Year Of Water Storage Research Articles

Influence of titanium dioxide nanotubes with alkyl ammonium alkyl bromide on the physicochemical properties and adhesion of experimental adhesive resins to dentin

ObjectiveThis study evaluated the effect of the incorporation of titanium dioxide nanotubes with alkyl trimethyl ammonium bromide (ntTiO2/ATAB) into experimental adhesive resins on their physicochemical properties and adhesion to dentin. Materials & methodsThe experimental adhesive resins were formulated with 66.66 wt% Bis-GMA and 33.33 wt% HEMA, photoinitiator with addition of ntTiO2/ATAB (1:1) in different concentrations: G1%, G2.5%, and G5%. One groups with no ntTiO2/ATAB addition was used as control (G0%). An optical tensiometer was used to analyze the contact angle (COA) by the sessile drop method (distilled water and α-bromonaphthalene) (n = 5), while the surface free energy (SFE) was calculated using Owens-Wendt-Rabel-Kaelble method. Flexural strength (FS) test (three-point bending) of polymerized adhesive samples was performed according to ISO 4049:2019 (n = 10) after 24 h or one year of water storage at 37 °C, as well as for the microtensile bond strength (μTBS) test, in which a commercial adhesive (GSBMP) was also used as control (n = 10). The adhesive-dentin interfaces were evaluated by scanning electron microscopy and X-ray spectrometry (n = 5). Data were analyzed by one-way (COA and SFE), two-way (FLE and μTBS) ANOVA and Tukey's test (α = 0.05). ResultsG5% showed the highest COA with nonpolar liquid and higher SFE than G0%. The G5% showed decreased FS compared to G0%. The μTBS of both controls (G0% and GSBMP) decreased after one year. TiO2/ATAB-containing adhesives to dentin showed no significant decrease after one year. All adhesives formed hybrid layer and the resin tags inside the dentinal tubules. ConclusionsThe incorporation of 1 and 2.5% of ntTiO2/ATAB into experimental adhesive resins did not impar the SFE. After one year, any concentration of ntTiO2/ATAB reduced the FS compared with control, but did not impair the μTBS.

Does the absence of HEMA in universal adhesive systems containing MDP affect the bonding properties to enamel and dentine? A one-year evaluation

ObjectivesTo evaluate the effect of the absence of HEMA in commercial universal adhesives containing MDP on the adhesive properties of dentine and enamel immediately and after one year of water storage. Methods144 third molars were used to evaluate bonding to dentine (n = 64) and enamel (n = 80). For each substrate, teeth were divided into eight experimental groups, following the main variables: 1) Adhesives: Scotchbond Universal/SBU; Gluma Bond Universal/GBU; Solare/SUB and Zipbond Universal/ZIP; 2) Adhesive strategies: etch-and-rinse/ER and self-etch/SE; and 3) Time: immediately and after one year of water storage. For both substrates, after restoration, the specimens were sectioned, and the adhesive interfaces tested by bond strength (μTBS in dentin and μSBS in enamel) or nanoleakage (NLD = dentin and NLE = enamel). The evaluation of μTBS, μSBS, NLD and NLE was performed immediately and after one year of water storage. The data for each substrate and property were subjected to three-way repeated measures ANOVA and Tukey's test (α = 0.05). ResultsThe SBU and ZIP showed the highest μTBS, μSBS, and lower NLD values when compared to GBU and SUB for both strategies and storage time (p = 0.001). ER showed higher values of μTBS and μSBS when compared to the SE strategy (p = 0.001) for both storage time, except for SBU. For all adhesives and adhesive strategies evaluated, lower NLD was observed in the immediate time when compared to 1 year (p = 0.0002). ConclusionConsidering that two HEMA-free universal adhesives, namely Gluma Universal Bond and Solare Universal Bond, exhibited lower bonding performance compared to one HEMA-free adhesive universal adhesive (ZipBond). Clinicians should also consider additional factors such as the solvent used and pH when choosing between HEMA-free and MDP-containing universal adhesives. Clinical significanceThe adhesive efficacy of commercial MDP-containing universal adhesives and HEMA-free alternatives on dentin and enamel appears to be contingent upon the specific material employed, in comparison to a HEMA-containing adhesive.

Effect of silver diamine fluoride on the longevity of the bonding properties to caries-affected dentine

ObjectivesThis study aimed to evaluate the adhesive properties in dentine after the application of silver diamine fluoride (SDF) on carious dentine lesions immediately and after 2 years of water storage. Methods96 human molars used were subjected to artificial dentine caries production, and then randomly divided into 12 experimental groups according to 1. application of an SDF solution (carious dentine lesion without SDF treatment [control], with 12 % silver diamine fluoride [SDF 12 %] or 38 % silver diamine fluoride [SDF 38 %]); 2. Universal adhesives (Clearfil Universal Bond Quick [CUQ] and Single Bond Universal [SBU]); 3. adhesive strategy (etch-and-rinse [ER] and self-etch [SE]). After restoration, the specimens were sectioned and submitted to the microtensile bond strength test (μTBS) and energy-dispersive X-ray spectrometry analysis (SEM/EDX). All tests were performed immediately and after 2 years of water storage. Data from the μTBS were analyzed using four-way ANOVA and Tukey's test (α = 0.05). ResultsOnly the interaction of factors 'SDF' vs 'time' was significant (p = 0.03). After 2 years of storage, the groups where SDF was applied showed higher μTBS values compared to the control group. No significant decrease in μTBS values was observed for SBU when comparing immediate and 2-year results, but a significant reduction in μTBS values was observed after 2 years for CUQ. ConclusionIndependent of the adhesive strategy, the use of SDF may be a promising alternative to maintain the bonding of universal adhesives to carious dentinal lesions. Clinical significanceThis study may clarify and support clinicians regarding the longevity of resin-based restoration in caries-affected dentine treated with silver diamine fluoride.

Evaluation of Microbiological Susceptibility and Long-term Adhesive Properties to Dentin of Primers with Terminalia catappa Linn.

To investigate the antibacterial effects of Terminalia catappa Linn (TCL) leaf extracts at different concentrations and the effects of these extracts used as primers on the long-term adhesive properties of two universal adhesives. After extract preparation, the antimicrobial and antibacterial activities of TCL against Streptococcus mutans (UA 159) were assessed in microdilution assays to provide the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Additionally, to provide quantitative data on the ability of TCL extract to reduce cell viability, colony forming units (CFU) were counted. To examine adhesive properties, 288 human molars were randomly assigned to 32 experimental conditions (n = 9) according to the following variables: (1) treatment agent: negative control (untreated surface), and primers at concentrations of 1xMIC, 5xMIC, and 10xMIC; (2) adhesives: Scotchbond Universal (SBU) and Futurabond Universal (FBU); (3) adhesive strategy: etch-and-rinse (ER) or self-etch (SE); and (4) storage time: 24 h or after 2 years. Primers were applied for 60 s, upon which the teeth were incrementally restored and sectioned into adhesive-dentin bonded sticks. These were tested for microtensile bond strength (μTBS) and nanoleakage (NL) after 24-h and 2-year water storage, as well as in-situ degree of conversion (DC) at 24 h. The chemical profile of the hybrid layer was determined via micro-Raman spectroscopy. Biofilm assay data were analyzed using the Kruskal-Wallis test; the pH of culture media and the chemical profile were analyzed by one-way ANOVA. The adhesive properties (µTBS, NL, DC) were evaluated using a four-way ANOVA and Tukey's test. Significance was set at 5%. Similar values of MIC and MBC were observed (2 mg/ml), showing bactericidal potential. CFU analysis demonstrated that concentrations of 5xMIC and 10xMIC significantly inhibited biofilm formation (p < 0.001). The application of the TCL primer at all concentrations significantly increased the immediate μTBS and DC, and decreased the immediate NL values when compared to the control group (p < 0.05), regardless of the adhesive and adhesive strategies. Despite an increase in the NL values for all groups after 2 years (p > 0.05), in groups where the TCL primer was applied, the μTBS remained constant after 2 years for both adhesives, while a decrease in the μTBS was observed in the control groups (p < 0.05). Usually, 10xMIC showed better results than 1xMIC and 5xMIC (p < 0.05). The application of TCL promoted cross-linking; cross-linking rates increased proportionally to the concentration of TCL (p < 0.05). Primers containing TCL promoted bactericidal and bacteriostatic action, as well as cross-linking with dentin, while maintaining the adhesive properties of the adhesive-dentin interface after 2 years of water storage.

Long-term Evaluation of Dentin Bonding Properties of the Photoinitiator System Contained in Universal Adhesives Used in Fiber-Post Luting Procedures.

This study evaluated the long-term push-out bond strength (PBS) and nanoleakage (NL) of universal adhesives with different photo-initiator systems in the root canals of teeth in which fiber posts were luted. One-hundred twenty endodontically treated human premolars were randomly divided into 12 groups based on the following factors: adhesives (Scotchbond Universal [SBU], Ambar Universal [AMB], and Ambar Universal APS [AMB-APS]); adhesive strategy (etch-and-rinse and self-etch), and time of testing (immediately vs after 2 years). The posts were cemented, sectioned into slices, tested for PBS at 0.5 mm/min, and examined for NL using scanning electron microscopy immediately thereafter or after 2 years of water storage. Data were evaluated using a four-way ANOVA (root thirds vs time vs universal adhesive vs adhesive strategies) and Tukey's test (α = 5%). For both evaluation times, AMB-APS demonstrated no significant difference in the PBS or NL when different radicular thirds were compared (p > 0.05). However, for SBU and AMB, the cervical third demonstrated higher PBS and lower NL than those of the apical third at both time points (p < 0.0001). AMB-APS exhibited higher PBS and lower NL in the apical third in comparison with SBU and AMB (p < 0.0001). SBU and AMB displayed a significant decrease in the PBS and increased NL after 2 years (p < 0.0001), whereas AMB-APS demonstrated no significant signs of degradation even after 2 years of water storage (p > 0.05). Independent of the root third evaluated, the universal adhesive containing APS photo-initiator system demonstrated bonding stability at the adhesive interface between the root canal and fiber posts, even after 2 years of water storage.

Effect of Sodium Ascorbate, Grape Seed Extract, and Aloe Vera Application after In-Office Bleaching on the Bond Strength of Enamel: A 3-Year Evaluation

Introduction. Dental bleaching is the first choice to improve smile esthetics, but, in some cases, it needs to be associated with resin composite restoration to obtain a satisfactory result. Unfortunately, the bonding of resin-based materials can be impaired due to residual oxygen molecules, which can decrease the durability of the restoration. Objectives. To evaluate the effect of the antioxidant application on the bond strength of bleached enamel after 24 hr and 3 years of water storage. Methods. In total, 84 bovine teeth were used in this study. Of these, 77 were bleached with 35% hydrogen peroxide in a single session for three cycles of 15 min. Then, the specimens were divided into groups (n = 7 each): control (without bleaching), without antioxidant (WA) use; application of 10% sodium ascorbate (SA) gel, grape seed (GS) extract, and aloe vera (AV). The restorative procedure was performed immediately after bleaching, 7 and 14 days after bleaching. Specimens were sectioned and evaluated using microtensile bond strength (μTBS). Half of the resin-enamel sticks were tested after 24 hr, and the remaining half after 3 years of water storage. µTBS data were analyzed using a three-way analysis of variance, Tukey’s test, and Dunnett’s test. Results. The lowest µTBS values were observed when the restoration was performed immediately after bleaching in the AV, GS, and WA groups when compared with the SA group ( p &lt; 0.005 ). However, no significant differences were observed among all groups after 3 years of water storage ( p &lt; 0.001 ). Conclusions. SA at 10% was the most effective antioxidant agent for improving the immediate bond strength. However, independent of the antioxidant agent used, the bond strength values were maintained or recovered after 3 years of water storage. SA at 10% could be used to avoid delayed bonding procedures after in-office whitening without compromising bond strength over time. Clinical Significance. The use of antioxidants after dental bleaching can be effective in improving the bonding durability of the adhesive restorations.

Does the application of dimethyl sulfoxide improve resin bonding to eroded dentine? Four-year in vitro evaluation.

To evaluate the effect of dimethyl sulfoxide (DMSO) on the microtensile bond strength (µTBS) and nanoleakage (NL) of universal adhesives on eroded dentine, immediately and after four years of water storage. Sixty-four sound human molars were distributed into 16 groups according to (1) Dentine surface (sound and eroded dentine); (2) dimethyl sulfoxide application (with or without); (3) Application mode (etch-and-rinse or self-etch) and (4) Storage time (immediate and four years). One mild universal adhesive was used (Scotchbond Universal). The restoration was then performed with a composite resin and the specimens were sectioned into resin-dentine bonded sticks. Resin-dentine bonded sticks were tested (immediately and after four years of water storage) for µTBS (0.5mm/min) or used to assess NL. Data on μTBS and NL were analyzed using four-way ANOVA and Tukey's test (α=0.05). Only the 3-way cross-product interaction 'substrate vs DMSO vs time' was statistically significant (p=0.007). Eroded dentine showed a lower mean of µTBS and a higher mean of NL values than sound dentine. However, when DMSO was applied, no significant decrease of μTBS or NL values was observed after four years of water storage, regardless of adhesive strategies, or dentine evaluated, when compared to immediate results. Water-based DMSO pre-treatments not only prevent degradation of MDP-containing simplified adhesives but also serve as a potential alternative to improve long-term bonding properties to eroded dentine. The versatility of using a single pre-treatment for both self-etch or etch-and-rinse bonding to eroded dentin may facilitate future clinical applications.

Bonding performance of universal adhesives to eroded dentine: A 6-year evaluation

ObjectivesTo evaluate the microtensile bond strength (µTBS) and nanoleakage (NL) of several universal adhesives to eroded dentine (ED) using etch-and-rinse (ER) and self-etch (SE) strategies, immediately and after 6 years of water storage. Material and methodsFour hundred and eighty human molars were distributed into 60 groups according to dentine substrate (sound dentine [SD], eroded with soft drink, or eroded with citric acid), application method of the adhesive (SE or ER), and the adhesives used: 1. All-Bond Universal, 2. Ambar Universal, 3. Clearfil Universal, 4. Futurabond U, 5. One Coat 7 Universal, 6. Peak Universal Bond, 7. Prime&Bond Elect, 8. Scotchbond Universal, 9. Tetric n-bond Universal, and 10. Xeno Select. The restoration was then performed with a composite resin, and the specimens were sectioned into resin-dentine bonded sticks. The sticks were tested (immediately or after 6 years of storage) for µTBS (0.5 mm/min) or used to assess NL. The eroded dentine surfaces were also examined using FE-SEM to evaluate the NL. Data for µTBS were analyzed by four-way ANOVA and Tukey's post-hoc test (a = 0.05), and the NL was analyzed by Kruskal–Wallis and the Wilcoxon Signed Rank Sum test (a = 0.05). ResultsIn ED, there was no difference in μTBS and NL between ER and SE strategies (p > 0.05). Most μTBS and NL values obtained for ED were lower and higher, respectively, than those for SD (p < 0.005). Additionally, the worst results (μTBS and NL) were observed for erosion with citric acid groups in comparison with erosion with soft-drink groups (p < 0.007). After 6y, μTBS was generally lower and NL higher for all substrates, adhesives, and strategies (p < 0.05), except for AMB, SBU, and TEU in dentine eroded with citric acid. The lowest μTBS and highest NL values were observed for ABU, FBU, OCU, PUB, PBE, and XEN in both types of eroded dentine and evaluation times (p < 0.002). Conclusion: The use of MDP-containing adhesives seems to be essential to maintain adhesion to eroded dentine. However, other factors such as acidity should be considered. Clinical significanceThe bonding of eroded dentine is a challenge. However, the use of MDP-containing universal adhesives showed less degradation after long-term evaluation.

Effect of irradiance and exposure time on the adhesive properties of universal adhesives after 2years of storage.

This study aims to evaluate the effects of exposure time and irradiance on the dentin bonding properties (microtensile bond strength (μTBS) and nanoleakage (NL)) of the Clearfil Universal Bond Quick (CUQ) adhesive and Scotchbond Universal Adhesive (SBU) immediately and after 2years of water storage. Hence, 128 human molars were randomly assigned to 16 groups based on adhesive strategy, irradiance/exposure times, and storage time for each universal adhesive tested. The adhesives were applied using the etch-and-rinse and self-etch strategies and were light-cured using four different irradiance/exposure times: 1400 mW/cm2 for 5s (1400 × 5), 1400 mW/cm2 for 10s (1400 × 10), 3200 mW/cm2 for 5s (3200 × 5), and 3200 mW/cm2 for 10s (3200 × 10). Then, each sample was restored and sectioned into a resin-dentin bonded stick to be tested for μTBS and NL (immediately and after 2years of water storage). The mean μTBS and NL of all resin-dentin bonded sticks from the same hemi-tooth (factor time) were statistically analyzed using a three-way ANOVA and Tukey's test (a = 0.05). Despite a significant decrease in the μTBS values for all groups after 2years of water storage, the 3200 × 5 group showed higher μTBS values, whereas the 3200 × 10 group showed lower μTBS values for both universal adhesives tested. Although a significant increase in the NL values was observed for all groups after 2years of water storage, the 3200 × 10 group showed higher NL values than the other groups (p < 0.001). Results indicate that light-curing the adhesive layer with 14-16J/cm2 led to an improvement in the stability of the resin-dentin adhesive interface. A longer exposure time (10s) coupled with a higher irradiance (3200 mW/cm2) resulted in a greater degree of degradation of the adhesive interface. To guarantee better stability of the adhesive interface, clinicians could be preferred a light-cured universal adhesive layer with 14-16J/cm2. Higher irradiances should be avoided.

Bond durability of a silane-containing self-adhesive and conventional resin cements to CAD/CAM glass and hybrid ceramics

To evaluate the effect of CAD/CAM materials surface treatments for bonding of different cementing systems on shear bond strength, including conventional and silane-containing resin cements, after 24 h and one year of water storage. Samples (12 mm × 6 mm × 1 mm) of each CAD/CAM material (IPS E.Max; Suprinity; Enamic; Cerec Bloc; IPS Empress) were divided into 4 groups: G1) 4.5% hydrofluoric acid (HFA) + silane + adhesive + RelyX Veneer (conventional); G2) HFA + Clearfil Ceramic Primer + Tooth Primer + Panavia V5 (conventional); G3) HFA + Panavia SA Cement Universal; G4) blasting with Al2O3 + Panavia SA Cement Universal. After the bonding procedures, two resin cement cylinders (1.5 mm × 1.5 mm) were constructed on each sample and tested after 24 h or one year of water-storage, using shear bond strength testing (n = 10). Data were submitted to generalized linear models’ analysis (p < .05). The conventional treatment for glass ceramics with HFA and silanization or priming (G1 and G2) did not necessarily yielded higher bond strength than the simplified technique (G3 and G4). For IPS E.Max and Suprinity, all protocols had bond strength reduction after one year. For Enamic, Cerec Bloc and IPS Empress, G3 did not reduced statistically at one year. Panavia SA Cement Universal seemed not appropriate when IPS E.Max and Suprinity were blasted with Al2O3. On the other hand, the bond strength to etched or blasted with Al2O3 Enamic, Cerec Bloc and IPS Empress showed no difference or was higher than conventional luting protocols.

Micro-Hardness and Fracture Toughness of Thermosens Thermoplastic Material Versus the Conventional Heat-Cured Acrylic Resin After One Year of Water Storage

Micro-Hardness and Fracture Toughness of Thermosens Thermoplastic Material Versus the Conventional Heat-Cured Acrylic Resin After One Year of Water Storage

Effect of Ceramic Conditioners on Surface Morphology, Roughness, Contact Angle, Adhesion, Microstructure, and Composition of CAD/CAM Ceramics.

The objective of this study was to investigate the effect of surface treatments in maximum profile valley depth (Rv), surface roughness (Sa), contact angle (Ca), shear bond strength (SBS) of a light-cured resin cement, microstructure, and composition of two CAD/CAM ceramics: Cerec Blocs/Dentsply Sirona (feldspathic - FEL) and Empress CAD/Ivoclar Vivadent (leucite-reinforced - LEU). The ceramic specimens were submitted to six surface treatments: (1) 5% hydrofluoric acid (HF) - 20 seconds; (2) 5% HF - 60 seconds; (3) 10% HF - 20 seconds; (4) 10% HF - 60 seconds; (5) self-etching ceramic primer (MEP) - 20 seconds; and (6) MEP - 60 seconds. Specimens treated with HF received silane application for 1 minute. Rv and Sa were evaluated in a confocal laser microscope (n=10) and the Ca in a goniometer (n=6). For the SBS test, two resin cement cylinders were bonded to each specimen, one tested after 24 hours in distilled water storage (37°C) and the other after one year (n=10). The microstructures and compositions were analyzed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (n=4). Rv, Sa, and Ca data were analyzed by two-way ANOVA, and the SBS data by three-way ANOVA, all followed by post-hoc Tukey's test (α=0.05). Results: Surface treatments with HF always produced higher Rv and Sa, and lower Ca than MEP 60s for both ceramics. After 1-year water storage, FEL ceramic treated with MEP for 60 seconds produced higher SBS values than HF treatments, whereas for LEU ceramic there were no differences among treatments. Application of MEP for 20 or 60 seconds produced no difference in Rv, Sa, Ca, and SBS for both ceramics. Surface treatments produced considerable differences in ceramic topography, but subtle ones in composition, for both ceramics. Conclusions: The results indicated that for FEL ceramic, MEP application for 60 seconds yielded higher SBS compared with HF etching, while for LEU ceramic the surface treatments did not influence the SBS results.

Are universal adhesives in etch-and-rinse mode better than old 2-step etch-and-rinse adhesives? One-year evaluation of bonding properties to dentin

ObjectivesThis study compared the bonding properties of dentin of three 2-step etch-and-rinse adhesives (2-ERAs) to those of three universal adhesives (UAs) applied with an etch-and-rinse strategy (ER), immediately and after 1 year of water storage. MethodsSixty caries-free molars were divided into 6 groups according to the adhesive systems used (n = 10). The 2-ERA systems included were: 1) Adper Single Bond 2 (SB), 2) Tetric N-Bond (TB), and 3) Ambar (AM); and the UAs systems were: 4) Single Bond Universal (SBU) 5) Tetric N-Bond Universal (TBU), and 6) Ambar Universal (AMU). The occlusal third of each tooth was removed and the adhesives were applied. After the composite build-up, specimens were sectioned and tested for microtensile bond strength (µTBS) and nanoleakage (NL) immediately and after 1 year of water storage. In situ degree of conversion (DC) was only evaluated in the immediate time. For water sorption (WS), solubility (SO), and mass change (MC) tests, 48 disk-shaped specimens were prepared (n = 8) and assessed according to ISO 4049:2009. ResultsUAs showed higher µTBS and lower NL values than 2-ERAs did after 1 year of water storage (p = 0.001). Regarding DC, 2-ERAs showed higher DC values than UAs (p = 0.001). Regarding WS, 2-ERAs showed higher WS values than those of UAs (p = 0.00001), except for AM and AMU. Lower WS was observed for AM than for other 2-ERAs (p = 0.00001). ConclusionThe use of UAs applied with the ER strategy seems to be a more effective technique for maintaining adhesion to dentin substrate than 2-ERAS. Clinical significanceThis study may support clinicians in selecting the most adequate adhesive system to be used in ER strategy in dentin, demonstrating that UAs were more effective, considering the longevity of the resin restorations.

Long-term water sorption/solubility of two dental bonding agents containing a colloidal dispersion of titanium dioxide.

The aim was to analyze the influence of the incorporation of 4% by mass of colloidal dispersion of titanium dioxide (TiO2) nanoparticles on the long-term water sorption and solubility of two commercial universal bonding agents. In vitro studies. A colloidal dispersion of TiO2 nanoparticles was formulated and blended into two commercial dental bonding agents, i.e., Ambar Universal (FGM, Brasil) and G-Premio Bond Universal (GC, America) at 4% by mass. Forty bonding agent discs were fabricated and segregated into four bonding agent groups of 10 discs each, i.e., GA: Ambar Universal (control), GB: Ambar Universal (4% TiO2 incorporated), GC: G-Premio Bond universal (control), and GD: G-Premio Bond (4% TiO2 incorporated). The bonding agent discs were developed by dispensing the bonding agents into a silicone cast of 5 mm diameter and 1 mm depth. After bonding agent discs were desiccated, the cured discs were weighed and kept in distilled water to be evaluated for water sorption and solubility over 1 year storage period. Statistical analysis was performed by independent variable t-test performed using the IBM SPSS software (Chicago, IL: SPSS Inc). The incorporated bonding agent groups (GA and GB) showed significantly lower (P < 0.05) water sorption and solubility following 1 year of water storage in comparison to the control bonding agents. Both GC and GD demonstrated remarkably lower water sorption and solubility than GA and GB. Incorporation of the colloidal dispersion of TiO2 nanoparticles at 4% by mass into the universal bonding agents has significantly reduced their water sorption and solubility contrast to their control groups.

Influence of surface treatment and ageing on the bond strength of resin cement to hybrid and glass-ceramic CAD/CAM materials.

The influence of different surface treatments and ageing on the shear bond strength (SBS) of computer-aided design/computer-aided manufacturing (CAD/CAM) materials is still contentious. Therefore, this study evaluated the effect of surface treatments and ageing on the SBS of resin cement to polymer-infiltrated ceramic network (PICN) and zirconia-reinforced lithium silicate (ZLS) CAD/CAM materials. Specimens of PICN (n=10) and ZLS (n=10) were submitted to four surface treatment groups: 1) 5% hydrofluoric acid etching (HF) + silanisation (SI); 2) Air abrasion (AB)+HF+SI; 3) HF + universal adhesive (UA); 4) AB+HF+SI+UA. The treated specimens were bonded with resin cement cylinders and tested in SBS after 24 h and one year of water storage. Data were assessed by "analysis of variance" (ANOVA) and Tukey test (α=0.05) and failure modes were classified. No significant differences were observed among treatments at each evaluation time (p>0.05). SBS decreased after one year of storage, except for PICN treated with HF+UA (p=0.068). Air-abraded groups displayed a lower SBS reduction for ZLS. PICN and ZLS exhibited predominantly adhesive and mixed failures, but at one year, PICN cohesive failures increased. In conclusion, HF+UA is an effective surface treatment for PICN, while the combination AB+HF+SI+UA was more appropriate for ZLS. The water storage for one year reduced the SBS for most groups.

Effect of dentin pretreatment with dialdehyde carboxymethyl cellulose on dentin properties and long-term adhesion

ObjectivesThe aim of this in vitro study was to evaluate the effect of pretreatment of dentin with different concentrations (0, 1%, 2.5% or 5%) of dialdehyde carboxymethyl cellulose (DCMC) on the biodegradation rates, mechanical properties of the dentin and long-term dentin bonding (μTBS and nanoleakage). MethodsIn all tests, specimens were designated to 4 groups: Control (without DCMC), DCMC1%, DCMC2.5% and DCMC5%. For the biodegradation evaluation, dentin beams (n = 5) were prepared (2x2x6mm), dehydrated, and demineralized. After, the beams were immersed in test solutions for 24h. After, the biodegradation rate was quantified by hydroxyproline assay. The nano-indentation technique was used to measure nanohardness and elastic modulus. 2 mm thick dentin slices (n = 5) were prepared. After dentin etching, the pretreatment solution (according to groups) was applied for 1 min, followed by drying with absorbent paper. After bonding procedure and restoration, the specimens were polished and the nanohardness and modulus of elasticity were evaluated. For μTBS, the dentin of forty-eight teeth (n = 6) was etched and pretreated for 1 min according to groups, the adhesive system was applied, and resin composite buildups were constructed incrementally. Beams (1 mm2) were obtained and μTBS was evaluated after 24h and 1 year of water storage. 2 beams of each tooth were separated for nanoleakage tests (after 24h and 1 year of water storage). ResultsControl and DCMC1% presented higher biodegradation rates when compared to DCMC2.5% and DCMC5%. The nanohardness of dentin and hybrid layer was higher for DCMC1%, DCMC2.5% and DCMC5% when compared to Control. DCMC2.5 and DCMC5% increased the modulus of elasticity of hybrid layer, when compared to Control and DCMC1%. DCMC1%, DCMC2.5% and DCMC5% showed lower immediate μTBS than Control, but they showed no decrease in μTBS and nanoleakage after 1 year of storage. Control showed significant decrease of μTBS and significant increase of nanoleakage after aging. ConclusionsThe use of DCMC as a dentin pretreatment decreased the biodegradation rate, improved the mechanical properties of dentin, and preserved the long-term bond strength.

Long-term Evaluation of Bonding Performance of Universal Adhesives based on Different Dentinal Moisture Levels.

To evaluate the microtensile bond strength (μTBS) and silver nitrate uptake (SNU) of three universal adhesives used in etch-and-rinse (ER) and self-etch (SE) modes on dry, wet, and oversaturated dentin surfaces after 24 h and 1 year of water storage. The morphology of the hybrid layer (MHL) and the degree of conversion (DC) were also evaluated. Human molars were divided into 36 groups according to combinations of the following variables: (i) universal adhesives (Ambar Universal APS [AMB], Prime&Bond Active [PBA], Scotchbond Universal Adhesive [SBU]), (ii) adhesive strategies (ER or SE), (iii) moisture level (dry, wet, or oversaturated dentin surface), and (iv) storage time (24 h or 1 year). After restoration, the specimens were sectioned into resin-dentin sticks and tested for μTBS and SNU according to storage time. For MHL, the specimens were sectioned and evaluated after 24 h using SEM. DC was evaluated using FTIR. ANOVA and Tukey's test were used for statistical analyses (5%). When 24-h vs 1-year data were compared, there was a significant decrease in μTBS and an increase in SNU values for the majority of experimental groups (p < 0.0001). On dry (ER) and oversaturated (ER and SE) dentin, AMB showed higher μTBS than did PBA (p < 0.00001). No significant decrease in μTBS was observed when universal adhesives were applied in the SE mode to dry dentin (p > 0.05). Regarding SNU, at all moisture levels, AMB showed lower SNU values than SBU (p < 0.001). Regarding MHL, SBU showed several imperfections when applied to oversaturated dentin in comparison with AMB and PBA. Regarding DC, when dentin was kept dry or was oversaturated, AMB showed a higher DC than PBA (p < 0.0001). The behavior of the different universal adhesives evaluated did not vary when applied to wet or dry dentin. However, the results with oversaturated dentin were dependent on the universal adhesive. Independent of the moisture level and the universal adhesive evaluated, significant degradation of the bonding properties occurred after 1 year of water storage, with the exception of universal adhesives applied to dry dentin in the SE strategy.

Effect of build orientation in accuracy, flexural modulus, flexural strength, and microhardness of 3D-Printed resins for provisional restorations

PurposeThis study evaluated the effects of 3D-printing build orientation on accuracy, flexural modulus (FM), flexural strength (FS), and microhardness of selected, commercial 3D-printed provisional resins (3DRs). Material and methodsPMMA CAD/CAM provisional material (Vita Temp/Vita) served as Control. Four 3DRs (Cosmos-SLA/Yller, Cosmos-DLP/Yller, PriZma-Bioprov/Makertech, Nanolab/Wilcos) were used in three printing orientations (0°, 45°, and 90°). Printed samples were cleaned with isopropyl alcohol prior to post-curing in specific post-curing units. For each group, 20 bar-shaped samples (25 × 2x2 mm) and ten disc-shaped samples (15-mm diameter, 2.5-mm thick) were obtained. The dimensions of bar samples were measured and the mean percent errors were compared to the reference (digital) values to obtain “accuracy” (n = 20). Samples were then aged in distilled water at 37 °C and half were submitted to a three-point bend test in a universal testing machine after 24 h and the other half after 1 year (n = 10). Disc samples were polished prior to microhardness evaluation (n = 10). Microstructure and elemental composition of filler particles in the 3DRs were analyzed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (n = 3). Accuracy and microhardness were submitted to two way-, and FM and FS to three way-ANOVA, followed by Tukey’s tests. Results of experimental groups were compared to a milled PMMA Control using Dunnett’s tests, and Student’s t-tests compared FM and FS to Control at different aging periods (α = 0.05). ResultsExcept for Cosmos-DLP, the 90° orientation demonstrated the best overall accuracy in all dimensions evaluated. The overall accuracy of Cosmos-SLA was not significantly different from Control and higher than other 3DRs. The FM of all 3DRs was lower than Control, regardless of orientation and aging period. After 1 year of aging, FS of 45°-Cosmos-SLA and all orientations of PriZma were not different from Control, while 90°-Cosmos-SLA was higher. Build orientation had no influence on microhardness of the 3DRs: Nanolab was the only resin harder than Control. Very few nanometric spherical filler particles were found in Cosmos-SLA, Cosmos-DLP, and PriZma, while Nanolab presented higher number of particles having irregular shapes and sizes. ConclusionsIn general, although build orientation did not influence microhardness results, the 90° -orientation resulted in the best overall accuracy for most 3DRs. After 1-year water storage, Cosmos-SLA printed vertically showed the highest FS, while the PMMA Control obtained the highest FM for both aging periods.

Four-year effects of copper-nanoparticles on durability of resin-dentin interfaces

ObjectiveTo evaluate the effect of the addition of copper nanoparticles (CuNp) at different concentrations in an etch-and-rinse (ER) adhesive on the resin-dentin bond strength (μTBS), nanoleakage (NL) and presence of copper nanoparticles within the hybrid layer, in the immediate time (IM) and after 4 years of water storage (4 y). Material and methodsSeven experimental adhesive systems were formulated according to the concentration of CuNp (0 [control], 0.0075, 0.015, 0.06, 0.1, 0.5 and 1 wt%) added into the ER adhesive Ambar (FGM). The adhesives were applied to flat occlusal dentin surfaces after acid etching, and then a resin restoration was build-up. Specimens were longitudinally sectioned to obtain resin-dentin beam-like, which were used for evaluation of μTBS, NL and identification of presence of CuNp within the hybrid layer, at the IM and 4 y periods. ANOVA and Tukey's test were applied (α = 0.05). ResultsAddition of CuNp up to 0.5% in the adhesive system significantly increased the μTBS at IM (p < 0.05). After 4 y, copper-containing adhesives showed higher values of μTBS compare to control (p < 0.05). All adhesives showed a significant decrease in μTBS over time (p < 0.05). Significant decreases in the NL values were observed in the copper-containing adhesives in IM in comparison with control group (p < 0.05). After 4 y, all copper-containing adhesives showed significantly decreased NL values compare to control group. All adhesives showed a significant increase in NL over time (p < 0.05). Presence of copper within the hybrid layer was identified from 0.06% concentration even after 4 y of water storage. ConclusionThe addition of copper nanoparticles from 0.06% to 0.5% concentrations in an adhesive decreased the degradation of the adhesive interface, mainly because it is still present in the hybrid layer even after 4 years of water storage.

Bonding of Resin Cements to Ultra-Translucent Zirconia After Aging for 24 Hours and 1 Year.

To evaluate the effect of different luting techniques on the shear bond strength (SBS) of ultra-translucent multi-layered zirconia (UTML) after 24 hours and 1 year of water storage and to analyze the influence of primers on the wettability of the UTML MTU-6 surface. Four commercial resin cements were evaluated: Variolink Esthetic LC (Ivoclar Vivadent); RelyX Ultimate (3M); Estecem II (Tokuyama); and Panavia V5 (Kuraray Noritake). Panavia V5 was tested with and without Panavia V5 Tooth Primer (Kuraray Noritake). The SBS immediately after cement/primer application and after aging, scanning electron microscopy of the surfaces, and the contact angle of the primers on the UTML surfaces were analyzed. At 24 hours, Panavia V5 with Tooth Primer exhibited the highest SBS. After 1 year, the SBS of Variolink Esthetic LC and Panavia V5 with Tooth Primer decreased, and RelyX Ultimate increased. There was no statistical difference between RelyX Ultimate and Panavia V5 with Tooth Primer at 1 year. For all groups, the rate of adhesive failures increased after 1 year. The highest contact angle was observed on the control (no primer) group, and the lowest contact angles were obtained when the YSZ surface was treated with Scotchbond Universal and the combination of Clearfil Ceramic Primer Plus and Tooth Primer. Clinicians should prefer 10-MDP-based cementation systems that can be properly polymerized to achieve a stable long-term bond strength to YSZ restorations. Also, the use of ceramic primers improves the capability of the cement to establish an intimate contact with the intaglio of the restoration.