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1.
Braz Dent J ; 31(3): 272-280, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32667522

RESUMEN

The purpose of this study was to evaluate the influence of the application mode of three universal adhesive systems on interfacial physical properties of indirect composite restorations adhesively cemented to dentin cavities. Seventy-eight bovine lower incisors were selected and a slice of dentin (thickness: 2 mm) between the buccal surface and pulp chamber was obtained for each tooth. Conical cavities were made on this surface. The internal walls of the cavities were then coated with a hydrophilic gel, filled with composite resin and photopolymerized. The dentin/cone sets were divided into 6 groups (n=10) according to type of universal adhesive (TETRI: Tetric N Bond, FUT: Futura Bond U, SBU: Single Bond Universal) and acid etching on dentin (A: with acid etching; WA: without acid etching). The acid etching and the adhesive systems were applied to the surface of the dentin. All composite resin cones were sandblasted (Al2O3, 20 s) and silanized. After surface treatment, the cones were cemented (RelyX Ultimate) into the dentin cavity and photopolymerized. After thermocycling (10,000 cycles), samples were submitted to marginal adaptation analysis (using caries detector dye), push-out test (0.5 mm/min), and failure mode analysis. Additional samples were prepared for nanoleakage analysis (SEM). The data (MPa) were analyzed by two-way ANOVA and Tukey's post-test (5%). The groups in which the dentin was acid etched showed significantly lower bond strength values in the push-out test (p<0.01). Dentin acid etching significantly reduced the bond strength between universal adhesive systems and dentin in indirect restorative procedures.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Animales , Bovinos , Resinas Compuestas , Cementos Dentales , Cavidad Pulpar , Dentina , Ensayo de Materiales , Cementos de Resina , Propiedades de Superficie , Resistencia a la Tracción
2.
J Indian Soc Pedod Prev Dent ; 38(2): 138-144, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32611859

RESUMEN

Background: Use of silver diamine fluoride (SDF) after selective caries excavation can arrest the further progress of the carious lesion. Application of potassium iodide (KI) can reduce the staining due to SDF. Aim: The aim of the study was to evaluate the effect of the application of SDF, with and without acid etching and KI on the bond strength of resin-modified glass ionomer cement (RMGIC) to the carious dentin of primary teeth. Materials and Methods: In thisin vitro study, caries was induced on the occlusal surface by inoculating Streptococcus mutans strain in 36 extracted primary molars. The teeth were divided into four groups (n = 9), and the following treatments were done to the carious dentin prior to final restoration with RMGIC: Group I: 10% polyacrylic acid conditioner, Group II: 38% SDF, Group III: 37% phosphoric acid etchant followed by 38% SDF, and Group IV: 37% phosphoric acid etchant followed by 38% SDF and 10% potassium iodide solution. The microtensile bond strength was measured using universal testing machine. Failure modes were recorded using a scanning electron microscope. Results: There was no significant difference in microtensile bond strengths between the groups (P = 0.665), with the highest value seen in Group III. Conclusions: Application of SDF with or without acid etching and KI does not affect the bond strength of RMGIC to carious dentin of primary teeth.


Asunto(s)
Recubrimiento Dental Adhesivo , Caries Dental , Dentina , Recubrimientos Dentinarios , Fluoruros Tópicos , Cementos de Ionómero Vitreo , Humanos , Ensayo de Materiales , Compuestos de Amonio Cuaternario , Cementos de Resina , Compuestos de Plata , Resistencia a la Tracción , Diente Primario
3.
Shanghai Kou Qiang Yi Xue ; 29(2): 150-154, 2020 Apr.
Artículo en Chino | MEDLINE | ID: mdl-32626877

RESUMEN

PURPOSE: To evaluate the effect of 2% chlorhexidine(CHX) on the self-etching adhesive to dentin. METHODS: Fifty carious free molars were selected to expose the flat dentin surface. The specimens were bonded with composite resin by self-etching adhesive ,which were pretreated by 2% CHX for 0, 15, 30, 45 and 60 s. The microtensile bond strength (µTBS) and scanning electron microscope(SEM) were evaluated before and after thermocycling. SPSS 19.0 software package was used for statistical analysis. RESULTS: µTBS of the 45 and 60s-CHX pretreated group had significant difference before thermocycling, significantly higher than the control group(P<0.05). The 60s-CHX pretreated group showed significant greater µTBS than the control group after thermocycling(P<0.05). CONCLUSIONS: 2%CHX pretreatment can improve the bonding strength of the self-etching adhesive, and slow down the aging progress of bonding interface.


Asunto(s)
Clorhexidina , Recubrimiento Dental Adhesivo , Resinas Compuestas , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Cementos de Resina , Estrés Mecánico , Resistencia a la Tracción
4.
J Adhes Dent ; 22(4): 393-398, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32666065

RESUMEN

PURPOSE: To assess the effect of the application of different electric currents on dentin bonding and resin infiltration of self-etching and etch-and-rinse adhesives. MATERIALS AND METHODS: Two hundred four sound third molars were selected and divided in groups according to the adhesive (self-etch [CSE, Clearfil SE Bond, Kuraray Noritake], universal [SBU, Single Bond Universal, 3M Oral Care], and etch-and-rinse [SB2, Adper Single Bond 2 (SB2), 3M Oral Care]) and electrical current used (0, 5, 10, 15, 20, 25, 30, and 35 µA). Light curing was performed for 10 s with an LED-curing unit at 1000 mW/cm2. Composite blocks were constructed of nanofilled composite in increments of 2 mm, which were light cured for 20 s. Specimens were sectioned into sticks with a cross-sectional area of ~1 mm2 and stored in distilled water at 37°C for 24 h. Microtensile bond strength (µTBS) testing (n = 8) was performed using a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The bonding quality (n = 2) of adhesives applied with or without 35-µA electric current was evaluated using confocal laser scanning microscopy. Bond strengths were analyzed with two-way ANOVA and Tukey's test (α = 0.05). RESULTS: CSE presented the highest µTBS for all electrical currents tested. For CSE and SBU, electrical currents from 0-20 µA showed the lowest µTBS. Electrical currents from 0-10 and 20-25 µA yielded the lowest µTBS for SB2. CSE and SB2 applied under 35 µA showed a greater number of resin tags in dentin tubules. Fluorescein penetration into the hybrid layer was found for SBU applied without electric current. CONCLUSION: The application of adhesives using 35-µA electric current improved the bond strength and quality of the adhesive interface.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Adhesivos , Resinas Compuestas , Dentina , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción
5.
J Adhes Dent ; 22(4): 399-407, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32666066

RESUMEN

PURPOSE: The aim of this study was to evaluate the chemomechanical properties, antibacterial activity, and cytotoxicity of an experimental adhesive resin containing halloysite nanotubes (HNT), doped with alkyl trimethyl ammonium bromide (ATAB). MATERIALS AND METHODS: A filler of HNT doped with ATAB was obtained (ATAB:HNT) and incorporated (5 wt%) into a resin blend made of bisphenol A glycerolate dimethacrylate, 2-hydroxyethyl methacrylate and a photoinitiator/co-initiator system (GATAB:HNT). The same resin blend without ATAB:HNT was used as control (Ctrl). The ATAB:HNT filler was assessed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two tested adhesives were evaluated for degree of conversion (DC) in vitro and in situ, softening in alcohol, dentin microtensile bond strength (µTBS), antibacterial activity, and cytotoxicity (n = 5). RESULTS: SEM showed that the nanotubes had a characteristic tubular-needle morphology, while the TEM analysis confirmed the presence of ATAB inside the lumens of HNT. The incorporation of ATAB:HNT induced no reduction (p > 0.05) of the DC either in situ or in vitro. No difference was encountered after the softening challenge test (p > 0.05) and no difference was found in µTBS between the two adhesives, both at 24 h (p > 0.05) and after 6 months of storage in distilled water (p > 0.05). However, ATAB:HNT reduced Streptococcus mutans viability (p < 0.05) without a cytotoxic effect on pulp cells (p > 0.05). CONCLUSIONS: GATAB:HNT adhesive demonstrated appropriate polymerization without significant differences in softening after solvent immersion, while concomitantly maintaining reliable bond strength after 6 months of water aging. Moreover, the ATAB:HNT filler can provide antibacterial activity to the adhesive resin without affecting pulp cell viability.


Asunto(s)
Recubrimiento Dental Adhesivo , Nanotubos , Bromuros , Arcilla , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Compuestos de Amonio Cuaternario , Cementos de Resina , Resistencia a la Tracción
6.
J Adhes Dent ; 22(4): 415-420, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32666068

RESUMEN

PURPOSE: To investigate whether interfacial enzymatic activity and adhesion receptiveness of artificial caries-affected dentin (ACAD) simulate those of natural caries-affected dentin (NCAD). MATERIALS AND METHODS: Thirty dentin specimens were prepared from human molars to determine interfacial gelatinolytic activity using in situ zymography and adhesion experiments (micropermeability and bond strength [µTBS]). Groups were formed according to the type of dentin: artificial caries-affected dentin (ACAD), natural caries-affected dentin (NCAD), or sound dentin. ACAD was produced by incubating dentin with Streptococcus mutans in a chemically defined medium (CDM) with 1% sucrose for 7 days at 37°C under anaerobic conditions. CDM was replaced daily, and the sterility as well as the pH of the culture was monitored. Adhesion experiments employed Single Bond Universal (3M Oral Care) in self-etch mode. Data were individually processed and analyzed using ANOVA and post-hoc tests (α = 0.05). RESULTS: The enzymatic activity of ACAD was similar to that of sound dentin, but was lower than that of NCAD, which elicited the highest activity (p < 0.05). Interfacial micropermeability intensity at the hybrid layer or in underlying dentin (5 µm below the interface) was similar in all types of dentin (p > 0.05). On the other hand, substrate permeability was higher for NCAD than for ACAD. The highest sealing ability was detected in sound dentin. Bond strengths to ACAD were higher than to NCAD. However, the highest µTBS was observed in sound dentin (p < 0.05). CONCLUSION: Artificial caries-affected dentin simulated neither the gelatinolytic activity nor bonding receptiveness of natural caries-affected dentin.


Asunto(s)
Recubrimiento Dental Adhesivo , Caries Dental , Dentina , Recubrimientos Dentinarios , Humanos , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción
7.
Dent Mater J ; 39(4): 534-538, 2020 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-32624553

RESUMEN

Self-etch adhesive (SEA) systems simplify bonding procedures. It is believed that good mechanical retention and chemical bonding are both important factors to obtain reliable bonding to enamel. The enamel acid-base resistant zone (ABRZ) has been confirmed at the adhesive/enamel interface by scanning electron microscopic observation. However, the formation of enamel ABRZ is influenced by the type and components of adhesive systems. Chemical interactions by a functional monomer with hydroxyapatite strongly support the explanation of the mechanism for enamel ABRZ formation. The ABRZ created by MDP-containing SEA systems has shown good potential to resist acid attack from simulated recurrent caries models. In addition, fluoride release may enhance acid resistance. It has been proposed that such a reinforced enamel be termed "Super Enamel". The concept of the formation of super enamel may contribute to protecting enamel, and conserve tooth structure leading to improved restoration longevity.


Asunto(s)
Grabado Ácido Dental , Recubrimiento Dental Adhesivo , Cementos Dentales , Esmalte Dental , Dentina , Recubrimientos Dentinarios , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Cementos de Resina , Propiedades de Superficie
8.
Braz Dent J ; 31(2): 179-185, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32556018

RESUMEN

The aim was to evaluate, in vitro, the influence of pH cycling on microtensile bond strength (µTBS) and percentage of nanoleakage (%NL) in the dentin-adhesive interface. Flat dentin surfaces were obtained in 56 extracted third molars. The teeth were randomly divided into four groups (n=14): G1- Single Bond Universal (etch-and-rinse mode); G2- Single Bond Universal (self-etch mode); G3- Scotchbond Multi-Purpose; G4- Clearfil SE Bond. A block of composite was built on the adhesive area. Eight tooth/resin sets were cut parallel to the tooth's long axis to obtain 48 beams (0.8 mm2) for each group. Half of the beams were submitted to four cycles of pH cycling (demineralizing solution for 6 h and remineralizing solution for 18 h). The samples were submitted to µTBS test in a universal testing machine. Six tooth/resin sets were cut parallel to the tooth's long axis to obtain three slices of the central region (1.0 mm thickness). Half of the slices were submitted to pH cycling. The nanoleakage methodology was applied to obtain the %NL at the adhesive interfaces. According to two-way ANOVA, the interaction between factors (adhesive system x storage) was significant (p=0.0001) for µTBS and %NL. After pH cycling, there was a significant decrease in µTBS and a significant increase in %NL for all adhesives. The adhesives applied in the self-etch mode obtained lower %NL, differing significantly from the etch-and-rinse adhesives. It was concluded that the pH cycling negatively influenced the µTBS and %NL for all adhesives evaluated. However, self-etch adhesives allowed less %NL.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Cementos Dentales , Dentina , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción
9.
J Contemp Dent Pract ; 21(3): 242-248, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32434968

RESUMEN

AIM: To determine the effect of three different cavity disinfectants (2% chlorhexidine gluconate, 2.5% sodium hypochlorite, and 2% iodine solution) on microleakage in a seventh-generation dentin-bonding system. MATERIALS AND METHODS: Class V cavity was prepared on 50 extracted molars (n = 50). The respective experimental groups were treated with cavity disinfectants and Adper Easy One Bond. Preparations without cavity disinfectants worked as negative control and those with neither disinfectant nor dentin-bonding resin application worked as positive controls. After the cavity preparations were restored with resin composite (Filtek™ Z 350), the teeth were then subjected to dye leakage tests. Microleakage was assessed for both occlusal and gingival margins, using a stereomicroscope. Data were analyzed using (ANOVA; Kruskal-Wallis) test. RESULTS: No statistically significant differences were observed among 2% chlorhexidine gluconate, 2.5% sodium hypochlorite, and 2% iodine and also no statistically significant differences were observed between occlusal and gingival margins of groups. CONCLUSION: (1) 2% chlorhexidine gluconate, 2.5% sodium hypochlorite, and 2% iodine produced significantly higher microleakage when used with seventh-generation dentin-bonding agent. (2) 2% chlorhexidine gluconate produced lesser microleakage in comparison with 2.5% sodium hypochlorite and 2% iodine. (3) The gingival margins exhibited greater microleakage than occlusal margins. CLINICAL SIGNIFICANCE: The application of cavity disinfectants on prepared tooth before the application of dentin-bonding agent could help to reduce the potential risk of residual caries and postoperative sensitivity.


Asunto(s)
Filtración Dental , Desinfectantes , Restauración Dental Permanente , Dentina , Recubrimientos Dentinarios , Humanos
10.
J Adhes Dent ; 22(3): 285-296, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32435769

RESUMEN

PURPOSE: To investigate the long-term effect of 0.05% or 0.1% caffeic acid phenethyl ester (CAPE) on dentin matrix stability and hybrid layer stability, using an etch-and-rinse (Adper Scotchbond Multipurpose/ASB) or a self-etch adhesive (Clearfil SE Bond/CSE). MATERIALS AND METHODS: Dentin matrix specimens were assigned to five groups: 0.05% or 0.1% CAPE, green tea (GT), and the controls distilled water (DW) and dimethyl sulfoxide (DMSO). Following immersion of specimens for 1 h, modulus of elasticity (ME) and dentin mass change (MG) were determined at 3 post-treatment time points: immediately afterwards and at 3 and 6 months. Collagen solubilization (CS) was estimated by hydroxyproline (HYP) quantification. Resin-dentin interfaces with both adhesives were assessed with in situ zymography tests to evaluate gelatinolytic activity (GA). The dentin pretreatments were actively applied for 60 s. The sealing ability of aged resin-bonded slices was assessed by nanoleakage tests. RESULTS: GT increased immediate ME, which decreased significantly after 3 months (p < 0.0001). The CAPE groups did not differ from the control groups. GT provided a significant increase in dentin matrix mass after treatment (p < 0.0001). No significant differences regarding MG were observed for CAPE 0.1%, CAPE 0.05%, DW, and DMSO groups after 3 and 6 months. Cumulative HYP release revealed that CAPE groups and GT were statistically similar to DW and DMSO; the GT group exhibited statistically significantly less HYP release than did CAPE groups (p = 0.0073). Treatment with 0.05% or 0.1% CAPE presented lower GA when applied to ASB before acid conditioning (p < 0.05), but no differences were detected when the CAPE groups were applied to CSE. CAPE at 0.1% significantly reduced nanoleakage for CSE, and 0.05% CAPE with CSE presented levels of nanoleakage similar to those of the CSE control group. CONCLUSION: CAPE at 0.05% or 0.01% did not influence ME, MG, or CS, but reduced GA when applied to ASB before acid conditioning. CAPE at 0.1% with CSE promoted adhesive layer integrity.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Ácidos Cafeicos , Cementos Dentales , Dentina , Ensayo de Materiales , Alcohol Feniletílico/análogos & derivados , Resistencia a la Tracción
11.
J Adhes Dent ; 22(3): 297-309, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32435770

RESUMEN

PURPOSE: To evaluate the remineralization effects of Bioglass 45S5 (BAG) on dentin composition, adhesive-dentin bond strength, as well as interface and diffusion zone thickness. MATERIALS AND METHODS: Dentin specimens were assigned to a control group (CG), in which the adhesive was applied following the manufacturer's instructions, and a remineralized group (RG), in which remineralization treatment was carried out by rubbing a remineralization solution (0.015 g of BAG with 1.35 ml of distilled water) on the etched dentin surface for 30 s before applying the adhesive. For bioactive analysis (n = 10), control and remineralized dentin were investigated using micro-Raman spectroscopy (mRS) and scanning electron microscopy (SEM). Stick specimens prepared with a three-step etch-and-rinse adhesive were submitted to a microtensile bond strength (µTBS) test (n = 10) after 24 h (24 h) and eight months (8 m). Micro-RS 3D-maps (n = 10) characterized the adhesive-dentin interface composition and diffusion zone thickness, and SEM images (n = 10) evaluated interface thickness. Data were analyzed using Student's t-test or two-way ANOVA and Tukey-Kramer's post-hoc test (α = 0.05). RESULTS: Remineralization treatment increased the mineral content of dentin. Mean µTBSs were statistically different at 24 h, with RG higher than CG; however, this difference was not significant at 8 m. When the adhesive was applied on remineralized dentin, its penetration was reduced, its physical interaction with phosphate was improved, and its degree of conversion increased. The diffusion zone in the CG did not differ from that of the RG, and interface thickness values of the CG did not differ from that of the RG. CONCLUSION: Remineralization treatment promoted mineral growth on the dentin surface, improved the interaction of dentin with adhesive monomers, and consequently resulted in higher immediate bond strengths.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Humanos , Resistencia a la Tracción
12.
J Adhes Dent ; 22(3): 311-320, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32435771

RESUMEN

PURPOSE: To evaluate the effects of double application of resin cement primers to dentin prepared with different diamond burs on the cement-dentin bond strengths. MATERIALS AND METHODS: Sixty flat dentin surfaces were prepared and divided into 12 groups (n = 5) according to three experimental factors: 1. resin cements: RelyX Ultimate (RU), Multilink Automix (ML), and Panavia V5 (PV); 2. resin cement primer application: single or double; 3. dentin surface preparation with regular or superfine diamond burs. Cement-dentin sticks (1 mm2) were prepared for and underwent microtensile bond strength testing (µTBS). Statistical analysis was performed using three-way ANOVA and Duncan's test (α = 0.05). Fractured surfaces and cement-dentin interfaces were observed using SEM. Additional teeth were used to observe the demineralization effect of resin cement primers with SEM and transmission electron microscopy (TEM). RESULTS: All tested factors demonstrated significant effects on µTBS (p < 0.001). The combination of PV with superfine-grit bur and double application yielded the highest bond strengths. Surfaces prepared with superfine-grit burs demonstrated higher µTBS than did the regular-grit group, but a significant effect was not observed for all groups. The double application of primer significantly increased the bond strength for most combinations, except for PV with superfine-grit bur-prepared dentin. CONCLUSIONS: PV showed higher bond strengths than other resin cements. Double application of primer improved the bond strength of all cements to dentin. Bond strengths were higher when dentin was prepared with a superfine-grit bur.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Dentina , Recubrimientos Dentinarios , Diamante , Ensayo de Materiales , Propiedades de Superficie , Resistencia a la Tracción
13.
J Adhes Dent ; 22(3): 321-330, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32435772

RESUMEN

PURPOSE: To investigate the effects of root-canal dentin pretreatment with the crosslinker EDC combined with chitosan nanoparticles (Csnp) on the bonding quality of fiber posts in root canals in terms of bond strength, nanoleakage, quantification of collagen degradation, and degree of conversion (DC) of adhesive. MATERIALS AND METHODS: Forty-eight single-rooted teeth were prepared endodontically and etched using UNI-ETCH (Bisco) as per the adhesive procedure for fiber posts. They were randomly divided into three groups before adhesive (All-Bond 3) application, according to different pretreatments: a. immersed in 2.5% glutaraldehyde for 24 h; b. treated with Csnp solution under ultrasonic agitation for 60 s and immersed in EDC crosslinker for 24 h; c. without treatment (control). Bond strength, nanoleakage, DC within the interface, and collagen fiber degradation were evaluated. RESULTS: The pretreatments had a significant influence on the bonding stability of fiber posts in root canals, but not on the degree of conversion (p = 0.552). Enzymatic degradation significantly influenced bond strength for all groups (p = 0.001), with the greatest effect found in group c. The amount of amino acids released from the adhesive interface differed significantly between groups after hydrolysis and enzymatic degradation (p = 0.000); group c released the highest amount of amino acids. CONCLUSIONS: Csnp binding to dentin in combination with EDC reduced degradation of dentinal collagen and improved the stability of the adhesive interface without jeopardizing adhesive polymerization.


Asunto(s)
Quitosano , Recubrimiento Dental Adhesivo , Nanopartículas , Técnica de Perno Muñón , Cavidad Pulpar , Recubrimientos Dentinarios , Cementos de Resina
14.
J Contemp Dent Pract ; 21(1): 91-96, 2020 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-32381808

RESUMEN

AIM: The aim of this study was to assess if the curing mode and the etching mode could affect the push-out bond strength of different post cementation systems using two universal adhesives. MATERIALS AND METHODS: A total of 100 single-rooted teeth were divided into Prime & Bond Elect (PBE), Prime & Bond Active (PBA), and Prime & Bond XP (PBXP) as a control. The PBE, PBA, and PBXP were used in the self-etch (SE) and etch and rinse (E&R) mode. Post cementation was performed using Core X flow used in dark-cure and in light-cure. Data were analyzed using the one-way ANOVA test and post hoc Bonferroni and Dunnet tests. The Student's t test was performed to find significance between two independent groups. RESULTS: Bond strength was significantly influenced by the adhesive strategies. The PBE and PBA obtained higher values when used in the SE mode (p < 0.001). Light-cured groups obtained significantly higher values (p < 0.001) compared to dark-cured groups. The post space region also had a significant effect on the bond strength; the apical third recorded lower values in all groups (p < 0.001). CONCLUSION: The PBA and PBE universal adhesives obtained higher PBS values when used in the SE mode and followed by the light-curing of resin cement. CLINICAL SIGNIFICANCE: Universal adhesives represent a good alternative to the conventional total-etch adhesive system for fiber post cementation. Since they perform better in SE, they would be recommendable in clinical practice, as they can be used with a simplified technique.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Cementos Dentales , Dentina , Humanos , Cementos de Resina
15.
Braz Oral Res ; 34: e020, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32236317

RESUMEN

This in vitro study aimed to assess the effects of different pretreatments used to adapt glass-fiber posts cemented to root canals with different resin cements, regarding porosity percentage and bond strength. Twelve bovine incisor roots were prepared with Largo drills. After post space preparation, the specimens were randomized into two types of pretreatment groups (n = 3): water-wet bonding and ethanol-wet bonding. After the post were cemented, the roots were stored in 100% humidity at room temperature for 7 days. The samples were scanned by microcomputed tomography (micro-CT). Images were reconstructed by NRecon software, and CTAn software was used to analyze the porosity percentage (%) at the luting interface. Evaluation of the push-out bond strength was performed by serially cutting the roots, and submitting the slices to testing. Additionally, the resin cement post-gel shrinkage values (%) were measured using the strain-gauge method (n = 10). Data were analyzed by two-way ANOVA, Tukey's test and Student's t test (a = 0.05). The roots prepared with ethanol-wet bonding using RelyX™ U200 had significantly lower porosity in the coronal and apical thirds (p < 0.05). The group prepared with ethanol-wet bonding using RelyX™ ARC presented better bond strength results in the coronal and apical thirds (p < 0.05). RelyX™ ARC (0.97%) produced a higher post-gel shrinkage value than RelyX™ U200 (0.77%). Canals pretreated with ethanol-wet bonding presented better outcomes in regard to porosity percentage and push-out bond strength.


Asunto(s)
Recubrimientos Dentinarios/farmacología , Etanol/farmacología , Técnica de Perno Muñón , Cementos de Resina/química , Raíz del Diente/efectos de los fármacos , Animales , Bovinos , Recubrimiento Dental Adhesivo , Materiales Dentales/química , Cavidad Pulpar , Vidrio , Ensayo de Materiales , Porosidad , Irrigantes del Conducto Radicular/química , Microtomografía por Rayos X
16.
Dent Mater ; 36(5): 687-697, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32241557

RESUMEN

OBJECTIVES: The purpose of this study was to synthesize chlorhexidine (CHX)-encapsulated aluminosilicate clay nanotubes (Halloysite®, HNTs) and to incorporate them into the primer/adhesive components of an etch-and-rinse adhesive system (SBMP; Scotchbond Multipurpose, 3M ESPE) and to test their effects on degree of conversion, viscosity, immediate and long-term bonding to dentin. METHODS: CHX-modified HNTs were synthesized using 10% or 20% CHX solutions. The primer and the adhesive components of SBMP were incorporated with 15wt.% of the CHX-encapsulated HNTs. Degree of conversion (DC) and viscosity analyses were performed to characterize the modified primers/adhesives. For bond strength testing, acid-etched dentin was treated with one of the following: SBMP (control); 0.2%CHX solution before SBMP; CHX-modified primers+SBMP adhesive; SBMP primer+CHX-modified adhesives; and SBMP primer+CHX-free HNT-modified adhesive. The microtensile bond strength test was performed after immediate (24h) and long-term (6 months) of water storage. Data were analyzed using ANOVA and Tukey (α=5%) and the Weibull analysis. RESULTS: DC was greater for the CHX-free HNT-modified adhesive, whereas the other experimental adhesives showed similar DC as compared with the control. Primers were less viscous than the adhesives, without significant differences within the respective materials. At 24h, all groups showed similar bonding performance and structural reliability; whereas at the 6-month period, groups treated with the 0.2%CHX solution prior bonding or with the CHX-modified primers resulted in greater bond strength than the control and superior reliability. SIGNIFICANCE: The modification of a primer or adhesive with CHX-encapsulated HNTs was an advantageous approach that did not impair the polymerization, viscosity and bonding performance of the materials, showing a promising long-term effect on resin-dentin bonds.


Asunto(s)
Recubrimiento Dental Adhesivo , Nanotubos , Clorhexidina , Dentina , Recubrimientos Dentinarios , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Polimerizacion , Reproducibilidad de los Resultados , Cementos de Resina , Propiedades de Superficie , Resistencia a la Tracción
17.
Dent Mater ; 36(5): 660-671, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32278482

RESUMEN

OBJECTIVES: To obtain an accurate picture of the temporal development of bond strength between resin composites and tooth structures during cure for assessing debonding at the tooth-composite interface. METHODS: An assembly of uncured composite sandwiched between a glass block and a dentin slab with a layer of pre-cured adhesive was used in this study. A conventional composite was compared against a bulk-fill composite. The rate of bond formation was determined by measuring the tensile bond strength of specimens of different thicknesses at different time points during cure. The changing light irradiance exiting the composite as it cured was also recorded. Mode of fracture was analyzed by examining the fracture surfaces. RESULTS: Photo-bleaching occurred in both resin composites. The development of the dentin-composite bond strength was initially dictated by the developing cohesive strength of the resin composite, and its final value was capped by the strength of the preformed dentin-adhesive bond. The higher interfacial irradiance in the bulk-fill composite did not lead to faster development of the overall bond strength. This was caused by its slower rate of cohesive strength development as reflected in the longer time for its interfacial irradiance to plateau and the greater proportion of cohesive failure seen in the initial stage of polymerization. The law of reciprocity did not hold for the development of dentin bond strength. SIGNIFICANCE: The results from this study, when compared with the development of shrinkage stress, can be used as a basis for ensuring the integrity of the dentin-composite interface during cure.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Resinas Compuestas , Dentina , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción
18.
J Adhes Dent ; 22(2): 139-147, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32322835

RESUMEN

PURPOSE: To evaluate the degree of conversion (DC%), water sorption (Sp), solubility (Sl), dentin bond strength (µTBS) (immediate and after 12 months of storage), and the antibacterial effect of an experimental adhesive containing different concentrations (%) of proanthocyanidin (PA): 0, 1%, 2%, 4.5%, and 6% (PA0, PA1%, PA2%, PA4.5% and PA6%, respectively). MATERIALS AND METHODS: DC% was measured by FT-IR and the Sp and Sl were determined based on the ISO 4049 specification. For µTBS, resin composite buildups were constructed incrementally and specimens (n = 8) were sectioned to obtain sticks (1 mm2). The µTBS was evaluated after 24 h and 12 months of water storage at 37°C. The failure mode was analyzed. The antibacterial effects were evaluated by analyzing the bacterial growth (S. mutans) (n = 5) and antibiofilm activity (n = 5) of the adhesives by spectrophotometry. RESULTS: The incorporation of PA did not affect the Sp, Sl, or DC%. Immediate µTBS was similar for all groups. After 12 months, PA4.5% presented significantly higher µTBS than PA0, while the other groups did not differ from PA0 and PA4.5%. Groups PA0 and PA1% underwent significant reduction in µTBS. In the experimental groups PA2%, PA4.5% and PA6%, µTBS was maintained after storage. All groups showed antibacterial activity. CONCLUSION: Incorporation of 2%, 4.5%, and 6% PA maintained the dentin µTBS after 12-month storage, without affecting the Sp, Sl, or DC% of experimental adhesives. PA4.5% presented higher µTBS values than PA0 after 12 months. The adhesive presented antibacterial effect irrespective of PA concentration.


Asunto(s)
Recubrimiento Dental Adhesivo , Proantocianidinas , Antibacterianos , Cementos Dentales , Recubrimientos Dentinarios , Ensayo de Materiales , Metacrilatos , Cementos de Resina , Espectroscopía Infrarroja por Transformada de Fourier
19.
Oral Health Prev Dent ; 18(2): 145-152, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32238986

RESUMEN

PURPOSE: To evaluate the microtensile bond strength of dentine/self-adhesive resin cement interface after several treatments on a dentine surface. MATERIALS AND METHODS: Twenty-eight human molars were selected and divided into four groups: no treatment (control (C)); 2% chlorhexidine digluconate (CHX); 25% polyacrylic acid (PA); and 23 ppm dispersive solution of silver nanoparticle (SN). Prepolymerised TPH resin composite (Dentsply) blocks were luted on the dentine surface using RelyX U200 self-adhesive resin cement (3M ESPE). Microtensile bond strength was measured (MPa) in a universal testing machine 24 h and 6 months after the bonding process. The fractured specimens were examined in an optical microscope and classified according to the fracture pattern. A representative sample of each group was observed by scanning electronic microscope. Data were submitted to analysis of variance (ANOVA) and Tukey's test to compare the mean among the groups (p <0.05). RESULTS: The highest microtensile bond strength values after 24 h were found for the PA group (13.34 ± 6.36 MPa), with no statistically significant difference for the C group (9.76 ± 3.11 Mpa). After 6 months, the highest microtensile bond strength values were found for the C group (9.09 ± 3.27 Mpa), with statistically significant difference only for the CHX group (2.94 ± 1.66 MPa). There was statistically significant difference only for the PA group when comparing the periods studied. Regardless of the surface treatment applied, there were more adhesive failures in both periods of time. CONCLUSION: Dentinal pretreatment with PA, as well as use of SN before the bonding procedure of self-adhesive resin cement to dentine, may be alternative bonding protocols.


Asunto(s)
Recubrimiento Dental Adhesivo , Nanopartículas del Metal , Resinas Compuestas , Cementos Dentales , Análisis del Estrés Dental , Dentina , Recubrimientos Dentinarios , Humanos , Ensayo de Materiales , Cementos de Resina , Plata , Propiedades de Superficie , Resistencia a la Tracción
20.
Am J Dent ; 33(2): 64-68, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32259409

RESUMEN

PURPOSE: To evaluate the effect of dentin biomodification on the long-term strength of sound and caries-affected (CA) dentin as a strategy to stabilize the dentin matrix. The biomodification strategy utilized a naturally occurring proanthocyanidin-rich Vitis vinifera grape seeds (Vv), and compared with glutaraldehyde (GD). METHODS: Dentin from sound and carious human molars were sectioned from mid-coronal dentin. The temperature denaturation (Td) was assessed using differential scanning calorimetry in sealed pans. The inhibitory effect of the agents on the activity of recombinant MMP-2 and -9 were assessed using colorimetric assay. The ultimate tensile strength (UTS) of demineralized dentin were determined 24 hours after treatment and after 12 months storage in simulated body fluid. Data were statistically analyzed using ANOVA and post-hoc tests ( α= 0.05). RESULTS: There was no statistically significant difference in the Td between sound and CA dentin (P= 0.140); however, Vv and GD significantly increased the Td of both substrates (P< 0.001), indicating formation of collagen cross-linking. The activity of MMP-2 and MMP-9 were reduced by Vv and GD in a concentration dependent manner. The UTS of dentin matrix was significantly affected by treatments and storage times (P< 0.001). After a 12-month period, a significant decrease in UTS was observed for sound and CA, with complete solubilization of the CA dentin matrix. Vv and GD stabilized the UTS of both dentin substrates (P< 0.05). Sound and CA dentin matrix were susceptible to degradation after the 12-month period. Degradation of dentin matrix due to endogenous proteases activity was more pronounced in CA dentin. Dentin biomodification strategies increased the thermal stability and enhanced the long-term mechanical properties of both sound and CA dentin matrix. CLINICAL SIGNIFICANCE: Carious dentin matrix is more susceptible to breakdown over time than sound dentin; however, the degradation process can be impaired by dentin biomodification. This biomimetic strategy increases the long-term tensile strength of the dentin matrix. Reinforcement of caries-affected dentin may increase longevity of adhesive interfaces.


Asunto(s)
Recubrimiento Dental Adhesivo , Caries Dental , Biomimética , Dentina , Recubrimientos Dentinarios , Humanos , Ensayo de Materiales , Diente Molar , Resistencia a la Tracción
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