Effectiveness and biological compatibility of different generations of dentin adhesives

Besides possessing good mechanical properties, dental materials should present a good biological behavior and should not injure the involved tissues. Bond strength and biocompatibility are both highly significant properties of dentin adhesives. For that matter, these properties of four generations of adhesive systems (Multi-Purpose/Single Bond/SE Plus/Easy Bond) were evaluated.Eighty bovine teeth had their dentin exposed (500- and 200-mu m thickness). Adhesive was applied on the dentin layer of each specimen. Following that, the microshearing test was performed for all samples. A dentin barrier test was used for the cytotoxicity evaluation. Cell cultures (SV3NeoB) were collected from testing materials by means of 200- or 500-mu m-thick dentin slices and placed in a cell culture perfusion chamber. Cell viability was measured 24 h post-exposition by means of a photometrical test (MTT test).The best bonding performance was shown by the single-step adhesive Easy Bond (21 MPa, 200 mu m; 27 MPa, 500 mu m) followed by Single Bond (15.6 MPa, 200 mu m; 23.4 MPa, 500 mu m), SE Plus (18.2 MPa, 200 mu m; 20 MPa, 500 mu m), and Multi-Purpose (15.2 MPa, 200 mu m; 17.9 MPa, 500 mu m). Regarding the cytotoxicity, Multi-Purpose slightly reduced the cell viability to 92 % (200 mu m)/93 % (500 mu m). Single Bond was reasonably cytotoxic, reducing cell viability to 71 % (200 mu m)/64 % (500 mu m). The self-etching adhesive Scotchbond SE decreased cell viability to 85 % (200 mu m)/71 % (500 mu m). Conversely, Easy Bond did not reduce cell viability in this test, regardless of the dentin thickness.Results showed that the one-step system had the best bond strength performance and was the least toxic to pulp cells. In multiple-step systems, a correct bonding technique must be done, and a pulp capping strategy is necessary for achieving good performance in both properties.The study showed a promising system (one-step self-etching), referring to it as a good alternative for specific cases, mainly due to its technical simplicity and good biological responses.

Stress distribution on dentin-cement-post interface varying root canal and glass fiber post diameters. A three-dimensional finite element analysis based on micro-C data

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inactivation of Matrix-bound Matrix Metalloproteinases by Cross-linking Agents in Acid-etched Dentin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Exposed Collagen In Resin Bonds to Caries-affected Dentin After Dentin Treatment with Aqueous and Alcoholic Chlorhexidine Solutions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stabilization of dentin matrix after cross-linking treatments, in vitro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of the Interaction Between Sodium Hypochlorite and Several Formulations Containing Chlorhexidine and its Effect on the Radicular Dentin-SEM and Push-Out Bond Strength Analysis

The aim of the current study was to evaluate the presence of debris and smear layer after endodontic irrigation with different formulations of 2% chlorhexidine gluconate (CHX) and its effects on the push-out bond strength of an epoxy-based sealer on the radicular dentin. One hundred extracted human canines were prepared to F5 instrument and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Fifty teeth were divided into five groups (n=10), according to the final irrigation protocol with different 2% CHX formulations: G1 (control, no final rinse irrigation), G2 (CHX solution), G3 (CHX gel), G4 (Concepsis), and G5 (CHX Plus). In sequence, the specimens were submitted to scanning electron microscopy (SEM) analysis, in the cervical-medium and medium-apical segments, to evaluate the presence of debris and smear layer. The other 50 teeth were treated equally to a SEM study, but with the root canals filled with an epoxy-based endodontic sealer and submitted to a push-out bond strength test, in the cervical, middle, and apical thirds. G2, G3, G4, and G5 provided higher precipitation of the debris and smear layer than G1 (P<0.05), but these groups were similar to each other (P>0.05), in both segments. The values obtained in the push out test did not differ between groups, independent of the radicular third (P>0.05). The CHXs formulations caused precipitation of the debris and smear layer on the radicular dentin, but these residues did not interfere in the push-out bond strength of the epoxy-based sealer. Microsc. Res. Tech. 77:17-22, 2014. (c) 2013 Wiley Periodicals, Inc.

Bond strength of composite to dentin: effect of acid etching and laser irradiation through an uncured self-etch adhesive system

This study evaluated the effect on micro-tensile bond strength (mu-TBS) of laser irradiation of etched/unetched dentin through an uncured self-etching adhesive. Dentinal surfaces were treated with Clearfil SE Bond Adhesive (CSE) either according to the manufacturer's instructions (CSE) or without applying the primer (CSE/NP). The dentin was irradiated through the uncured adhesive, using an Nd: YAG laser at 0.75 or 1 W power settings. The adhesive was cured, composite crowns were built up, and the teeth were sectioned into beams (0.49 mm(2)) to be stressed under tension. Data were analyzed using one-way ANOVA and Tukey statistics (alpha = 5%). Dentin of the fractured specimens and the interfaces of untested beams were observed under scanning electron microscopy (SEM). The results showed that non-etched irradiated surfaces presented higher mu-TBS than etched and irradiated surfaces (p < 0.05). Laser irradiation alone did not lead to differences in mu-TBS (p > 0.05). SEM showed solidification globules on the surfaces of the specimens. The interfaces were similar on irradiated and non-irradiated surfaces. Laser irradiation of dentin through the uncured adhesive did not lead to higher mu-TBS when compared to the suggested manufacturer's technique. However, this treatment brought benefits when performed on unetched dentin, since bond strengths were higher when compared to etched dentin.

Bond Strength of Different Resin Cement and Ceramic Shades Bonded to Dentin

Purpose: To evaluate the microtensile bond strength (MTBS) of ceramic cemented to dentin varying the resin cement and ceramic shades.Materials and Methods: Two VITA VM7 ceramic shades (Base Dentine 0M1 and Base Dentine 5M3) were used. A spectrophotometer was used to determine the percentage translucency of ceramic (thickness: 2.5 mm). For the MTBS test, 80 molar dentin surfaces were etched and an adhesive was applied. Forty blocks (7.2 x 7.2 x 2.5 mm) of each ceramic shade were produced and the ceramic surface was etched (10% hydrofluoric acid) for 60 s, followed by the application of silane and resin cement (A3 yellow and transparent). The blocks were cemented to dentin using either A3 or transparent cement. Specimens were photoactivated for 20 s or 40 s, stored in distilled water (37 degrees C/24 h), and sectioned. Eight experimental groups were obtained (n = 10). Specimens were tested for MTSB using a universal testing machine. Data were statistically analyzed using ANOVA and Tukey's post-hoc tests (alpha <= 0.05).Results: The percentage translucency of 0M1 and 5M3 ceramics were 10.06 (+/- 0.25)% and 1.34 (+/- 0.02)%, respectively. The lowest MTBS was observed for the ceramic shade 5M3. For the 0M1 ceramic, the A3 yellow cement that was photocured for 20 s exhibited the lowest MTBS, while the transparent cement that was photocured for 40 s presented the highest MTBS.Conclusions: For the 2.5-mm-thick 5M3 ceramic restorations, the MTBS of ceramic cemented to dentin significantly increased. The dual-curing cement Variolink II photocured for 40 s is not recommended for cementing the Base Dentine 5M3 feldspathic ceramic to dentin.

Effect of Resin Cement Type on the Microtensile Bond Strength to Lithium Disilicate Ceramic and Dentin Using Different Test Assemblies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of the interfacial area measurement parameters on the push-out strength between fiber post and dentin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bonding of Y-TZP to Dentin: Effects of Y-TZP Surface Conditioning, Resin Cement Type, and Aging

Purpose: To evaluate the effects of two surface treatments, aging, and two resin cements on shear bond strength between dentin and yttrium-stabilized tetragonal zirconia polycrystal ceramic (Y-TZP).Materials and Methods: Eighty human molars were embedded in acrylic resin and sectioned 3 mm below the occlusal plane. These teeth and 80 cylindrical Y-TZP specimens (height, 4 mm; diameter, 3.4 mm) were divided into eight groups (n=10) using the following factors: Y-TZP surface treatment (Vi: low-fusing porcelain [vitrification] + hydrofluoric acid etching + silanization or Si: tribochemical silicatization); cementation strategies (PF: Pan avia or CC: Clearfil); and storage (nonaging or aging). Bonding surfaces of 40 Y-TZP specimens received Vi treatment, and the rest received Si treatment. Half of the ceramic-tooth assemblies were cemented with Panavia, the rest with Clearfil. Shear tests were executed using 0.4-mm-thick wire at 0.5 mm/min. Data were analyzed by three-way analysis of variance and Tukey test (alpha=0.05). Fractures were analyzed.Results: Y-TZP surface treatments did not affect bond strength (p=0.762, Vi = Si), while resin cements (p<0.001, Panavia > Clearfil) and aging (p=0.006, nonaging > aging) showed a significant effect. Most failures were in adhesive at dentin-cement interfaces; no failure occurred between zirconia and cement.Conclusion: When Y-TZP ceramic is bonded to dentin, the weakest interface is that between dentin and resin cement. The resin cement/Y-TZP interface was less susceptible to failures, owing to Y-TZP surface treatments.

Effect of Dental Surface Treatment with Nd:YAG and Er:YAG Lasers on Bond Strength to Recently Bleached Dentin

The objective of this study was to evaluate the effect of surface treatment with Er:YAG and Nd:YAG lasers on resin composite bond strength to recently bleached dentin. A total of 120 bovine incisors were distributed into two groups: C- without bleaching; and B- bleached with 35% hydrogen peroxide. Each group was divided into three subgroups: N- without laser treatment; Nd- Nd:YAG laser irradiation; and Er- Er:YAG laser irradiation. The adhesive system (Adper Single Bond 2) was applied and composite build-ups were constructed with Filtek Supreme (3M/ESPE). The teeth were sectioned to obtain dentin-resin sticks (1x1mm(2)) and tested by microtensile bond testing. The bond strength values in group B, subgroup N (16.1 +/- 3.5MPa) presented no significant difference compared with group B, subgroup Er (14.7 +/- 6.1MPa). Group C, subgroup N (26.8 +/- 7.4MPa) presented no significant difference compared with group B, subgroup Nd (28.8 +/- 5.6MPa). Group C, subgroup Nd (36.1 +/- 7.9MPa) presented a significant increase in bond strength compared with the other groups. The Er:YAG laser did not influence the bond strength of bleached specimens, and the use of the Nd:YAG laser on bleached specimens was able to reverse the immediate effects of bleaching, obtaining bond strength values similar to those of the control group.

Dentin Bond Strength: Influence of Er:YAG and Nd:YAG Lasers

The aim of this study was to investigate the effects of Er:YAG and Nd:YAG lasers on the shear bond strength of composite resin to dentin. The coronal portion of 56 human molars was divided into three parts, and the dentin thickness was standardized at 2 mm. A 3-mm hole was marked in the center of each tooth with sealing tape paper. The specimens (n = 14) were then divided into four groups: (1) acid etching + Single Bond (SB) (control), (2) acid etching + SB + Nd: YAG laser irradiation (before adhesive curing), (3) thermal etching with the Er: YAG laser + SB, and (4) thermal etching with the Er: YAG laser + SB + Nd: YAG laser irradiation (before adhesive curing). A composite resin cylinder was built into the delimited area for conducting the shear bond strength test on the universal testing machine. The means +/- standard deviations were: group 1, 17.05 +/- 4.15 MPa; group 2, 16.90 +/- 3.36 MPa; group 3, 12.12 +/- 3.85 MPa; and group 4, 12.92 +/- 2.73 MPa. Groups 1 and 2 presented significantly higher values than groups 3 and 4. It was concluded that conventional etching with 37% phosphoric acid yielded significantly higher bond strength values compared to thermal etching with the Er:YAG laser. The Nd:YAG laser did not significantly influence the bond strength.

Blood clot stabilization on root dentin conditioned by the combination of tetracycline and EDTA

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)