Evaluation of the effect of four final irrigation protocols on root canal dentin components by polarized light microscopy and scanning electron microscopy

Abstract

The present study aimed to evaluate the effects of four endodontic chelating agents, followed by 2.5% sodium hypochlorite (NaOCl), as final irrigation regimens on organic and inorganic components of human root dentin. Sixty mandibular incisors were prepared and randomly divided into six groups (n = 10): QMiX, 1% peracetic acid (PA), 17% EDTA, 10% citric acid (CA), 2.5% NaOCl (solution control) and distilled water (DW-negative control). After irrigation with the chelating agents, a final flush was performed with 2.5% NaOCl. The specimens were split longitudinally in halves; one was designated for organic component analysis by polarized light microscopy (PLM) and the other for inorganic structure analysis by scanning electron microscopy (SEM). Scores data obtained in the PLM analysis were submitted to Kruskal-Wallis' test, followed by Dunn's test (p < .05). SEM findings were presented descriptively. NaOCl and DW groups showed uniformity in the fibrillar network and smear layer obliterating the dentinal tubules, while CA group presented alteration in organic and inorganic components of dentin. EDTA group did not show differences from others in the organic component, but altered the inorganic structure. QMiX and PA groups did not cause a significant morphological alteration in collagen and removed the smear layer without inorganic structure modification. As final irrigation, QMiX and PA solutions, followed by 2.5% NaOCl, showed better behavior than the other chelating agents tested, preserving organic and inorganic components of human root dentin.

Effect of QMix irrigant in removal of smear layer in root canal system: a systematic review of in vitro studies

“…Eleven studies compared QMix to various irrigants like EDTA [ 23 24 25 26 27 28 29 30 31 33 35 ], 4 studies on MTAD [ 23 31 34 35 ], 5 studies on NaOCl [ 23 27 28 29 33 ], 2 studies on 7% EDTA (SmearClear) [ 30 32 ], 10% citric acid [ 29 33 ], one study on chitosan [ 32 ], glyde [ 32 ], 1% peracetic acid [ 33 ], Tubulicid Plus [ 34 ] and 7% maleic acid [ 28 ]. The effectiveness of smear layer removal was measured by different scoring systems.…”

“…The effectiveness of smear layer removal was measured by different scoring systems. Four studies used Hülsmann et al scoring system [ 25 26 30 35 ], 2 studies used Takeda et al system [ 27 29 ], 3 studies used Torabinejad et al scoring system [ 28 31 34 ] and others included Gishi et al scoring system [ 33 ], Dai et al scoring system [ 23 ] and Rome et al scoring system [ 32 ] respectively. One study did not mention the scoring system and adhered to counting the number of open and closed tubules using imaging software, Adobe Photoshop CS3 [ 24 ].…”

“…Some studies have shown that QMix removes smear layer more effectively than other irrigants whereas some results were contradictory. Thirteen studies have claimed that higher effectiveness was affected by the duration of QMix irrigation [ 23 24 25 26 27 28 29 30 31 32 33 34 35 ].…”

Effect of EDTA, sodium, and calcium hypochlorite on the inorganic component of root canal dentin: A SEM analysis

“…When used alone inside the root canal, NaOCl is as ineffective as distilled water to remove the smear layer produced during root canal preparation (Torabinejad et al, ; Baldasso, Cardoso, da Silva, Morgental, & Kopper, ). Therefore, some studies have shown that the use of a combination of NaOCl and EDTA is particularly effective in the removal of smear layer and debris (Goldman, Goldman, Cavaleri, Bogis, & Lin, ; Yamada, Armas, Goldman, & Lin ; Baldasso et al, ). EDTA is widely used as a chelating agent and is able to react with calcium ions in hydroxyapatite crystals, removing calcium ion from the dentin (Calt & Serper, ).…”

“…EDTA is widely used as a chelating agent and is able to react with calcium ions in hydroxyapatite crystals, removing calcium ion from the dentin (Calt & Serper, ). However, when NaOCl is associated with EDTA, alteration of the organic and inorganic dentin components and erosion are observed (Lottanti, Gautschi, Sener, & Zehnder, ; Baldasso et al, ).…”