phosphorus (P), and calcium (Ca) in the enamel were determined. The data were submitted to ANOVA and Student-Newman-Keuls test (p < 0.001). ResultsThe 1100F group was statistically inferior to the groups associated with MW for %SH, ΔKHN, and the concentration of P and Ca in the enamel (p < 0.001). Blocks treated with FT + MW 225F and FT + MW 100F-TMP showed significantly lower %SH compared to the other groups (p < 0.001). The FT + MW 100F - TMP group exhibited the lowest depth mineral loss (ΔKHN), and higher concentration de P in enamel (p < 0.001). ConclusionThe adjunct use of MW with FT produces a greater protective effect in inhibiting enamel demineralization, and the supplementation of TMP to the MW with 100F provides a superior effect compared to MW with 225F. Clinical significanceThis combination of treatments could be regarded as one of several alternative fluoride supplements for subjects at elevated risk of caries.

Characterization of a Novel TiF4 Inclusion Complex and in vitro Evaluation of Its Effect on Inhibiting Enamel Demineralization

Introduction: Titanium tetrafluoride (TiF4) is an anticariogenic agent with high remineralizing potential. However, the acidic pH of TiF4 solution can limit its clinical application. The present study aimed to prepare and characterize a new TiF4-dendrimer inclusion complex and evaluate its ability to inhibit enamel demineralization under pH cycling conditions. Methods: PEG-citrate dendrimer and TiF4-dendrimer inclusion complex were synthesized and their molecular structures were evaluated using Fourier-transform Infrared Spectroscopy (FTIR), Hydrogen Nuclear Magnetic Resonance (HNMR), and Liquid Chromatography-Mass Spectrometry (LC-MS) tests. Forty-eight enamel samples were prepared and randomly divided into four groups: distilled water (negative control), TiF4 solution (T), dendrimer solution (D), and TiF4-dendrimer solution (TD). The microhardness of the samples was measured initially. Next, the samples underwent pH cycling, were exposed to the solutions, the microhardness was measured again, and microhardness loss was calculated. EDX analysis was performed on the surface and cross-sectional segments of the samples. Results: The microhardness loss was significantly higher in control (−65.1 ± 6.0) compared to other groups. No significant difference was observed between T (−47.9 ± 5.6) and D (−41.7 ± 12.0) and also D and TD (−40.5 ± 9.4) in this regard. Microhardness loss was significantly higher in T compared to TD group. The TD samples showed similar fluoride and titanium content in both surface and subsurface regions, while the T group had higher concentrations in the surface region. Moreover, the TD solution had a higher pH of 3.4 compared to the T solution’s pH of 1.1. Conclusion: No significant difference was observed between the efficacy of TiF4-dendrimer and TiF4 solution in inhibiting demineralization while TiF4-dendrimer solution had the added advantage of having a higher pH.

Effect of composite resin containing antibacterial filler on sugar-induced pH drop caused by whole saliva bacteria

Secondary caries around restorations is a major problem and can be attributed to bacteria invading microgaps formed at the tooth-restoration interface. An antibacterial composite resin containing quaternary ammonium silica (QASi) filler has been reported to inhibit enamel demineralization in situ. However, whether the prevention of enamel demineralization by QASi-containing composite resin is because of the reduced metabolic activity of acid-producing saliva bacteria is unclear. The purpose of this study was to compare the effects of QASi-containing composite resin and 2 other restorative materials on the viability of salivary bacteria and sugar-induced acid production. Whole saliva from each of the 30 study participants, 14 at high risk and 16 at low risk for caries, was brought into contact with quadruplicate specimens of 3 restorative materials, Infinix Flowable Composite, an anti-bacterial composite resin containing 1.5% QASi filler (Nobio), Filtek Supreme Flowable Restorative (3M), a conventional flowable composite resin, and dental amalgam (Silmet). Bacterial growth and sugar-induced acid production on each restorative material were measured every 20 minutes for 18 hours. Caries risk groups were compared using the t test and repeated measures analysis of variance (α=.05). When significant, Bonferroni multiple comparisons were used. On average, the saliva with the QASi-containing composite resin specimens maintained a near-neutral pH, not dropping below pH 6.0. The saliva associated with both conventional restorative materials exhibited a pH drop below 5.5 (P<.001), the critical threshold for tooth demineralization according to the Stephan curve. Virtually no growth was measured on the surface of the antibacterial composite resin, whereas bacteria grew on the conventional composite resin and dental amalgam (P<.001). No differences were observed between participants at high and low risk of caries. Unlike amalgam and conventional composite resin, the QASi-containing composite resin showed a near-complete shutdown of the metabolic activity of salivary bacteria upon contact and virtually no bacterial viability. This suggests that the prevention of tooth demineralization by QASi-containing restoratives is associated with a significant reduction in bacterial metabolic activity.

Effect of Fluoride Release on Enamel Demineralization Adjacent to Orthodontic Brackets.

This study aimed to evaluate the ability of fluoride-releasing adhesives to inhibit enamel demineralization surrounding orthodontic brackets. Two groups of 40 sound human premolars were sectioned mesio-distally. The halves were varnished, and orthodontic brackets were bonded with different adhesive materials. An area 1 mm wide surrounding the brackets was left exposed. Each specimen was immersed daily in a pH cycle for 28 days. In the second group, the specimens were exposed daily to a fluoride solution (250 ppm F-) at 37°C. The fluoride release from different groups was measured. Quantitative light-induced fluorescence (QLF) was used to quantify fluorescence loss of enamel surfaces adjacent to the brackets. Results were statistically analyzed using ANOVA at (p<0.05). Fluoride released from the three fluoride-releasing adhesives was significantly higher (p<0.001) in the group with daily fluoride exposures than in the group without fluoride exposures. Enamel adjacent to brackets bonded with Fuji Ortho LC, Ketac Cem, and Dyract Cem showed significantly less (p<0.001) changes in (ΔQ) value (less demineralization) than enamel bonded with Transbond, the control adhesive material. Using fluoride-releasing adhesives significantly reduced the level of demineralization adjacent to orthodontic brackets.

Effect of polydopamine and fluoride ion coating on dental enamel remineralization: an in vitro study

BackgroundFluoride treatment is one of the most effective dental caries prevention methods. To continuously prevent dental caries, stably immobilizing the fluoride on the tooth enamel is highly desirable. This study aimed to evaluate the remineralization of tooth enamels by one-pot coating using polydopamine and fluoride ions.MethodsTo prepare the enamel specimens for polydopamine- and fluoride ion-coating, they were treated with polydopamine- and fluoride-containing gels. The enamel specimens were collected from human molars in a blind manner (n = 100) and were randomized into five treatment groups (n = 20, each): 1) untreated, 2) polydopamine-coated, 3) fluoride-containing gel-treated, 4) F varnish-treated, and 5) polydopamine- and fluoride ion-coated enamels. Vickers hardness number (VHN), morphology, and fluoride contents of the specimens were measured before and after the pH-cycling regimen.ResultsPolydopamine- and fluoride ion-coated enamels showed the highest fluoride content and lowest VHN reduction among the samples. The fluoride content of the polydopamine/fluoride ion (PD/F)-coated enamel was increased to 182 ± 6.6%, which was far higher than that of the uncoated enamel (112.3 ± 32.8%, P < 0.05). The changes in the VHN values (ΔVHN) of PD/F-coated enamel substrates showed a slight reduction in the VHN (-3.6%, P < 0.05), which was far lower than that in the control group (-18.9%, P < 0.05). In addition, scanning electron microscopy clearly supported the effect of polydopamine- and fluoride ion-coatings on the remineralization of enamel specimens.ConclusionOur findings suggest that one-pot treatments with polydopamine and fluoride ions could significantly enhance remineralization by inhibiting enamel demineralization through the prolonged retention of fluoride ions.

Comparison of different doses of Er:YAG laser irradiation combined with MI-varnish on the inhibition of enamel demineralization

Comparison of different doses of Er:YAG laser irradiation combined with MI-varnish on the inhibition of enamel demineralization

Dispersion and Demineralization Inhibition Capacity of Novel Magnesium Oxide Nanoparticles Varnish on Enamel Surfaces against Streptococcus mutans (an In Vitro Study)

This research analyzed the dispersion and impact of magnesium oxide nanoparticles (MgONPs) varnish on inhibiting enamel demineralization. A novel MgONPs varnish was prepared in absolute ethanol with rosin in 10%, 5%, 2.5%, and 1.25% concentrations. The samples were classified into six groups, including four tested with MgONPs varnish, one commercial 5% NaF varnish, and control groups of non-protected and sound dental enamel groups. Each group included five enamel samples and three broths of 20 mL per sample. The examinations were started by applying different concentrations of varnishes on the enamel surfaces, which were then exposed to Streptococcus mutans (S. mutans) in three sequences of time for 144 h. A scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to examine the MgONPs’ dispersion. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to quantify the calcium (Ca) released from the enamel. The SEM and EDX evaluations of the enamel samples showed a significantly increased dispersion for the 5% MgONPs varnish, with the highest median. The ICP-OES test showed significant inhibition levels of the Ca release capacity in the 2.5% and 1.25% MgONPs varnishes, similar to the 5% NaF varnish. The MgONPs varnish revealed increasing dispersion of MgONPs, from 1.25% to 5%, and the maximum protection capacity was associated with the 1.25% and 2.5% varnishes, which was similar to the 5% NaF varnish in inhibiting the demineralization effect on enamel.

Effect of Surface Pre-Reacted Glass Ionomer Containing Dental Sealant on the Inhibition of Enamel Demineralization.

The effect of a surface pre-reacted glass ionomer (S-PRG)-containing sealant on the demineralization inhibition and remineralization of intact enamel adjacent to the sealant material was investigated. BeautiSealant (BTS, S-PRG sealant, Shofu), Teeth Mate F-12.0 (TMF, fluoride-releasing sealant, Kuraray Noritake Dental), and an experimental silica-filler sealant were investigated. After pH cycling for 10 days, the enamel surface adjacent to the sealant material was observed using confocal laser microscopy and scanning electron microscopy. The polymerized sealant disks were immersed in a demineralized solution (pH: 4.3) to measure pH change. The enamel specimens with polymerized sealant disks were additionally immersed in demineralized solution, followed by energy-dispersive X-ray spectroscopy. The demineralized area of BTS was significantly smaller than that of TMF and SS (p &lt; 0.05). The surfaces adjacent to the sealant of TMF and SS were demineralized, while the surface of BTS was comparatively intact. An increase in pH values were observed in the BTS and TMF groups. Enamel surfaces presented an inhibition of demineralization for BTS and TMF, but not for SS. Fluoride uptake from the polymerized sealant was greater for BTS than for TMF. The S-PRG-containing sealant showed a buffering ability, demineralization inhibition, promotion of remineralization, and it can be advised for clinical applications.

Effects of hybrid inorganic-organic nanofibers on the properties of enamel resin infiltrants – An in vitro study

This in vitro study aimed to evaluate the overall mechanical properties of resin infiltrants doped with bioactive nanofibers and their ability in inhibiting enamel demineralization or achieving remineralization of the adjacent enamel to white spots. A commercial resin infiltrant (ICON, DMG) was doped with hybrid inorganic-organic nanofibers and analyzed for degree of conversion (DC, n = 3) and surface hardness (SH, n = 6). Subsequently, enamel specimens (6 × 4 × 2 mm3) were prepared and submitted to a demineralizing/remineralizing process to produce a subsurface caries-like lesion. The specimens were treated with one of the following materials: ICON infiltrant, DMG (control); ICON + nanofibers of poly-lactic acid (PLA)-filled with silica (PLA-SiO2); ICON + nanofibers of (PLA)-filled with calcium incorporated into a silica network (SiO2–CaP). Then, the specimens were subjected to a pH-cycling demineralizing/remineralizing model for 7 days at 37 °C. The %ΔSH change (after treatment), %SH loss and %SH recovery (after pH-cycling regimen) were calculated after SH evaluation (n = 9/group). The Ca/P weight ratio before and after pH-cycling regimen was evaluated through SEM/EDX. The results of DC were analyzed through the T-test (p < 0.05). ANOVA followed by Tukey's test (p < 0.05) was performed for hardness and EDX. A significant SH increase was observed in the ICON/SiO2CaP group (p < 0.05). The ICON/PLA-SiO2 presented higher DC values than the control group (p = 0.043). All groups presented significant difference in %ΔSH (p < 0.05), although the specimens treated with ICON/SiO2CaP presented greater values. Regarding the %SHL and %SHR, the ICON/SiO2CaP and ICON/PLA-SiO2 were significantly different compared to the control group (p < 0.001). However, no difference was observed between the ICON/SiO2CaP and ICON/PLA-SiO2. The Ca/P ratio showed that the ICON/SiO2CaP and ICON/PLA-SiO2 after the pH-cycling regimen differed from sound enamel and modified infiltrants before pH-cycling. In conclusion, tailored hybrid nanofibers may be incorporated into enamel resin infiltrants without compromise the mechanical properties of such experimental materials. These latter can inhibit the demineralization of enamel and increase its hardness during pH-clycling challange.

Effect of Xylitol Varnishes on the Inhibition of Demineralization in Vitro

Objective: To evaluate the efficacy of xylitol varnishes in the inhibition of enamel demineralization in vitro. Material and Methods: Bovine enamel blocks (n=120) were randomly allocated to four groups (n = 30), and the surface hardness (SH) was measured at baseline. The blocks were treated with the following varnishes: 20% xylitol, 20% xylitol plus F (5% NaF), Duraphat™ (5% NaF, positive control), and placebo (no-F/xylitol, negative control). The varnishes were applied and removed after 6 h of immersion in artificial saliva. The blocks were subjected to pH cycles (demineralization and remineralization for 2 and 22h/day, respectively, for 8 days). Surface and cross-sectional hardnesses were measured to calculate the percentage of SH loss (%SHL) and the integrated loss of the subsurface hardness (ΔKHN). Data were statistically analyzed using Kruskal-Wallis and Tukey’s tests (p<0.05). Results: %SHL was significantly decreased by 20% xylitol plus F, Duraphat™, and 20% xylitol varnishes compared to placebo. The use of 20% xylitol plus F varnish led to a significantly lower percentage of SH loss compared to the use of 20% xylitol varnish without F. However, the experimental and commercial varnishes led to significantly lower subsurface demineralization compared to placebo and did not differ from each other. Conclusion: Xylitol varnishes, especially when combined with F, effectively prevent enamel demineralization.

A Hydroxypropyl Methylcellulose Film Loaded with AFCP Nanoparticles for Inhibiting Formation of Enamel White Spot Lesions.

ObjectiveThis study investigated the effects of mineralizing film consisting of hydroxypropyl methylcellulose (HPMC) and amorphous fluorinated calcium phosphate (AFCP) nanoparticles on enamel white spot lesions (WSLs).Material and MethodsThe AFCP nanoparticles and mineralizing film were prepared via nanoprecipitation and solvent evaporation, respectively. They were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), inductively coupled plasma atomic emission spectrometry (ICP-AES), and fluoride ion selective electrode. Thirty-two human enamel slices (4 mm × 4 mm × 1.5 mm) were highly polished and randomly assigned to four groups: negative control (no treatment); pure HPMC film; mineralizing film; GC Tooth Mousse Plus® (contains 10% CPP-ACP and 0.2% NaF). Subsequently, samples were challenged by a modified pH-cycling and characterized by color measurement, Micro-CT, SEM/EDX, and nanoindentation.ResultsThe mineralizing film could sustain release of Ca, P and F ions over 24 h and maintain AFCP nanoparticles in metastable state over 8~12 h. During 4 weeks of pH cycling, the mineralizing film group exhibited least color change (∆E), mineral loss and lesion depth (120 ± 10 µm) among four groups (p < 0.05). SEM findings revealed that the porosities among enamel crystals increased in negative control and pure HPMC film groups after pH cycling, whereas in mineralizing film group, the original microstructure of enamel was well conserved and mineral deposits were detected between enamel prisms. Mineralizing film group demonstrated a least reduction of nanomechanical properties such as elastic modulus of 77.02 ± 6.84 GPa and hardness of 3.62 ± 0.57 GPa (p < 0.05).ConclusionThe mineralizing film might be a promising strategy for prevention and management of WSLs via inhibiting enamel demineralization and promoting enamel remineralization.

The Potential of a Bioactive, Pre-reacted, Glass-Ionomer Filler Resin Composite to Inhibit the Demineralization of Enamel in Vitro.

A prereacted, glass-ionomer filler fluoride-containing resin composite had lower remineralization potential than glass-ionomer cements but was able to inhibit enamel demineralization; thus, it may be an option for restoring dental surfaces for patients at high risk of caries. Evidence is lacking on the use of surface prereacted glass-ionomer filler resin composites to inhibit demineralization and that simulate real clinical conditions. The present laboratory study evaluated the potential of such composites to prevent demineralization and quantified fluoride (F) and other ions released from restorative materials after a dynamic pH-cycling regimen applied to the tooth material interface in vitro. The pH-cycling regimen was assessed by measuring surface hardness (SH) along with energy dispersive X-ray spectroscopy (EDX). Ninety blocks of bovine enamel were subjected to composition analysis with EDX, and were further categorized based on SH. The blocks were randomly divided into 6 treatment groups (n=15 each): F IX (Fuji IX Extra; GC Corporation); IZ (Ion Z, FGM); F II (Fuji II LC, GC Corporation); B II (Beautifil II, Shofu); F250 (Filtek Z250 XT, 3M ESPE); and NT (control, no treatment). The blocks were subjected to a dynamic pH-cycling regimen at 37°C for 7 days concurrently with daily alternations of immersion in demineralizing/remineralizing solutions. EDX was conducted and a final SH was determined at standard distances from the restorative materials (150, 300, and 400 μm). The EDX findings revealed a significant increase in F concentration and a decrease in Ca2+ in the enamel blocks of group B II after the pH-cycling regimen (p<0.05). SH values for groups F IX, IZ, and F II were greater than those for groups B II, F250, and NT at all distances from the materials. The results suggest that each of 3 restorative materials, F IX, IZ, and F II, partially inhibited enamel demineralization under a dynamic pH-cycling regimen.

Characterization and effect of nanocomplexed fluoride solutions on the inhibition of enamel demineralization created by a multispecies cariogenic biofilm model.

The aim of this study was to assess the in vitro caries preventive effect of nanocomplexed solutions of hydroxypropyl-β-cyclodextrin and γ-cyclodextrin associated with titanium tetrafluoride (TiF4) after different complexation times (12 or 72h). Enamel blocks were randomly distributed in 9 groups (n = 11): negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, TiF4, hydroxypropyl-β-cyclodextrin:TiF4 12h, hydroxypropyl-β-cyclodextrin:TiF4 72h, γ-cyclodextrin:TiF4 12h, γ-cyclodextrin:TiF4 72h, and NaF (positive control). The solutions were applied for 1min and the blocks were exposed to a biofilm model. Nanocompounds were characterized by differential scanning calorimetry and X-ray powder diffraction. The percentage of surface microhardness loss (%SML), mineral density changes (ΔZ), lesion depth, surface morphology (scanning electron microscopy-SEM), and chemical characterization (energy-dispersive spectroscopy-EDS) were assessed. No oxidation was observed, and the formation of the nanocomplexes was evidenced by changes in the melting point compared to pure cyclodextrins and the loss of crystallinity of the materials. Hydroxypropyl-β-cyclodextrin:TiF4 72h resulted in lower %SML than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, and TiF4 (p< 0.05). NaF differed from all groups (p< 0.05), except for hydroxypropyl-β-cyclodextrin:TiF4 72h (p= 0.83). ΔZ of hydroxypropyl-β-cyclodextrin:TiF4 72h was higher than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, γ-cyclodextrin:TiF4 1 2h, γ-cyclodextrin:TiF4 72h, and NaF (p< 0.05) and similar to TiF4 and hydroxypropyl-β-cyclodextrin:TiF4 12h (p> 0.05). SEM/EDS detected Ti in the blocks subjected to TiF4-products. The hydroxypropyl-β-cyclodextrin:TiF4 72h solution showed caries preventive effect on the surface and subsurface of the enamel. A hydroxypropyl-β-cyclodextrin nanosystem, in association with TiF4 after 72h of complexation, may be a promising agent for the prevention of enamel demineralization.

Effect of Pit and Fissure Sealants on the Prevention of Enamel Demineralization After Exposure to Streptococcus mutans Biofilm: An Vitro Study

Objective: The aim of this study was to evaluate the effect of sealants on the prevention of enamel demineralization and on biofilm metabolic activity. Materials and Methods: Cavity preparations were performed on 45 blocks of bovine teeth (4x4x4 mm) randomly assigned to three groups (n=15): RI-Riva Light Cure®/SDI; EM-Embrace™ WetBond™ Pulpdent Corp.®; and CO-Natural Flow/DFL resin (negative control). The sealed blocks were subjected to thermocycling (500 cycles/30 s). Half of the blocks were covered with acidresistant varnish to create a control area (RI, EM, and CO) and an experimental area (RI-EX, EM-EX, and CO-EX). They were subsequently exposed to Streptococcus mutans biofilm for assessment of demineralization by the Knoop microhardness test (50 g/15 s), at 25, 50, 100, 150, and 200 μm from the interface. In another test, the cylinders of the sealants (4 mmx3 mm) were subjected to the biofilm metabolic activity test. Results: The RI-EX group showed higher microhardness than CO-EX (p&lt;0.05) and less demineralization when compared to RI at all distances. Microbial activity was lower in EM compared to CO, but not statistically significant in relation to RI. Conclusion: Both sealants can inhibit enamel demineralization in the presence of S. mutans biofilm.

Comparative Evaluation of Two Remineralizing Agents on Enamel around Orthodontic Brackets: An in vitro Study:

Objective: This study was designed to compare the relative efficiency of GC, Tooth Mousse, which contains 10% ACP-CPP and GC Tooth Mousse Plus which contains amorphous calcium phosphate casein phosphopeptide (ACP-CPP) with sodium fluoride 0.2% w/w (900 ppm) to inhibit enamel demineralization adjacent to orthodontic brackets in vitro. Materials and methods: Forty-five non-carious, human maxillary premolars with no visible enamel defects were collected and bonded with stainless pre-adjusted stainless steel premolar brackets with light-cure composite resin. The teeth were randomly assigned into three groups of 15 teeth and each group coded with unique colored nail varnish leaving a rectangular window extending occlusally. The teeth in each group were immersed separately in an artificial saliva solution for 11 hours and an acid solution for 1 hour maintained at room temperature. Group I, control group did not receive any application, as Groups II and III received GC Tooth Mousse and GC Tooth Mousse Plus respectively. The teeth were immersed alternately in the saliva and acid solution for 31 days. Two sections, each approximately 0.5 mm thick were obtained from each specimen. The sections were photographed with a polarized light microscope at 4× magnification. The depths of demineralized enamel in each section were measured at three sites. Results: The results of this study showed that GC Tooth Mousse Plus on daily application will provide maximum protection against the enamel demineralization in orthodontic patients, by reducing the lesion formation and simultaneously remineralizing the demineralized area by providing calcium phosphate ions and fluoride ions constantly. Conclusion: GC Tooth Mousse Plus (ACP-CPPF) showed better efficiency in reducing the demineralization and enhancing the remineralization around the orthodontic brackets and have maximum benefit compared to GC Tooth Mousse with good patient compliance.

Effect of Er:YAG laser irradiation on deciduous enamel roughness and bacterial adhesion: An in vitro study.

Laser irradiation has been proposed as a preventive method against dental caries since it is capable to inhibit enamel demineralization by reducing carbonate and modifying organic matter, yet it can produce significant morphological changes. The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on superficial roughness of deciduous dental enamel and bacterial adhesion. Fifty-four samples of deciduous enamel were divided into three groups (n = 18 each). G1_control (nonirradiated); G2_100 (7.5 J/cm2 ) and G3_100 (12.7 J/cm2 ) were irradiated with Er:YAG laser at 7.5 and 12.7 J/cm2 , respectively, under water irrigation. Surface roughness was measured before and after irradiation using a profilometer. Afterwards, six samples per group were used to measure bacterial growth by XTT cell viability assay. Adhered bacteria were observed using confocal laser scanning microscopy (CLSM) and a scanning electron microscopy (SEM). Paired t-, one-way analysis of variance (ANOVA), Kruskal-Wallis and pairwise Mann-Whitney U tests were performed to analyze statistical differences (p < .05). Before treatment, samples showed homogenous surface roughness, and after Er:YAG laser irradiation, the surfaces showed a significant increase in roughness values (p < .05). G3_100 (12.7 J/cm2 ) showed the highest amount of Streptococcus mutans adhered (p < .05). The increase in the roughness of the tooth enamel surfaces was proportional to the energy density used; the increase in surface roughness caused by laser irradiation did not augment the adhesion of Streptococcus sanguinis; only the use of the energy density of 12.7 J/cm2 favored significantly the adhesion of S. mutans.

A nano-CaF2-containing orthodontic cement with antibacterial and remineralization capabilities to combat enamel white spot lesions

ObjectivesThe objectives of this study were to develop a resin-modified glass ionomer containing nanoparticles of calcium fluoride (nCaF2) and dimethylaminohexadecyl methacrylate (DMAHDM) for the first time and investigate the antibacterial and remineralization properties. MethodsnCaF2 was synthesized using a spray-drying method and characterized using a transmission electron microscope. Twenty weight percentage (wt%) nCaF2 and 3 wt% DMAHDM were incorporated into a RMGI (GC Ortho LC). Enamel shear bond strength (SBS) and cytotoxicity were determined. Fluoride (F) and calcium (Ca) ion releases were assessed. Biofilm live/dead staining, metabolic activity, polysaccharide and lactic production, and colony-forming units (CFU) were evaluated. The remineralization ability was determined by measuring the effects of cements on enamel surface hardness and lesion depth. ResultsIncorporating 20 wt% nCaF2 and 3 wt% DMAHDM did not compromise the SBS (p > 0.1). The decrease of pH from 7.0 to 4.0 significantly increased the F and Ca ion releases. The new cement greatly reduced the metabolic activity, polysaccharide and lactic acid productions, and lowered the biofilm CFU by 3 log, compared to commercial control (p < 0.05). The new cement increased the enamel hardness by 56% and decreased the lesion depth by 43%, compared to control (p < 0.05). The cell viability at 7 days against the new cement extracts was 82.2% of that of the negative control in culture medium without any extracts. ConclusionsThe novel orthodontic cement containing nCaF2 and DMAHDM achieved much stronger antibacterial and remineralization capabilities and greater enamel hardness than the commercial control did, without compromising the orthodontic bracket-enamel SBS and biocompatibility. Clinical SignificanceThe novel bioactive and nanostructured orthodontic cement is promising to inhibit enamel demineralization, white spot lesions and caries in orthodontic treatments.

Novel Protein-Repellent and Antibacterial Resins and Cements to Inhibit Lesions and Protect Teeth

Orthodontic treatment is increasingly popular as people worldwide seek esthetics and better quality of life. In orthodontic treatment, complex appliances and retainers are placed in the patients’ mouths for at least one year, which often lead to biofilm plaque accumulation. This in turn increases the caries-inducing bacteria, decreases the pH of the retained plaque on an enamel surface, and causes white spot lesions (WSLs) in enamel. This article reviews the cutting-edge research on a new class of bioactive and therapeutic dental resins, cements, and adhesives that can inhibit biofilms and protect tooth structures. The novel approaches include the use of protein-repellent and anticaries polymeric dental cements containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and dimethylaminododecyl methacrylate (DMAHDM); multifunctional resins that can inhibit enamel demineralization; protein-repellent and self-etching adhesives to greatly reduce oral biofilm growth; and novel polymethyl methacrylate resins to suppress oral biofilms and acid production. These new materials could reduce biofilm attachment, raise local biofilm pH, and facilitate the remineralization to protect the teeth. This novel class of dental resin with dual benefits of antibacterial and protein-repellent capabilities has the potential for a wide range of dental and biomedical applications to inhibit bacterial infection and protect the tissues.