Residues of different gel formulations on dentinal walls: A SEM/EDS analysis

Abstract

The aim of this study was to evaluate the presence of residues of sodium hypochlorite gel, chlorhexidine gel, and EDTA gel on dentinal walls after canal preparation through chemical SEM- elemental chemical microanalysis (EDS) analysis. Forty-eight single-rooted teeth were selected. They had their crowns sectioned and were instrumented with a reciprocating system. The canals were irrigated with 5 mL of saline solution during root canal preparation. After instrumentation, the root canals were irrigated with 3 mL 17% EDTA followed by 1 min of ultrasonic passive activation (3× 20 sec) to remove the smear layer, and then irrigated with 3 mL of saline solution. The specimens were randomized into three groups (n = 12) according to the chemical substance that filled the root canal for 30 min: GI: 5.5% sodium hypochlorite gel; GII: 2% chlorhexidine gel; GIII: 24% EDTA gel; Negative control group: no substance was used. Then, the root canals were irrigated with 6 mL of saline solution followed by 1 min of ultrasonic passive activation (3× 20 sec). After ultrasonic activation, the canals were irrigated with 2 mL saline. The roots were sectioned, and the percentage of each chemical element present in the samples was analyzed through chemical SEM-EDS microanalysis. All experimental groups showed a significantly higher percentage of chemical elements (Na and/or Cl) than the control group (P < 0.03). This in vitro study has shown that, regardless of chemical solutions used even after the final irrigation protocol, chemical residues of different substances remained attached to the root canal walls.

Effects of different peracetic acid formulations on post space radicular dentin

“…These chemicals are also routinely detected in the smear layer after the chemical-mechanical preparation of post spaces. 10 This fact supports the use of glass ionomer, which bonds to the tooth substrate by means of chemical bonds from its carboxylic radicals to the calcium ions existing either in the enamel, dentin, or cement structures. 33 Even though 1% peracetic acid solution at low hydrogen peroxide concentration demonstrated adequate cleaning of the preparation for fiber post placement, further studies are needed to evaluate the impact of this solution, as well as the effects of hydrogen peroxide on the bond strength of resin-based adhesive systems.…”

“…The possible presence of this ion in the smear layer of some specimens finally irrigated with peracetic acid solution may be a by-product of the sodium hypochlorite used during the chemicalmechanical preparation of the root canals. 10,13,18 The ability of peracetic acid to clean the dentin surface is satisfactory, regardless of its concentration in the solution, and is similar to that of EDTA. 19,25 In this study, the solution with a low concentration of hydrogen peroxide was more effective at removing the smear layer, suggesting that the presence of residues is directly related to the concentration of hydrogen peroxide present in the solution.…”

“…completely and interferes with the bonding of fiber posts. [10][11][12][13] Other solutions including chlorhexidine digluconate, phosphoric acid, and ethylenediaminetetraacetic acid (EDTA) have been proposed to achieve the same goals. [14][15][16][17][18][19][20][21][22] However, these solutions also have adverse effects and/or limited antimicrobial activity, which makes them less than ideal for irrigating the post space before cementation.…”

Effect of antioxidants after post‐space irrigation on the adhesive interface of glass fiber post cementation

“…The irrigation protocol that has the best in vitro result is 5% sodium hypochlorite in association with EDTA 17% 4–7 . However, sodium hypochlorite solutions negatively affect the bonding of adhesive systems to dentin due to the presence of oxidant radicals 8–11 and residues on the dentin walls, 12 compromising the adhesion of the resin cementation systems 13,14 …”

“…2 The irrigation protocol that has the best in vitro result is 5% sodium hypochlorite in association with EDTA 17%. [4][5][6][7] However, sodium hypochlorite solutions negatively affect the bonding of adhesive systems to dentin due to the presence of oxidant radicals [8][9][10][11] and residues on the dentin walls, 12 compromising the adhesion of the resin cementation systems. 13,14 Peracetic acid (PA) can be an alternative solution due to its antibacterial activity and the ability of cleaning the dentin with the dissolution of smear layer.…”