Degree Of Conversion Of Adhesives Research Articles

Polyphenols and Brazilian red propolis incorporated into a total-etching adhesive system help in maintaining bonding durability

ObjectivesThe aim of this study was to evaluate the degree of conversion and bond strength of a commercial dental adhesive modified by the incorporation of quercetin, resveratrol (RES), and Brazilian red propolis (BRP). MethodsBRP markers were identified using ultra-performance liquid chromatography coupled with a diode array detector, and the antioxidant activity (AAO) of the three substances was analyzed. Single Bond 2 adhesive (3M ESPE) was modified by adding BRP, quercetin, and RES, separately, at 20 μg/mL, 250 μg/mL, and 500 μg/mL, respectively. The degree of conversion (DC) was measured using near-infrared spectroscopy 24 h after photopolymerization. Measurements of the resin-dentin microtensile bond strength (μTBS) were carried out after 1 day and 1 year. Student's t test and ANOVA with Tukey's test were used for data analysis (α = 0.05). ResultsThe markers daidzein, liquiritigenin, pinobanksin, isoliquiritigenin, formononetin, pinocembrin, and biochanin A were found in the ethanolic extract of BRP. Quercetin, RES, and BRP showed high AAO. The DC of the tested adhesives remained adequate for this category of material, with a slight increase in the DC of adhesives with quercetin and BRP (P > 0.05). Comparisons between μTBS measurements made at 1 day and 1 year showed that, contrary to the control group, μTBS values for all modified adhesives were maintained after 1 year in distilled water (P > 0.05). ConclusionsThese findings suggest that quercetin, RES, or BRP might be useful in adhesive dentistry to help improve hybrid layer resistance. Clinical significanceDentin bonding agents with quercetin, RES, and BRP have potential to increase the longevity of composite restorations.

Development and assessment offluorinated grapheme nanoparticles modified dental adhesives

Background: The success of adhesion to the tooth structure plays an important role in the dental restoration,which can effectively avoid the terrible clinical problems during the bonding process, including the secondarycaries and the loading of adhesive compositions with fillers and nanoparticles with antibacterial propertieshas led to a significant reinforcement effect of the adhesive.Objective: The current study is designed to investigate the effects of addition of 2% of fluorinated grapheneon the adhesive-dentin hybrid layer for two types of commercially available universal adhesive, guidedusing the etch and rinse technique as a bonding procedure.Method: Forty extracted premolar teeth will be divided into four groups of ten teeth. Group I: the nonincorporated (Prime & Bond Universal) bonding agent (Control group). Group II:using the 2% FGnanoparticles incorporated (Prime & Bond Universal) bonding agent. Group III: non-incorporated (AllBond Universal) bonding agent (Control group). Group IV: using the incorporated (All Bond Universal)bonding agent. The degree of conversion was also measured using Fourier transform infrared spectroscopy(FTIR). The antibacterial activity of the adhesives was evaluated using agar diffusion test against thefollowing bacteria: Streptococcus mutans and Lactobacillus salivarius obtained from saliva.Results: A significantly greater antibacterial activity was obtained with adhesives containing a 2% fluorinatedgrap hene nanoparticles than other groups (P<.01). Degree of conversion of tested adhesives was not changesignificantly after addition of 2% of fluorinated grap hene nanoparticles.Conclusion: The antibacterial effect of adhesives that incorporated with 2% of fluorinated graphenenanoparticles was higher than the non-incorporated etch- and rinse adhesive systems. The degree ofconversion of adhesives was not significantly different.