Search Results (114)

Dental composites are widely used in restorative dentistry; however, their long-term clinical performance is strongly influenced by mechanical and tribological behavior under oral conditions. Understanding the relationship between material structure, surface characteristics, and functional properties is therefore essential. This preliminary methodological study evaluated the mechanical, tribological, and wetting properties of three light-cured dental composites—Enamel Plus HRi, Amaris, and Estelite Asteria—commonly used in clinical practice. The materials were characterized in terms of surface morphology, hardness, Young’s modulus, coefficient of friction, and wear resistance under controlled laboratory conditions. Instrumental indentation and tribological tests were performed, and results were expressed as mean values with standard deviations calculated from multiple measurements. The results demonstrated that filler composition and surface topography affected material performance. Estelite Asteria exhibited the highest hardness (HIT > 300 MPa), while Enamel Plus HRi showed the highest Young’s modulus (EIT ≈ 14.5 GPa). Materials with more complex surface morphology retained lubricating artificial saliva more effectively, resulting in lower friction coefficients (minimum µ = 0.85), although this did not reduce wear. The highest wear was observed for Estelite Asteria, with a wear scar approximately 62% greater than that of Enamel Plus HRi. These preliminary findings provide a methodological basis for further investigations under more clinically relevant conditions. Full article

This study aimed to develop bioactive toothpaste and compare its remineralization potential on initial enamel lesions with toothpaste containing other active agents. Sixty extracted human maxillary incisors were randomly assigned to six groups: Group EXP (Experimental toothpaste), Group SRP (Sensodyne Repair & Protect), Group ZAC (Zubio Active Carbon Whitening), Group GTM (GC Tooth Mousse), Group CSP (Colgate Sensitive Pro-Relief), and Group ASS (Artificial saliva, control). Artificial caries were induced by immersion in a demineralization solution for three days. Specimens then underwent a seven-day pH-cycling protocol, during which toothpaste was applied twice daily for two minutes. Analyses were performed at baseline, post-demineralization, and post-remineralization using ATR-FTIR, SEM-EDS, and Vickers micro-hardness testing. Statistical analyses were conducted using SPSS (version 27.0, IBM Corp., Chicago, IL, USA). All treatment groups, except the control, showed significant microhardness recovery after remineralization, with the highest increase in group CSP followed by group EXP (p < 0.05). Granular surface deposits were observed, most pronounced in groups SRP and GTM (p < 0.05). Calcium and phosphorus contents increased in all groups (p < 0.05), with calcium highest in group GTM and phosphorus in group EXP. The mineral-to-matrix ratio increased in all groups, and a statistically significant difference was identified between the experimental toothpaste (EXP) and the other toothpaste formulations (p < 0.05). It is hypothesized that pomegranate seed essential oil may exhibit a remineralizing effect due to its content of anthocyanidins, anthocyanins, and various polyphenolic compounds. Therefore, the development of a toothpaste with enhanced remineralization potential was targeted by incorporating pomegranate seed essential oil into the experimental formulation in addition to bioactive agents such as bioactive glass, hydroxyapatite, and casein phosphopeptide. Full article

The purpose of this in vitro study was to evaluate the remineralization effect of five preventive treatments on bovine enamel after artificial caries challenge. Sixty sound bovine incisors were randomly distributed into six experimental groups (n = 10). Each group received the following daily preventive treatments for two weeks during pH cycling to assess remineralization efficacy: Group 1—no treatment (control), Group 2—CPP-ACPF treatment, Group 3—fluoride-containing bioactive glass treatment (BioMin™F), Group 4—SnF₂ treatment, Group 5—toothpaste containing fluoride and hydroxyapatite (HA), and Group 6—toothpaste containing HA. Surface hardness changes were evaluated using a nanoindentation tester. Scanning electron microscopy was used to observe changes in surface morphology, and the mineral composition of enamel in each group was analyzed using energy-dispersive X-ray spectroscopy (EDS). Groups 2, 3 and 6 exhibited the highest surface hardness values after pH cycling, with no statistically significant differences among them (p > 0.05), whereas groups 4 and 5 presented significantly lower values (p < 0.05). Although all treatments demonstrated significant remineralization potential—resulting in an 18.7–35.2% increase in surface hardness—none of them fully restored the hardness loss caused by demineralization. SEM observations revealed precipitations mainly in groups 2–4 after the treatments. EDS showed a similar elemental composition on enamel across the groups with no differences compared to the control. Additionally, line scans of the Ca and P content from the surface to the deeper layers resulted higher values in the tested groups compared to the control corresponding to the surface hardness values. The tested remineralizing treatments may be useful to limit the demineralizing effect during caries formation. Full article

Background/Objectives: Dental caries, one of the most common oral diseases worldwide, represents a major public health concern. Contemporary dentistry has established several non-invasive approaches and resin infiltration, as a micro-invasive path, in the treatment of white spot lesions (WSLs). This study aimed to evaluate the effect of different WSL treatments on enamel surface microhardness. Materials and Methods: Seventy-five intact human premolars extracted upon orthodontic indication and the demineralizing solution composed of acetic acid, monopotassium phosphate and calcium chloride with pH = 4.4 and exposure time 96 h were used. The samples were randomly divided into five groups (n = 15): I—intact enamel (control group); II—artificial white spot lesion; III—artificial WSL treated with fluoride varnish; IV—artificial WSL treated with casein phosphopeptide—amorphous calcium phosphate (CPP-ACP) paste; V—resin-infiltrated artificial WSL. The surface microhardness was determined using the Oliver–Pharr method and a spherical indenter (Shimadzu Indenter, Kyoto, Japan). One-way analysis of variance (ANOVA) followed by a Post Hoc test (Bonferroni) was used with a level of significance set at p < 0.05. Results: Resin-infiltrated white spot lesions showed comparable microhardness mean value as the control group: 68.23 (±21.45) and 63.57 (±18.89), respectively (p > 0.05). Also, resin infiltration increased enamel microhardness compared to WSL values, with a statistically significant difference (p < 0.05). Fluoride varnish and CPP-ACP treatment resulted in equivalent values (50.84 ± 14.35 and 50.99 ± 15.31, respectively). Conclusions: Different WSL treatments (fluoride varnish, CPP-ACP and resin infiltration) produced comparable enamel microhardness values. Among the tested agents, resin infiltration resulted in higher microhardness values, while fluoride varnish and CPP-ACP demonstrated equivalent outcomes. Full article

Background and Objectives: The rapid increase of whitening products use raises questions about enamel safety. We compared three high-concentration protocols—Opalescence Quick (45% carbamide peroxide ≈ 15% H₂O₂), Opalescence Boost (40% H₂O₂), and BlancOne Ultra (35% H₂O₂ + LED)—under controlled conditions to balance color change (ΔE) with enamel integrity (microhardness, FTIR). We also constructed a qualitative cytotoxicity risk profile from published data; no biological assays were performed in this study. Methods: Seventy-two matched half-crowns were randomized to Control or one of the three protocols. Outcomes were a change in Vickers microhardness, spectrophotometric color difference, and FTIR carbonate-to-phosphate ratio after 24 h in artificial saliva. We also compiled a qualitative cytotoxicity risk profile from published evidence; no biological assays were performed. One-way ANOVA with Tukey HSD on Δ-scores, Shapiro–Wilk and Levene’s tests for assumptions, Welch’s t-tests for tooth-class comparisons, and Pearson correlation between ΔE and ΔMH. Results: All active protocols produced clearly visible whitening (mean ΔE 5.7–6.3). Hydrogen-peroxide gels showed greater hardness loss and carbonate depletion than the carbamide-peroxide gel under similar contact time. The association between greater shade change and hardness loss was moderate and not predictive for individuals. Conclusions: Under harmonized conditions, all systems whitened effectively. Pursuing changes beyond ~6 units offered little extra benefit while increasing enamel impact. Carbamide-based Opalescence Quick achieved comparable aesthetics with lower acute enamel effects. Clinicians should individualize exposure time and pair in-office whitening with short-term remineralising care. Cytotoxicity comments are qualitative and literature-based only. Full article

Background/Objectives: Dental enamel constitutes the first barrier of defense against external factors that constantly generate wear and damage. This study aimed to evaluate in vitro the abrasion and roughness of dental enamel using toothpaste with and without activated charcoal and to analyze this under scanning electron microscopy (SEM). Materials and methods: The research design was experimental; 10 enamel blocks were randomly assigned to each group to perform brushing cycles with soft- and medium-filament brushes with two types of toothpaste, one with activated charcoal and one without activated charcoal. A pumice stone with etching acid was used as the positive control and artificial saliva served as the negative control; both were analyzed separately. Roughness was evaluated using a roughness meter and abrasion with an analytical balance. The surface of the enamel blocks of each group was randomly analyzed under an SEM. Statistical analysis was performed using the Shapiro–Wilk test and the homogeneity of variances with Bartlett’s test. Student’s t-test (two-tailed) was applied to compare tooth enamel roughness and abrasion. Results: Both enamel roughness (p = 0.0016) and abrasion (p = 0.0001) were significantly higher in the groups using activated charcoal paste and medium-filament brushes. SEM observation revealed greater alteration on the surface of the enamel subjected to brushing cycles with activated charcoal paste and a medium-filament brush. Conclusions: The in vitro study showed that the use of toothpaste with activated charcoal increases the roughness and abrasion of tooth enamel, especially when the medium-filament brush is used. Full article

Objective: This in vitro study quantitatively compared the time-dependent remineralization potential of three professional agents on artificially induced enamel lesions using Scanning Electron Microscopy (SEM) and energy-dispersive X-ray analysis (EDX). Methods: Sixty extracted sound molars were randomly assigned to three groups (number = 20): G_CPP-ACP, treated with casein phosphopeptide–amorphous calcium phosphate; G_Zn-HA, treated with zinc-hydroxyapatite; and G_F-ACP, treated with fluoridated amorphous calcium phosphate. The crown of each tooth was divided into three areas: one represented the control (CTRL, sound enamel), one underwent demineralization (DEMIN, demineralized enamel), and the third one was at first demineralized and then treated with a remineralizing agent, allowing intra-sample comparison. Artificial lesions were produced by immersion in 0.1 M lactic acid (72 h). Groups were subdivided according to remineralization time (7, 14, 21, and 28 days). Samples underwent daily treatment under a pH-cycling regimen. Surface morphology and Ca/P ratios were evaluated by SEM-EDX, and data were statistically analyzed (p < 0.05). Results: All agents promoted a progressive increase in Ca/P ratio over time, confirming a time-dependent remineralization effect. At day 7, G_Zn-HA showed higher Ca/P values, but from day 14 onward, G_F-ACP produced significantly greater mineral gain than the other groups (p < 0.05). By day 21, G_F-ACP reached Ca/P values approaching CTRL, while G_CPP-ACP and G_Zn-HA remained at lower levels, reaching a plateau respectively at 21 and 14 days. SEM observations supported these findings: G_CPP-ACP and G_Zn-HA showed partial surface recovery, whereas G_F-ACP exhibited a compact, homogeneous enamel-like structure at 28 days. Conclusions: All tested agents demonstrated time-dependent remineralization, enhanced with prolonged exposure, suggesting that the time of application represents a key factor for clinical success. Full article

Background: Substituted hydroxyapatites (HAps) are widely used in oral-care formulations for enamel repair; however, head-to-head comparisons among commercial grades remain limited. Objective: To compare four commercial HAps: A (Kal-HAp), B (FL-HAp), C (FL-HAp-SC), and D (microRepair^®, a biomimetic Zn–carbonate-substituted HAp) and to evaluate their ability to form an enamel-like coating in vitro. Methods: We characterized the powders by X-ray diffraction (crystalline phase, Landi crystallinity index), FTIR-ATR (phosphate/carbonate bands), SEM/EDS (morphology, surface Ca/P), and DLS (particles size, ζ-potential). In vitro, human enamel sections were treated with 5% slurries in artificial saliva; surface coverage was quantified by image analysis on SEM. Results: All commercial materials analyzed in this work were composed of HAp. Differences were observed between HApin terms of crystallinity-range [2 Theta 8.0–60.0°], carbonate substitution (ATR [carbonate group evaluated −870 cm⁻¹]), and particle size (DLS [in a range 0.1–10,000 nm], Z-mean [mV]). On enamel, all samples form a hydroxyapatite layer; coverage differed between groups ([A] 28.83 ± 7.35% vs. [B] 31.11 ± 3.12% vs. [C] 57.20 ± 33.12% vs. [D] 99.90 ± 0.12%), with the biomimetic Zn–carbonate-substituted HAp showing the highest coverage, and the post-treatment Ca/P ratio approached values similar to those of dental enamel. Conclusions: Complementary physic-chemical signatures (crystallinity, carbonate substitution, and morphology) relate to enamel-surface coverage in vitro, providing evidence base for selecting HAp grades for enamel-repair formulations, which is a practical implication for product design. Full article

Background/Objectives: Within the minimum intervention oral care (MIOC) delivery framework, the management and improvement in the esthetics of enamel white spot lesions (WSLs) are recommended. This study evaluated the chemomechanical and morphological characteristics of WSLs treated by four therapeutic approaches using Raman spectroscopy, Knoop microhardness (KH), and field-emission scanning electron microscopy (FESEM). Methods: Sixty human enamel slabs were divided into six groups: non-treated (baseline), WSLs (8% methylcellulose gel with 0.1 M lactic acid, pH 4.6 at 37 °C for 21 days), and four treated groups, namely bovine collagen supplement (Nutravita Ltd., Maidenhead, Berkshire, UK), Regenerate system (NR-5, Bordeaux, France), Sylc air abrasion (AquaCare, Denfotex Research Ltd., Edinburgh, UK), and CO₂ laser (JHC1180, Jinan, China). Treatment lasted 28 days, followed by four weeks of storage in artificial saliva (pH = 7.0, 37 °C). Bovine collagen was analyzed using Fourier-Transform Infrared Spectroscopy (FTIR). The mineral content, including the phosphate peak intensities (PO₄ ν₁, ν₂, and ν₄) and carbonate (CO₃), as well as tissue microhardness, were assessed at varying depths (50–200 µm), followed by morphological assessment. Results: The FTIR spectrum of bovine collagen powder confirms the presence of amide I, II, and III. It produced a statistically significant enhancement in the phosphate content and KHN compared to WSLs of up to 150 µm in depth (p < 0.001). Regenerate-treated surfaces recorded the highest phosphate content among groups at the superficial layer. All treatment interventions enhanced the morphology of lesions by covering the exposed prisms and inter-prismatic structure. Conclusions: Bovine collagen supplements can enhance the phosphate content and surface properties of enamel white spot lesions (WSLs) and could be considered a potential modality comparable to other micro-invasive approaches for addressing incipient enamel lesions. This could significantly impact dental care management. Full article

Although approximately half of global lithium consumption is used in the rechargeable battery industry, lithium is also in demand for other specialized applications, such as high-temperature lubricants, ceramics, glass, and pharmaceuticals. The growing need for efficient lithium recovery and recycling underscores the importance of fast and accurate analytical tools for determining lithium concentrations in non-compliant and waste materials generated by industrial processes. In this paper, we present a machine learning-based procedure utilizing Laser-Induced Breakdown Spectroscopy (LIBS) to accurately quantify lithium concentrations in lithium-rich non-compliant materials derived from the industrial production of enamels used for coating metallic surfaces. This procedure addresses challenges such as strong self-absorption and matrix effects, which limit the effectiveness of conventional univariate calibration methods. By employing a multivariate approach, we developed a single model capable of quantifying lithium content across a wide concentration range. A comparison of the LIBS results with those obtained using conventional laboratory analysis (Inductively Coupled Plasma–Optical Emission Spectrometry, ICP-OES) confirms that LIBS can deliver the speed, precision, and reliability required for potential routine applications in the lithium recovery and recycling industry. Full article

Background: Dental caries is a prevalent dental problem affecting primary and permanent teeth. Early demineralization of enamel lesions can be reversed through remineralization. Many studies have focused on caries prevention and disease progression arrest using silver diamine fluoride (SDF). No in vitro studies have compared the remineralization effects of different 38% SDF solutions on artificially demineralized enamel lesions. This study aimed to compare the remineralization potential of three commercial 38% silver diamine fluoride formulations on artificial enamel lesions in primary teeth using a pH cycling model. The hypothesis was as follows: different commercial SDF formulations would exhibit varying remineralization effects, as measured by surface microhardness, due to potential differences in their compositions. Materials and Methods: In this study, 75 primary molars were randomized into five groups (N = 15): I: baseline, II: SDF Riva Star Aqua^® 38%, III: Riva Star^® 38%, IV: SDF Advantage Arrest^® 38%, and V: control. Artificial caries were created by submerging teeth in 10 mL of demineralization solution (pH 4.5) for three days in a light-resistant container, ensuring distinct visual changes in the enamel as per the International Caries Detection and Assessment System (ICDAS level 2). After pH cycling, all samples underwent a standardized Vickers microhardness test (VMHT) with a 50 g load for 15 s. Data were analyzed using one-way ANOVA and Tukey’s post hoc test, with a significance level set at p ≤ 0.05. Results: The one-way ANOVA test indicated a significant difference in microhardness among the groups (SDF Riva Star Aqua, SDF Riva Star, and SDF Advantage Arrest), with an F-value of 167.73 and p < 0.001. The post hoc Scheffé test showed that SDF Riva Star Aqua and SDF Riva Star were not significantly different (p = 0.388). However, SDF Advantage Arrest had a significantly higher mean microhardness compared to both groups (p < 0.001). Overall, these results show that SDF Advantage Arrest leads to greater microhardness than SDF Riva Star Aqua or SDF Riva Star. Conclusions: SDF Advantage Arrest showed superior performance among the SDF-treated groups, significantly increasing microhardness compared to SDF Riva Star Aqua and SDF Riva Star. This suggests that SDF Advantage Arrest offers enhanced remineralization and structural strengthening, making it the most effective option for managing demineralized primary teeth. Future research should investigate the long-term performance and mechanisms of these treatments to optimize clinical protocols for preserving primary tooth integrity. Full article

Background/Objectives: It is unclear whether enamel margins should be beveled in direct resin-based restorations. This study evaluated the influence of enamel beveling on the marginal quality of mesio-occluso-distal (mod) cavity boxes. Methods: Seventy-five caries-free human molars were divided into three groups. Mod-cavities with the entire margin in the enamel were prepared ± proximal bevel (n = 25). Twenty-five beveled mod-cavities served as control. Each group was restored with five material combinations: micro hybrid composite with etch-and-rinse (ER) or self-etch (SE) adhesive, compomer with ER or SE, and low-shrinkage composite with ER. A complex filling technique was used in the control. After artificial aging (1000 thermal cycles, 5/55 °C), the percentage of continuous margins (PCM) of the proximal boxes was analyzed by scanning electron microscopy using epoxy replicas (×300), and the marginal seal was assessed by light microscopy after dye penetration (×64). Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney U tests (p < 0.05). Results: No significant differences in PCM were found between the restorative systems (p = 0.075). The composite with low shrinkage showed the highest mean PCM of all groups (78.1%). Significant differences in marginal seal were observed between the restoratives after bevel preparation (p < 0.05). Beveling significantly improved the PCM only for the hybrid composite (p < 0.05), whereby the effect on marginal seal was less pronounced. Conclusions: Clinicians should be aware that beveling mod-cavities does not necessarily improve the marginal quality of direct resin-based restorations bonded with well-established adhesives and may be more beneficial for traditional hybrid composites. Full article

Background: Dental enamel demineralization is a critical early event in the development of dental caries. To address this, bioactive compounds have been explored for their potential to mitigate enamel demineralization and promote remineralization. Previous studies have demonstrated that varnishes containing natural compounds such as trans,trans-farnesol (tt-farnesol), quercetin, and theobromine exhibit antimicrobial activity, suggesting potential in caries prevention. Thus, this laboratory study assessed the ability of these varnishes to prevent enamel caries lesion formation by using a chemical model to determine whether these natural compounds interfered with de- and remineralization processes in the absence of a cariogenic biofilm. Methods: Sixty bovine enamel specimens, each measuring 5 × 5 × 2 mm, were selected according to their initial surface hardness (SHI), measured by Knoop hardness in three indentations spaced 100 µm apart. The specimens were allocated to the following groups in a random manner (n = 15): an experimental varnish without compounds (NC/negative control); experimental varnishes containing the combination of tt-farnesol, quercetin, and theobromine at concentrations of 1.5% (E1) and 4.5% (E2); and Duraphat™ (NaF 5%/gold standard—D). After applying the varnishes, they remained in artificial saliva for 6 h. The specimens were then subjected to 8 pH cycles, including 4 h of demineralization and 20 h of remineralization. Surface hardness was measured again to calculate the percentage of surface hardness loss (%SHL), and three specimens from each group were examined using scanning electron microscopy. Comparisons were made using ANOVA (p < 0.05). Results: The D group (5% NaF) demonstrated a significantly lower %SHL (75.5% ± 7.88) than the other groups (p < 0.05). E1 (86.3% ± 5.33) was statistically similar to NC (81.8% ± 4) but lower than E2. E2 showed the highest %SHL (91.6% ± 3.64) compared to the other groups. Surface demineralization was evident in all specimens post pH cycling. Conclusion: The bioactive varnishes containing tt-farnesol, quercetin, and theobromine at concentrations of 1.5% and 4.5% did not exhibit a protective effect against mineral loss in dental enamel in the absence of a cariogenic biofilm. Full article

Amorphous calcium phosphate (ACP) is a well-established bioceramic material known to promote the remineralization of dental hard tissues. White spot lesions (WSLs) represent the initial stage of enamel demineralization and are frequently observed in patients with fixed orthodontic appliances or inadequate oral hygiene. Although recommendations for remineralizing agents include both the prevention of lesion progression and the stimulation of tissue remineralization, the clinical efficacy of ACP-based materials remains under debate. This systematic review, registered in the PROSPERO database (CRD42024540595), aims to evaluate the clinical efficacy of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-based products in the remineralization of WSLs and to compare these outcomes with those achieved using non-bioceramic approaches. Inclusion criteria comprised randomized clinical trials, prospective cohort studies, and pilot studies conducted on human subjects with WSLs affecting permanent teeth. Studies involving artificial WSLs or non-cariogenic enamel lesions were excluded. The quality of the included studies was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool. Fourteen articles met the inclusion criteria and were analyzed. The main findings indicate that CPP-ACP is clinically effective in promoting the remineralization of WSLs, although the results were inconsistent across studies. Comparisons with placebo and resin infiltration treatments revealed greater efficacy for CPP-ACP. The combination of CPP-ACP with fluoride appeared to further enhance the remineralizing effect on WSLs. Additional standardized clinical studies with longer follow-up periods are warranted to confirm these outcomes. Full article

Background: Early caries management is essential to enable reversal of white spot lesions without the further need for operative interventions, especially in primary dentition. Silver-based compounds can be quite effective in arresting caries lesions; however, a major drawback is teeth staining. This study aimed to evaluate the remineralization potential and aesthetic effects of novel, green-synthesized nano-silver fluoride (NSF) on artificial white spot lesions in primary teeth in comparison to 38% silver diamine fluoride (SDF) and silver diamine fluoride/potassium iodide (SDF/KI). Materials and Methods: NSF was synthesized using green tea extract. Sixty primary teeth specimens with artificial enamel lesions were randomly divided into five groups depending on the applied material: 38% SDF, 38% SDF/KI, single and double application of NSF, and control group. Treatments were followed by pH cycling. Surface microhardness and photographic analysis were conducted to assess remineralization and staining. Statistical analysis was conducted using non-parametric tests including Kruskal–Wallis and Mann–Whitney U tests with Bonferroni correction. Results: The greatest increase in microhardness was observed in the group receiving double NSF application. Its remineralizing potential was comparable to that of 38% SDF/KI, with no statistically significant difference (p = 1.000). Importantly, NSF-treated samples exhibited no teeth discoloration, unlike the black staining observed in SDF and SDF/KI groups. Conclusions: Green-synthesized NSF is a promising alternative to conventional SDF and SDF/KI, offering remineralization benefits without compromising aesthetics. The eco-friendly formulation and non-staining properties support its potential for clinical use in pediatric dentistry. Full article