Root Canal Penetration of a Sodium Hypochlorite Mixture Using Sonic or Ultrasonic Activation

Abstract

The purpose of this ex vivo study was to determine, in "open" and "closed" systems, whether the design has an influence on the penetration length of sodium hypochlorite mixed with a radiopaque contrast medium, measured in millimeters, when delivered using positive pressure (PP) and using sonic (SI) or passive ultrasonic (PUI) activation. Sixty single-rooted teeth were divided into two groups: open and closed systems (n=30). Root canal shaping was performed to a working length of 17 mm. The samples were divided into three sub-groups (n=10) according to irrigant delivery and activation: PP, and SI or PUI activation. By using radiographs, penetration length was measured, and vapor lock was assessed. For the closed group, the penetration distance means were: PP 15.715 (±0.898) mm, SI 16.299 (±0.738) mm and PUI 16.813 (±0.465) mm, with vapor lock occurring in 53.3% of the specimens. In the open group, penetration to 17 mm occurred in 97.6% of the samples, and no vapor lock occurred. Irrigant penetration and distribution evaluation using open and closed systems provide significantly different results. For closed systems, PUI is the most effective in delivering the irrigant to working length, followed by SI.

Effect of sonic and ultrasonic activation on organic tissue dissolution from simulated grooves in root canals using sodium hypochlorite and EDTA

“…For the final rinse, when assessing the volume of irrigant, 6 mL of NaOCl was used, based on a previous study which demonstrated the mechanical efficacy of this specific volume (Sedgley et al 2005). Similarly, the depth of needle placement and activation times were consistent with previous studies testing EA and PUI effect on penetration of irrigants using 'closed systems' (De Gregorio et al 2009, Merino et al 2013, Sainz-Pardo et al 2014), although a further study used a more coronally placed needle (WL-5), together with a shorter activation time (20 s) (Paragliola et al 2010). Arbitrary, however clinically relevant, total irrigation time and EDTA volume were used for the 'final rinse', due to the absence of published reference standards.…”

“…, Sainz‐Pardo et al . ), although a further study used a more coronally placed needle (WL‐5), together with a shorter activation time (20 s) (Paragliola et al . ).…”

“…Sonic activation generates mechanical agitation primarily on the tip of files, whereas ultrasonic activation generates microstreaming around the file and a secondary acoustic streaming (Ahmad et al 1987, De Gregorio et al 2009, Gu et al 2009, Gulabivala et al 2010. Ex vivo studies in root canal systems with restricted flow through the apical foramen, which better simulates fluid flow in clinical conditions (Tay et al 2010), revealed that penetration of solutions is enhanced by ultrasonics and, to a lesser degree, sonic activation (De Gregorio et al 2009, Paragliola et al 2010, Sainz-Pardo et al 2014.…”

Antimicrobial efficacy of 0.5% peracetic acid and EDTA with passive ultrasonic or manual agitation in an Enterococcus faecalis biofilm model

“…Penetration of solutions is enhanced by passive ultrasonic agitation (PUI), as suggested by several ex vivo studies in root canal systems with restricted flow through the apical foramen . A final rinse of EDTA with PUI has been associated clinically with a higher per cent of negative cultures, when compared with saline .…”

Effect of sonic versus ultrasonic activation on aqueous solution penetration in root canal dentin.

“…and Sáinz-Pardo et al 24 have positioned ultrasound as the most efficient method, but other authors state that sonic agitation obtains similar or even better results.…”