Penetration of Sodium Hypochlorite Modified with Surfactants into Root Canal Dentin

Abstract

The aim of this study was to evaluate the effect of concentration, exposure time and temperature of sodium hypochlorite (NaOCl) added with surfactants on its penetration into dentinal tubules. Sixty-five extracted human permanent maxillary anterior teeth with single canals were prepared by ProTaper SX hand-operated instruments. The teeth were then sectioned perpendicular to the long axis. The crowns and apical thirds of all the teeth were removed. The remaining roots were processed into 4-mm-long blocks and stained overnight in crystal violet. One hundred and thirty stained blocks were further split into halves and treated by nine different types of NaOCl-based solutions. Three solutions were added with surfactants (Hypoclean, H6, Chlor-Xtra) and the others were regular hypochlorites at increasing concentrations (1%, 2%, 4%, 5.25%, <6%, 6% NaOCl) from different brands. The dentin blocks were exposed to the solutions for 2, 5, and 20 min at 20 °C, 37 °C and 45 °C, respectively. The depth of NaOCl penetration was determined by bleaching of the stain and measured by light microscopy at 20 × and 40×. Statistical comparisons were made by using a generalized linear model with Bonferroni's post-hoc correction. The shortest penetration (81±6.6 μm) was obtained after incubation in 1% NaOCl for 2 min at 20 °C; the highest penetration (376.3±3.8 μm) was obtained with Chlor-Xtra for 20 min at 45 °C. Varying NaOCl concentration produced a minimal effect while temperature and exposure time had a significant direct relationship with NaOCl penetration into dentinal tubules, especially those with lowered surface tension. The exposure time and temperature of sodium hypochlorite as well as the addition of surfactants may influence the penetration depth of irrigants into dentinal tubules. P e n e t r a t i o n o f S o d i u m H y p o c h l o r i t e M o d i f i e d w i t h

Penetration of sodium hypochlorite into root canal dentine: effect of surfactants, gel form and passive ultrasonic irrigation

“…The increase in NaOCl concentration from 2.5% to 6% did not significantly increase the penetration depth, in agreement with a study that showed no difference in the penetration depth of 2% and 6% NaOCl (Palazzi et al . ). Wong & Cheung () reported no significant difference between 0.5% and 3% NaOCl relative to the effect against a dual‐species biofilm ( E. faecalis and Porphyromonas gingivalis ) in the first 100 μm of radicular dentine.…”

“…On the other hand, Palazzi et al . (,b) reported that Chlor‐Xtra had greater penetration depth than 6% NaOCl. As regards activity against E. faecalis in dentinal tubules, no differences were found between 6% NaOCl and Chlor‐Xtra (Wang et al .…”

“…() and Palazzi et al . () who reported that contact time with root canal dentine influenced the penetration depth of NaOCl solution into dentinal tubules. The increase in NaOCl concentration from 2.5% to 6% did not significantly increase the penetration depth, in agreement with a study that showed no difference in the penetration depth of 2% and 6% NaOCl (Palazzi et al .…”

“…), increasing their wettability (Cameron ) and consequently increasing the penetration of root canal irrigants into dentinal tubules (Palazzi et al . ). Cetrimide reduces the surface tension of fluids and exhibits antibacterial activity (Baca et al .…”

Influência da solução irrigadora na formação de defeitos dentinários após preparo com Sistema Reciproc®

“…Devido ao rápido preparo mecânico dos canais radiculares pelos instrumentos reciprocantes, o hipoclorito de sódio está sendo empregado em concentrações mais elevadas, para compensar o curto tempo da solução no canal radicular 9 . Assim, uma vez que instrumentos de níquel titânio (NiTi) podem gerar trincas em movimento reciprocante, este estudo teve como proposta avaliar o que ocorre nas paredes dentinárias do canal radicular após o emprego do sistema Reciproc, utilizando como solução irrigadora o hipoclorito de sódio a 5,25%.…”