Biocompatible Inorganic PVD MeSiON Thin Films (Me = Cr or Zr) Used to Enhance the Bond Strength Between NiCr-Based Metallic Frameworks and Ceramic in Dental Restorations

• Published in: Dentistry journal Vol. 13; no. 7; p. 318
• Main Authors: Dinu, Mihaela, Cotrut, Cosmin Mihai, Vladescu (Dragomir), Alina, Baciu, Florin, Parau, Anca Constantina, Pana, Iulian, Constantin, Lidia Ruxandra, Vitelaru, Catalin
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 14.07.2025; MDPI
• Subjects: 3-point bending test; Adhesion; Adhesives; Alloys; Analysis; Arc deposition; Bias; Biocompatibility; Bond strength; Bonding strength; cathodic arc evaporation; Ceramic coatings; Ceramic materials; Ceramics; Chemical bonds; Chromium; Chromium alloys; Clay; Coatings; Contact angle; dental restoration; Dental restorative materials; Dentistry; Dielectric films; Hypotheses; Interfaces; Interlayers; Investigations; Kaolin; Mechanical properties; Morphology; Nickel chromium alloys; NiCr; Oxidation; oxynitrides; Stoichiometry; Structural analysis; Substrates; Surface properties; Surface roughness; Thin films; Zirconium dioxide; United States; Massachusetts; Romania; United States > US; Japan
• ISSN: 2304-6767; 2304-6767
• DOI: 10.3390/dj13070318

Background/Objectives: The increasing demand for aesthetics in dentistry has driven significant advancements in both materials and techniques. The primary cause of ceramic detachment in dental restorations is extensive mechanical stress, which often results in detachment and clinical complications. This study aims to improve the bond strength between NiCr-based metal frameworks and ceramic coatings by introducing biocompatible inorganic MeSiON thin films (Me = Cr or Zr) as interlayers. Methods: MeSiON coatings with a thickness of ~2 μm were deposited on NiCr alloy using cathodic arc evaporation. To tailor the stoichiometry, morphology, and mechanical properties of the coatings, the substrate bias voltage was varied: −50 V, −100 V, −150 V, −200 V. Structural and surface characterization was performed using SEM/EDS, XRD, profilometry, and contact angle analysis. The coating adhesion was evaluated by using standardized scratch testing, while the bond strength was evaluated using a three-point bending test. Results: The NiCr alloy exhibited a dendritic microstructure, and the ceramic layer consisted mainly of quartz, feldspar, kaolin, and ZrO2. ZrSiON coatings showed superior roughness, elemental incorporation, and adhesion compared to Cr-based coatings, these properties being further improved by increasing the substrate bias. The highest bond strength was achieved with a ZrSiON coating deposited at −200 V, a result we attributed to increased surface roughness and mechanical interlocking at the ceramic-metal interface. Conclusions: CrSiON and ZrSiON interlayers enhanced ceramic-to-metal adhesion in NiCr-based dental restorations. The enhancement in bond strength is primarily ascribed to substrate bias-induced modifications in the coating’s stoichiometry, roughness, and adhesion.