This study aimed to develop a novel abutment material with good esthetic and mechanical properties by producing a white oxide layer on a zirconium-14 mass% niobium (Zr-14Nb) alloy substrate using a thermal oxidation process. Oxidation temperatures ranged 700-1000°C and oxidation time ranged 30-180 min. The color of the oxide layer varied depending on temperature and time. A white oxide layer was obtained under appropriate conditions. The oxide layer thickness increased with increased temperature and time, as revealed by scanning electron microscopy with energy-dispersive X-ray spectroscopy. Moreover, X-ray diffraction and X-ray photoelectron spectroscopy revealed that the oxide layer was predominantly monoclinic ZrO2, tetragonal ZrO2, and Nb2O5. The oxide layer revealed good abrasion resistance and high adhesion to the substrate. This novel process for producing white materials with good mechanical properties will be useful for abutments and prostheses in dental implant treatment.