Máquinas lavadoras ultrassônicas de instrumentos odontológicos, médicos e cirúrgicos: avaliação do desempenho do processo de limpeza

Abstract

The cleaning of dental, medical and surgical instruments (DMSI) with ultrasonic cleaning equipment (UCE) makes use of mechanical (sound vibrations – cavitation), chemical (detergent solutions) and thermal (temperature) energies associated with exposure time. To check the performance of the cleaning process it is necessary the use of tests recommended by international standards. In this study we have evaluated the performance of UCE concerning its minimal acceptable parameters by means of tests described on standards as well as discussing the interfering factors which could compromise the cleaning process of DMSI. Initially, a survey analyzed the operating conditions of UEC through a questionnaire answered by professionals of several health care establishments (HCE) of Curitiba city. The results showed wide use of UCE in the investigated HCE, technical procedures for preparation of the cleaning process, time/temperature relationship and load cycle profiles according to literature recommendations. However there was no agreement on the type test selection or adoption of technical standards. Considering those results, practical tests were carried out for aluminium foils and strips, Sono Check® chemical indicators and TOSI® Lum Check for cannulated instruments, based on international standards. Aluminium foils (100%) and strips (89%) have showed uniformity in the produced holes, indicating efficiency of the cavitation. Some strips presented few modifications (11%), indicating failures in the test and/or functioning of the equipment. Chemical indicators Sono Check®| presented positive results (75%) proving the effectiveness of ultrasonic activity, however some (25%) presented negative results indicating blind spots due to difficulties in the cavitation process, which can be attributed to interfering factors such as: use the same cleaning solution in several cycles, type and disposition of the load, level of the solution in the tank, temperature and divergence of ultrasonic waves between instrument and walls of the equipment. TOSI® Lum Check for cannulated instruments showed negative results which can be attributed to reduced exposure time, not adequate temperature, water quality, incorrect dilution of the cleaning solution, test bad positioned, overload and/or incorrect load of the instruments, and inefficiency of the cleaning solution. It was concluded that the control tests can prove the effectiveness of the ultrasound in the cleaning activity and detect performance failures for UCE assigned to the cited interfering factors. Therefore, it is recommended the development of a technical standard in Brazil which should include types of tests, procedures and operational control of the cycle parameters in order to ensure the quality control of the ultrasonic cleaning process.