Search Results (379)

Zeolites are becoming potentially important multifunctional fillers in dentistry, providing a distinctive blend of mechanical reinforcement, remineralization, and antimicrobial properties. Their crystalline aluminosilicate frameworks offer ion-exchange capacity, the controlled release of therapeutic ions (Ag⁺, Zn²⁺, Ca²⁺, Sr²⁺, Cu²⁺), and compatibility with various dental composites. Sustainable and cost-effective zeolite production has become possible due to recent developments in synthetic strategies. These include the valorization of industrial and agricultural residues that are abundant in Si and Al. The incorporation of zeolites into dental adhesives, restorative composites, glass ionomer cements, root canal sealers, prosthetic materials, and implant coatings has been shown to improve mechanical stability and remineralization potential, and enhance antibacterial protection. The unique advantage of zeolites in integrating multifunctionality within a single system is emphasized when compared with other fillers, such as hydroxyapatite nanoparticles and bioactive glass. Nevertheless, obstacles persist with respect to clinical validation, regulatory pathways, and long-term biocompatibility. This review critically assesses the structure–function relationships, synthesis strategies, and dental applications of zeolites, while also delineating future perspectives for their translation into clinically approved, sustainable dental biomaterials. Full article

The long-term success of composite restorations largely depends on the performance of dental adhesives at the adhesive–tooth interface. Despite ongoing improvements, secondary caries remains the leading cause of restoration failure, primarily due to the adhesive layer’s susceptibility to hydrolytic degradation, bacterial invasion, and limited biological functionality. This review provides a comprehensive overview of recent advances in bioactive dental adhesives for preventing recurrent caries, focusing on their mechanisms of action, material performance, therapeutic functions, and clinical potential. Bioactive adhesives combine durable bonding with biofunctional benefits, including remineralization, antimicrobial activity, enzymatic inhibition, and support for tissue regeneration. By integrating these properties, they enhance both the durability of the adhesive interface and oral health. Recent strategies include the incorporation of ion-releasing fillers such as calcium phosphate and bioactive glass, antimicrobial monomers such as MDPB and quaternary ammonium methacrylates, enzymatic inhibitors, and hydrolytically stable resin matrices. Together, these components strengthen the adhesive interface and provide biologically active effects to prevent recurrent caries. Although in vitro findings are promising, challenges remain, including limited long-term clinical data, the absence of standardized evaluation protocols, and barriers to clinical translation. Addressing these gaps is essential to ensure predictable clinical outcomes. Bioactive dental adhesives represent a paradigm shift in restorative dentistry, evolving from passive bonding agents to multifunctional therapeutic materials. By combining structural durability with biological protection, they hold significant potential to prevent recurrent caries and improve the long-term success of composite restorations. Full article

Background/Objectives: Adhesion to caries-affected dentin remains challenging due to its altered structure and composition. Remineralizing agents have been proposed to strengthen this substrate and improve bonding. This study evaluated the effect of three remineralization treatments, CPP-ACP, self-assembling peptide P11-4, and silver diamine fluoride (SDF), on the microtensile bond strength (μTBS) of universal adhesive systems applied to caries-affected dentin, using both etch-and-rinse and self-etch strategies. Methods: Seventy human molars were sectioned and artificially demineralized to simulate caries-affected dentin. Samples were divided into ten groups: four untreated and six treated with CPP-ACP (MI Paste™), P11-4 (Curodont™ Protect), or SDF (Riva Star™). Universal adhesives were applied via etch-and-rinse or self-etch mode, followed by composite restoration. Microtensile bond strength was measured using a universal testing machine, and results were statistically analyzed with ANOVA and t-tests (p < 0.05). Results: Untreated caries-affected dentin showed significantly lower μTBS than sound dentin (C3: 18.3 ± 5.4 MPa vs. C1: 41.3 ± 2.7 MPa). Remineralization agents improved μTBS considerably. CPP-ACP achieved the highest recovery (S1: 31.8 ± 2.6 MPa; S2: 29.2 ± 4.6 MPa), nearing sound dentin levels. P11-4 yielded moderate gains (S3: 24.4 ± 6.5 MPa; S4: 24.1 ± 4.7 MPa), while SDF provided the lowest, yet significant, improvements (S5: 23.7 ± 7.5 MPa; S6: 21.3 ± 5.3 MPa). Etch-and-rinse generally produced higher μTBS than self-etch, but differences were not statistically significant (p > 0.05). Conclusions: Pre-treatment of caries-affected dentin with CPP-ACP, P11-4, or SDF enhances universal adhesive bond strength, with CPP-ACP showing the most pronounced effect. Remineralization protocols represent a valuable adjunct in restorative procedures involving compromised dentin. 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

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: The treatment of cavitated lesions has evolved with minimally invasive dentistry (MID), whereby we can leave demineralized enamel that could potentially be remineralizable with the use of materials such as resin-modified glass ionomer cements (RMGICs) that allow these lesions to be repaired and remineralized while removing less tooth tissue. The aim of our study was to compare the influence of aging on adhesion to sound enamel, demineralized enamel, and the healthy dentin of five RMGICs (Vitremer^®, ACTIVA BioACTIVE Restorative, Riva LC, Ionolux^®, and GC Fuji II LC) and fluoride release. There are currently no studies on adhesion in demineralized enamel. Method: A total of 1035 bovine incisors were analyzed in 45 groups of 23 teeth each. The groups were established based on three factors: time (24 h, 1 month, and 3 months); substrate (sound enamel, demineralized enamel, and healthy dentin); and type of material. In each group, 20 samples underwent shear bond strength (SBS) and fracture type analysis. Adhesive interfaces were observed in three samples from each group using field emission scanning electron microscopy (FESEM). Daily and cumulative fluoride release rates were calculated. Results: Adhesion improved over time on both demineralized and sound enamel. ACTIVA BioACTIVE Restorative had the highest SBS values (33.63 ± 10.69 MPa), and Vitremer^® had the lowest (4.10 ± 4.63). Most fractures were adhesive. Vitremer^® and Ionolux^® showed the highest daily and cumulative fluoride release rates (Vitremer daily (24 h): 225.30 ± 26.28 ppm/g; Vitremer cumulative (30 days): 635.99 ± 305.38 ppm/g; Ionolux daily (24 h): 207.59 ± 48.43 ppm/g; Ionolux cumulative (30 days): 501.21 ± 138.71 ppm/g) and ACTIVA BioACTIVE Restorative showed the lowest (ACTIVA daily (24 h): 10.50 ± 0.85; ACTIVA cumulative (30 days): 39.10 ± 2.16). Conclusions: ACTIVA BioACTIVE Restorative was the material with the best adhesion values on all substrates and at all times, but it showed the lowest fluoride release rates. Full article

Ocean Alkalinity Enhancement (OAE) is a promising carbon dioxide removal strategy, but its ecological impacts on marine microbial communities under varying nutrient conditions remain poorly understood. We conducted laboratory incubations using a natural North Atlantic microbial assemblage to investigate the response to OAE under both natural and nutrient-enriched regimes. We tracked phytoplankton and bacterioplankton dynamics, biomass, and leucine aminopeptidase (LAP) and alkaline phosphatase (ALP) activity as indicators of organic matter remineralization. OAE consistently reduced phytoplankton abundance in both nutrient regimes, potentially due to CO₂ limitation, resulting in lower production of phytoplankton-derived organic matter. This reduction was reflected in decreased LAP activity and shifts in the relative abundance of phytoplankton-associated bacterial taxa. These findings indicate that OAE can directly affect phytoplankton through carbonate chemistry alterations, with potential microbial responses largely mediated by changes in organic matter availability. While short-term microbial disruptions were modest, the ecological consequences of altered bloom dynamics should be carefully considered in future OAE deployment strategies. Full article

This study examined the application of rhyolite filler in agroecological farming systems in the Fourth Colony of Italian Immigration (Quarta Colônia de Imigração Italiana), Rio Grande do Sul, Brazil. The aim was to explore sustainable alternatives to synthetic fertilizers in line with organic agriculture principles. The region’s designation as the Quarta Colônia UNESCO Global Geopark reinforces the relevance of this initiative. The research involved petrographic characterization, incubation experiments, and chemical analyses of rhyolite samples. Incubation tests with pigeon pea and elephant grass assessed combinations of rock filler and poultry litter. The results showed that rhyolite filler supported plant growth, especially with poultry litter, which supplies nitrogen and microorganisms that accelerate mineral weathering. Petrographic observations indicated that elephant grass promoted stronger mineral alteration, likely due to its dense fibrous roots and substrate interaction. Chemical analyses confirmed the rhyolite’s quartz content and trace elements remain within safety limits defined by Brazilian legislation on soil remineralizers. The K₂O content and the base sum (CaO, MgO, and K₂O) also complied with minimum legal requirements. Beyond mineralogical and chemical aspects, the study emphasized the economic feasibility of using locally sourced rock fillers, offering lower costs than synthetic fertilizers and supporting sustainable, resilient agroecological systems. Full article

Introduction: Fluoride varnishes are widely used in caries prevention, but the rate and duration of fluoride ion release differ depending on material composition and environmental factors. Objectives: This systematic review synthesized evidence from in vitro studies on human teeth to identify key factors influencing fluoride release. Methods: A systematic literature search was conducted in July 2025 in PubMed, Scopus, Web of Science, Embase, and the Cochrane Library using the terms “fluoride release” AND “varnish” in titles and abstracts. Study selection followed PRISMA 2020 guidelines, predefined eligibility criteria, and was structured according to the PICO framework. Of 484 retrieved records, 15 studies met the inclusion criteria and were analyzed qualitatively. Results: The primary outcome was the magnitude and duration of fluoride release from varnishes. Most studies reported peak release within the first 24 h, followed by a marked decline, although some formulations (e.g., Clinpro XT and Duraphat) maintained more stable long-term release. Substantial methodological heterogeneity was observed across studies, including differences in sample type, storage medium, pH, temperature, and measurement protocols, which influenced fluoride release dynamics. Reported secondary outcomes included enamel remineralization, changes in surface properties, and antibacterial activity, with bioactive additives such as CPP–ACP and TCP enhancing preventive effects. Acidic conditions consistently increased fluoride release. Conclusions: The magnitude and persistence of fluoride release from varnishes depend on both intrinsic material properties and external environmental conditions. Bioactive additives may prolong fluoride availability and provide additional preventive benefits. Full article

Background: Enamel surface roughness after bracket debonding is an important issue due to its impact on plaque accumulation and the potential development of carious lesions. This in vitro study aimed to assess enamel roughness after the removal of metallic and sapphire brackets and the effect of a remineralization treatment. Methods: Two hundred extracted human permanent teeth with healthy enamel were randomly distributed into two groups (n = 100) and bonded with either metallic or sapphire brackets using the same adhesive (3M™ Transbond™ XT (St. Paul, MN, USA), Minnesota Mining and Manufacturing Company, MN, USA). The enamel surface roughness was measured before bonding, after debonding, and after remineralization using SEM and a TR200 roughness (SaluTron GmbH, Frechen, Germany) tester. The parameter Ra was used to quantify the surface roughness. One-way ANOVA, the normality test, variance homogeneity, and the Bonferroni post hoc test were used to analyze the data. Results: Debonding significantly increased the enamel surface roughness in both groups. The sapphire bracket group presented significantly higher mean Ra values post debonding (4.14 ± 0.36 µm) compared to the metallic group (2.56 ± 0.52 µm). Remineralization led to a decrease in surface roughness in both groups, though not to baseline levels. The changes were statistically significant (p < 0.01), with a power of the test of 1.0. Conclusions: The bracket material significantly affects enamel surface roughness after orthodontic debonding. Sapphire brackets produced greater surface irregularities than metallic ones. Remineralization partially reduced roughness in both groups, with the final values in the metallic group being closer to baseline levels. Crucially, these values remained far above the clinical threshold for plaque retention, highlighting the need for improved debonding techniques. Full article

Background/Objectives: This in vitro study evaluated the effects of fluoride-free toothpaste, fluoride-containing toothpaste, and a color-correcting gel on the morphology, composition, and mechanical properties of demineralized human enamel. The hypothesis was that fluoride-containing formulations would better preserve enamel integrity compared to non-fluoride and cosmetic products. Methods: Extracted human teeth (n = 3 per group) were demineralized with 36% phosphoric acid and assigned to four groups: E0 (control), E1 (fluoride-free toothpaste), E2 (fluoride-containing toothpaste), and E3 (color-correcting gel). Brushing was performed manually twice daily for 7 days using standardized force. Surface morphology and elemental composition were assessed via SEM–EDX; chemical changes were analyzed by FTIR; mechanical properties were evaluated using the Vickers microhardness test. Results: E1 exhibited the highest microhardness (343.6 HV) but also the highest Ca/P ratio (2.37) and most pronounced surface roughness (p < 0.05 vs. control). E2 showed a balanced Ca/P ratio (2.07), smoother morphology, and detectable fluoride incorporation, despite a lower hardness value (214.5 HV). E3 presented moderate changes in both morphology and composition, with a Ca/P ratio similar to the control (2.06) but surface irregularities visible by SEM. The apparent paradox in E1—high hardness with structural damage—may be due to superficial mineral precipitation without true remineralization. Conclusions: Fluoride-containing toothpaste preserved enamel morphology and chemistry more effectively than the other formulations. Increased hardness in E1 does not necessarily indicate clinical benefit. In vivo studies with longer protocols and pH cycling are needed to confirm these findings. Full article

Background/Objectives: Fluoride ion plays a crucial role in protecting teeth against caries by re-mineralizing the caries lesion. The objective of this study was to quantify and compare the fluoride release and recharge of restorative dental materials and their correlation with mass stability. Methods: For this study, 5 × 5 × 2 mm blocks were prepared from GIC, RMGI L, GIOMER, Resin Composite, and RMGI R using a customized silicone index. The amount of fluoride released from each material was quantified using a fluoride electrode at 0 h, 1 day, 3 days, 1-week, and 2-week periods. The fluoride recharge of each material was calculated by quantifying the amount of fluoride uptake from high concentration fluoride solution over a period of 1-week. The mass stability of the materials was measured be quantifying the weight loss/weight gain during fluoride release and recharge phase. The correlation of fluoride release/recharge with weight loss/gain were analyzed using Pearson correlation. Results: One-way ANOVA showed a statistically significant difference in the amount of fluoride released from each group (p < 0.05). The maximum amount of fluoride release was observed on the 3rd day in all the groups except the GIC group, which showed an ascending concentration of fluoride release till 2 weeks. One-way ANOVA showed statistically significant differences in weight loss/gain among the rested group (p < 0.05). GIC showed the highest amount of weight loss and weight gain among the tested materials. Conclusions: The GIC material has the highest fluoride release and RMGI L has the highest fluoride recharge capability. The conventional GIC showed the least mass stability during fluoride release/recharge. Full article

Background and Objectives: Chairside bleaching can alter enamel morphology and mineral content. This in vitro study compared surface changes and elemental shifts after three in-office protocols using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Materials and Methods: Forty-two human premolars/molars were sectioned; matched halves served as control or received Opalescence Quick 45% carbamide peroxide (CP), Opalescence Boost 40% hydrogen peroxide (HP), or BlancOne Ultra+ 35% HP with light activation. Gels were applied per manufacturers’ instructions. SEM assessed topography (×500–×1100); EDS quantified atomic percent of O, Ca, P, C and trace elements. One-way ANOVA compared Ca and P between bleached groups (α = 0.05). Results: Controls showed compact surfaces with preserved Ca and P. After Quick, SEM revealed roughness, fissures and microcracks; Ca fell from 11.5 to 12.5 to 9.53–11.73 at% and P from 7.5 to 8.9 to 7.41–8.59 at%. Boost produced mild superficial restructuring and granular deposits with variable Ca 13.80–27.94 at% and P 7.32–14.65 at%. BlancOne Ultra+ caused diffuse erosion and loss of prismatic clarity with marked demineralization (Ca 1.42–7.85 at%, P 1.22–6.71 at%); C rose locally to 46.61 at%. Across bleached groups, Ca and P differed significantly (both p < 0.001). Oxygen remained dominant (~39–50 at%) in all spectra; occasional Al/Si/Cl/K likely reflected residues or preparation artifacts. Conclusions: All protocols produced surface and compositional alterations, with a severity gradient: BlancOne Ultra+ > Boost > Quick. High-concentration, light-activated HP yielded the largest Ca/P losses. Clinically, neutral-pH, non-activated or chemically activated regimens and immediate post-bleach remineralization should ideally be used when feasible, particularly before adhesive procedures. Full article

Dental caries is a prevalent health condition affecting 87% of the population. The application of fluorinated varnishes to incipient lesions promotes remineralization. To evaluate the remineralizing effect of three fluorinated varnishes through chemical and physical characterization of incipient enamel lesions in vitro, a total of 150 enamel surfaces were randomly divided into five groups (n = 30): healthy enamel, initial lesion, Fluor-Protector, β-Clinpro-White-Varnish, and Duraphat. All groups, except for the healthy enamel, were immersed in a demineralizing solution (pH 4.4) for 96 h. Remineralization was assessed using a pH cycling model over 5, 10, and 15 days. Fluoride release was measured via ISE-F, and enamel was analyzed by Raman spectroscopy (PO₄³⁻), roughness, and Vickers hardness. Data were analyzed using ANOVA and a post hoc test (Tukey). Ion Selective Electron-Fluor showed a residual F concentration of 0.40 ppm for the Fluor-Protector remineralizing solution: 40.00 ppm for Clinpro-White-Varnish, and 50.0 ppm for Duraphat. Raman analysis confirmed PO₄³⁻ at 956 cm⁻¹ mainly in CDu group. Roughness decreased with varnish application: Fluor-Protector (0.36 µm), β-Clinpro-White-Varnish (0.73 µm), and Duraphat (0.65 µm). Hardness increased with Fluor-Protector. Statistically significant differences were found between FP and other types of varnish. Fluorinated varnishes enhance remineralization and reduce enamel roughness and demineralization. Fluor Protector and β-Clinpro-White-Varnish showed the most favorable results, suggesting their recommendation for high-risk pediatric patients. Full article

This study evaluated a biomimetic filler strategy for two-step universal dental adhesives by integrating amine-functionalized mesoporous silica nanoparticles (MSNs) loaded with polyacrylic acid-stabilized amorphous calcium phosphate (PA–ACP) into the primer phase. MSNs were synthesized and characterized by FTIR, N₂ sorption (BET), and HRTEM to confirm structural integrity and effective PA–ACP loading. Two commercial adhesives (G2 Bond and OptiBond eXTRa) were modified by incorporating different volumes fractions (10, 15, 20 vol%) of PA–ACP/MSN. Wettability (contact angle), microtensile bond strength (μTBS), and cytotoxicity (indirect MTT assay using human periodontal ligament fibroblasts, HPLFs) were assessed. The results demonstrated that incorporating up to 15 vol% PA–ACP/MSN maintained favorable wettability and bond strength, comparable to those of the unmodified controls. At 20 vol%, significant increases in contact angles and reductions in bond strength indicated impaired primer infiltration. Cytotoxicity testing confirmed high fibroblast viability (>70%) across all tested concentrations, verifying the biocompatibility of PA–ACP/MSN-filled primers. This work confirms the feasibility of a biomimetic adhesive design using PA–ACP/MSN in the primer phase without compromising immediate wettability and immediate μTBS up to 15 vol%. Remineralization is a potential capability that requires verification in future studies. Full article