Percorrer por autor "Ferreira, Marta Nunes"
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- Effect of varying functional monomers in experimental self-adhesive composites : polymerization kinetics, cell metabolism influence and sealing abilityPublication . Ferreira, Marta Nunes; Santos, Marta Neves Dos; Fernandes, Inês; Marto, Carlos Miguel; Laranjo, Mafalda; Silva, Diana; Serro, Ana Paula; Carrilho, Eunice; Botelho, Maria Filomena; Azul, Ana Mano; Delgado, António H. S.The aim was to evaluate the effects of adding different functional monomers to experimental self-adhesive composites (SACs) on polymerization kinetics, cell metabolic activity, and sealing ability. SACs were formulated using urethane dimethacrylate as the base monomer and triethylene glycol dimethacrylate. Additionally, 10 wt.% of distinct functional monomers were added - 10-methacryloyloxydecyl dihydrogen phosphate, glycerol phosphate dimethacrylate (GPDM), 2-hydroxyethyl methacrylate (HEMA) or hydroxyethyl acrylamide (HEAA). ATR-FTIR was used to determine real-time polymerization kinetics (20 min, n = 3). The final extrapolated conversion and polymerization rates were determined (DC,max;Rp,max). The DC,max values were employed to calculate volumetric shrinkage. The MTT assay was performed on MDPC-23 cells using disc extracts at different concentrations (n = 8). Class V cavities were prepared in 60 sound human molars, assigned to six groups (n = 10), depending on the composite used and aging type (T0 or TC, if thermocycled for 10 000 cycles). One-way ANOVA, two-way, and Kruskal–Wallis tests were employed to treat the data (ɑ = 0.05). Varying the functional monomers had a large impact on DC,max, as confirmed by one-way ANOVA (p<0.001). The highest was obtained for HEMA (64 ± 3%). The HEMA and HEAA formulations were found to be significantly more toxic at concentrations below 100%. For microleakage, having a functional monomer or not did not show any improvement, irrespective of margin or aging period (Mann–Whitney U, p > 0.05). Larger functional monomers MDP and GPDM affected polymerization properties. Conversely, their acidity did not seem to be detrimental to cell metabolic activity. Regarding sealing ability, it seems that the functional monomers did not bring an advantage to the composites. Varying the functional monomer in SACs had a clear impact on the polymerization kinetics as well as on their cytotoxic potential. However, it did not confer better microleakage and sealing. Claiming self-adhesiveness based only on functional monomers seems dubious.
- Physico-chemical properties and performance of functional monomers used in contemporary dental adhesive technologyPublication . Delgado, António H. S.; Ahmed, Mohammed H.; Ferreira, Marta Nunes; Azul, Ana Mano; Polido, Mário; Yoshihara, Kumiko; Van Meerbeek, BartThis comprehensive literature-based review critically examines the physico-chemical properties of functional monomers present in contemporary dental adhesive formulations or dental materials relying on self-adhesive technology. A qualitative synthesis of evidence was conducted through searches in PubMed, Scopus, and LILACS over a 20-year period (2005–2025), without language restrictions. Data on the chemical structure, composition, adhesive performance, pKa, etching efficacy, polymerization, mechanical properties, toxicity, and hydrolytic stability/degradation were analyzed from peer-reviewed studies and manufacturer technical information. Several relevant acidic functional monomers are covered, but key players include 10-MDP, GPDM, and 4-META. Notably, 10-MDP emerged as the most prevalent monomer in commercial adhesives, appearing in nearly 50% of the current adhesives in the market. Its superior adhesive performance and longevity stem from its unique chemical characteristics, whereas other commercial acidic monomers, including GPDM and 4-META, are still present in many adhesive formulations despite their structural limitations and comparatively lower bonding efficacy. Understanding the chemical composition of dental adhesives is essential for achieving improved clinical outcomes and driving material development. This knowledge allows clinicians to select adhesive materials based on performance requirements and informs future innovations to address challenges such as degradation pathways, biocompatibility, and their overall long-term bonding efficacy.
- Self-adhesive flowable resin composites—Are we going somewhere?Publication . Delgado, António H. S.; Alves, Miguel; Pires, Inês; Ferreira, Marta Nunes; Cuevas-Suárez, Carlos EnriqueObjective: To map laboratory/clinical evidence on self-adhesive flowable resin composites (SAFRCs), tracing their chemical evolution, performance, and behavior, and to identify gaps that must be addressed to drive their optimization. Overview: A comprehensive literature search was performed in PubMed/MEDLINE, Scopus, and LILACS without language restrictions. To date, 11 commercial SAFRCs are available. These contain 5wt%–10 wt% hydrophilic monomers and ≤ 55 vol% fillers, as a flowable option, although susceptible to water sorption and color changes. Functional monomer trends shift from 4-META/GPDM to 10-MDP or phosphate-amide hybrids; meta-analytical and recent laboratory data confirm that μTBS to dentin is extremely low (rarely > 10 MPa). Inefficacy to bond/seal is the main reason for failure. Clinical evidence is scarce and short-term: RCTs suggest that small Class-I restorations survive comparably to controls at ≤ 24 months, but failures are frequent. Emerging strategies such as alternative conditioning, collagen depletion, or incorporation of bio-interactive fillers may improve outcomes. Conclusions: Current SAFRCs simplify placement and reduce technique sensitivity but are constrained by very low bond strengths, poor sealing, and high hygroscopicity. Until chemistry, paste acidity, and smear-layer interaction are co-optimized, their use should remain limited. Future research must couple novel chemical formulations and low-water-uptake matrices while validating performance in adequately powered RCTs.