Abstract
The present research analyzed the reciprocating instrumentation associated to chlorhexidine (CHX) substantivity as its correlation with E. faecalis viability in ex vivo root canals. Eighty extracted single-rooted human teeth were used, being 40 to high-performance liquid chromatography (HPLC) and 40 to confocal laser scanning microscopy (CLSM). In both, teeth were decoronated and the cervical third was prepared. In the CLSM analysis, the root canals were inoculated with E. faecalis for 14 days. Samples were divided into 4 groups (n=10) according to instrumentation technique: no instrumentation and irrigation with distilled water (control); manual instrumentation (K-File); rotary instrumentation (ProTaper Next); and reciprocating instrumentation (Reciproc R25). Two percent chlorhexidine was applied as irrigating substance in experimental groups. Longitudinal grooves resulted in 2 halves root and 20 proof bodies in each group. Samples were divided by chance in two groups (n=10) and the outcomes were evaluated after two days and one week. The retained chlorhexidine and live cells after instrumentation techniques in each evaluation time was measured by HPLC and CLSM, respectively. Specific analysis was applied for experimental tests (p≤0.05). Both rotary as well as reciprocating techniques significantly reduced the amount of chlorhexidine on dentin in all observation periods (p<0.05). After evaluation times, all experimental groups presented lower live cells compared to control, but without statistically difference. Intragroup comparisons in times of evaluation showed no differences in instrumentation techniques, in chlorhexidine retention and number of live cells (p>0.05). Reciprocating instrumentation does not interfere on chlorhexidine substantivity.
Highlights
Microorganisms are the primary etiologic agents of endodontic infection, promoting the progression of pulp and periapical diseases (Rôças and Siqueira 2010)
The retained chlorhexidine and live cells after instrumentation techniques in each evaluation time was measured by high-performance liquid chromatography (HPLC) and confocal laser scanning microscopy (CLSM), respectively
The methodology was divided into two sections: CHX quantification with High-performance Liquid Chromatography (HPLC) and bacterial viability analysis by Confocal laser scanning microscopy (CLSM)
Summary
Microorganisms are the primary etiologic agents of endodontic infection, promoting the progression of pulp and periapical diseases (Rôças and Siqueira 2010). Among these microorganisms, Enterococcus faecalis (E. faecalis) is a gram-positive and facultative bacteria, which is strongly resistant and usually associated with endodontic failure (Williams et al 2006). Auxiliary chemical substances as well as endodontic apparatus are very important in performing effective chemo-mechanical preparation, with the aim of providing endodontic decontamination (Dal Bello et al 2019). Different auxiliary chemical substances can be used for root canal disinfection. The use of reciprocating files is recommended to perform root canal shaping, because this technique applies less stress to the instrument and increase resistance to flexural fatigue (Gavini et al 2012), removes bacteria (Neves et al 2016) and induces lower apical extrusion of bacteria and debris during instrumentation (Alves et al 2018)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
