Evaluate the effects of incorporating silica-coated silver nanoparticles (Ag@SiO2 NPs) into odontological clinic resin materials.
Silver nanoparticles coated with silicon dioxide were added to the ...experimental resin matrix at 1, 3, and 5wt%. Degree of conversion (DC), optical properties (total transmittance and color change), and microstructural analysis were evaluated. Materials were tested for silver ion release, cytotoxicity in dental pulp fibroblasts, Streptococcus mutans biofilm growth by Colony-Forming Unit (CFU) and confocal laser scanning microscopy (CLSM).
Groups had a similar DC, despite significant differences observed in transmittance and color change analysis for all groups with NPs. Silver ion release values were below the detection limit after 72h for all groups, and NPs incorporation did not show a statistical difference from the control on pulp fibroblasts assay. After 72h, the CFU count was significantly reduced by 74% from 3wt% of Ag@SiO2NPs. CLSM evaluation on
colonies showed a dose-dependent decrease in the emitted fluorescence.
The application of Ag@SiO2 NPs in a resinous matrix, demonstrates a significant reduction of
CFU in oral biofilm, at concentrations from 3wt%, without an increase in cytotoxicity. The reduced transmittance values did not affect the DC, although a significant color change was perceived in all concentrations.
Nanoparticles, Silver Compounds, Composite Dental Resin, Anti-Bacterial Agent, Optical Imaging.
this study evaluated dentin microtensile bond strength (µTBS) and failure modes (at 24 h and one year), bonding interface regarding hybridization, surface morphology regarding demineralization, in ...situ metalloproteinase (MMP) activity, and antibacterial effect of three dentin etchants compared to 35% phosphoric acid (PA).
The Adper Single Bond 2 adhesive (3 M Oral Care) was applied on moist dentin etched with PA (control) or on air-dried dentin etched with 3% aluminum nitrate + 2% oxalic acid (AN), 6.8% ferric oxalate + 10% citric acid (FO), or 10% citric acid (CA). The µTBS test used 40 human teeth (n = 10). Failure modes and surface morphology were analyzed by scanning electron microscopy (n = 3), while bonding interface morphology and MMP activity were evaluated by laser scanning confocal microscopy (n = 3). Antibacterial activity was evaluated against S. Mutans biofilm by means of viable cells count (CFU/mL).
PA presented the highest bond strengths regardless of aging time. PA, AN, and CA showed stable bond strengths after one year of storage. Adhesive and mixed failures were predominant in all groups. Thin hybrid layers with short resin tags were observed for the experimental etchants. The AN-based etchant was able to inhibit MMP activity. All tested etchants presented antibacterial activity against S. Mutans biofilm.
This study suggests different dentin etchants capable of inhibiting MMP activity while also acting as cavity disinfectants.
•Phosphoric acid bond strength was higher than the tested etchants.•Ferric oxalate + citric acid showed significant bond strength reduction at 1 year.•Gelatinolytic activity was inhibited by aluminum nitrate + oxalic acid.•Bacteria cell viability was reduced according to the pH of the acids.
In recent years, alternative pulpal therapies targeting dentinogenesis signaling pathways using different peptides have been investigated. The aim of this study was to verify the effectiveness of ...poly(aspartic acid), pAsp, in dentin regeneration using an animal model. Methods: Mechanical pulp exposure was performed in the upper molars of 56 Wistar rats, randomly divided as follows (n = 14): control (no treatment); MTA group—pulp capping with mineral trioxide aggregate (MTA Angelus); pAsp group—application of 20 μL of pAsp solution (25 mg·mL−1); MTA+pAsp group—application of MTA mixed with pAsp (5:1 by mass). Animals were euthanized after 7 or 21 days. Histological sections were submitted to hematoxylin-eosin and Brown and Brenn staining and immunohistochemical analysis for osteopontin (OPN) and dentin matrix protein 1 (DMP 1). Results: At 7 days, an acute inflammatory infiltrate and the presence of disorganized mineralized tissue were observed in all groups. At 21 days, the quality and thickness of the reparative dentin in treated groups were superior to the control, and bacterial contamination was observed in two MTA-pAsp specimens. While all treated groups showed intense immunostaining for OPN at 21 days, only the pAsp group expressed DMP 1, indicating the presence of fully differentiated odontoblast-like cells. Conclusion: Poly(aspartic) acid promoted dentin regeneration in rat molars in the absence of an additional calcium source and may be an alternative to MTA as a pulp-capping agent.
Highlights • CT-B and CT-K co-occur on the dentin organic matrix, but they are differently distributed. • Both MMPs and CTs are responsible for dentin proteolytic activity. • The activity of MMPs is ...preponderant over CTs in sound dentin matrix.
Objective
To evaluate the influence of surface treatment on roughness (SA), topography, and shear bond strength (SBS) of computer‐aided designer and manufacture (CAD/CAM) zirconia‐reinforced lithium ...silicate (ZLS) and feldspathic (FEL) glass–ceramics.
Materials and methods
FEL and ZLS specimens were submitted to 5% or 10% hydrofluoric acid (HF) or self‐etching ceramic primer (MEP) and different application times (20, 40, and 60 s), or to sandblasting (Control, 20 s). Resin cement cylinders were bonded to the specimens and tested in shear (n = 10) after 24 h and 16‐months of water storage. SA and topography were evaluated by atomic force (AFM, n = 10) and scanning electron microscopy. Data were analyzed by ANOVA and Bonferroni test (α = 0.05).
Results
Sandblasting promoted the highest SA for ZLS, but 10% HF (40, 60 s) promoted higher SBS at 16 months. 10% HF produced the highest SA for FEL, but sandblasting and 5% HF (20 s) maintained SBS after 16 months, without differences from 10% HF (20 s) (p > 0.05). Overall, MEP produced lower SA and SBS among groups (p < 0.05). HF displayed greater morphological changes on FEL.
Conclusion
10% HF (40 s) provided better results for ZLS, while 5% or 10% HF (20 s) was suitable for FEL.
Clinical significance
Surface treatments influenced SA, topography, and SBS of materials. HF etching is the surface treatment of choice for both CAD/CAM glass–ceramics.
This study evaluated dentin bond strength and dentin-resin interfacial morphology using phosphoric acid-etching and EDTA-conditioning. The occlusal enamel of twenty-four human third molars was ...removed to expose the dentin surfaces, which were polished with a SiC paper (600 grit). Teeth were randomly divided into three groups (n = 8): etching with 37% phosphoric acid (15s), conditioning with 0.1M EDTA (60s) and 0.5M EDTA (120s). Adhesive (XP Bond, Dentsply) was applied and three layers (2mm each) of composite (EsthetX, Dentsply) were placed and light-activated separately (20s). Teeth were sectioned to obtain specimens for the microtensile bond strength test (1mm2 at cross section). Half of the specimens was tested in a universal testing machine (EZ Test, Shimadzu) after 24h and the other half after storage for 10 months. Failure mode and adhesive interface were analyzed using scanning electron microscopy. Data were analyzed by mixed models for repeated measures (PROC MIXED) and Tukey-Kramer test, considering a significance level of 5%. Mean bond strength values (SD) after 24h and 10 months were, respectively (in MPa): phosphoric acid: 37.3 (7.7) / 33.9 (6.7); 0.1M EDTA: 14.7 (7.3) / 15.1 (10.1); 0.5M EDTA: 25.1 (7.7) / 21.1 (14.1). Dentin treatment with EDTA and phosphoric acid resulted in hybrid layer and resin tags formation. Mixed failures were prevalent for all groups tested after 24h. Storage for 10 months changed the failure mode for the 0.5M EDTA group to adhesive failure (between dentin and bonding agent). EDTA applied for 60s yielded lower bond strength results compared to phosphoric acid and EDTA (120s), but there was no significant reduction after 10 months of storage for any of the tested groups.
This study evaluated the cell viability and expression of different major genes involved in mineralization in odontoblast-like cells exposed to sodium trimetaphosphate (STMP). It was also ...investigated the influence of STMP on the rate of calcium phosphate crystal growth, its anti-proteolytic action against the enzymatic degradation of type I collagen, the binding mechanism of STMP to collagen fibrils, and the potential mechanism to induce collagen stabilization.
Immortalized rat odontoblast MDPC-23 cells were cultured. Cell viability was assessed by trypan blue staining, and the changes in gene expression balance induced by STMP were assessed by quantitative reverse transcription (qRT) PCR assays. Crystalline particle formation was monitored by light-scattering detectors to estimate pH variation and the radial size of the crystalline particles as a function of reaction time (pH 7.4, 25°C) in the presence of STMP in supersaturated calcium phosphate solution (Ca/P=1.67). Images were obtained under atomic force microscopy (AFM) to measure the particle size in the presence of STMP. A three-point bending test was used to obtain the elastic modulus of fully demineralized dentin beams after immersion in STMP solution. The binding mechanism of STMP to collagen fibrils and potential stabilization mechanism was assessed with circular dichroism spectrometry (CD). The data were analyzed statistically (α=0.05).
STMP had no significant influence on the cell viability and gene expression of the MDPC-23 cells. STMP greatly increased the rate of crystal growth, significantly increasing the average radial crystal size. AFM corroborated the significant increase of STPM-treated crystal size. Mineralized collagen I fibrils exhibited less collagenase degradation with lower STMP concentration. CD analysis demonstrated changes in the conformational stability after STMP binding to type I collagen.
The increased resistance of collagen against the proteolytic activity of collagenases appears to be related to the conformational change induced by STMP binding in collagen I and the STMP capacity for promoting biomimetic mineralization in type I collagen fibrils.
Clinical issues have been raised about problems related to cytotoxic effects caused when applying self-adhesive cement. It was hypothesized that byproducts eluted from self-adhesive cements modulate ...oxidative stress response, the gene expression of signaling pathways of inflammatory process/transcriptional activators, and the expression and activity of interstitial collagenases, and modify the phenotypic characteristics of cellular proliferation and mineral deposition in odontoblastic-like cells.
Cements (MaxCem Elite MAX and RelyX U200 U200)) were mixed, dispensed into moulds, and photoactivated according to the manufacturers’ instructions. Immortalized rat odontoblast-like cells (MDPC-23) were cultured and exposed to polymerized specimens of cements for 4 h. Reactive oxidative specimen production and quantification of gene expression were evaluated. Cell proliferation assay and alizarin red staining were also performed to evaluate the disturbance induced by the cements on cellular proliferation and mineralization.
Despite their cytotoxic effects, both self-adhesive cements influenced the metabolism in the odontoblast cells on different scales. MAX induced significantly higher oxidative stress in odontoblast cells than U200. Gene expression varied as a function of exposure to self-adhesive cements; MAX induced the expression of pro-inflammatory cytokines such as TNF-α, whereas U200 downregulated, virtually depleted TNF-α expression, also inducing overexpression of the transcriptional factor Runx2. Overexpression of heme oxygenase-1 (HO-1) and thioredoxin reductase 1 (TRXR1) occurred after exposure to both cements, antioxidant genes that are downstream of Keap1-Nrf2-ARE system. MAX significantly induced the overexpression of collagenase MMP-1, and U200 induced the expression of gelatinase MMP-2. MAX significantly inhibited cell proliferation whereas U200 significantly activated cell proliferation. Alizarin red staining revealed significantly decreased mineral deposition especially when exposed to MAX.
These results support the hypothesis that byproducts of different self-adhesive cements play important roles in the highly orchestrated process which ultimately affect the cellular proliferation and the mineral deposition in odontoblastic-like cells, possibly delaying the reparative dentin formation after cementation of indirect restorations, especially on recently exposed dentin preparations.
•We evaluated the cytotoxicity of self-adhesive cements activated with different protocols.•Volatilized compounds from polymerized cements were evaluated by headspace GC–MS.•All of the cements tested ...significantly reduced the cell viability, irrespective of the activation protocol.•Total cell death increased, especially when exposed to chemically activated cements.•Chromatograms revealed 28 compounds released from the cements, some with carcinogenic effects.
To evaluate the cytotoxic effects of exposing odontoblast cells to a variety of commercial self-adhesive cements polymerized using different activation modes.
Five cements: MaxCem Elite (MAX), Bifix SE (BSE), G-Cem LinkAce (GCE), Clearfil SA Luting (CAS), and RelyX U200 (U200) were mixed, dispensed into molds, and distributed in groups, according to polymerization protocols: immediate photoactivation; delayed photoactivation (10min self-curing plus light-activation); and chemical activation (no light exposure). Immortalized rat odontoblast cells (MDPC-23) were cultured. Cell viability was assessed by Trypan Blue staining and total cell death was assessed by annexin V-APC/7-AAD double staining and flow cytometry. Volatilized compounds from polymerized specimens of cements were evaluated by gas chromatography/mass spectrometry (GC–MS). Data was analyzed with 2-way ANOVA/Tukey tests (α=0.05).
Exposure to all of the cements tested significantly reduced the cell viability, irrespective of the activation protocol (p<0.05). The least harmful cements were CSA and U200. Total death of cells significantly increased when exposed to BSE, GCE, and MAX, especially when chemically activated (p<0.05). Characteristic apoptotic cells increased after exposure to cements, mainly for MAX, regardless of the activation mode. Chemical activation of MAX also induced necrosis. Moreover, GCE and MAX exhibited higher percentages of late apoptotic/dead cells. Chromatograms revealed 28 compounds released from the cements tested, some of them with known carcinogenic effects. Selection of self-adhesive cements and polymerization protocols affect the cytotoxicity and cell viability of odontoblastic cells.
Despite the simplified cementation protocol, care is needed when cementing indirect restorations with self-adhesive cements, especially on recently exposed dentin. This category of material may cause differential cytotoxic effects and should be considered when selecting a cement. This is particularly true in clinical cases of light attenuation, where the polymerization depends on chemical activation, inducing higher cytotoxic damages when using some of the cements tested.
ABSTRACT Objective: This cross-sectional study evaluated the bone thickness on mini-implants insertion site, the factors that influence the digital planning of MARPE appliance (miniscrew-assisted ...rapid palatal expansion), and its different designs. Methods: A total of 135 plannings were assessed regarding the size of the expander screw used, the positioning and the type of the mini-implant rings, and their location in relation to the teeth. Bone thickness measurements were assessed in the region of the mini-implants’ trajectory. Differences between the sexes was verified using the ANOVA test (5% significance). Results: 73 cases were planned with 4 mini-implants and 62 cases, with 6 mini-implants. In 90% of cases, teeth #16 and #26 were used as supports, and the most used expander screw was 13mm (64.1% of cases). The anterior mini-implants of conventional MARPE showed more pronounced insertion in bone in males (5.9 ± 2mm; p= 0.025). The extra mini-implants (anterior region) were inserted with greater bone thickness in males (11.1 ± 2.3mm) compared to females (9.9 ± 1.8mm; p=0.041). A greater bone thickness was observed in males (10.1 ± 2.1 mm) when using mini-implants in the paramedian region. Conclusion: Additional rings allow more pronounced bone insertion. Male patients had greater bone thickness, which may be related to greater difficulty in opening the sutures. The alveolar process region seems to be a satisfactory site for mini-implants to those patients with reduced bone thickness in the paramedian posterior region. MARPE appliance must be customized for each patient, due to bone thickness and anatomical variations.
RESUMO Objetivo: Avaliar os fatores que influenciam o planejamento digital do expansor MARPE (miniscrew-assisted rapid palatal expansion), a espessura óssea no local de inserção dos mini-implantes, e os diferentes possíveis desenhos desse aparelho. Métodos: Foram avaliados 135 planejamentos quanto ao tamanho do parafuso expansor utilizado, posicionamento, tipo dos anéis dos mini-implantes, e sua localização em relação aos dentes de apoio. As medidas de espessura óssea foram avaliadas na região de inserção dos mini-implantes. As diferenças entre os sexos foram verificadas por meio do teste ANOVA (5% de significância). Resultados: Os planejamentos tiveram uma distribuição de 73 casos com quatro mini-implantes e 62 casos com seis mini-implantes. Em 90% dos casos, os dentes #16 e #26 foram usados como dentes de apoio, e o parafuso expansor mais usado foi o de 13 mm (64,1% dos casos). Os mini-implantes anteriores do MARPE convencional mostraram uma inserção com maior espessura óssea em homens (5,9 ± 2mm; p= 0,025). Os mini-implantes extras (região anterior) foram inseridos com maior espessura óssea nos homens (11,1 ± 2,3 mm), em comparação com as mulheres (9,9 ± 1,8 mm; p=0,041). Foi observada maior espessura óssea em homens (10,1 ± 2,1 mm) na região paramediana. Conclusões: Anéis adicionais permitem uma inserção óssea mais pronunciada. Os pacientes do sexo masculino apresentaram maior espessura óssea, o que pode estar relacionado à maior dificuldade de abertura das suturas.
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