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  • Extrafibrillar demineralization technique on the interfacial quality of dentin restored with self-adhesive composites
    Publication . Marques, Mariana Gomes Santos Godinho; Delgado, António Sales
    Objectives: To evaluate whether an extrafibrillar demineralization technique can provide a dentin substrate capable of supporting the formation of a stable hybrid layer when restored with selfadhesive flowable resin composites (SAFRCs), potentially overcoming their limitations. Materials and Methods: Eighteen sound human molars were sectioned (Accutom-50, 0.350 mm/s, Struers, Denmark) and allocated into six groups (n=3), combining two SAFRCs (Vertise™ Flow, Kerr; Constic, DMG) with three pretreatments: 37.5% phosphoric acid (control; OPA) for 15 s, glycol-chitosan methacrylate (GQ), and poly(amidoamine) dendrimers (PAMAM) for 60 s with active rubbing. Restorations were performed using the respective SAFRCs, applying a 0.5 mm layer and light-curing for 20 s (LED unit, 450–470 nm, ~950 mW/cm²). After 24 h in distilled water at 37 °C, each tooth was sectioned into 2 mm slices and randomly assigned to Raman microspectroscopy or Masson’s Trichrome staining. Chemical Transition Width (CTW, μm), defined as the 25–75% rise of the Raman ratio profile, was calculated to assess interface abruptness. Data were analyzed using non-parametric statistics (α=0.05). Results: Both pretreatment and SAFRC type influenced the dentin–resin interface. Raman analysis showed that PAMAM generated the narrowest and most abrupt chemical transitions (CTW ≈2.3 μm for VF; 1.1 μm for CC), whereas GQ produced broader interphases with persistent amide-rich residues (CTW≈1.9 μm for VF; 0.8 μm for CC). OPA resulted in irregular profiles (CTW ≈ 2.5 μm for VF; 0.6 μm for CC). Despite no statistically significant group differences (p=0.147), PAMAM yielded cleaner interfaces with minimal collagen exposure, while GQ showed more red bands, especially with Constic. Conclusions: Extrafibrillar demineralization influenced the dentin substrate by modulating collagen exposure and interfacial organization, but it did not overcome the intrinsic limitations of SAFRCs. Refinement of pretreatment approaches and composite development is required to achieve predictable and durable adhesion.
    2025-10-25Dissertação de mestrado Acesso embargado Ver mais