Effectiveness of conservative instrumentation in root canal disinfection

Abstract

Objectives The impact of conservative instrumentation on the disinfection of root canals with different curvatures has not yet been determined. This ex vivo study aimed to evaluate and compare the effect of conservative instrumentation with TruNatomy (TN) and Rotate and a conventional rotary system, ProTaper Gold (PTG), on root canal disinfection during chemomechanical preparation of straight and curved canals. Materials and methods Ninety mandibular molars with straight (n = 45) and curved (n = 45) mesiobuccal root canals were contaminated with polymicrobial clinical samples. Teeth were divided into three subgroups (n = 14) according to the file systems and the curvature. Canals were instrumented with TN, Rotate, and PTG, respectively. Sodium hypochlorite and EDTA were used as irrigants. Intracanal samples were taken before (S1) and after (S2) instrumentation. Six uninfected teeth were used as negative controls. The bacterial reduction between S1 and S2 was measured by ATP assay, flow cytometry, and culture methods. Kruskal–Wallis and ANOVA tests were followed by the Duncan post hoc test (p < 0.05). Results Bacterial reduction percentages were similar for the three file systems in straight canals (p > 0.05). However, PTG showed a lower reduction percentage of intact membrane cells in flow cytometry than TN and Rotate (p = 0.036). For the curved canals, no significant differences were obtained (p > 0.05). Conclusion Conservative instrumentation of straight and curved canals using TN and Rotate files resulted in similar bacterial reduction compared to PTG. Clinical relevance The disinfection efficacy of conservative instrumentation is similar to conventional instrumentation in straight and curved root canals.

Novel Ti surface coated with PVA hydrogel and chitosan nanoparticles with antibacterial drug release: An experimental in vitro study

“…19,51,52 Different methods were employed to test antimicrobial activity of the DDs as there is no gold standard technique. 43 CFU recovers viable microorganisms but it does not detect viable but non-culturable bacteria (VBNC), resulting in miscalculation in oral biofilms-around 50% of the oral population is in this VBNC state. 43 On the contrary, the ATP assay quantifies the microbial ATP production of the whole community including viable and VBNC bacteria.…”

“…43 CFU recovers viable microorganisms but it does not detect viable but non-culturable bacteria (VBNC), resulting in miscalculation in oral biofilms-around 50% of the oral population is in this VBNC state. 43 On the contrary, the ATP assay quantifies the microbial ATP production of the whole community including viable and VBNC bacteria. 43,51,53 However, the amount of ATP generated could differ depending on the species, and therefore estimating the microbial cell count in a multispecies biofilm can be challenging.…”

“…43 On the contrary, the ATP assay quantifies the microbial ATP production of the whole community including viable and VBNC bacteria. 43,51,53 However, the amount of ATP generated could differ depending on the species, and therefore estimating the microbial cell count in a multispecies biofilm can be challenging. 51 CLSM and the LIVE/DEAD technique were furthermore included because it classifies the cells according to the state of the membrane so that intactmembrane bacteria could be considered alive and damaged cells as dead.…”

“…The main limitation of this technique is that intact membrane cells can be metabolically inactive, thus dead, whereas damaged membrane cells may still be alive, leading to false results. 43,53 The antimicrobial activity of the films was tested after 4 and 24 h since maintaining a controlled release of dosage within the first hours is crucial to ensure an aseptic environment with the aim of preventing bacterial adhesion. 47 According to Hetrick and colleagues (2006), there is a "decisive period" after implantation during which preventing bacterial adhesion is critical for ensuring the long-term success of an implant.…”

“…At 4 and 24 h, the disks were washed with as relative light units (RLUs). 43 Three additional samples per group were contaminated as explained above and prepared for CLSM observation. For this purpose, after incubation, the samples were rinsed with saline solution and were stained the LIVE/DEAD BacLight Bacterial Viability kit (Invitrogen, Eugene, OR).…”