Despite aesthetic trends, metal–ceramic restorations continue to be widely accepted due to their durability, and variations in surface preparation process can significantly influence bond strength outcomes. The purpose of this study was to determine whether there are differences in the bond strength depending on three surface treatment protocols for veneering ceramics on Ni-Cr alloys. The following surface treatments were used: (1) control (C) (no treatment), (2) airborne-particle abrasion (APA) with 50 µm Al₂O₃ (G1-APA), (3) APA followed by oxidation (G2-APA-O), and (4) APA-O, with a second APA (G3-APA-O-APA). Subsequently surface roughness (R_a and R_z) was evaluated using profilometry, hardness was measured through Leeb’s hardness dynamic test (HLD), morphology was investigated through scanning electron microscopy (SEM), and the chemical composition of the alloy surface was evaluated using energy-dispersive spectroscopy (EDS). After surface treatments, veneering ceramic was applied, the debonding crack initiation strength (DCIS) was investigated through the three-point bending test, failure mode was classified using a stereoscopic microscope, and chemical characterization of the fractured surfaces was performed using Raman spectroscopy (RS). For DCIS, G2-APA-O demonstrated the highest value 63.97 ± 44.40 (MPa) (p < 0.05). The results of this study indicate that oxidation treatment has a positive effect on the bonding strength between veneering ceramic and Ni-Cr alloys.

Raman spectroscopy is a widely used analytical technique; however, the choice of container material can significantly affect repeatability due to noise and unwanted Raman bands. This paper describes the interaction of excitation radiation with the sample’s environment and the materials surrounding or containing it. Polytetrafluoroethylene (PTFE) and Barium Sulphate are analyzed as contact surfaces with the containers. We aim to investigate how different container materials affect the Raman spectrum and identify the optimal material to minimize measurement bias. We compared the Raman spectra of containers made of dissimilar materials, including plastic, glass, quartz, and aluminum, to assess their effects on the spectra, and we propose a container design that enhances Raman spectroscopy signals. We consider Raman bands from biological samples of glucose (in water) and urine (urea and creatinine), which serve as references for comparison in the in vitro analysis of these substances across different containers and backgrounds.