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The objective of this study was to evaluate the bonding performance of model resin-based adhesives doped with bioactive glass or calcium-silicate modified dicalcium-phosphatedihydrate microfillers to root canal wet-dentine with water or ethanol. The experimental resin was prepared by using urethane-dimethacrylate (UDMA), triethylene-glycol-dimethacrylate (TEGDMA) and hydroxyethyl-methacrylate (HEMA). This resin blend was mixed with 50 wt% ethanol to create the experimental primers. Bioactive glass 45S5 (BAG) or calcium-silicate modified dicalcium-phosphate dihydrate (DCPD) microfillers were mixed at 40 wt% to the blend. The bonding performance to root canal was assessed by push-out bond strength, SEM analysis of fractures, and interfacial confocal microscopy after filling the canals with the core composite Bis-Core (Bisco). Three-way ANOVA (bonding technique, adhesive resin and dentine area) and Student–Newman–Keuls post-hoc were used to statistically compare the results (α=5%). Filler-free adhesive applied on water-wet dentine showed lower bond strength than the same resin applied on ethanol-wet dentine (p 0.05) but did improve using the water-wet strategy. BAG and DCPD also promoted mineral deposition and tubular occlusion in the well-hybridised fractured root surfaces especially using the ethanol-wet technique. The confocal interfacial analysis showed impaired resin infiltration only using the filler-free resin on water-wet dentine. As a conclusion, bioactive glass and DCPD micro-fillers as well as the ethanol-wet bonding were able to improve the adhesion of etch-and-rinse adhesives to radicular dentine.

The number of carbon atoms and/or ester/polyether groups in spacer chains may influence the interaction of functional monomers with calcium and dentin. The present study assessed the chemical interaction and bond strength of 5 standard-synthesized phosphoric-acid ester functional monomers with different spacer chain characteristics, by atomic absorption spectroscopy (AAS), ATR-FTIR, thin-film x-ray diffraction (TF-XRD), scanning electron microscopy (SEM), and microtensile bond strength (μTBS). The tested functional monomers were 2-MEP (two-carbon spacer chain), 10-MDP (10-carbon), 12-MDDP (12-carbon), MTEP (more hydrophilic polyether spacer chain), and CAP-P (intermediate hydrophilicity ester spacer). The intensity of monomer-calcium salt formation measured by AAS differed in the order of 12-MDDP=10-MDP>CAP-P>MTEP>2-MEP. FTIR and SEM analyses of monomer-treated dentin surfaces showed resistance to rinsing for all monomer-dentin bonds, except with 2-MEP. TF-XRD confirmed the weaker interaction of 2-MEP. Highest µTBS was observed for 12-MDDP and 10-MDP. A shorter spacer chain (2-MEP) of phosphate functional monomers induced formation of unstable monomer-calcium salts, and lower chemical interaction and dentin bond strength. The presence of ester or ether groups within longer spacer carbon chains (CAP-P and MTEP) may affect the hydrophilicity, μTBS, and also the formation of monomer-calcium salts.

Objectives Zinc-doped dentine adhesives have been recently advocated to interfere with metallo-proteinases-mediated collagen degradation. Nevertheless, there is a little information about the effects of zinc ions on the chemical interaction of self-etch functional monomers to dentine. The aim of this study was to assess if the inclusion of zinc into the primers of self-etch adhesives containing MDP (10-methacryloyloxi-decyl-dihydrogen-phosphate) may interfere with their chemical interaction to calcium/dentine. Methods Caries-free human molars were bonded using two commercial self-etching adhesives [Clearfil SE bond (CSE) and S3 bond (S3)] doped with zinc nitrate and submitted to microtensile bond strength (μTBS) and interface nanoleakage evaluation. Moreover, MDP was synthesised to evaluate the chemical interaction with calcium/dentine through atomic absorption spectroscopy (AAS) and SEM-EDX in the presence or absence of zinc ions. Results AAS showed increasing formation of MDP–zinc rather than MDP–calcium salts (p = 0.002) in the presence of zinc. SEM-EDX confirmed the formation of zinc-rich phosphate deposits that were probably responsible for the significant reduction in μTBS and increased interfacial nanoleakage attained with zinc-doped CSE and S3. Conclusion These outcomes demonstrated that the excessive presence of zinc ions may jeopardise the bonding performance of MDP-containing self-etch adhesives.

Objectives: The aim of this study was to assess the effects direct or indirect water exposure on the 3 months hydrolytic degradation of three dentin bonding agents. Materials and methods: The samples were divided in three groups: Clearfil SE Bond, Clearfil S3, Adper Singlebond 2; and the samples were restored with Filtek Z350. Subsequent to the restorative procedures, the specimens of each group were divided into three subgroups (immersed in water deionised): Control (24h-37oC), Direct Water exposure DWE for 3 months (37o), Indirect water exposure (IWE-3m) with enamel margins for 3 months (37oC). After the storage the samples were sectioned into sticks and µTBS testing (EZ test) and Scanning Electronic Microscopy assessed the failure mode. The µTBS data were statistically analysed using two-way ANOVA and Tukey’s test at α=0.05%. The samples were processed for nanoleakage evaluation immersed in 50 wt% ammoniacal silver nitrate (24 h), rinsed and immersed in a photo-developing solution for 8 h. Results: After 3 months CSE was the least affected by water degradation regardless the aging strategy. IWE afforded very little variation on µTBS after 3 m. Intense nanoleakage was observed with DWE groups with increases incidence of mixed failures instead Conclusion: Bonded dentin margins are more prone to hydrolytic degradation than resin-enamel interfaces. The increased nanoleakage and the drop of bond strength showed this.

To evaluate the tensile bond strength at repaired interfaces of aged dental composites, either dimethacrylate- or silorane-based, when subjected to different surface treatments.The composites used were Filtek P60 (methacrylate-based, 3M ESPE) and Filtek P90 (silorane-based, 3M ESPE), of which 50 slabs were stored for 6 months at 37°C. The surface of adhesion was abraded with a 600-grit silicone paper and the slabs repaired with the respective composite, according to the following surface treatment protocols: G1: no treatment; G2: adhesive application; G3: silane + adhesive; G4: sandblasting (Al2O3) + adhesive; G5: sandblasting (Al2O3) + silane + adhesive. After 24-h storage in distilled water at 37°C, tensile bond strength (TBS) was determined in a universal testing machine (Instron 4411) at a crosshead speed of 0.5 mm/min. The original data were submitted to two-way ANOVA and Tukey's test (α = 5%).The methacrylate-based composite presented a statistically significantly higher repair potential than did the silorane-based resin (p = 0.0002). Of the surface treatments for the silorane-based composite, aluminum-oxide air abrasion and adhesive (18.5 ± 3.3MPa) provided higher bond strength than only adhesive application or the control group without surface treatment. For Filtek P60, the control without treatment presented lower repair strength than all other groups with surface treatments, which were statistically similar to each other. The interaction between the factors resin composite and surface treatment was significant (p = 0.002).For aged silorane-based materials, repairs were considered successful after sandblasting (Al2O3) and adhesive application. For methacrylate resin, repair was successful with all surface treatments tested.

Aim To evaluate the effects of two methods to simulate physiological pulpal pressure on the dentine bonding performance of two all-in-one adhesives and a two-step self-etch silorane-based adhesive by means of microtensile bond strength (μTBS) and nanoleakage surveys. Methodology The self-etch adhesives [G-Bond Plus (GB), Adper Easy Bond (EB) and silorane adhesive (SIL)] were applied to flat deep dentine surfaces from extracted human molars. The restorations were constructed using resin composites Filtek Silorane or Filtek Z350 (3M ESPE). After 24 h using the two methods of simulated pulpal pressure or no pulpal pressure (control groups), the bonded teeth were cut into specimens and submitted to μTBS and silver uptake examination. Results were analysed with two-way anova and Tukey's test (P

To evaluate in the laboratory the roughness (Ra) and micromorphology surface of the nanofilled resin-modified glass-ionomer (Ketac N100) subjected to biomechanical degradation, compared to Vitremer, Ketac Molar Easymix and Fuji IX.Specimens obtained from the ionomers were divided into two storage groups (n = 10): relative humidity and S. mutans biofilm (biodegradation). After 7 days, Ra values and micrographs were obtained. Then, the brushing abrasion test (mechanical degradation) was conducted with dentifrice slurry (three-body) and the specimens were reassessed. Data were submitted to repeated measures three-way ANOVA and Tukey tests (P0.05).There was significant interaction among the factors: material, storage and abrasion (before/after). Vitremer showed similar Ra values between storage groups, while the other materials presented higher Ra values after biodegradation test. Concerning biomechanical challenge, Ketac N100 presented the lowest Ra values. Ketac Molar Easymix and Fuji IX presented undesirable roughening of their surfaces under the detrimental conditions tested. The eroded aspect after biodegradation with filler exposure after mechanical degradation was evident.

To compare the effects of two etching procedures using meta-phosphoric (MPA) or ortho-phosphoric acid (OPA) on dentine demineralisation, resin-dentine bonds durability and interface nanoleakage/ultra-morphology.Middle-dentine specimens were etched using 37% OPA (15s) or 40% MPA (60s) and submitted to infrared spectroscopy (FTIR) or ultra-morphology dye-assisted (calcium-staining) confocal microscopy (Ca-CLSM). A three-step etch-and-rinse adhesive was formulated, applied onto dentine and light-cured for 30s before composite build-up. After 24h, the dentine-bonded specimens were cut into 1mm(2) beams; half were immediately submitted to microtensile bond strength (μTBS) and half stored in DW for six months. The μTBS results were analysed with repeated-measures ANOVA and Tukey's test (p0.05). Further teeth were bonded and prepared for interface nanoleakage/ultra-morphology confocal evaluation.FTIR and Ca-CLSM analyses showed dicalcium phosphate dihydrate (Brushite) precipitation in MPA-etched dentine and on the bottom (front of demineralisation) of the OPA-etched dentine. Statistical analysis showed similar μTBS for both etching procedures after 24h. The μTBS of specimens in OPA-group dropped significantly (p0.05) after six month; the specimens in the MPA group showed no statistically difference (p0.05). CLSM depicted no evident sign of nanoleakage within the resin-dentine interface of the MPA-treated specimens, while the specimens in OPA-group presented intense nanoleakage and interface degradation.The use of MPA (60s) as an alternative dentine conditioning agent in etch-and-rinse bonding procedures may be a suitable strategy to create more durable resin-dentine bonds.

SUMMARY The aim of this study was to evaluate the effects of extended light-curing procedures on the microtensile bond strength (μTBS) of one-step self-etch adhesives (1-SEAs) submitted to simulated pulpal pressure. Coronal deep-dentin specimens were bonded using Clearfil S3 Bond (S3), Adper Easy Bond (EB), or G-Bond Plus (GB) following the manufacturers' recommendations and light-cured for 10 seconds or 40 seconds. The dentin-bonded specimens were stored in distilled water for 24 hours without pulpal pressure (control) or submitted to 20 cm H2O simulated pulpal pressure for 24 hours. The specimens were cut into matchsticks and subjected to μTBS testing. The data were statistically analyzed using the three-way analysis of variance and Tukey's tests (p

Objectives This study aimed at evaluating the therapeutic bioactive effects on the bond strength of three experimental bonding agents containing modified Portland cement-based micro-fillers applied to acid-etched dentin and submitted to aging in simulated body fluid solution (SBS). Confocal laser (CLSM) and scanning electron microscopy (SEM) were also performed. Methods A type-I ordinary Portland cement was tailored using different compounds such as sodium–calcium–aluminum–magnesium silicate hydroxide (HOPC), aluminum–magnesium–carbonate hydroxide hydrates (HCPMM) and titanium oxide (HPCTO) to create three bioactive micro-fillers. A resin blend mainly constituted by Bis-GMA, PMDM and HEMA was used as control (RES-Ctr) or mixed with each micro-filler to create three experimental bonding agents: (i) Res-HOPC, (ii) Res-HCPMM and (iii) Res-HPCTO. The bonding agents were applied onto 37% H 3 PO 4 -etched dentin and light-cured for 30 s. After build-ups, they were prepared for micro-tensile bond strength (μTBS) and tested after 24 h or 6 months of SBS storage. SEM analysis was performed after de-bonding, while CLSM was used to evaluate the ultra-morphology/nanoleakage and the mineral deposition at the resin–dentin interface. Results High μTBS values were achieved in all groups after 24 h. Only Res-HOPC and Res-HCPMM showed stable μTBS after SBS storage (6 months). All the resin–dentin interfaces created using the bonding agents containing the bioactive micro-fillers tested in this study showed an evident reduction of nanoleakage and mineral deposition after SBS storage. Conclusion Resin bonding systems containing specifically tailored Portland cement micro-fillers may promote a therapeutic mineral deposition within the hybrid layer and increase the durability of the resin–dentin bond.

To evaluate a new method of simulated pulpal pressure in vitro in comparison with the conventional one.Four adhesives were analyzed: a three-step etch-and-rinse (Scotchbond Multi-Purpose [SBMP]), a two-step etch-and-rinse (Single Bond 2 [SB]), a two-step self-etching (Clearfil SE Bond [SE]), and a one-step self-etching (Clearfil S3 [S3]) system. Restorations were built up in flat, deep dentin from extracted molars. After two methods of simulated pulpal pressure or no pulpal pressure (control groups), the samples were cut into sticks and submitted to microtensile bond strength (µTBS) testing and nanoleakage evaluation. Results were analyzed with two-way ANOVA and Tukey's test (p0.05).In general, statistical analysis of µTBS showed SBMPSB=SES3. For both methods of simulated pulpal pressure, the µTBS of SB and S3 was lower than in control groups. For SBMP and SE, the µTBS remained stable with simulated pulpal pressure. Conventional and experimental methods of simulating pulpal pressure resulted in similar µTBS (p = 1.00) and nanoleakage patterns. Silver impregnation was higher with SB and S3, especially after simulated pulpal pressure with both methods.The experimental simulated pulpal-pressure method tested here was similar to the conventional method and can be an alternative to it. The simplified adhesives show reduction in bond strength after simulated pulpal pressure. The multistep adhesives have stable bond strengths under simulated pulpal pressure. Therefore, the separate application of hydrophobic resin can achieve resistance to bonding deterioration after hydrostatic pressure.

To evaluate the effects of four different light-curing protocols on the microtensile bond strength (μTBS), ultimate tensile strength (UTS), Knoop micro-hardness (KH) and cross-link density (CLD) of a nano-filled resin composite.Filtek Supreme XT (3M-ESPE) was used for the entire experiments following four light-curing approaches: ST, standard irradiance; HI, high irradiance; PD, pulse delay; SS, soft start. The specimens were submitted to different storage periods (24h or 6 months), cut into match-sticks and subsequently submitted to μTBS testing. Hourglass specimens were also prepared for UTS and KH. Cylindrical specimens were prepared for the CLD evaluation after absolute ethanol challenge. The results were statistically analyzed with a two-way ANOVA and Tukey's test (α=0.05).For UTS and KH, continuous irradiance (PD and SS) induced statistically higher results (p0.05) both after 24h and 6 months of water storage compared to ST and HI groups. However, a drop in UTS and KH was obtained after 6 months in all groups. The μTBS was not affected by the different light-curing approaches and, no statistical differences (p0.05) were observed between 24h and 6 months storage. The CLD evaluation showed a statistical drop in KH after 24h of ethanol storage for PD and SS (step-curing protocols) compared to those attained in continuous mode (ST and HI).The soft-start mode may improve the UTS and KH of nano-filled resin composites without compromising the resin-dentine μTBS. However, both the step-curing protocols may reduce the cross-link density of the composite polymeric network.High irradiances photo-polymerization may be adequate for direct aesthetic restorations such as veneers and onlays. Meanwhile, the soft start protocol would seem more appropriate for the photo-polymerization of high c-factors class I and II restorations.

Purpose: to evaluate the shrinkage, polymerization stress, elastic and bulk modulus resulting from composites formulated by siloranes, 2 nd generation ormocers, and dimethacrylates. Materials and Methods: The bonded disc method was used to evaluate volumetric shrinkage. The polymerization stress was evaluated by mean of the Bioman. Cylindrical specimens (5 mm thickness and 6 mm diameter) were submitted to gradual loading. Young's and bulk modulus were obtained from the slope of the stress/strain curve. Data were analyzed using one-way analysis of variance and Tukey's test (5%). Results: Grandio and ormocer showed significant higher elastic and bulk modulus. Silorane presented significant lowest bulk modulus and maximum shrinkage. Ormocer and silorane presented lower values for the maximum rate of shrinkage. Extra-low shrinkage (ELS) composite presented the greatest maximum shrinkage. The higher maximum rate of shrinkage was attained by Grandio and ELS, statistically similar from each other. The silorane showed lower values of maximum stress and maximum rate of stress. The higher values of maximum stress were presented by ELS and Grandio, statistical similar between them. Grandio showed the significantly greatest maximum rate of stress. Conclusion: Silorane showed to promote lower shrinkage/stress among the composites, with the lowest elastic modulus. Ormocer showed lower shrinkage/stress than methacrylates despite of its high modulus.

ObjectivesTo evaluate the effects of acidic functional monomers with different hydrophilicity and spacer carbon chain length on the degree of conversion (DC), wettability (contact angle), water sorption (WS) and ultimate tensile strength (UTS) of experimental one-step self-etch adhesives (1-SEAs).MethodsA series of standard resin blends was prepared with each formulation containing 15mol% of each acidic monomer. The structural variations of the acidic monomers were MEP (spacer chain with 2 carbons), MDP (10-carbons), MDDP (12-carbons), MTEP (more hydrophilic polyether spacer) and CAP-P (intermediate hydrophilicity ester spacer). Dumbbell-shaped and disc specimens were prepared and tested for UTS and WS, respectively. DC was assessed by FTIR, while the wettability of each 1-SEA was evaluated on glass slides and flat dentine surfaces. Results were analysed with one-way ANOVA and Tukey's test (p0.05).ConclusionAt similar molar percentage, different acidic functional monomers induced similar degree of conversion and different UTS when included in a 1-SEA. However, the inclusion of highly hydrophilic monomer may increase the wettability on dentine and the WS.

Este estudo in vitro avaliou o efeito do uso de própolis associada a suspensão de Biosilicato na resistência de união (RU) à dentina de restaurações em compósito. Foram selecionados 320 dentes molares humanos hígidos e preparadas cavidades oclusais (5 mm de comprimento, 4 mm de largura e 4 mm de profundidade) utilizando brocas carbide. Metade das amostras foram submetidas a protocolos Des-Re para formação de cárie artificial. Posteriormente, todos os dentes foram separados em oito grupos (n = 20) de acordo com o tratamento recebido antes do adesivo (Single Bond Universal - 3M ESPE): Grupo Controle - Sistema Adesivo; Grupo CHX - Cloredixina a 0,12% (CHX); Grupo Bio - Suspensão de Biosilicato a 10% (Bio); Grupo P16 - Extrato de própolis com baixo teor de polifenóis (P16); Grupo P45 - Extrato de própolis com alto teor de polifenóis (P45); Grupo CHX Bio - CHX + Bio; Grupo P16 Bio - P16 + Bio; P45 Bio - P45 + Bio. Após restauração (Filtek Z350, 3M ESPE), as amostras foram seccionadas em formato de palitos, divididos e armazenados em água destilada a 37 ºC por 24 horas, 6 meses e 1 ano. Após o período de armazenamento, foram submetidos ao teste de microtração (0,5 mm/min). Os dados foram analisados (ANOVA de dois fatores, teste de Bonferroni, p < .05), os padrões de fratura observados com microscópio óptico (VH-M100, Keyence) e MEV (EVO MA10, ZEISS); e a interface adesiva, através da MET (JEM-1010, JEOL). A associação de tratamentos resultou em maior RU (p < .05) nos dentes cariados em relação às amostras Controle, testados após 24 horas, sem diferença entre si (p > .05). Entre os hígidos testados após 6 meses, o grupo P16 mostrou maior RU que os grupos Bio e Controle (p < .05). Dentre os dentes cariados, o grupo P45 mostrou maior RU do que o grupo CHX Bio (p < .05) quando testados após 1 ano. O envelhecimento das amostras só foi significativo (p < .05) para os substratos cariados, de forma que houve menor RU após 6 meses para o grupo P45 Bio e após 1 ano para o grupo CHX Bio. As imagens em MEV demonstraram que substratos hígidos apresentam padrão clássico de condicionamento obtido com sistemas self-etch. Nos cariados, nota-se maior remoção da smear layer e formação dos tags de resina em maior quantidade. Encontraram-se túbulos mais expostos e fibrilas colágenas desorganizadas. Foi possível identificar partículas de Biosilicato nos grupos tratados com esse biomaterial. Nos substratos cariados, foi possível identificar partículas de própolis sobre a dentina tratada. Na MET foi observada boa interação do adesivo com as fibrilas colágenas e a formação da camada híbrida. No substrato cariado percebe-se um tecido conjuntivo mais frouxo e desorganizado. Foi também possível identificar partículas de Biosilicato e do extrato de própolis. O tratamento com própolis com baixo teor de polifenóis, resultou em melhor resistência de união em substrato hígido após 6 meses de envelhecimento. A associação de tratamentos com Biosilicato promove melhor resistência de união após 24 horas em substratos cariados. Não houve diferença na resistência de união em virtude do envelhecimento no substrato hígido. O padrão de fratura mais prevalente foi o não adesivo, que aumentou à medida que houve maior tempo de envelhecimento. This in vitro study evaluated the effect of the use of propolis associated with Biosilicate suspension on the bond strength (BS) of composite restorations to dentin. 320 sound human molars were selected and occlusal cavities (5 mm length, 4 mm width and 4 mm depth) were prepared with carbide burs. Half of them were submitted to Des-Re protocols for development of artificial caries. Then, all teeth were separated into eight groups (n = 20) according to the treatment received before the adhesive system (Single Bond Universal - 3M ESPE): Control Group - Adhesive System; CHX Group - 0,12% Chlorhexidine (CHX); Bio Group - 10% Biosilicate suspension (Bio); P16 Group - Propolis extract with low levels of polyphenols (P16); P45 Group - Propolis extract with high levels of polyphenols (P45); CHX Bio Group - CHX + Bio; P16 Bio Group - P16 + Bio; P45 Bio Group - P45 + Bio. After restorations (Filtek Z350, 3M ESPE), samples were sectioned into sticks, separated and stored in distilled water at 37 ºC for 24 hours, 6 months and 1 year. After that, the sticks were submitted to microtensile test (0,5 mm/min). Data was analyzed (2-way ANOVA, Bonferroni\'s Test, p < .05), fracture patterns were observed with optical microscope (VH-M100, Keyence) and SEM (EVO MA10, ZEISS); and the adhesive interface, under TEM (JEM-1010, JEOL). In caries-affected dentin (CAD), the association of treatments resulted in higher BS (p < .05) compared to Control group, tested after 24 hours, with no difference among them (p > .05). Among the sound dentin (SD) tested after 6 months, P16 group showed higher BS than Bio and Control groups (p < .05). On CAD tested after 1 year, P45 group presented higher BS than CHX Bio Group (p < .05). Aging was significant (p < .05) for CAD; thus, there was lower BS after 6 months for P45 Bio group and after 1 year for CHX Bio group. SEM displayed that SD present the classical etching pattern obtained with self-etch systems. Among CAD, there was greater removal of smear layer and higher amount of resin tags. It was also found dentinal tubules more exposed and disorganized collagen fibrils. It was identified Biosilicate particles in groups treated with this biomaterial. On CAD, it was possible to identify propolis particles on the treated dentin. TEM showed good interaction between adhesive and collagen fibrils, and the formation of the hybrid layer. In CAD, a looser and more disorganized connective tissue was noticed. It was also identified Biosilicate and propolis particles. The treatment with propolis with low levels of polyphenols resulted in the best bond strength on sound dentin after 6 months of aging. The association of treatments with Biosilicate promoted the best bond strength after 24 hours on caries-affected dentin. On sound substrates, there was no difference in bond strength due to aging. The most prevalent fracture pattern was the non-adhesive fracture, which increased with longer aging periods.