Corrosion of Prosthetic Keys Made of AISI 420 Used in Dental Practice: Case Study

The corrosion behaviour of AISI 420 martensitic stainless steel, frequently employed in dental prosthetics due to its mechanical strength and cost-effectiveness, necessitates a thorough and multidimensional investigation. While this steel offers advantageous machinability, its lower corrosion resistance compared to that of austenitic steels raises concerns, particularly when influenced by factors such as inclusions, residual stresses, and contamination from machining processes. This study aims to elucidate the causes of pitting corrosion on prosthetic keys fabricated from AISI 420. It highlights critical manufacturing stages, particularly washing and passivation processes, which are vital for mitigating corrosion risks. Experimental analyses revealed that corrosion initiation can be attributed to metal residues, inadequate passivation, and contaminated washing water. Furthermore, it was determined that the presence of rust is more closely associated with improper storage and drying practices than with inherent material defects. These findings underscore the importance of meticulous handling and verification of prosthetic components prior to packaging and highlight the need for standardised procedures during sterilisation in clinical settings. The outcomes of this research contribute significantly to enhancing the longevity and reliability of dental prosthetic applications, emphasising the necessity for technological interventions to prevent corrosion in clinical environments.