Browsing by Author "Cruz, Joana Vasconcelos e"
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- Dentin bonding and SEM analysis of a new experimental universal adhesive system containing a dendrimerPublication . Cruz, Joana Vasconcelos e; Polido, Mário; Brito, José; Gonçalves, Luísa L.Due to their polymerization characteristics, hyper-branched dendrimers have lately shown to be promising candidates for use in dental materials. In this study, a new dental adhesive system was prepared, using a dendrimer derived from 2-isocyanatoethyl methacrylate (G-IEMA), and its adhesive properties were investigated. The exposed dentin was treated with four universal adhesives (UAs): SBU (Scotchbond Universal™), FUT (Futurabond M+™), AE1 (experimental adhesive with Bis-GMA) and AE2 (experimental adhesive with G-IEMA), using Etch & Rinse (ER) or Self Etch (SE) protocols. Composite build-ups were prepared and stored for 24 h at 37 °C in distilled water. Composite/dentin beams were prepared with cross-sectional areas of 1 ± 0.3 mm2 and µTBS (Micro-tensile bond strength) test was performed at 0.5 mm/min. Failures modes were evaluated by stereomicroscopy, and bonding interfaces were observed by scanning electron microscopy (SEM). Statistical analysis of µTBS data was performed using General Linear (GLM) and Linear Mixed Models (LMM). The effect of adhesive type on µTBS was significant (p = 0.010), with AE1 presenting significantly higher µTBS than SBU (p = 0.019). No other differences between adhesives were observed. ER showed significantly better results than SE (p = 0.019), and no significant interactions between the adhesives and protocols were determined. Results obtained so far pinpoint the emergence of a new paradigm in the dental materials field, as G-IEMA can be used successfully as an alternative to Bis-GMA.
- A new experimental adhesive system containing G-IEMA – physicochemical propertiesPublication . Cruz, Joana Vasconcelos e; Brito, José; Polido, Mário; Gonçalves, Luísa L.The ultimate goal of this study was the development of a new Bis-GMA-free dental adhesive system with improved adhesive properties. Instead of Bis-GMA, a dendritic macromer (G-IEMA), derived from 2-isocyanatoethyl methacrylate (IEMA), was used and its physicochemical properties were investigated. G-IEMA was synthesized and subsequently incorporated into an experimental adhesive (AE2) formulated without Bis-GMA. Double bond conversion (DBC), polymerization shrinkage (PS), water sorption (WS) and solubility (SL) were evaluated and results were compared with three other adhesives: – an experimental adhesive formulated with Bis-GMA (AE1); Scotchbond™ (SBU); and, Futurabond M+™ (FUT). Comparisons between adhesives for DBC, PS, WS and SL properties were performed using One-Way ANOVA and the Kruskal-Wallis test, at the 5% significance level. Statistical analysis of DBC data, using one-way ANOVA, revealed significant differences between adhesives (p < .001). AE2 presented a significantly higher DBC than SBU (p < .001) and FUT (p = .004); no significant differences were observed between AE2 and AE1 (p = .403) with 60 s of light-curing. Kruskal-Wallis test revealed no significant differences between adhesives (p = .094) for PS. One-Way ANOVA showed no significant differences among adhesives for WS (p = .213) and SL (p = .175). In conclusion, G-IEMA-based adhesive AE2 presented comparable DBC, PS, WS and SL when compared to Bis-GMA-based adhesive AE1. The results obtained so far are promising, revealing that G-IEMA macromer might be a good substitute monomer to prepare Bis-GMA-free adhesive systems.