SEM Evaluation of Debris Removal from Files after Ultrasonic Cleaning

Objectives: The purpose of the present study was to quantify the surface debris on files removed from the manufacturer's packaging and after cleaning when different placements of the instruments in an ultrasonic cleaner were employed. Methods: Forty-eight unused stainless steel hand instruments were used. The instruments were randomly divided into two experimental groups each one consists of 24 instruments. Then the instruments of group 1 were placed at the bottom of an ultrasonic cleaner and the instruments of group 2 were placed in an ultrasonic beaker. After that the ultrasonic cleaner was activated for 15 minutes. The instruments were observed by a scanning electron microscope and the amount of remaining debris was evaluated before and after ultrasonic cleaning. Chi square test was performed for statistical analysis. Results: Results showed that group 1 instruments showed cleaner surface than group 2 after ultrasonic cleaning (p<0.05). Conclusion: This study showed that the efficacy of ultrasonic cleaning was improved when endodontic files had a direct contact with the bottom of ultrasonic tank. Although, manufacturers have emphasized that when an ultrasonic cleaner is on, nothing should come in direct contact with the tank's bottom.