Structural effects of sodium hypochlorite solutions on gutta-percha cones: atomic force microscopy study.

Atomic force microscope (AFM) is a well-established methodology for structural characterization of materials. The purpose of this study was to investigate the effects of sodium hypochlorite (NaOCl) solutions on gutta-percha cone structure using AFM. Three standardized gutta-percha cones were cut 3 mm from the tip, attached to a glass base and immersed in 0.5, 2.5, or 5.25% NaOCl solutions. After 1 and 5 min the samples were positioned in the atomic force microscope. The analyses were performed on twelve different points (n=12) located between 1 and 2 mm from the tip after each period of immersion in NaOCl. Gutta-percha cone without any NaOCl treatment were used as control. Root mean square (RMS) parameters for contact mode imaging and force modulation microscopy variations were measured. The differences between RMS values were tested by ANOVA with Fisher's protected LSD test for multiple comparisons (p<0.05). Aggressive deteriorative effects on gutta-percha cone elasticity were observed for 5.25% NaOCl at 1 min when compared to the control (p<0.05). In addition, 2.5% and 5.25% NaOCl solutions caused topographic changes after 5 min when compared to the control (p<0.05). Conversely, 0.5% NaOCl solution did not cause any alteration on topography or elasticity of gutta-percha cone structure when compared to the control (p<0.05). Thus, 0.5% NaOCl solution is a safe alternative for rapid decontamination of gutta-percha cones.

[1]  J. Sakai,et al.  Fracture of nickel-titanium superelastic alloy in sodium hypochlorite solution , 2004 .

[2]  V. Neagu,et al.  Acrylic weak base anion exchangers and their chemical stability in aggressive media , 2004 .

[3]  S. Dorn,et al.  The crystallization of sodium hypochlorite on gutta-percha cones after the rapid-sterilization technique: an SEM study. , 2003, Journal of endodontics.

[4]  M. Hashimoto,et al.  Degradation of resin-dentin bonds using NaOCl storage. , 2003, Dental materials : official publication of the Academy of Dental Materials.

[5]  F. Teixeira,et al.  Chemical and X-ray analyses of five brands of dental gutta-percha cone. , 2003, International endodontic journal.

[6]  A. Wennerberg,et al.  The influence of a chemo-mechanical caries removal solution on the topography of dental ceramic materials. , 2002, Biomaterials.

[7]  Ricardo Garcia,et al.  Dynamic atomic force microscopy methods , 2002 .

[8]  M. Morris,et al.  Effects of sodium hypochlorite and RC-prep on bond strengths of resin cement to endodontic surfaces. , 2001, Journal of endodontics.

[9]  J. Nicoli,et al.  Efficacy of chemical sterilization and storage conditions of gutta-percha cones. , 2001, International endodontic journal.

[10]  C. L. Cardoso,et al.  Rapid decontamination of gutta-percha cones with sodium hypochlorite. , 1999, Journal of endodontics.

[11]  J. Siqueira,et al.  Effectiveness of four chemical solutions in eliminating Bacillus subtilis spores on gutta-percha cones. , 1998, Endodontics & dental traumatology.

[12]  D. Orstavik,et al.  Influence of antiseptic storage solutions on physical properties of endodontic guttapercha points. , 1985, Scandinavian journal of dental research.