Ugwuanyi Uchenna Barnabas - Federal College of Dental Technology and Therapy Trans-Ekulu Enugu, Nigeria
Adeniyi Ayodele - Federal College of Dental Technology and Therapy Trans-Ekulu Enugu, Nigeria
Eze John Onyeka - Federal College of Dental Technology and Therapy Trans-Ekulu Enugu, Nigeria
Kungawo Friedrich Nchuwa - Rhodes University, South Africa

Zirconia Toughened Alumina (ZTA) composites possess excellent mechanical and tribological properties, which make it relevant to both industries and biomedical practice. Failure of monolithic alumina and zirconia in dental and orthopedic restorations has made researchers to explore innovative applications of ZTA as excellent biomechanical and biocompatible prostheses. Significant technological and scientific attention has focused on biomaterials that are of great interest to patients and care-givers seeking for optimal solution, hence the study. The study involves Design of Experiment (DoE) that encompasses modified conventional slurry method of specimen production, Mechanical testing with micro hardness tester FM-۷, and scanning electron microscopy, optical microscope, using America Society for Testing and Material protocols. The MINITAB ۱۸-based Response Surface Methodology was used in Central composite Inscribed Design (CCID) design of experiment involving two factors: sintering temperature and composition of range ۱۵۰۰-۱۶۵۰℃ and ۵-۱۵wt% respectively on hardness and fracture toughness .The test results of experimentation were analysed using RSM while Desirability Function Analysis (DFA) was applied in optimization. The result indicated on surface plot that increase in sintering temperature (Ts) increases hardness and fracture toughness. Similarly, increase in composition of ZrO۲ decreased hardness but increased fracture toughness. At optimal setting of ۱۶۸۱.۰۱℃ and ۹.۳۵۷wt%, the Vickers hardness and fracture toughness of ۱۵.۲۹۶۳GPa and ۴.۹۱۷۲ MPa𝒎𝟏/𝟐 and composite desirability (D) of ۰.۶۸۷۵ of was achieved in ZTA composite. The ZTA has improved fracture toughness of ۱۹.۹۳% and ۹.۲۷% and a compensatory reduction in hardness of ۶.۵% and ۴.۰% on monolithic alumina and zirconia respectively. The excellent mechanical properties can complement aesthetics, long- term biocompatibility and superior biomechanical properties to define the future of dental prostheses.

Desirability optimization methodology, hardness, sintering, fracture toughness, zirconia toughened alumina, composite desirability