Effect of ultrasound streaming on the disinfection of flattened root canals prepared by rotary and reciprocating systems

Abstract

New technical and scientific developments have been advocated to promote the success of the endodontic treatment. In addition to rotary and reciprocating systems, irrigating solution agitation has been suggested and passive ultrasonic irrigation (PUI) is the most used. Objective: To evaluate, in vitro, the effect of ultrasound streaming (US) in the disinfection of flattened root canal systems prepared by the ProTaper, BioRaCe and Reciproc systems, utilizing the microbiological culture. Methodology: Extracted human mandibular incisors (n=84) were used. Suspensions of Enterococcus faecalis (ATCC 29212) were standardized and inserted along with the teeth immersed in brain-heart infusion (BHI) broth. The contamination was made following a protocol during 5 days. The teeth were randomly divided into six groups: G1, ProTaper Universal; G2, ProTaper Universal with US; G3, BioRaCe; G4, BioRaCe with US; G5, Reciproc; and G6, Reciproc with US. Irrigation was performed with saline solution. After biomechanical preparation, microbiological samples were performed with sterilized paper points, which were diluted and spread on BHI agar; after 48 h, the colony forming units (CFU/mL) were counted for each sample. Results: Groups using ultrasonic agitation presented a greater antibacterial effect than the other ones, even using saline solution as irrigant. The ProTaper Universal system showed the best antibacterial activity of the tested systems (median of 0 CFU/mL with and without surfactant or ultrasonic activation [PUI]). Even with PUI, Reciproc (median of 2.5 CFU/mL with PUI and 5 without it) could not reduce as many colonies as ProTaper Universal without US. The BioRaCe system had greater bacterial reduction when using US (median of 0 CFU/mL with PUI and 30 without it). Conclusions: US promoted greater reduction in the number of bacteria in the flattened root canals prepared with nickel-titanium mechanized systems. Regarding the instruments used, the ProTaper Universal system was the most effective in reducing the bacterial number.

Effectiveness of complementary irrigation routines in debriding pulp tissue from root canals instrumented with a single reciprocating file

“…A recent study demonstrated the ability of ultrasonic irrigation to reduce significantly the bacterial load in flattened canals instrumented with a reciprocating file (Vasconcelos et al . ). In the same study, the number of microbial colonies present in canals instrumented by a single file was greater than that in canals instrumented with a multi‐file system, clearly indicating the need for complementary irrigation approaches to enhance the disinfection of canals instrumented by single files.…”

“…It is important to highlight the findings relating to the capability of ultrasonic irrigation to improve the quality of pulp tissue debridement in root canals instrumented using a single reciprocating file especially in canals with more challenging anatomy such as an oval shape. A recent study demonstrated the ability of ultrasonic irrigation to reduce significantly the bacterial load in flattened canals instrumented with a reciprocating file (Vasconcelos et al 2017). In the same study, the number of microbial colonies present in canals instrumented by a single file was greater than that in canals instrumented with a multi-file system, clearly indicating the need for complementary irrigation approaches to enhance the disinfection of canals instrumented by single files.…”

Can kinematics, file diameter, and PUI influence the intracanal decontamination and apical bacterial extrusion?

“…Next, three ultrasonic baths were performed with 1% NaOCl, 17% ethylenediaminetetraacetic acid (EDTA), and phosphate-buffered saline (PBS) solution, respectively, for 10 min each, followed by distilled water to eliminate EDTA and NaOCl residues and open up the dentinal tubules according to a previously described protocol. 6,13 The specimens were sterilized individually in microtubes with distilled water in an autoclave (Cristófoli, Campo Mourão, Brazil) at 121°C for 24 min, inserted in Brain Heart Infusion (BHI) sterile culture media (Difco, Detroit, USA), and submitted to an ultrasonic bath for 10 min for maximum penetration of the culture broth into the dentinal tubules.…”

“…4 Conventional syringe irrigation (CSI) has been routinely used; nevertheless, there are several limitations related to this technique. 5 Aiming for better antisepsis of the root canal system, agitation of the irrigation solution was performed by passive ultrasonic irrigation (PUI), wherein an activation of an ultrasonic tip inside the root canal along the working length (WL) is performed and moved passively in up-and-down motions, 6 helping to remove debris and remnants of the pulp tissue. 6,7 However, further studies must be carried out to fully clarify the issue of debris extrusion performed by PUI activation.…”

Efeito da irrigação ultrassônica e da medicação intracanal com hidróxido de cálcio na quantidade e no metabolismo de bactérias que persistiram após o preparo dos canais radiculares de dentes com periodontite apical

“…Porém, esse fenômeno pode ser influenciado por diversos fatores dentro do canal radicular: os pequenos volumes de irrigante (van der Sluis et al, 2007, Macedo et al, 2014a; o tempo de agitação ultrassônica (Macedo et al, 2014b); a potência do equipamento de ultrassom (Chen et al, 2013); o contato da solução ativada com o ar atmosférico (Chen et al, 2013;Macedo et al, 2014a); o tipo de instrumento ativado (van der Sluis et al, 2007;Chen et al, 2013;Macedo et al, 2014a,b); a anatomia do canal radicular (Castelo-Baz et al, 2012;Vasconcelos et al, 2017), e as regiões de istmos (Thomas et al, 2014 (Paiva et al, 2012(Paiva et al, , 2013Nakamura et al, 2018 (Harrison et al, 2010;Cachovan et al, 2013). A PUI apresentou os melhores níveis de desinfecção em dentes contaminados com Enterococcus faecalis em canais com anatomia transversal ovalada (Vasconcelos et al, 2017). Estudo in vitro, comparando a efetividade antimicrobiana da PUI com sistema de irrigação por pressão negativa, mostrou que a PUI foi mais efetiva na desinfecção de canais simulados do que o sistema EndoVac (Townsend et al 2009).…”