Sodium Hypochlorite with Reduced Surface Tension Does Not Improve In Situ Pulp Tissue Dissolution

Abstract

INTRODUCTION: Sodium hypochlorite (NaOCl) solutions with added wetting agents are advertised to dissolve necrotic tissue in root canals faster than their counterparts without a lowered surface tension. This was tested in the current study, and the null hypothesis formulated was that there was no difference between a commercially available NaOCl solution with a lowered surface tension (Chlor-XTRA; Vista Dental Products, Racine, WI) and a counterpart containing the same amount of available chlorine without added wetting agents regarding the soft tissue that remains in oval-shaped canals after mechanical preparation and irrigation. METHODS: Formerly vital extracted teeth (N = 44, 22 pairs) with similar anatomy were radiographically paired and chemomechanically prepared. In 1 tooth from each pair, a 5.25% NaOCl solution with reduced surface tension was used; in the other, a pure, technical-grade NaOCl solution of 5.25% was used. The percentage of remaining pulp tissue (PRPT) was histologically assessed in root cross-sections. The non-Gaussian raw data were subjected to Kruskal-Wallis and MannWhitney U tests to verify the respective effect of the cross-section level and solution on the PRPT. The relationship between the cross-section level and the PRPT was estimated by the Spearman correlation test. The alpha-type error was set at 5%. RESULTS: The cross-section level significantly influenced the PRPT (P < .05), whereas the PRPT was not influenced by the solution used (P > .05). A significant inverse correlation was found between the cross-section level and the PRPT (P < .05, r = -0.330). The lower the distance to the apex, the higher the PRPT regardless of the solution used. CONCLUSIONS: Contrary to the advertised statement, the dental solution with a reduced surface tension did not dissolve vital pulp tissue in oval root canals any better than a conventional NaOCl solution of similar strength. Closer to the apex, pulp tissue dissolution is less efficient irrespective of the solution.

Bovine Pulp Tissue Dissolution Ability of Irrigants Associated or Not to Ultrasonic Agitation

“…The average dissolution time was 36 min with a speed of 0.18 mg/min, similar to NaOCl alone. These results agree with the findings of Clarkson et al (8) and De-Deus et al (23), which did not observe faster dissolution when combining NaOCl with a surfactant. It is important to notice that the rate used in this study was 1:1 diluted NaOCl and different rates deserve to be further investigated.…”

Influence of surfactants addition on the properties of calcium hypochlorite solutions

“… 29 However, this is one of the most common tests used for evaluating antibacterial activity against a chemical agent, and, also, it can be considered a relevant protocol. 32 …”

Calcium hypochlorite solutions — An in vitro evaluation of antimicrobial action and pulp dissolution

“…Chlorine is also an active oxidizer, allowing the irreversible inhibition of essential bacterial enzymes (2). The effectiveness of organic tissue dissolution by NaOCl is well known (3)(4)(5)(6)(7)(8)(9). However, NaOCl is chemically unstable, and external agents, such as temperature, light, and storage conditions, can influence the availability of chlorine ions and interfere with its effectiveness (1,10).…”