New Generation of Orthodontic Elastomeric Ligature to Prevent Enamel Demineralization In Vivo.

This study aimed to synthesize a novel elastomeric ligature with dimethylaminohexadecyl methacrylate (DMAHDM) grafted, providing a new strategy for improving the issue of enamel demineralization during fixed orthodontics. DMAHDM was incorporated into elastomeric ligatures at different mass fractions using ultraviolet photochemical grafting. The antibacterial properties were evaluated and the optimal DMAHDM amount was determined based on cytotoxicity assays. Moreover, tests were conducted to evaluate the in vivo changes in the mechanical properties of the elastomeric ligatures. To assess the actual in vivo effectiveness in preventing enamel demineralization, a rat demineralization model was established, with analyses focusing on changes in surface microstructure, elemental composition, and nanomechanical properties. Elastomeric ligatures with 2% DMAHDM showed excellent biocompatibility and the best antibacterial properties, reducing lactic acid production by 65.3% and biofilm bacteria by 50.0% within 24 h, without significant mechanical property differences from the control group (p > 0.05). Most importantly, they effectively prevented enamel demineralization in vivo, enhancing elastic modulus by 73.2% and hardness by 204.8%. Elastomeric ligatures incorporating DMAHDM have shown great potential for application in preventing enamel demineralization, providing a new strategy to solve this issue during fixed orthodontics.

Effect of Biomin F toothpaste and Diode laser on remineralization of white spot lesions (in vitro study).

BACKGROUND: White-spot lesions are considered an initial carious stage characterized by an outer enamel layer with significantly reduced mineralization. This study was conducted to assess the combined effect of Biomin F toothpaste and Diode laser on remineralization of white spot lesions. MATERIALS AND METHODS: An invitro study conducted on a total of 30 premolars divided into three groups; Group A (Biomin F Tooth paste), Group B (Biomin F with laser application for 30 sec), Group C (Negative control). The three groups were submitted to three stages; stage 1:Baseline,stage 2:After demineralization ,and stage 3:After remineralization. In each stage, elemental analysis(calcium, phosphorus, and fluoride)was measured quantitatively using Energy Dispersive X-ray (EDX) analysis and qualitatively by micrographs using scanning electron microscope. The data were tested to find significant difference between mineral changes during stages by using (ANOVA) test and Bonferroni test. RESULTS: Calcium, phosphorus and fluoride ions decreased in all groups after demineralization. In stage 3, after application of remineralizing agents, Calcium ions increased significantly in groups A and B where p<.05. As regards to the phosphorus ions, a significant increase was observed in all groups with group A showed the highest gain as phosphorus level percentage change (%mass) was 56.52±18.02 . Fluoride ions increased significantly in groups A and B (p<0.05) but decreased significantly in group C. There was no statistical significant difference between group A and B (p ≥.05) in calcium, phosphorus, and fluoride level after remineralization. CONCLUSION: Within the limitation of the present study, we concluded that Biomin F toothpaste is promising in the repairing of white spot lesions on the surface of the demineralized enamel. Diode laser did not affect the remineralizing ability of Biomin F toothpaste.

Effect of the use of remineralization agents before resin infiltration on the treatment of initial enamel lesions: an in-vitro study.

AIM: This study aimed to evaluate the effect of the use of remineralization agents before the application of resin infiltration on the treatment of initial enamel lesions. MATERIALS AND METHODS: Eighty buccal enamel samples were prepared from human molars, and artificial initial lesions were formed after 96 h of incubation with a demineralizing solution. The samples were randomly divided into 8 groups (n = 10) including a remineralizing agent (Tooth Mousse, Medical Mineral Gel, Remin Pro), resin infiltration (ICON), and a combined treatment of both. Remineralizing agents were applied in pH cycle for 7 days. Baseline, demineralization, and after-treatment fluorescence (FluoreCam and DIAGNOdent Pen), surface microhardness (HMV-2T), surface roughness (M300C), OCT (Maestro-2) and ultrasonic system (Novascope 4500) data were obtained for all groups. The sample surfaces were examined under SEM/EDX (SU3500) at x1000. Data were statistically analyzed using the Two-Way Robust ANOVA and Bonferroni tests (p < 0.05). RESULTS: There was no statistically significant difference between the groups for microhardness, roughness, OCT, DIAGNOdent Pen, ultrasound, and FluoreCam size/intensity values (p = 0.582; p = 0.963; p = 0.884; p = 0.923; p = 0.051; p = 0.268; p = 0.793 respectively). The effect of the treatment procedure showed a significant difference (p < 0.001), except for the roughness values (p = 0.984). The lowest Calcium (Ca) ratio (%atomic) was observed in the RI group in the EDX analysis. CONCLUSION: Remineralizing agents and resin infiltration methods may be used in combination or alone in the treatment of initial enamel lesions. Combining remineralizing agents with resin infiltration does not alter the efficacy of the treatment.

The Effect of Resin Infiltration Technique on the Calculated Color Change of Demineralized Lesions of Different Severities.

OBJECTIVE: To assess the color change of demineralized enamel lesions of different severities after resin infiltration using both clinical spectrophotometry and digital photography. METHODS AND MATERIALS: Sixty sound human premolars were randomly divided into 3 groups according to the demineralization level. All the teeth were immersed in a demineralizing solution of a pH adjusted to 4.4 at 37°C. Three levels of demineralization were obtained (D1 shallow, D2 moderate, D3 deep) according to the demineralization time. The demineralized area was then infiltrated by low-viscosity resin (ICON, DMG, Germany). Two instrumental methods were utilized to assess the color difference, a clinical spectrophotometer and digital photography at three time points (sound, demineralized, and infiltrated enamel) to calculate the color difference between sound and demineralized enamel (ΔE1) and between sound and infiltrated enamel (ΔE2). Statistical analysis was performed by ANOVA, followed by Tukey's post hoc test. The correlation was analyzed using linear regression. RESULTS: Two-way ANOVA showed statistically significant differences for both levels of the study (p≤0.05). The color change (ΔE1) and (ΔE2) for different demineralization levels showed statistically significant differences between all groups. For both clinical spectrophotometry and digital photography, D3 showed the highest difference followed by D2 and then D1. As for (ΔE1) calculations, digital photography had a significantly higher difference than spectrophotometry for the D1 group (5.47±0.93 vs 2.78±0.58). As for (ΔE2) digital photography had a statistically significantly lower difference than spectrophotometry (5.55±1.05 vs 6.48±0.76) for the D3 group. CONCLUSIONS: Color correction after resin infiltration is affected by the demineralization level of enamel. Clinical spectrophotometry and digital photography can detect similarly the color change of demineralized enamel after resin infiltration in shallow and moderate demineralization. However, in deep demineralization clinical spectrophotometry tends to exaggerate the color change compared to digital photography.

The effect of different conditioning agents on dentin roughness and collagen structure.

OBJECTIVES: To assess the impact of various organic and inorganic acids on the roughness, demineralization, and collagen secondary structures of human dentin and to compare these effects with those of traditional agents, specifically phosphoric acid (PA) and ethylenediaminetetraacetic acid (EDTA). METHODS: Coronal dentin discs (n = 10) were examined by optical profilometry (roughness) and ATR-FTIR before and after conditioning with 32 % PA, 3 % nitric acid (NA), 20 % citric acid (CA), 20 % phytic acid (IP6) or 17 % EDTA. Spectra data were processed to quantify dentin demineralization (DM%) and percentage area of amide I curve-fitted components of ß-turns, 310-helix, α-helix, random coils, ß-sheets, and collagen maturation index. Statistical analysis was performed by one-way ANOVA or Kruskal-Wallis for DM% and roughness parameters, and paired t-test/Wilcoxon test for amide I components at significance level set at α = 0.05. RESULTS: All treatments resulted in increased roughness parameters, with the most significant changes occurring primarily with PA, while EDTA exhibited the least changes. DM% was NA>PA>IP6>CA>EDTA in a descending order. Regarding amide I components, NA demonstrated a significant reduction in ß-turns, 310-helices, and α-helices and it increased ß-sheets and random coils. PA resulted in reduction in ß-turns and α-helices while it increased ß-sheets. CA and EDTA did not cause significant changes. The collagen maturation index significantly increased only after IP6 treatment. CONCLUSIONS: The effect on dentin roughness parameters, demineralization, and collagen secondary structures varied based on the type of dentin surface treatment. CLINICAL SIGNIFICANCE: Understanding the impact of acids on the intrinsic properties of dentin is clinically essential for gaining insights into how these effects influence adhesion to dentin, the long-term stability of resin-based restorations, and the success of remineralization therapies.

Impact of acidic beverages on composition and surface characteristics of human teeth: scanning electron microscopic, stereomicroscopic and energy dispersive x-ray analyses.

OBJECTIVES: The objective of this study was to evaluate the effect of acidic beverages on the surface topography and elemental composition of human teeth. METHODS: A total of five highly acidic beverages (Red Bull, Pepsi, Apple Cidra, Tang Mosambi, and Tang Orange) were investigated. The tooth specimens of experimental groups were submerged in each beverage and incubated at 37 °C for 7 days, whereas, the tooth specimens of control groups were placed in distilled water. Afterwards, tooth specimens were analyzed using scanning electron microscopic (SEM), stereomicroscopic, and energy dispersive x-ray (EDX) techniques. RESULTS: All experimental groups revealed a decline in the tooth elements compared to controls, however, such decline was not statistically significant. Nevertheless, comparing the experimental groups, the Red Bull beverage caused a marked reduction in the percentage of both calcium and phosphorus elements compared to the Pepsi, Apple Cidra, Tang Mosambi, and Tang Orange beverages but it was insignificant as well in contrast to its control counterpart. All five acidic beverages demonstrated erosive potential under SEM analysis; however, each group of specimens showed a diverse amount of demineralization. In addition, all experimental groups exhibited significant discoloration of tooth specimens compared to their respective control counterparts. CONCLUSIONS: Within the limitations of study, all five acidic beverages demonstrated erosive potential in the simulated in vitro conditions under SEM analysis; however, each group of specimens exhibited a different extent of demineralization. In addition, the overall effect of all beverages was insignificant under EDX analysis as no substantial difference was revealed between the elemental composition of experimental and control group specimens.

The damage and remineralization strategies of dental hard tissues following radiotherapy.

OBJECTIVES: This study pursued two main purposes. The first aim was to expound on the microscopic factors of radiation-related caries (RRC). Further, it aimed to compare the remineralization effect of different remineralizing agents on demineralized teeth after radiotherapy. METHODS: The enamel and dentin samples of bovine teeth were irradiated with different doses of radiation. After analysis of scanning electron microscope (SEM), X-Ray diffraction (XRD), and energy dispersive spectrometer (EDS), the samples irradiated with 50 Gy radiation were selected and divided into the demineralization group, the double distilled water (DDW) group, the Sodium fluoride (NaF) group, the Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group, the NaF + CPP-ACP group, and the Titanium tetrafluoride (TiF4) group. After demineralization, remineralizing agents treatment, and remineralization, the samples were evaluated using SEM, atomic force microscope (AFM), EDS, and transverse microradiography (TMR). RESULTS: A radiation dose of 30 Gy was sufficient to cause damage to the dentinal tubules, but 70 Gy radiation had little effect on the microstructure of enamel. Additionally, the NaF + CPP-ACP group and the TiF4 group significantly promoted deposit formation, decreased surface roughness, and reduced mineral loss and lesion depth of demineralized enamel and dentin samples after radiation. CONCLUSIONS: Radiation causes more significant damage to dentin compared to enamel. NaF + CPP-ACP and TiF4 had a promising ability to promote remineralization of irradiated dental hard tissues. ADVANCES IN KNOWLEDGE: This in vitro study contributes to determining a safer radiation dose range for teeth and identifying the most effective remineralization approach for RRC.

The Synergistic Effect of High Intensity Focused Ultrasound on In-vitro Remineralization of Tooth Enamel by Calcium Phosphate Ion Clusters.

Background: Remineralization of dental enamel is an important intervention strategy for the treatment of demineralized lesions. Existing approaches have limitations such as failure to adequately reproduce both the ideal structural and mechanical properties of the native tooth. The ability of ultrasound to control and accelerate the crystallization processes has been widely reported. Therefore, a new approach was explored for in-vitro enamel remineralization involving the synergistic effect of high-intensity focused ultrasound (HIFU) coupled with calcium phosphate ion clusters (CPICs). Methods: The demineralized enamel was treated with CPICs, with or without subsequent HIFU exposure for different periods (2.5, 5, and 10 min). The specimens were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy. The surface hardness and crystallographic properties of the treated specimens were evaluated using Vickers microhardness testing and X-ray diffraction (XRD), respectively. Results: SEM revealed distinct, organized, and well-defined prismatic structures, showing clear evidence of remineralization in the combined CPIC/HIFU treatment groups. AFM further revealed a decrease in the surface roughness values with increasing HIFU exposure time up to 5 min, reflecting the obliteration of interprismatic spaces created during demineralization. The characteristic Raman band at 960 cm-1 associated with the inorganic phase of enamel dominated well in the HIFU-treated specimens. Importantly, microhardness testing further demonstrated that new mineral growth also recovered the mechanical properties of the enamel in the HIFU-exposed groups. Critical to our aspirations for developing this into a clinical process, these results were achieved in only 5 min. Conclusion: HIFU exposure can synergise and significantly accelerate in-vitro enamel remineralization process via calcium phosphate ion clusters. Therefore, this synergistic approach has the potential for use in future clinical interventions.

Comparing Shear Bond Strength Between Pink Opaquer and Other Tooth-Colored Restorative Materials on Demineralized Dentin Treated with Silver Diammine Fluoride.

Purpose: The purposes of this study were to evaluate the effect of silver diammine fluoride (SDF) on the shear bond strength (SBS) of pink opaquer (PO) compared to resin-modified glass ionomer (RMGI) and conventional composite (COMP) on demineralized dentin, and also to investigate the mode of failure (MOF). Methods: Sixty extracted third molars were prepared, demineralized for 14 days, and divided into four groups: (1) COMP; (2) SDF+PO; (3) SDF+RMGI; and (4) SDF+COMP (restoration size: two by two mm). SBS, MOF, modified adhesive remnant index (MARI), and remnant adhesive volume (RAV) were evaluated using an Instron® machine, light microscopy, 3D digital scanner ( 3Shape©), and GeoMagic Wrap© software. Results: There was no significant difference in SBS (MPa) among the COMP mean??standard deviation (2.5±1.59), SDF+COMP (2.28±1.05), SDF+PO (3.31±2.63), and SDF+RMGI groups (3.74±2.34). There was no significant difference in MOF and MARI among the four groups (P>0.05). There was no significant difference in RAV (mm3) among the COMP (0.5±0.33), SDF+COMP (0.39±0.44), SDF+PO (0.42±0.38), and SDF+RMGI groups (0.42±0.38; P>0.05). A significant correlation existed between MOF and RAV (R equals 0.721; P<0.001). MOF, MARI, and RAV did not show any correlations with SBS (P>0.05). Conclusions: Silver diammine fluoride does not affect shear bond strength between carious dentinal surface and tooth color restorative materials. The amount of material left on the interface is not related to the amount of shear force needed to break the restoration.

Comparative evaluation of the remineralizing potential of Salvadora persica and probiotic yogurt on incipient enamel lesions: An ex-vivo study.

BACKGROUND: Salvadora persica (miswak) is known to exert antibacterial, antifungal, antioxidant, and anticariogenic effects by elevating the pH of plaque after the consumption of sucrose. OBJECTIVES: The study aimed to compare the effectiveness of S. persica and probiotic yogurt in the remineralization of tooth enamel on artificially produced enamel lesions. MATERIAL AND METHODS: A total of 40 intact human premolars were collected and each tooth was sectioned longitudinally into 2 identical halves in a buccolingual direction. The buccal halves were selected for inclusion in this study, and standardized windows (5 mm × 3 mm) were isolated on the buccal surface of the enamel. The samples were incubated in a demineralizing solution at 37°C for 96 h. Subsequently, they were randomly selected for treatment with one of the experimental remineralizing solutions (S. persica or probiotic yogurt). After treatment, the samples were examined using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and polarized light microscopy at baseline, after demineralization and after remineralization. RESULTS: The remineralizing effect of S. persica was found to be greater than that of probiotic yogurt. With regard to mineral content, S. persica exhibited the highest calcium and phosphorus levels among all groups. No significant differences were observed between the samples treated with S. persica and normal enamel. CONCLUSIONS: Salvadora persica extract has been demonstrated to effectively reduce the demineralization of enamel in experimental conditions. Furthermore, it has the potential to restore the mineral content to its original level.

Comparison of biofilm models for producing artificial active white spot lesions.

OBJECTIVE: This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models. METHODOLOGY: In total, 45 human enamel specimens were sterilized and allocated into three groups based on the biofilm model: Streptococcus sobrinus and Lactobacillus casei (Ss+Lc), Streptococcus sobrinus (Ss), or Streptococcus mutans (Sm). Specimens were incubated in filter-sterilized human saliva to form the acquired pellicle and then subjected to the biofilm challenge consisting of three days of incubation with bacteria (for demineralization) and one day of remineralization, which was performed once for Ss+Lc (four days total), four times for Ss (16 days total), and three times for Sm (12 days total). After WSL creation, the lesion fluorescence, depth, and chemical composition were assessed using Quantitative Light-induced Fluorescence (QLF), Polarized Light Microscopy (PLM), and Raman Spectroscopy, respectively. Statistical analysis consisted of two-way ANOVA followed by Tukey's post hoc test (α=0.05). WSL created using the Ss+Lc protocol presented statistically significant higher fluorescence loss (ΔF) and integrated fluorescence (ΔQ) in comparison to the other two protocols (p<0.001). RESULTS: In addition, Ss+Lc resulted in significantly deeper WSL (137.5 µm), followed by Ss (84.1 µm) and Sm (54.9 µm) (p<0.001). While high mineral content was observed in sound enamel surrounding the WSL, lesions created with the Ss+Lc protocol showed the highest demineralization level and changes in the mineral content among the three protocols. CONCLUSION: The biofilm model using S. sobrinus and L. casei for four days was the most appropriate and simplified protocol for developing artificial active WSL with lower fluorescence, higher demineralization, and greater depth.

In vitro effect of TiF4/NaF solution on the development of radiation-induced dentin caries.

OBJECTIVE: To evaluate the protective effect of an experimental solution containing TiF4/NaF on the development of radiation-induced dentin caries lesions. METHODOLOGY: bovine root samples were irradiated (70Gy) and distributed as following (n=12/group): Commercial Saliva (BioXtra), NaF (500 ppm F-), TiF4 (500 ppm F), TiF4/NaF (TiF4: 300 ppm F-, NaF: 190 ppm F-), and Phosphate buffer solution (PBS, negative control). Biofilm was produced using biofilm from irradiated patients and McBain saliva (0.2% of sucrose, at 37oC and 5% CO2) for five days. The treatments were applied 1x/day. Colony-forming units (CFU) were counted and demineralization was quantified by transversal microradiography. The ANOVA/Tukey test was applied for all parameters. RESULTS: All treatments reduced CFU for total microorganisms. TiF4 reduced Lactobacillus sp. (7.04±0.26 log10 CFU/mL) and mutans streptococci (7.18±0.28) CFU the most, when compared to PBS (7.58±0.21 and 7.75±0.17) and followed by NaF (7.12±0.31 and 7.34±0.22) and TiF4/NaF (7.16±0.35 and 7.29± 0.29). TiF4 and Commercial saliva showed the lowest integrated mineral loss (ΔZ-vol%.mm) (1977±150 and 2062±243, respectively) when compared to PBS (4540±335), followed by NaF (2403±235) and TiF4/NaF (2340±200). Commercial saliva was the only to significantly reduce mineral loss (LD-µm) (111±25) compared to PBS (153±24).Mean mineral loss (R-vol%) decreased by 35.2% for TiF4 (18.2±3.3) when compared to PBS (28.1±2.9) Conclusion: TiF4/NaF has a comparable anti-cariogenic effect to TiF4 and Commercial saliva under the model in this study.

Protecting primary teeth from dental erosion through bioactive glass.

OBJECTIVES: The present study aimed to evaluate the effectiveness of bioactive glass (BAG) in preventing dental erosion in primary teeth. METHODS: Enamel and dentin specimens (2 × 2 × 2 mm) were obtained from extracted primary teeth, which were randomly divided into the following groups based on the pretreatments (n = 12): DW (deionized water), NaF (2 % sodium fluoride), 2BAG (2 % BAG), 4BAG (4 % BAG), 6BAG (6 % BAG), and 8BAG (8 % BAG). The specimens were immersed in the respective solutions for 2 min and subjected to in vitro erosive challenges (4 × 5 min/d) for 5 d. The erosive enamel loss (EEL), erosive dentin loss (EDL), and the thickness of the demineralized organic matrix (DOM) were measured using a contact profilometer. The surface microhardness (SMH) was measured, and the percentage of SMH loss (%SMHL) was calculated. The surface morphology and mineral composition were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. RESULTS: After the erosive challenges, the EEL, EDL, and%SMHL of the 2BAG, 4BAG, 6BAG, and 8BAG groups significantly reduced, with the greatest reduction was observed in the 6BAG (EEL: 6.5 ± 0.2 µm;%SMHL in enamel: 12.8 ± 2.6; EDL: 7.9 ± 0.3 µm; %SMHL in dentin: 22.1 ± 2.7) and 8BAG groups (EEL: 6.4 ± 0.4 µm;%SMHL in enamel: 11.0 ± 1.9; EDL: 7.8 ± 0.5 µm; %SMHL in dentin: 22.0 ± 2.5) (P < 0.05). With increasing BAG concentrations, the number of surface deposits containing Ca, P, and Si increased. CONCLUSIONS: 6BAG was the most effective for preventing dental erosion in primary teeth and showed a particularly strong potential for dentin erosion prevention. CLINICAL SIGNIFICANCE: Bioactive glass, especially at a 6 % concentration, has proven effective in reducing erosive tooth wear and surface microhardness loss while also protecting demineralized organic matrix in primary dentin.

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.

Acid challenge exacerbates activation of matrix metalloproteinases in permanent teeth undergoing radiotherapy.

The aim of this study was to investigate the effect of acid challenge on the activation of matrix metalloproteinases (MMPs) in the Dentinoenamel junction of primary and permanent teeth submitted to radiotherapy. For this purpose, a total of 178 dental fragments obtained from molars were used, and randomly divided into 2 groups (primary and permanent teeth) / 4 experimental subgroups (irradiated and non-irradiated, demineralized and non-demineralized). The fragments were exposed to radiation, with a dose fraction of 2 Gy, for 5 consecutive days, until a total dose of 60 Gy was reached, with a total of 30 cycles, for 6 weeks. To determine the activity of MMPs on the dentinoenamel junction (DEJ), in situ zymography assays on 0.6mm dental fragments were performed. To assess whether MMP activity would be impacted by an acidic environment, the fragments were placed in a demineralizing solution (pH of 4.8). The finding was that irradiation activated MMPs in DEJ and these effects were more evident in permanent when compared with primary teeth. When the effect of an acid challenge on MMPs activity was investigated, demineralization was observed not to increase MMPs activity in non-irradiated teeth, but it did increase MMPs activity in irradiated teeth. In conclusion, an acid challenge was found to exacerbate activation of MMPs in DEJ of permanent teeth submitted to irradiation, but not in primary teeth.

Inhibition of incipient caries lesion progression by different fluoridated varnishes.

The aim of this in vitro study was to evaluate the potential of different fluoridated varnishes to inhibit the progression of incipient caries lesions after cariogenic challenge. Seventy-five enamel specimens of bovine teeth were prepared and selected based on the initial surface microhardness (SMH). The specimens were first subjected to artificial demineralization (in buffer solution) after which SMH was re-analyzed (SM1). They were then randomly assigned to five experimental groups: 1- CONTROL (pH cycling), 2 - MI VAR (MI Varnish with RECALDENTTM - CPP-ACP), 3 - PROFL (Profluorid®), 4 - CLIN (ClinproTM White Varnish with TCP), and 5 - DUR (Duraphat®) (n=15). The varnishes were applied in a thin layer and the specimens were then subjected to pH cycling for eight days. The SMH and cross-sectional microhardness (CSMH) were then analyzed (SM2). The fluoride and calcium ion concentrations in the solution were analyzed by the indirect method and atomic absorption spectrophotometry, respectively. Data were statistically analyzed by Student's t-test, ANOVA/Tukey-Kramer, or Kruskall-Wallis/Dunn tests for individual comparisons (p˂0.05). All varnishes led to significantly higher surface and subsurface remineralization compared with the control group but did not differ from each other. The varnishes with the highest fluoride release were: PROFL and CLIN, followed by MI VAR and DUR. The varnishes with significantly higher release of calcium were: DUR, CLIN, and PROFL. In conclusion, all commercial fluoridated varnishes tested have good potential to inhibit the progression of demineralization, regardless of the ion release mechanisms.

Enamel Matrix Derivative, 58S5 Bioactive Glass, and Fluoride Varnish for Enamel Remineralization: A Multi-analysis Approach.

PURPOSE: This study aimed to evaluate the enamel remineralization efficacy of enamel matrix derivative (EMD), experimental bioactive glass (BAG), and fluoride varnish in vitro. METHODS AND MATERIALS: Artificial initial caries lesions were developed on fifty human enamel specimens using demineralization solution (pH 4.5, 37°C, 96 hours). Specimens were randomly assigned to five groups (n=10): I-5% NaF varnish (Enamelast), II-experimental 58S5 BAG+37% phosphoric acid (PA), III-EMD (Emdogain) + Ethylenediaminetetraacetic Acid (EDTA), IV-EMD+37% PA, V-Control (untreated). All remineralization agents were applied with pH cycling for seven days. The specimens were scanned by spectral domain optical coherence tomography (SD-OCT) at baseline, at demineralization, and after pH cycling. Lesion depths were measured using image analysis software (ImageJ). Lesions were evaluated using surface microhardness (SMH) and two fluorescence methods (FluoreCam and DIAGNOdent Pen [DDPen]). The data were statistically analyzed by Kruskal Wallis, Friedman, and Wilcoxon tests (α=0.05). RESULTS: According to SD-OCT results, fluoride varnish was found to be the most effective agent in reducing lesion depth (p=0.005). All agents increased the SMH values after pH cycling. No significant difference was found among fluoride varnish, BAG, and EMD+PA groups. These SMH values were significantly higher than EMD+EDTA and control groups (p<0.001). All groups showed lower DDPen scores compared with the control group (p<0.001), however, no significant difference was found among the remineralization agents. In FluoreCam assessment, size and intensity values of all treated groups showed improvement. However, there was no significant difference between the treatment groups in terms of FluoreCam size measurements (p=0.186). CONCLUSION: 58S5 BAG and EMD+PA have remineralization capacity as effective as fluoride varnish. EMD+PA showed better SMH and lesion intensity results than EMD+EDTA.

Enhanced anti-biofilm and anti-caries potential of arginine combined with calcium glycerophosphate and fluoride.

OBJECTIVE: The aim of this work was to evaluate the antibiofilm and anticaries properties of the association of arginine (Arg) with calcium glycerophosphate (CaGP) and fluoride (F). METHODS: An active attachment, polymicrobial biofilm model obtained from saliva and bovine teeth discs were used. After the initial biofilm growth period, the enamel discs were transferred to culture medium. The treatment solutions were added to the culture media to achieve the desired final concentration. The following groups were used: negative control (Control); F (110 ppm F); CaGP (0.05 %); Arg (0.8 %) and their associations (F + CaGP; Arg + F; Arg + CaGP; Arg +F + CaGP). The following analyses were carried out: bacterial viability (total bacteria, aciduric bacteria and mutans streptococci), pH assessment of the spent culture medium, dry weight quantification, evaluation of surface hardness loss (%SH) and subsurface mineral content. Normality and homoscedasticity were tested (Shapiro-Wilk and Levene's test) and the following tests were applied: two-way ANOVA (acidogenicity), Kruskall-Wallis (microbial viability) and one way ANOVA (dry weight, %SH, mineral content). RESULTS: The association Arg + F + CaGP resulted in the lowest surface hardness loss in tooth enamel (-10.9 ± 2.3 %; p < 0.05). Arg +F + CaGP exhibited highest values of subsurface mineral content (10.1 ± 2.9 gHAP/cm3) in comparison to Control and F (p < 0.05). In comparison to Control and F, Arg +F + CaGP promoted the highest reduction in aciduric bacteria and mutans streptococci (5.7 ± 0.4; 4.4 ± 0.5 logCFU/mL, p < 0.05). CONCLUSIONS: The Arg-F-Ca association demonstrated to be the most effective combination in protecting the loss of surface hardness and subsurface mineral content, in addition to controlling important virulence factors of the cariogenic biofilm. CLINICAL SIGNIFICANCE: Our findings provide evidence that the Arg-F-Ca association showed an additive effect, particularly concerning protection against enamel demineralization. The combination of these compounds may be a strategy for patients at high risk of caries.

Enamel remineralisation prospect of Moringa Oleifera hydrogel, eggshell hydrogel versus sodium fluoride varnish on artificially demineralised primary teeth: in vitro study.

PURPOSE: The purpose of the present in vitro study is to investigate and compare the remineralising potential of Moringa Oleifera extract, eggshell, and sodium fluoride varnish on microhardness of artificially demineralised enamel of primary teeth with biomimetic minimally invasive approach following the world paradigm shift towards natural products in paediatric dentistry. MATERIAL AND METHODS: Sample size included 44 primary molars. The mineral content and surface microhardness of all specimens were initially assessed using energy dispersive x-ray examination (EDX) and Vickers microhardness. The specimens were artificially demineralised for 96 h at a temperature of 37°C and then reassessed directly after demineralisation. The demineralised enamel specimens were randomly divided into four groups according to the remineralisation regimen utilised. Group 1: Artificial saliva (control); Group 2: Sodium fluoride varnish; Group 3: Eggshell hydrogel; and Group 4: Moringa Oleifera hydrogel. The specimens were stored for 8 days and then subsequently evaluated using EDX and microhardness assessment by Vickers microhardness test and scanning electron microscope (SEM).  Results: Regarding the microhardness test, there was a significant difference between the Moringa Oleifera group and Eggshell group compared to fluoride varnish (p < 0.05). Regarding EDX analysis, there was a statistically significant difference (p < 0.05) between Moringa Oleifera group and Eggshell group compared to fluoride varnish as the highest values were for Moringa Oleifera and Eggshell. On the other hand, there was no statistically significant difference (p > 0.05) between Moringa Oleifera and Eggshell in both the measurements. CONCLUSION: Moringa Oleifera and Eggshell might be considered as a biomimetic natural material capable of guiding enamel tissue remineralisation in early carious lesion of primary teeth. CLINICAL RELEVANCE: This research demonstrated the capability for early enamel caries to be remineralised using novel materials with a naturally counterpart implicated in biomineralisation as proved to be more effective than traditionally used fluoride varnish in primary teeth.

Influence of different pre-treatments on the resin infiltration depth into enamel of teeth affected by molar-incisor hypomineralization (MIH).

OBJECTIVES: This in vitro pilot study aimed to evaluate whether different pre-treatments (demineralization, deproteinization, (chemo-)mechanical reduction of the surface layer) influence the penetration depth of a resin infiltrant into MIH-affected enamel compared to initial carious lesions. METHODS: Thirty extracted human permanent molars with non-cavitated initial carious lesions (n = 5) or MIH (n = 25) were chosen and randomly assigned to six experimental groups: IC: initial caries; M: MIH; MN: MIH, 5.25% sodium hypochlorite; MM: MIH, microabrasion; MA: MIH, air abrasion; MAN: MIH, air abrasion and 5.25% sodium hypochlorite. A modified indirect dual fluorescence staining method was adopted to assess the penetration depth (PD) of the resin infiltrant and the lesion depth (LD) by confocal laser scanning microscopy (CLSM). Exemplarily, scanning electron microscopic (SEM) images were captured. The relationship between group assignment and penetration/lesion depth was estimated using a linear mixed model incorporating the tooth as random effect (two observations/tooth). The significance level was set at p < 0.05. RESULTS: For MIH-affected molars, the mean PD (in µm; median, [minimum-maximum]) were M (178.2 [32.5-748.9]), MN (275.6 [105.3-1131.0]), MM (48.7 [0.0-334.4]), MA (287.7 [239.4-491.7]), and MAN (245.4 [76.1-313.5]). Despite the observed differences in PD between the groups, these could not be statistically verified (Bonferroni, p = 0.322). The percentage penetration was significantly higher for IC than for MIH groups (Bonferroni, p < 0.05). SIGNIFICANCE: Compared to IC, resin infiltration into MIH-affected enamel ist more variable. Different pre-treatments influence the resin penetration into developmentally hypomineralized enamel to a fluctuating level.