Akademik Veri Yönetim Sistemi
Dental Materials, 2025 (SCI-Expanded, Scopus)
Objectives: This study aimed to investigate the effects of three polymeric coatings—polyethylene glycol (PEG), polyether ether ketone (PEEK), and polydopamine (PDA)—applied onto the external surfaces of hybrid CAD/CAM dental composites, on their biological and mechanical performance. Methods: Disc-shaped specimens were fabricated from three CAD/CAM hybrid materials: Cerasmart (CS), Vita Enamic (EN), and Lava Ultimate (LU). Prior to coating, all discs were exposed to pressurized nitrogen gas to eliminate potential surface contaminants. Each specimen surface was then treated with GC G-Multi Primer according to the manufacturer's instructions and gently air-dried for 30 s without subsequent light-curing. A layer of Optiglaze Color Clear was subsequently applied and photo-polymerized for 40 s using a high-intensity LED curing unit (Valo Cordless, 1000 mW/cm², Ultradent, South Jordan, UT, USA). No acid etching was performed before primer application in order to preserve the structural integrity of the substrates. To standardize the surface condition, this Optiglaze pretreatment was identically applied to all specimens—including the uncoated control groups—ensuring that any observed differences in performance could be attributed exclusively to the polymer coatings. Each disc was then surface-coated with one of the selected polymers using a spin-coating technique. Surface characterization was conducted using Fourier-transform infrared (FTIR) spectroscopy (Nicolet iS10, Thermo Fisher Scientific, USA), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) (Hitachi SU3500, Japan), and X-ray diffraction (XRD) analysis (Rigaku MiniFlex 600, Japan). Fibroblast adhesion and viability were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay at 24 and 48 h. Mechanical properties—including scratch resistance (via Revetest scratch test), nanohardness (Vickers), and elastic modulus—were quantitatively evaluated. Scratch testing was performed exclusively on polymer-coated CAD/CAM discs (PDA, PEG, PEEK), not on uncoated substrates, to assess the near-surface mechanical response of the coatings and their adhesion to the underlying substrates. Film thickness was quantified by profilometry on polymer coatings deposited under identical spin-coating conditions onto smooth silicon witness wafers, whereas surface roughness was directly measured on the coated CAD/CAM substrates using AFM. This approach ensured that thickness assessment was not confounded by the heterogeneous microstructure of the restorative substrates. Hydrophilic behavior was evaluated by static water contact angle measurements, and hydrolytic stability was determined through water sorption and solubility tests. Results: All coatings significantly enhanced fibroblast adhesion (p < 0.05), with PDA demonstrating the strongest effect at 48 h. Cell viability was significantly influenced by both coating type and substrate composition (p < 0.001). Among mechanical properties, PEEK-coated EN specimens showed the highest scratch resistance, whereas PEG-coated LU specimens exhibited the lowest. All coatings reduced water contact angles relative to controls, indicating improved surface wettability. PEEK-coated specimens displayed the lowest water solubility and the highest nanohardness, while PEG coatings produced the highest elastic modulus. Surface roughness was primarily dictated by substrate composition, with no significant effect of coating type. Significance: Although CAD/CAM composites possess favorable intrinsic mechanical properties, their surfaces lack optimal bioactivity. The application of ultrathin polymer coatings—particularly PEEK and PDA—demonstrated considerable potential to enhance both soft-tissue compatibility and structural durability. These findings underscore the translational relevance of polymer-based coatings in restorative dentistry, with implications for extending restoration longevity, improving soft-tissue sealing, and reinforcing functional performance.