Evaluation of the Effect of Various Concentration of Sodium Hypochlorite on the Surface Roughness of ProTaper Rotary Files Using Atomic Force Microscopy: An In Vitro Study

Abstract

Aim:The aim of this study was to evaluate the effect of different concentrations of sodium hypochlorite (NaOCl), solutions on the surfaces of nickel-titanium (Ni-Ti) rotary files using atomic force microscopy (AFM). Materials and methods:Sixteen unused ProTaper Ni-TI files of size F1, were selected for AFM evaluation at apical, middle and coronal segments. The selected files were then assigned into 4 groups • Group 1: Unused files (n = 4) • Group 2: 2.5% sodium hypochlorite irrigation (n = 4) • Group 3: 5.25% sodium hypochlorite irrigation (n = 4) • Group 4: 8.25% sodium hypochlorite irrigation (n = 4)The files were used as per the manufacturer's instruction, and the number of uses was restricted to five. Normal irrigation protocol was followed and the only variable being a concentration of sodium hypochlorite (2.5%, 5.25%, 8.25%). The post-treatment roughness average (RA) and root mean square (RMS) of apical, middle and coronal segments of the scanned profiles were then recorded using AFM and compared with the initial readings. The data was tabulated and analyzed using one-way analysis of variance (ANOVA). Conclusion:Within the limitations of the present study, it was concluded that different concentrations of sodium hypochlorite showed effect on the surface characteristics of Ni-Ti instruments.

Impact of endodontic irrigants on surface roughness of various nickel-titanium rotary endodontic instruments

“…This parameter is generally used to evaluate surface roughness; it is used to investigate the vertical surface topography of endodontic rotary instruments and perform the comparison [ 32 , 35 ]. It is well recognized that defects in surface microstructure may cause areas of stress concentration and the creation of cracks, which sequentially weaken the structural integrity of the Ni-Ti instrument [ 43 – 45 ].…”