Avaliação de diferentes concentrações de água ozonizada na desinfecção de canais radiculares contaminados: estudo in vitro

Abstract

In the clinical practice of dentistry, it is evident that despite technological advances, microbial agents are still the main responsible for endodontic failure. Mechanical chemical preparation, a technique used in endodontics, aims to remove necrotic tissue, microbial agents and their by-products from the root canal system. However, preparation is often not sufficient for satisfactory cleaning due to the anatomical complexity of the root canal system, which may lead to the permanence of microorganisms that may remain viable and active, interfering with the recovery process of periradicular tissues. In this way, it is necessary to search for ideal irrigating solutions that can provide better results in endodontic treatment. The aim of the present study was to evaluate and compare, in vitro, the effectiveness of different concentrations of ozonated water in the disinfection of root canals inoculated with Enterococcus Faecalis (E. Faecalis). We used 75 extracted human premolars, with a single canal, approved by the Research Ethics Committee (CEP), approval number 26629619.9.0000.5494. The teeth were sectioned and contaminated with E. Faecalis and incubated for 21 days at 37°C. Initial collections were performed with absorbent paper cones to confirm contamination. subsequently, PQM mechanical chemical preparation was performed, using mechanical instrumentation with a WaveOne® Primary file and the samples were divided into 5 groups according to the irrigating solutions (n = 15): Saline Solution Group (SS): irrigating solution was saline; 2.5% sodium hypochlorite group (NaOCl): 2.5% sodium hypochlorite irrigating solution; Ozone Group 10 (O10): the irrigating solution of ozonized water at a concentration of 10 µg/mL; Ozone Group 20 (O20): irrigating solution of ozonized water at a concentrationof 20 µg/mL; Ozone Group 30 (O30): irrigating solution of ozonized water at a concentration of 30 µg/mL. After mechanical instrumentation and irrigation, a second collection was performed with a paper cone, so the variables analyzed were the collections before and after the PQM. The main results show that the ozonated water used as an irrigating solution in the mechanical chemical preparation was effective in reducing the number of CFU Colony Forming Units at all concentrations (O10, 17,48%O20, 18,87% and O30, 32,87%) and the highest percentage of reduction was observed at the concentration of 30 μg/mL. However, it was not possible to observe a higher reduction of CFU in the groups treated with ozonated water when compared to the irrigant NaOCl. In conclusion, the ozonated water used as an irrigating solution, with emphasis on the concentration of 30 μg/mL, promoted antimicrobial action against E. Faecalis, one of the main microorganisms responsible for critical complications in endodontics, and can be proposed as an adjuvant in endodontic treatments.