<p><strong>Objective: </strong>Computed microtomography was used to evaluate the capacity of debris removal from simulated lateral canals, in conventional irrigation, passive ultrasonic irrigation (PUI), continuous passive irrigation (CUI), Endoactivator and EasyClean, for both types of motion (continuous and reciprocating). <strong>Material and Methods</strong>: Sixty acrylic incisors with 3 simulated lateral canals per tooth (cervical, middle and apical third) were instrumented with Reciproc 40/06 and then filled with dentin debris. The teeth were scanned and divided into 6 groups (n = 10) according to the irrigation protocol: G1 - conventional, G2 - PUI, G3 - CUI, G4 - Endoactivator, G5 - EasyClean continuous rotation and G6 - EasyClean reciprocating. After the irrigation protocols, the samples were scanned again. The initial and final volume images were analyzed and the percentage of debris removal were found for each group in all levels. <strong>Results:</strong> There were significant differences between the initial and final volume of debris after the protocols, with the exception of conventional irrigation group in the apical and cervical thirds, EasyClean reciprocating in the middle and cervical thirds, and CUI in the middle third. In the analysis between the groups: in the apical third, Endoactivator and PUI removed more debris than CUI (p &lt; 0.05); in the middle and cervical thirds, PUI was more efficient than conventional irrigation, EasyClean reciprocating and CUI (p &lt; 0.05). <strong>Conclusion:</strong> No method completely removed the debris. PUI was the method that showed greater effectiveness in cleaning the lateral canals.</p><p><strong>Keywords</strong></p><p>Root canal therapy; Microct; Dentin; Ultrasonic therapy.</p>

The aim of this in vitro study was to investigate the influence of ethylenediaminetetraacetic acid (EDTA) associated with the benzalkonium chloride (BAK) on the adhesion and formation of Enterococcus faecalis biofilms attached to coated dentin. Discs standard bovine dentin blocks were treated with the coating materials evaluated: Saline solution (control), 17 % EDTA, 17 % EDTA associated with 1 % BAK for 5 minutes and subsequently washed with saline solution. Afterwards, biofilms of E. faecalis (ATCC 29212) were grown on the surface of coated dentin blocks for time intervals of 1 hour and 7 days (n = 20) and were subsequently washed with phosphate-buffered saline (PBS). Bacterial viability and total biovolume were analyzed by confocal laser scanning microscopy (CLSM) using the Live/Dead technique. Nonparametric Kruskal-Wallis followed by Dunn tests were used to determine statistical differences (a = 5 %). The 17 % EDTA + 1 % BAK group showed significantly lower biovolume and bacterial viability values at the end of 1 hour (p < 0.05). After 7 days of contamination, the 17 % EDTA and 17 % EDTA + 1 % BAK groups showed similar results that differed statistically from those of the control group (p < 0.05). The saline solution group showed higher values. The use of BAK associated with EDTA on dentin blocks surfaces before exposure to contamination was able to interfere in the adhesion of E. faecalis to dentin. Also, dentin treatment by BAK associated with a chelating agent influences the secondary biofilm formation, which could have important effects on the long-term success of root canal treatment.

Agradeço primeiramente a Deus, por toda oportunidade que tive durante minha trajetória até o dia de hoje.Aos meus pais Pedro Roberto e Sueli, que foram essenciais para meu crescimento pessoal e profissional, me dando apoio sempre, seja qualquer fosse minha escolha.Aos excelentes professores que ajudaram de alguma forma na minha formação, meu muito obrigado pelo conhecimento compartilhado e pelas experiências obtidas, em especial agradeço meu orientador Prof. Dr. Marco Antonio Hungaro Duarte por toda oportunidade, desde minha iniciação cientifica sou eternamente grato, e aos professores do departamento da Endodontia:

OBJECTIVES:The study aimed to evaluate the potential for dissolution of organic tissue in areas of simulated complexity and cleaning of root walls of the new iVac® endodontic irrigation system. MATERIAL AND METHODS: Thirty mandibular premolars were evaluated by scanning electron microscopy before and after biomechanical preparation. Then, they were distributed according to the final irrigation protocol into groups with conventional irrigation, passive ultrasonic irrigation with metallic insert (PUI), and iVac® system, and new photomicrographs were obtained. For tissue dissolution analysis, glass capillaries filled with catgut were attached to the cervical and apical thirds of twenty prototyped upper incisors. They were weighed before and after the previously mentioned irrigation protocols. The data were statistically compared with a significance level of 5%. RESULTS:The final irrigation provided greater cleaning of the walls in the cervical, middle, and apical thirds of the root canals (P<0.05), with no statistically significant difference between PUI and iVac®, regardless of the analyzed thirds. Both ultrasonic irrigation protocols dissolved a significantly greater volume than the conventional irrigation protocol (P<0.05), with no difference between the two protocols (P<0.05). CONCLUSIONS:The iVac® system showed wall cleaning and tissue dissolution similar to PUI with a metallic insert, and both were superior to conventional irrigation. CLINICAL RELEVANCE: The new irrigation system iVac is more effective than conventional irrigation and has similar wall cleaning and tissue dissolution to PUI.