The Effect of Sodium Hypochlorite Irrigant Concentration on Tooth Surface Strain

Abstract

The effect of root-canal irrigation with different concentrations of sodium hypochlorite (3%, 5.1%, 7.3% NaOCI) on the mechanical properties of teeth was investigated in vitro. Root canals of 13 extracted, human premolars, denuded of enamel, were prepared with nickel-titanium rotary instruments (Quantec) to a standard size by using saline irrigation. An electrical strain gauge was bonded to the cervical aspect of each tooth. The 10 experimental teeth were subjected to 5 successive, 30-minute periods of irrigation. The irrigants were used in the following order: (a) saline; (b) 3.0% NaOCI; (c) 5.1% NaOCI; (d) 7.3% NaOCI; (e) saline. Three control teeth were irrigated with saline only for all five periods. After each irrigation, the teeth were cyclically loaded to 110N while the surface strain was measured. Changes in strain of the test teeth after each irrigation regimen followed broadly similar patterns that were different from the control teeth. There was no difference, however, in the strain recorded after irrigation by the different irrigants within the experimental group.

The effect of sodium hypochlorite and ethylenediaminetetraacetic acid irrigation, individually and in alternation, on tooth surface strain

“…The potential disadvantage of this combination may be that alternate depletion of organic and inorganic substrate may allow the tooth to be weakened further as demonstrated by an increase in tooth surface strain. To test this hypothesis, the previous work was repeated with a relevant study design and stringent attention to detail in order to overcome the data variation seen in the experiments of Goldsmith et al. (2002).…”

“…Sim et al. (2001) had standardized their sample by using mandibular second premolars with single mature roots, whilst Goldsmith et al. (2002) used a mixture of single and two‐rooted premolars with mature or immature apices.…”

“…A clear acrylic resin (epoxy) was used for mounting in this study because it showed minimal dimensional change after setting compared to self‐curing acrylic resin used by Goldsmith et al. (2002).…”

“…The single‐element strain gauge used by Goldsmith et al. (2002) was again chosen for this study in contrast to the rosette gauge used by Sim et al.…”

Influence of Different Restorative Techniques on the Strength of Endodontically Treated Weakened Roots

“…A further reduction in microhardness can be induced by the use of irrigating solutions during endodontic treatment [10, 11]. The loss of water and gutta-percha condensation procedures may also contribute to the weakness reported in endodontically-treated teeth [12, 13]. …”