Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 12.416
Filtrar
1.
J Colloid Interface Sci ; 607(Pt 1): 431-439, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509117

RESUMO

Polydopamine (PDA)-based self-adhesive hydrogel sensors are extensively explored but it is still a challenge to construct PDA-based hydrogels by free radical polymerization. Herein, a new approach to construct self-adhesive hydrogels by conducting free radical polymerization in both aqueous phase and micelle phase is developed. The following two-phase polymerization processes account for the formation of the self-adhesive hydrogels. The first one is the polymerization of acrylamide (AM) and dopamine (DA) in aqueous phase to form adhesive component PAM-PDA (PAM, polyacrylamide; PDA, polydopamine). The second one is the polymerization of hydrophobic monomer 2-methoxyethyl acrylate (MEA) in micelles of an amphiphilic block copolymer Pluronic F127 diacrylate (F127DA). The poly(2-methoxyethyl acrylate) (PMEA) networks help to maintain the high robustness of the hydrogel. Because PMEA and PDA form in relatively separated phases, the inhibition effect of PDA on the free radical polymerization process of PMEA is weakened. Based on this mechanism, mechanically strong and adhesive hydrogels are achieved. The introduced ions during preparation process, such as Na+, OH- and K+, endow the resulting hydrogels ionic conductivity. Resistive strain sensor of the hydrogel achieves a high gauge factor (GF) of 5.26, a response time of 0.25 s and high sensing stability. Because of the adhesiveness, such hydrogel sensor can be applied as wearable sensors in monitoring various human motions. To further address the freezing and drying problems of the hydrogels, organohydrogels are constructed in glycerol-water mixed solvent. The organohydrogels exhibit outstanding anti-freezing property and moisture retention ability, and their adhesiveness is well maintained in subzero conditions. Capacitive pressure sensors of the organohydrogels possessing a GF of 2.05 kPa-1, high sensing stability and reversibility, are demonstrated and explored in monitoring diverse human motions.


Assuntos
Adesivos , Hidrogéis , Radicais Livres , Humanos , Micelas , Polimerização , Cimentos de Resina , Água
2.
Braz. j. oral sci ; 20: e211656, jan.-dez. 2021. tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1253734

RESUMO

Aim: This study evaluated the water sorption and solubility of a light-cured resin cement, under four thicknesses and four opacities of a lithium disilicate ceramic, also considering three light-emitting diode (LED) units. Methods: A total of 288 specimens of a resin cement (AllCem Veneer Trans ­ FGM) were prepared, 96 samples were light-cured by each of the three light curing units (Valo ­ Ultradent / Radii-Cal ­ SDI / Bluephase II ­ Ivoclar Vivadent), divided into 16 experimental conditions, according to the opacities of the ceramic: High Opacity (HO), Medium Opacity (MO), Low Translucency (LT), High Translucency (HT), and thicknesses (0.3, 0.8, 1.5, and 2.0 mm) (n = 6). The specimens were weighed at three different times: Mass M1 (after making the specimens), M2 (after 7 days of storage in water), and M3 (after dissection cycle), for calculating water sorption and solubility. Results: The higher thickness of the ceramic (2.0 mm) significantly increased the values of water sorption (44.0± 4.0) and solubility (7.8±0.6), compared to lower thicknesses. Also, the ceramic of higher opacity (HO) generated the highest values of sorption and solubility when compared to the other opacities, regardless of the thickness tested (ANOVA-3 factors / Tukey's test, α = 0.05). There was no influence of light curing units. Conclusion: Higher thicknesses and opacities of the ceramic increased the water sorption and solubility of the tested light-cured resin cement


Assuntos
Cerâmica , Cimentação , Cimentos de Resina , Cura Luminosa de Adesivos Dentários
3.
Braz. j. oral sci ; 20: e211194, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1253930

RESUMO

Aim: The aim of this study was to evaluate the effect of ethanol-conditioned dentin on endodontic sealer penetration into dentinal tubules by confocal laser scanning microscopy (CLSM). Methods: Forty human maxillary anterior teeth were instrumented and divided into four groups (n = 10) according to the drying methods: 1) wet: vacuum only, 2) paper points: vacuum + absorbent paper points, (3) 70% ethanol: 70% ethanol (1 min) + vacuum + absorbent paper points, and (4) 100% ethanol: 100% ethanol (1 min) + vacuum + absorbent paper points. All root canals were filled with resin-based endodontic sealer. Four sections from each third (cervical, middle, and apical) were examined by CLSM. Root canal wall perimeter infiltrated by sealer, maximum depth of sealer penetration, percentage of penetrated area, and fluorescence intensity of rhodamine B were measured. Statistical analysis was performed by analysis of variance and Tukey's tests (α = 0.05). Results: No statistical difference was found when percentage of root canal wall coverage infiltrated by sealer were compared. The groups in which ethanol solutions were used presented greater depth of sealer penetration, higher percentage of penetrated area, and higher fluorescence intensity of rhodamine B (p< 0.05) when compared with the wet and paper point groups. Overall, 100% ethanol produced better results than 70% ethanol, except for rhodamine B intensity (cervical third). In addition, the absorbent paper points drying method behaved better than did vacuum only group, except for rhodamine B intensity (apical third). Conclusion: Ethanol-conditioned dentin improved the penetration of resin-based sealer into dentinal tubules, especially at the concentration of 100%


Assuntos
Humanos , Molhabilidade , Microscopia Confocal , Cimentos de Resina , Dentina , Etanol , Endodontia
4.
Braz. j. oral sci ; 20: e211670, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1254259

RESUMO

Aim: To evaluate the effect of different surface treatments and adhesive approaches on the microshear bond strength of resin cement to a polymer-infiltrated ceramic network (PICN). Methods: PICN blocks were randomly assigned into 9 groups (n=10): CTRL: no treatment; HF: 5% hydrofluoric acid etching; HF-S: HF + silane; HF-S-A: HF-S + adhesive (Adper Single Bond 2); HF-UA: HF + universal adhesive (Single Bond Universal); SB: sandblasting with 50 µm Al2O3 particles; SB-S: SB + silane; SB-S-A: SB-S + adhesive; SB-UA: SB + universal adhesive. Resin cement microcylinders (Ø = 0.96 mm; height = 1 mm) (RelyX Ultimate) were built upon the PICN surface after roughness and contact angle measurements. Next, microshear bonding tests (µSBS) were performed (0.5 mm/min) after water storage (37ºC, 90 days) and thermocycling (12,000 cycles; 5ºC-55ºC). Failure modes were observed under stereomicroscope. Bond strength data were analyzed by two-way ANOVA/Tukey's test and t-tests. Kruskal-Wallis/Dunn's tests were conducted for roughness and contact angle data (α = 0.05). Results: A rougher surface and lower contact angles were observed for Sandblasting. HF-S (18.54 ± 2.03 MPa), SB-S (19.00 ± 1.66 MPa) and SB-UA (18.07 ± 2.36 MPa) provided the highest bond strength values, followed by the other treated groups. The CTRL group resulted in lower bond strength (7.18 ± 2.34 MPa). Conclusion: Hydrofluoric acid etching followed by silane application and sandblasting followed by silane or universal adhesive are useful clinical steps to enhance bonding to PICN. Adhesive applications after HF etching have no advantages in bonding to PICN


Assuntos
Propriedades de Superfície , Cerâmica , Adesivos Dentinários , Cimentos de Resina , Abrasão Dental por Ar , Ácido Fluorídrico
5.
Stomatologiia (Mosk) ; 100(5): 88-95, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34752042

RESUMO

THE AIM OF THE STUDY: Was to review laboratory methods measuring the bond strength of adhesive dental materials to hard tooth tissues. The paper points out the impact of test conditions on the measured strength of adhesive bond to dentine and enamel. Various in vitro studies are discussed, including the analyses of fracture surfaces and test-induced stresses. These studies are found to be helpful to identify particularities, advantages, and limitations of each approach. We present a systematic picture of available bond-strength data aimed at revealing general trends in adhesive performance. No clear superiority of any particular method for determining the bond strength between restoration materials and tooth tissues can be identified on the basis of reviewed literature. Therefore, no single universal approach can be at present proposed for determining the strength of adhesive bond.


Assuntos
Colagem Dentária , Cimentos de Resina , Resinas Compostas , Cimentos Dentários , Materiais Dentários , Análise do Estresse Dentário , Dentina , Humanos , Laboratórios , Teste de Materiais , Resistência ao Cisalhamento
6.
J Contemp Dent Pract ; 22(8): 856-859, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34753835

RESUMO

AIM AND OBJECTIVE: The objective of this study was to monitor the pH stability over a period of 6 months of two-bottle self-etching (SE) primers. MATERIALS AND METHODS: Four commercially available two-bottle SE primer solutions, Adhese SE (Ivoclar Vivadent; Schaan, Liechtenstein), Clearfil SE (Kuraray; Tokyo, Japan), Contax Primer (DMG; Hamburg, Germany), and Enabond SE (Micerium; Avegno (Ge), Italy), containing water as the main solvent were selected. The pH values during a 6-month storage period at intermittent temperature were daily measured by means of a microprocessor-based pH/temperature meter and hence recorded, tabulated, and analyzed. RESULTS: The mean values of overall pH measurements and standard deviation for Adhese SE, Clearfil SE, Contax Primer, and Enabond SE are, respectively, 1.70 (±0.01), 1.72 (±0.01), 1.20 (±0.01), 1.80 (±0.01). One-way ANOVA did not detect any significant change of the mean pH values of all measurements over time. CONCLUSION: The conventional 6-months storage did not affect the pH values of the water-containing primers of two-bottle SE adhesives. CLINICAL SIGNIFICANCE: This study provides evidence that conventional storage under adequate conditions did not affect the pH values of the water-containing primers of two-bottle SE adhesives with different monomer formulations. Clinicians may rely on the known pH value of the selected SE adhesive during shelf-life.


Assuntos
Colagem Dentária , Cimentos de Resina , Condicionamento Ácido do Dente , Análise do Estresse Dentário , Dentina , Adesivos Dentinários , Concentração de Íons de Hidrogênio , Teste de Materiais , Resistência ao Cisalhamento , Água
7.
J Contemp Dent Pract ; 22(8): 876-881, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34753838

RESUMO

AIM AND OBJECTIVE: This study aimed to evaluate the effect of ozonated water used as an irrigant and dentin-cleaning solution on the bond strength of fiberglass pins in vitro, comparing it with the commonly used solutions. MATERIAL AND METHODS: Seventy-seven bovine roots were randomly divided into seven groups according to the irrigant and dentin-cleaning solution to be used: HP/HP, 2.5% sodium hypochlorite; DA/DA, distilled water; CHX/CHX, 2% chlorhexidine; OA/OA, 4 ppm ozonated water; HP/DA; HP/CHX; and HP/OA. In each group, the root canals were endodontically prepared by using the corresponding irrigant and stored in DA; after 7 days, they were cleared and cleaned with the corresponding cleaning solution. The fiberglass pins were cemented by using self-adhesive cement. After 7 days, the roots were sectioned (six discs each) and submitted to the push-out test. The type of fracture was analyzed with a 4.5x stereoscopic magnifying glass. The data were analyzed by the analysis of variance and the Tukey test at a 5% significance level. RESULTS: The OA/OA (11.67), HP/HP (11.21), and HP/OA (9.71) groups showed the highest mean push-out bond strength (MPa) in the cervical third. The same trend was maintained in the middle and apical thirds. CONCLUSION: Ozonated water and 2.5% sodium hypochlorite are the most relevant solutions for root dentin treatment. CLINICAL RELEVANCE: Teeth treated with ozonated water, sodium hypochlorite, and a combination of the two showed greater bond strength than those treated with other solutions.


Assuntos
Colagem Dentária , Técnica para Retentor Intrarradicular , Animais , Bovinos , Cavidade Pulpar , Dentina , Vidro , Teste de Materiais , Cimentos de Resina , Irrigantes do Canal Radicular , Água
8.
Braz Dent J ; 32(4): 106-115, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34787246

RESUMO

The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) on microtensile bond strength (µTBS) between an adhesive system and under 3 dentin conditions. For that, this study evaluated the adhesive interface at initial, after 6 months and 1 year of storage. Forty-eight human third molars were prepared and randomly divided into 3 groups, according to dentin substrates: sound dentin (Sd), caries-infected dentin (Ci) and caries-affected dentin (Ca). The groups were subdivided into two according to the dentin pre-treatment: application of 2% CHX or without pre-treatment (control). The dentin surfaces were etched with 35% phosphoric acid gel and bonded with Adper Single Bond 2 (3M ESPE) adhesive system according to manufacturer's instructions. Subsequently, the specimens were stored in deionized water at 37°C for 24h, 6 months and 1 year. Two additional teeth were used to analyze the bonding interfaces by SEM. Data was submitted to three-way ANOVA in a split plot design and Tukey's test (α = 0.05). The results showed that Ci decreased µTBS values when compared to Ca and Sd, regardless storages time or treatment. Stored samples for 6 months and 1 year decreased the µTBS for the control group, but no difference was found between storages time for the CHX group. As a conclusion, the 2% CHX application after etching showed improved dentin bond strength in the storage time, regardless of the substrates evaluated.


Assuntos
Colagem Dentária , Adesivos Dentinários , Resinas Compostas , Dentina , Humanos , Teste de Materiais , Cimentos de Resina , Resistência à Tração
9.
J Appl Biomater Funct Mater ; 19: 22808000211058867, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34816747

RESUMO

AIM: To investigate push-out bond strength (PBS) of fiber post to radicular dentin after using different cementation techniques. MATERIAL AND METHODS: Sixty single-rooted premolars were disinfected and cleaned by mechanical instrumentation. S1, S2, and SX were used for canal shaping and finishing of the canal was carried out using F1 and F2. This was followed by constant irrigation and smear layer removal using 17%EDTA. The canal was dried filled with gutta-percha and canal space was prepared using a peso reamer. Based on cementation techniques, samples were randomly allocated into six groups. Group 1: One-step Monoblock MC; Group 2: One-step, Monoblock MC-NA (no adhesive) GFP; Group 3: One-step, RX-MC-Monoblock; Group 4: Two-step, RX-MC; Group 5: Two-step, RX-FZ; and Group 6: Two-step RX-FZ-custom post. All specimens were mounted in polyvinyl pipes using acrylic resin up to cement enamel junction. All specimens were mounted in a universal testing machine subjected to push-out forces at a speed of 0.5 mm/min. Five samples from each group were sputter-coated with 6 nm gold thickness for 300 s at 250 mA. The coated specimens were assessed under the scanning electron microscope (SEM). Analysis of variance (ANOVA) and Tukey Kramer multiple comparisons tests were performed to compare means among groups maintaining the level of significance at (p < 0.001). RESULTS: The highest PBS was displayed in RX-MC-Monoblock (199.020 ± 21.432 MPa). Whereas, lowest PBS was found in Monoblock MC-NA (no adhesive)-GFP (76.440 ± 9.468 MPa). Among one-step groups, RX-MC Monoblock exhibited the highest PBS (199.020 ± 21.432 MPa) comparable to one-step Monoblock MC (134.28 ± 19.37 MPa) (p > 0.05). Similarly, among two-steps groups, two-step RX-MC demonstrated significantly higher PBS values than two-step RX-FZ (143.340 ± 23.68 MPa) and RX-FZ-custom post (86.90 ± 7.41 MPa) (p < 0.05). CONCLUSION: One-step RX-MC-Monoblock technique using self-adhesive cement and core foundation composite resin material multicore flow when cured simultaneously exhibited the highest bond integrity of post retention compared to other cementation technique.


Assuntos
Cimentação , Colagem Dentária , Adesivos , Dentina , Guta-Percha , Teste de Materiais , Cimentos de Resina
10.
J Adhes Dent ; 23(6): 497-503, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817965

RESUMO

PURPOSE: The aim of this clinical trial was to compare a self-adhesive flowable resin composite, a highly filled flowable resin composite used in combination with a universal adhesive applied in self-etch mode, and a conventional flowable resin composite used in combination with a universal adhesive applied using two different application modes in occlusal cavities. MATERIALS AND METHODS: Twenty-eight patients received 114 occlusal restorations. Cavities were divided into four groups: CS: a self-adhering flowable (Constic, DMG); GF: a highly filled flowable (G-ænial Universal Flo, GC) in combination with a universal adhesive applied in self-etch mode (G-Premio Bond, GC); TF-SE: a conventional flowable (Tetric N-Flow, Ivoclar Vivadent) in combination with a universal adhesive (Tetric N-Bond Universal, Ivoclar Vivadent) applied in self-etch mode; TF-ER: a conventional flowable (Tetric N-Flow, Ivoclar Vivadent) in combination with a universal adhesive (Tetric N-Bond Universal, Ivoclar Vivadent) applied in etch&rinse mode. Restorations were scored using modified USPHS criteria. Descriptive statistics were performed using chi-squared tests. RESULTS: At 24-month evaluations, none of the restorations were lost. The CS group showed significantly higher bravo scores for marginal adaptation than did the other experimental groups (p = 0.024). Significant changes were seen for CS and GF regarding marginal adaptation compared to baseline. CONCLUSION: Although the self-adhering flowable resin composite exhibited inferior marginal adaptation compared to the highly filled flowable and conventional flowable resin composites, the restored teeth demonstrated a clinically acceptable performance after 24 months.


Assuntos
Restauração Dentária Permanente , Cimentos de Resina , Resinas Compostas , Cimentos Dentários , Adaptação Marginal Dentária , Seguimentos , Humanos
11.
J Adhes Dent ; 23(6): 505-512, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817966

RESUMO

PURPOSE: A new two-step self-etch adhesive (2-SEA) free of hydrophilic monomers was evaluated. Its microtensile bond strength (µTBS) to dentin under various aging conditions, interfacial gap formation, water sorption/solubility, and formation of an acid-base resistant zone (ABRZ) were evaluated and compared with a gold-standard 2-SEA. MATERIALS AND METHODS: The new 2-SEA G2-Bond Universal (G2; GC) was compared to Clearfil SE Bond 2 (CSE2, Kuraray Noritake). Their µTBS to sound coronal dentin was tested after 1 week, 10,000 thermal cycles (TC), 20,000 TC, 6 months and 1 year. Failure mode was determined using scanning electron microscopy (SEM). Gap formation at the interface of 2-mm deep tapered cavities with an enamel border was observed using swept-source optical coherence tomography after 1 day, 1 week, 10,000 TC, and 20,000 TC. In addition, water sorption and solubility of the bonding agents was measured, and ABRZ formation was evaluated using SEM. RESULTS: There was no significant difference in µTBS between G2 and CSE2 (p > 0.05), and the aging conditions had no significant effect on µTBS (p > 0.05). In all groups, cohesive failures prevailed (55%-95%). Interfacial gap formation was initially similar for both adhesives (p > 0.05), but G2 exhibited a significantly lower gap formation than CSE2 after TC (p < 0.05). The water sorption of G2 was significantly lower compared to CSE2 (p < 0.05), and their solubility was statistically similar (p > 0.05). ABRZ of similar thickness was observed with both adhesives. CONCLUSION: The new 2-SEA exhibited stable dentin bonding and increased hydrophobicity resulting from the absence of hydrophilic monomers.


Assuntos
Colagem Dentária , Adesivos Dentinários , Cimentos Dentários , Dentina , Teste de Materiais , Cimentos de Resina , Resistência à Tração
12.
J Adhes Dent ; 23(6): 513-525, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817967

RESUMO

PURPOSE: To investigate the effect of pretreatment protocols involving Papacarie Duo gel and Scotchbond Universal (SU) on the microshear bond strength (µSBS) of resin composite (RC) to hypomineralised enamel (HE). MATERIALS AND METHODS: Specimens of normal enamel (NE) and HE were derived from extracted hypomineralised first permanent molars (FPMs). Based on the colour of demarcated opacities, HE specimens were classified as creamy/white (CW) or yellow/brown (YB). The specimens were randomly allocated into eight groups (n = 20). Each group involved pretreatment with Papacarie Duo gel or no pretreatment, and SU applied in etch-and-rinse (E&R) or self-etch (SE) mode. All specimens were bonded with RC and subjected to µSBS testing. Failure modes were analysed using an optical microscope and SEM. RESULTS: Comparing NE with HE, the following factors were found to be significant (p < 0.001): type of enamel substrate, deproteinising pretreatment, and etching mode. Comparing CW HE with YB HE, a significant interaction between "deproteinising pretreatment" and "etching mode" was demonstrated (p = 0.028). When subjected to the concurrent use of Papacarie Duo gel and phosphoric acid etching, HE specimens showed a significant increase in µSBS (p < 0.001). CONCLUSION: Deproteinising pretreatment using Papacarie Duo gel followed by the application of SU in E&R mode led to increased µSBS of resin composite to HE.


Assuntos
Condicionamento Ácido do Dente , Colagem Dentária , Resinas Compostas , Cimentos Dentários , Esmalte Dentário , Adesivos Dentinários , Teste de Materiais , Cimentos de Resina , Resistência ao Cisalhamento
13.
J Adhes Dent ; 23(6): 527-537, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817968

RESUMO

PURPOSE: To characterize experimental adhesives containing natural antimicrobial agents (proanthocyanidins, apigenin, tt-farnesol) in the primer and to evaluate their anti-caries effect. MATERIALS AND METHODS: Natural agents were incorporated in the primer of an experimental adhesive: 4.5% proanthocyanidins (PA), 1 mM apigenin (API), 1 mM apigenin + 5 mM tt-farnesol (API + FAR), and primer without antimicrobial agent (control). Microtensile bond strength (µTBS) to dentin and nanoleakage were measured immediately (n = 7) and after 1 year of storage (n = 7). Water sorption (WS), solubility (SO), and degree of conversion (DC%) of the adhesives were measured. The hardness loss of enamel (n = 6) and dentin (n = 6) at the restorative margin was evaluated after biofilm formation. RESULTS: DC%, nanoleakage, and immediate µTBS were similar for all groups. After 1 year, API + FAR showed higher nanoleakage and lower µTBS than the other groups, which were similar. WS and SO of API + FAR were lower than in the other groups. PA, API, and API + FAR presented less hardness loss than did the control group. At enamel, PA and API presented less hardness loss than the control and API + FAR groups at distances 50 µm and 100 µm; the hardness loss of enamel was similar for all groups 150 µm from the margin. CONCLUSION: The addition of proanthocyanidins and apigenin to the adhesives decreased the hardness loss of dentin and enamel submitted to biofilm formation, without jeopardizing the physical properties of the adhesives. The combination of apigenin + tt-farnesol decreased the hardness loss of dentin but not of enamel, and decreased the µTBS after 1 year of storage.


Assuntos
Anti-Infecciosos , Colagem Dentária , Cárie Dentária , Cariostáticos , Cimentos Dentários , Dentina , Adesivos Dentinários , Humanos , Teste de Materiais , Cimentos de Resina , Resistência à Tração
14.
J Adhes Dent ; 23(6): 539-548, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817969

RESUMO

PURPOSE: To validate the rationale of using a conventional light-curing resin-based composite (RBC) to lute thick indirect restorations by measuring mini-interfacial fracture toughness (mini-iFT). MATERIALS AND METHODS: Freshly exposed dentin of extracted third molars (n = 64) was immediately sealed with a thin layer of an experimental RBC with a 50 wt% or 75 wt% (IDS) filler load. Two- or 6-mm-thick CAD/CAM composite blocks were luted onto IDS using either pre-heated light-cure or dual-cure luting RBC, with the latter having served as control. Samples were cut into sticks, upon which a notch was prepared at the interface between IDS and luting RBC, prior to being submitted to a 4-point bending test to determine mini-iFT. The results were analyzed using a mixed linear model (LME). Failure mode at the fractured interface was determined using scanning electron microscopy (SEM). RESULTS: LME revealed that mini-iFT was not significantly affected by the composite block thickness (p = 0.39), but by the luting RBC (p < 0.0001) and the IDS RBC filler load (p = 0.0011). Mini-iFT was higher with 50 wt% filler-loaded RBC IDS and when luted using the light-curing RBC. CONCLUSION: This work provides the proof of concept that 2- and 6-mm-thick indirect restorations can safely be adhesively luted with pre-heated conventional light-cure RBC under controlled light-irradiation conditions. This strategy even seems beneficial in terms of mini-iFT compared to using a dual-cure luting RBC. IDS with lower filler content also appeared more favorable.


Assuntos
Colagem Dentária , Cimentos de Resina , Resinas Compostas , Luzes de Cura Dentária , Cimentos Dentários , Análise do Estresse Dentário , Cura Luminosa de Adesivos Dentários , Teste de Materiais , Propriedades de Superfície
15.
J Adhes Dent ; 23(6): 549-555, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817970

RESUMO

PURPOSE: To evaluate the effect of heated and room-temperature hydrofluoric (HF) acid on surface roughness parameters (Ra and Rq) and microtensile bond strength (µTBS) on feldspathic ceramic and lithium-disilicate glass-ceramics. MATERIALS AND METHODS: Disk-shaped samples made from both ceramics were divided into groups according to surface treatment: feldspathic ceramic polished surface (FP), feldspathic ceramic + 60 s of 9% HF acid etching at room temperature (FC), feldspathic ceramic + 60 s of 9% HF acid etching heated to 70°C (F70), lithium-disilicate polished surface only (LP), lithium disilicate + 20 s of 9% HF acid etching at room temperature (LC), and lithium disilicate + 20 s of 9% HF acid etching heated to 70°C (L70). To evaluate Ra and Rq, non-overlapping readings were taken on the surface of each sample with a contact stylus profilometer. To measure microtensile bond strength (µTBS), samples of groups FC, F70, LC and L70 received their corresponding surface treatment, were silanized and then bonded using a dual-cure composite cement to resin composite disks. After 24 h, samples were sectioned to obtain specimens for µTBS. Representative samples from each group were examined using scanning electron microscopy (SEM) to analyze the morphology of the etched surface. The data were analyzed for statistical significance using Welch's ANOVA with the Games-Howell multiple-comparison post-hoc test. RESULTS: For both surface roughness parameters and HF acid etching at room temperature (FC and LC) showed a significant increase (p < 0.001) in surface roughness when compared to polished surfaces (FP and LP). Furthermore, the use of heated HF acid etching significantly increased (p < 0.001) the surface roughness of the ceramic when compared to their counterpart sample of HF acid etching at room temperature. Group L70 obtained the highest µTBS of all groups (29.11 ± 8.26 MPa) and was significantly higher (p < 0.001) than that of the other experimental groups. There were no statistical differences (p > 0.05) between groups FC (19.94 ± 4.14), F70 (18.24 ± 5.29), and LC (17.87 ± 6.96). CONCLUSION: The use of 9% HF acid etching heated to 70°C resulted in significantly higher surface roughness and improved bond strength onto lithium-disilicate glass-ceramic compared to surface HF acid etching at room temperature.


Assuntos
Colagem Dentária , Ácido Fluorídrico , Cerâmica , Porcelana Dentária , Lítio , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície
16.
J Adhes Dent ; 23(6): 569-578, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817972

RESUMO

PURPOSE: To investigate the bond strength and durability of a novel dual-curing composite cement to zirconia under different curing conditions. MATERIALS AND METHODS: Zirconia plates of different thickness (0.5, 1, and 2 mm) were bonded with either a novel dual-curing composite cement (Panavia V5, PV5, Kuraray Noritake) or a traditional one (RelyX Ultimate, RUL, 3M Oral Care; Multilink Automix, MLA, Ivoclar Vivadent), in light-, self-, or dual-curing mode. Bonded specimens were subjected to shear bond strength (SBS) tests after 24 h of water storage or after artificially aging by 20,000 thermal cycles plus 150 days of water storage. The degree of conversion (DC) of the composite cements under different curing conditions was measured by Fourier transform infrared (FTIR) spectroscopy. The irradiance and translucency of the zirconia plates of different thickness were also investigated. RESULTS: The irradiance and translucency of zirconia decreased significantly with increasing thickness (p = 0.00). Both before and after aging, SBS of PV5 in self-curing mode was significantly higher than that of RUL (p = 0.07 before aging and 0.02 after aging) and MLA (p = 0.00 both before and after aging). However, for the three composite cements, light- and dual curing yielding the same SBSs for a constant Y-TZP thickness (p > 0.05). The FTIR analysis showed that, for all three dual-curing composite cements examined in this study, the mean DC values obtained in dual-curing mode were lower than those achieved in light-curing mode (p = 0.00 for PV5, RUL, and MLA). For RUL and MLA, lower mean DC values were obtained in self-curing than dual-curing mode (p = 0.00 for both RUL and MLA), while the DC values of PV5 showed no significant difference between self-curing and dual-curing mode (p = 0.33). CONCLUSION: When the photoactivation time is 60 s and the thickness of the zirconia restoration is less than 2 mm, it is safe to use the two traditional dual-curing composite cements RUL and MLA and PV5 for bonding zirconia. However, when the light exposure time is insufficient, PV5 provides improved bond strength and durability to zirconia.


Assuntos
Colagem Dentária , Cimentos de Resina , Materiais Dentários , Teste de Materiais , Propriedades de Superfície , Zircônio
17.
J Adhes Dent ; 23(6): 579-587, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817973

RESUMO

PURPOSE: To evaluate the effect of different HF-etching protocols on the dissolution depth and micromorphology of the etched and adjacent surfaces of ultrathin glass-ceramic specimens. MATERIALS AND METHODS: One hundred twenty specimens (6 x 6 x 0.3 mm) of leucite-reinforced glass-ceramic (LEU, IPS Empress, Ivoclar Vivadent) and lithium-disilicate-reinforced glass-ceramic (LD, IPS e.max, Ivoclar Vivadent) were prepared. Specimens were divided into 5 groups (n = 12) according to etching protocol: G1: control, untreated; G2: 5% hydrofluoric acid (HF) etching for 20 s (HF5%20s); G3: HF5%60s; G4: HF10%20s; and G5: HF10%60s. To analyze the dissolution depth, specimens were sectioned into two similarly sized halves using a chisel to create an internal surface (IS). Specimens were analyzed with scanning electron microscopy (SEM) on the following surfaces: HF application surface (AS), lateral surface (LS), internal surface (IS), and the surface opposite to the AS (OS). Dissolution patterns were identified. Data were submitted to one-way ANOVA and Bonferroni's test (α = 0.05). Dissolution depth data were submitted to Kruskal-Wallis and Mann-Whitney U-tests (α = 0.05). The prevalence of different dissolution patterns was analyzed using SEM. RESULTS: HF gel applied on the AS also affected the adjacent surfaces of all specimens. Different dissolution patterns were observed, which were dependent of HF-etching protocol and proportion of the glass phase in the ceramic. These patterns were categorized into four types for LEU (I-IV) and three for LD (I-III) according to the micropore size. The greater the micropore size, the more pronounced the etching pattern (p < 0.001). Higher HF times and concentrations showed prevalence of more severe etching patterns. HF10%60s produced greater dissolution depth in both materials when compared with other HF-etching groups (p < 0.05). CONCLUSION: Hydrofluoric acid etching not only affects the surface upon which it is applied, but internal, lateral and even opposite edges of glass ceramic. Different dissolution patterns and depths can be formed which are dependent of hydrofluoric acid concentration, application time, and proportion of the glass phase in the ceramic.


Assuntos
Colagem Dentária , Ácido Fluorídrico , Condicionamento Ácido do Dente , Cerâmica , Porcelana Dentária , Teste de Materiais , Cimentos de Resina , Solubilidade , Propriedades de Superfície
18.
J Adhes Dent ; 23(6): 589-598, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817974

RESUMO

PURPOSE: To evaluate the effect of dimethyl sulfoxide (DMSO) on the microtensile bond strength (µTBS), nanoleakage (NL), and degree of conversion (DC) of universal adhesives on eroded dentin. MATERIALS AND METHODS: One hundred thirty-four extracted (134) human third molars were selected for the study. After the dentin surface was exposed, 128 teeth were randomly assigned to 16 experimental groups as follows: dentin surfaces (sound dentin and eroded dentin), application of DMSO (without or with the application of DMSO), and adhesive strategies (etch-and-rinse [ER] and self-etch [SE]). The universal adhesive systems iBond Universal (IBU) and Scotchbond Universal (SBU) were applied and the teeth were restored using a resin composite. After 24 h in distilled water at 37°C, the samples were sectioned and evaluated for µTBS. Selected sticks from each tooth were used for evaluating NL and DC. The remaining six teeth were used to measure the thickness of the collagen layer of the artificially eroded dentin using scanning electron microscopy. Data on µTBS, NL, and DC (%) were analyzed using three-way ANOVA and Tukey's test (α = 0.05). RESULTS: Significantly lower µTBS (p = 0.0001) and DC (p = 0.01) were observed for eroded dentin than for sound dentin. However, a significant increase in the µTBS (p = 0.0007) and DC (p = 0.001) was observed for both substrates when DMSO was applied. Moreover, the application of DMSO decreased the concentration of silver nitrate at the bottom of the hybrid layer for both sound and eroded dentin (p = 0.002). Eroded dentin showed enlarged tubules with the presence of a collapsed collagen fibril layer approximately 5.0 ± 2.0 mm of thickness. CONCLUSION: The bonding performance of both tested universal adhesives improved on both sound and eroded dentin with DMSO pretreatment.


Assuntos
Colagem Dentária , Infiltração Dentária , Resinas Compostas , Dentina , Adesivos Dentinários , Dimetil Sulfóxido , Humanos , Teste de Materiais , Cimentos de Resina , Resistência à Tração
19.
J Indian Soc Pedod Prev Dent ; 39(3): 267-274, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34810343

RESUMO

Background: There are conflicting results concerning the ideal time for etching primary dentin and its effect on the bond strength of adhesive restorative materials. Aim: To assess in vitro, the effect of varied acid concentration and etch time on the morphological features and tensile bond strength of primary dentin. Materials and Methods: Forty healthy primary molars were prepared by exposing the dentin of the occlusal surface, creating a smear layer. A 3 mm × 3 mm test indow was demarcated, and specimens were randomly allocated to four groups (n = 10): Group 1A 10% phosphoric acid, 7 s; Group 1B 10% phosphoric acid, 15 s; Group 2A 37% phosphoric acid, 7 s and Group 2B 37% phosphoric acid, 15 s. Surface analysis was done using atomic force microscope and scanning electron microscope. For tensile bond strength evaluation, 24 specimens prepared as mentioned were mounted in acrylic blocks and allocated to four groups according to the prescribed etching protocol. Resin rods were bonded and tested in tension after 24 h (n = 6). Data were analyzed statistically using unpaired t-test. Results: Etching of primary dentin using 37% phosphoric acid for 7 s produced the highest tensile bond strength of 9.51 ± 2.19 MPa. Conclusion: Etching time of 7 s may improve the adhesion of resin restorative materials with primary dentin.


Assuntos
Colagem Dentária , Adesivos Dentinários , Condicionamento Ácido do Dente , Resinas Compostas , Dentina , Humanos , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Resistência à Tração
20.
Soft Matter ; 17(39): 8786-8804, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34596200

RESUMO

To overcome the wearable sensor's defects and achieve the goal of robust mechanical properties, long-term adhesion, sensitive electrical conductivity, the multifunctional hydrogels were inspired by various mussels on the base of catechol and its analogues. In this review, we review the strategies for improving the mechanical strength, adhesion, conductivity and antibacterial properties of mussel-inspired hydrogels as bioelectronics. Double network structures, nanocomposites, supramolecular block polymers and other strategies were utilized for achieving tough hydrogels to prevent tensile fractures under high deformation. Many mussel-inspired chemistries were incorporated for constructing skin-attachable hydrogel strain sensors and some strategies for controlling the oxidation of catechol were employed to achieve long-term adhesion. In addition, electrolytes, conductive fillers, conductive polymers and their relevant hydrophilic modifications were introduced for fabricating the conductive hydrogel bioelectronics to enhance the conductivity properties. Finally, the challenges and outlooks in this promising field are featured from the perspective of materials chemistry.


Assuntos
Hidrogéis , Nanocompostos , Adesivos , Condutividade Elétrica , Cimentos de Resina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...