Bonding Protocols to Reverse the Bond Strength of a Universal Adhesive to Hemostatic Agent-contaminated Dentin

OBJECTIVE

To evaluate the effect of different bonding protocols on the microtensile bond strength (μTBS) of a universal adhesive to dentin contaminated with a hemostatic agent.

METHODS AND MATERIALS

Ninety-five extracted premolars were used in this study. For the μTBS test, 80 teeth were cut to expose mid-coronal dentin and randomly divided into two groups (uncontaminated dentin and hemostatic agent-contaminated dentin). Each group was further divided into five subgroups (n=8/group): 1) SE: no additional treatment, 2) ER: etching with 32% phosphoric acid, 3) CHX: rinsing with 0.2% chlorhexidine, 4) EDTA: rinsing with 17% EDTA, and 5) T40: application of universal adhesive for 40 seconds. A universal adhesive was applied followed by resin composite build-up. μTBS test was performed after 24 hours of water storage. Two-way analysis of variance (ANOVA) was calculated followed by the Duncan testing (α=0.05). The failure mode was analyzed using light microscopy. Additional teeth were prepared for energy-dispersive X-ray (EDX) analysis (n=1/group) and resin-dentin interface observation (n=2/group) using scanning electron microscopy.

RESULTS

Adverse effects of hemostatic agent contamination on the bonding performance of a universal adhesive was found in the SE, CHX, and T40 groups (p<0.05). Fewer and shorter resin tags were observed in the SE, CHX, and T40 groups. A higher percentage of adhesive failure and mixed failure was found in contaminated dentin. All bonding protocols revealed lower amounts of Al and Cl after dentin contamination, except for the SE group.

CONCLUSIONS

Hemostatic agent contamination adversely affected dentin bond strength. However, this bond strength could be reversed using the etch-and-rinse technique or rinsing with EDTA prior to adhesive application.

EDTA-functionalized silica nanoparticles as a conditioning agent for dentin bonding using etch-and-rinse technique

OBJECTIVE

This study investigated the possibility of using ethylenediaminetetraacetic acid functionalized silica nanoparticles (EDTA-SiO₂) as a dentin-conditioning agent using etch-and-rinse technique to promote the durability of dentin bonding.

METHODS

The SiO₂-EDTA were synthesized by N- [(3- trimethoxysilyl) propyl] ethylenediamine triacetic acid (EDTA-TMS) and SiO₂ (50 nm), then characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The capacity of SiO₂-EDTA to chelate calcium ions from dentin was examined by inductively coupled plasma-optic emission spectrometry (ICP-OES). The dentin surfaces conditioned with SiO₂-EDTA were detected by field emission scanning electron microscopy (SEM), TEM and microhardness testing. For dentin bonding, dentin surfaces were adopted wet- or dry-bonding technique and bonded with adhesive (Adper^TM Single Bond2) and applied composite resin (Filtek Z350) on them. The durability of dentin bonding was evaluated by mircotensile bond strength test, in-situ zymography and nanoleakage testing.

RESULTS

FTIR, TGA and XPS results showed that SiO₂-EDTA contained N element and carboxyl groups. SEM, TEM and microhardness results indicated that SiO₂-EDTA group created extrafibrillar demineralization and retained more intrafibrillar minerals within dentin surface. In the dentin bonding experiment, SiO₂-EDTA group achieved acceptable bond strength, and reduced the activity of matrix metalloproteinase and nanoleakage along bonding interface.

CONCLUSION

It was possible to generate a feasible dentin conditioning agent (SiO₂-EDTA), which could create dentin extrafibrillar demineralization and improve dentin bond durability.

CLINICAL SIGNIFICANCE

This study introduces a new dentin conditioning scheme based on SiO₂-EDTA to create extrafibrillar demineralization for dentin bonding. This strategy has the potential to be used in clinic to promote the life of restoration bonding.

Adhesive Strength in Dentin Conditioned with 18% Ethylenediaminetetraacetic Acid versus 35% Phosphoric Acid: In Vitro Study with 1-Year Artificial Aging

The success and longevity of a resin composite restoration is determined by its good bonding to the tooth structure, with the adhesion being a challenge to dentin due to its complexity and structural heterogeneity. The present study aimed to compare the adhesive strength of dentin conditioned with 18% ethylenediaminetetraacetic acid (EDTA) versus 35% phosphoric acid (H3PO4) in human premolars. Materials and Methods: This in vitro experimental study was performed on 40 human premolars. The occlusal thirds were sectioned and randomly placed into four groups according to the type of dentin conditioning: Group 1 (control), Group 2 (18% EDTA), Group 3 (35% H3PO4) and Group 4 (18% EDTA plus 35% H3PO4). Then, 10,000 thermocycles between 5 +/− 2 °C and 55 +/− 2 °C were applied. Adhesive strength was tested by shearing with a digital universal testing machine at a crosshead speed of 0.75 mm/min. The values obtained were analyzed in megapascals (MPa). The mean and standard deviation were used as measures of central tendency and dispersion. In addition, a one-factor intergroup ANOVA test was applied with Tukey’s post hoc test considering a significance level of p < 0.05. Results: The 18% EDTA and 18% EDTA plus 35% H3PO4 showed significantly higher adhesive strength compared to the control group that did not receive dentin conditioning (p = 0.047 and p < 0.001, respectively). However, the group conditioned with 18% EDTA did not present significant differences compared to the group conditioned with 35% H3PO4 (p = 0.997). In addition, the group conditioned with 18% EDTA plus 35% H3PO4 showed significantly higher adhesive strength compared to the groups conditioned with 18% EDTA (p = 0.002) and 35% H3PO4 (p = 0.001). Conclusion: The adhesion of bulk fill resin composite to dentin was favorable when preconditioning was performed using 18% EDTA followed by 35% H3PO4. In contrast, when both etchants were used separately, the bulk fill resin composite showed similar bond strength values in both cases, but significantly lower compared to their sequential application.

Bond Strength of Universal Adhesives to Dentin: A Systematic Review and Meta-Analysis

Currently, the availability of a wide variety of universal adhesives makes it difficult for clinicians to choose the correct system for specific bonding situations to dentin substrate. This study aimed to determine whether there are any alternative techniques or additional strategies available to enhance the bond strength of universal adhesives to dentin through a systematic review and meta-analysis. Two reviewers executed a literature search up to September 2020 in four electronic databases: PubMed, ISI Web of Science, Scopus, and EMBASE. Only in vitro studies that reported the dentin bond strength of universal adhesives using additional strategies were included. An analysis was carried out using Review Manager Software version 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). The methodological quality of each in vitro study was assessed according to the parameters of a previous systematic. A total of 5671 potentially relevant studies were identified. After title and abstract examination, 74 studies remained in systematic review. From these, a total of 61 studies were included in the meta-analysis. The bond strength of universal adhesives to dentin was improved by the use of one of the following techniques: Previous application of matrix metalloproteinases (MMP) inhibitors (p < 0.001), prolonged application time (p = 0.007), scrubbing technique (p < 0.001), selective dentin etching (p < 0.001), non-atmospheric plasma (p = 0.01), ethanol-wet bonding (p < 0.01), prolonged blowing time (p = 0.02), multiple layer application (p = 0.005), prolonged curing time (p = 0.006), and hydrophobic layer coating (p < 0.001). On the other hand, the use of a shortened application time (p = 0.006), and dentin desensitizers (p = 0.01) impaired the bond strength of universal adhesives to dentin. Most of the analyses performed showed a high heterogenicity. The in vitro evidence suggests that the application of universal adhesives using some alternative techniques or additional strategies may be beneficial for improving their bonding performance to dentin. This research received no external funding. Considering that this systematic review was carried out only with in vitro studies, registration was not performed.

MDP-based universal adhesive system irradiated with Er,CR:YSGG: Analysis of its performance up to 6 months

This study aimed to analyze the interaction of a MDP-based universal dentin bonding system (DBS) with Er, Cr: YSGG laser irradiation, measuring the microtensile bond strength to dentin over a six-month period. The experimental design involved three factors: DBS (Adper Scotchbond Universal; Clearfil SE Bond, Adper Scotchbond Multipurpose and Adper Single Bond 2), laser (Control and Er, Cr: YSGG), and time (initial- 7 days and 6 months). Eighty dentin samples from molars were prepared (n=10) with laser irradiation after primer and DBS application. After 7 days, were subjected to micro tensile bond strength test. The data were analyzed by three-way ANOVA and Tukey tests (p<0.05). Both DBS and laser significantly affected the bonding performance and their interaction was statistically significant (p=0.0194). The self-etching mode of the MDP-based universal DBS maintained the bond strength on dentin irradiated with ER, Cr: YSGG after 6 months, while bonding with all other DBS deteriorated.

[Effects of various surface treatments on the bonding efficacy of noncarious cervical sclerotic lesions]

Noncarious cervical sclerotic lesions (NCSL) are dental cervical lesions with noncarious sclerotic dentine (NCSD), which appears smooth, hard, and either light yellow or dark brown. Most NCSLs are wedge or dish shaped and commonly occur in canines and premolars, leading to dental hypersensitivity and aesthetic defect. The principal treatment is composite resin restoration; however, many clinical problems, such as retention loss, should not be ignored. NCSL's bonding interface includes NCSD and enamel, and interface pre-treatment can promote the bonding effect. This review summarizes current surface treatment methods and their influence on the bonding effectiveness of NCSL to provide guidance for clinical practice.

A comparative study of the microtensile bond strength and microstructural differences between sclerotic and Normal dentine after surface pretreatment

Background

The resin bond strength of sclerotic dentine is significantly lower than that of the normal dentine, which paused a challenge for bonding procedures clinically. The aim of this study was to compare the effects of different surface pretreatments on the micro-tensile bond strength and microstructure between sclerotic dentine and normal dentine.

Methods

Eighty teeth that were collected, forty premolars with typical wedge-shaped defects visually graded as class III were assigned as the sclerotic dentine group (SD), the other forty normal premolars with artificial wedge-shaped defects were assigned as the normal dentine group (ND). Each group was randomly subdivided into eight subgroups according to the solution used: 35% phosphoric acid, 15% EDTA, 5% or 10% NaClO. Then the dentine surface was examined using a scanning electron microscope (SEM). The lesions were restored using self-etching adhesive and the subsequent resin composite. The teeth were sectioned into sticks for the micro-tensile bond strength analysis, and the data were analysed using the SPSS17.0 software package (α = 0.05).

Results

First, for the ND groups, after pretreatment using 35% phosphoric acid, and 35% phosphoric acid + 5% or 10% sodium hypochlorite, the bonding strengths of the normal dentine were higher than that of the other groups (P < 0.05). Second, for the SD groups, after pretreatment using 35% phosphoric acid, 15% EDTA, and 35% phosphoric acid + 5% or 10% sodium hypochlorite, the bonding strengths of the sclerotic dentine were higher than that of the other groups (P < 0.05). Third, the bond strengths of the sclerotic dentine were lower than that of the normal dentine without any pretreatment (P < 0.05). After pretreatment using 35% phosphoric acid + 5% or 10% sodium hypochlorite, the bonding strengths of the sclerotic dentine were higher than that of the normal dentine (P < 0.05). SEM observation showed that the appearances of dentine surface were changed after pretreatment using the above solutions, with the reduced smear layer, opened small groove and increased dentinal tubules.

Conclusion

Pretreatment of dentine using 35% phosphoric acid+ 5% or + 10% sodium hypochlorite changed the microstructure of the sclerotic dentine surface and subsequently increased the micro-tensile bond strength.

Universal dental adhesives: Current status, laboratory testing, and clinical performance

Increasing demand for simplified and user-friendly adhesive systems has led to the development of a new class of adhesives termed as Universal Adhesives (UAs). The term "Universal" reflects manufacturers' claims that these adhesives can be applied with any adhesion strategy and offer the versatility of use with a variety of direct and indirect restorative materials. The aim of this review was to synthesize the literature regarding the current status of UAs, their adhesion potential to various substrates and their performance in different restorative situations. In vitro studies, clinical trials and systematic reviews were identified utilizing controlled vocabulary and keyword searches in Medline and EMBASE databases. About 282 studies (272 in vitro studies; 11 clinical studies) were included. Available laboratory and clinical evidence does not support the claim that UAs can be used with any adhesive strategy. Although, they can chemically bond to various tooth and direct/indirect restorative substrates, the stability of this bond is material-dependent and subject to hydrolytic degradation. Hence, additional measures are still needed to ensure long-term durability. which undermines the versatility of UAs. The lack of long-term data regarding the clinical performance of UAs further complicates clinical decision-making. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2121-2131, 2019.