Effect of exposure to root canal irrigants on the push-out bond strength of calcium silicate-based cements

Dislodgement resistance and structural changes of tricalcium silicate-based cements after exposure to different chelating agents

This study aimed to evaluate the dislodgement resistance and structural changes of different mineral trioxide aggregate cements (MTA) like Pro-Root MTA, Ortho MTA, and Retro MTA after exposure to sodium hypochlorite (NaOCl), NaOCl-Ethylenediaminetetraacetic acid (EDTA), 1-hydroxyethylidene-1, 1-bisphosphonate (Dual Rinse HEDP), and NaOCl-Maleic acid (MA). The root canal spaces of 150 dentine slices were obturated using tricalcium silicate cements and divided into 3 groups (n = 50): Group1: ProRoot MTA, Group2: Retro MTA, and Group3: Ortho MTA. The samples in each group were further subdivided into four experimental (n = 10) and one control groups (n = 10): 2.5% NaOCl-17% EDTA, Dual Rinse HEDP, 2.5% NaOCl-7% Maleic acid, 2.5% NaOCl, distilled water (control). The dislodgement resistance and structural changes of cements were measured. Use of DR HEDP resulted in higher dislodgement resistance compared to17% EDTA and 7% MA in the samples obturated with Ortho MTA and Pro-Root MTA (p<0.001). In Retro MTA group, samples treated with DR HEDP and 17% EDTA had higher dislodgment resistance compared to 7% MA (p<0.001). On microstructural and elemental analysis of all the three MTA cements, samples treated with 17% EDTA and 7% MA were more amorphous and granular when compared to DR HEDP, which was pettle shaped. Calcium level was decreased more in samples treated with 17% EDTA and 7% MA when compared to DR HEDP.

Clinical applications of calcium silicate-based materials: a narrative review

Calcium silicate-based materials are hydrophilic materials with biocompatibility and bioactivity properties. Despite many advantages, they might present some problems related to discolouration, setting time, manipulation and solubility depending on the composition of the product and the type of clinical application. Calcium silicate-based materials can be evaluated under two types according to their intended use: calcium silicate-based cements (CSCs) and calcium silicate-based sealers (CSSs). CSCs can be used in many endodontic procedures including perforation repair, resorption repair, apical barriers, guided endodontic repair, vital pulp treatment, endodontic surgery, root fractures and root canal filling as a core obturation material. CSSs are available for use with gutta-percha to obturate root canals using cold and warm techniques, including the sealer-based obturation technique. The purpose of this review is to evaluate the available literature on CSCs and CSSs and to provide up-to-date information and recommendations for their clinical applications.

Impact of Final Irrigation Protocol on the Push-Out Bond Strength of Two Types of Endodontic Sealers

Aim: The aim of this study was to assess the impact of the final irrigation protocol on the push-out bond strength of calcium silicate-based sealers when compared to an epoxy resin-based sealer. Materials and Methods: Eighty-four single-rooted mandibular human premolars were shaped using the R25^® instrument (Reciproc, VDW, Munich, Germany) and then divided into three subgroups of 28 roots each depending on the final irrigation protocol: EDTA (ethylene diamine tetra acetic acid) and NaOCl activation, Dual Rinse^® HEDP (1-hydroxyethane 1,1-diphosphonate) activation or sodium hypochlorite (NaOCl) activation. Then, each subgroup was divided into two groups (14 each) according to the sealer used (AH Plus Jet^® or Total Fill BC Sealer^®) for single-cone obturation. Dislodgement resistance using a universal testing machine, samples' push-out bond strength and failure mode under magnification were determined. Results: EDTA/Total Fill BC Sealer^® showed significantly greater values of push-out bond strength compared with HEDP/Total Fill BC Sealer^® and NaOCl/AH Plus Jet^®, with no statistical difference with EDTA/AH Plus Jet^®, HEDP/AH Plus Jet^® and NaOCl/Total Fill BC Sealer^®, whereas HEDP/Total Fill BC Sealer^® showed significantly lower values of push-out bond strength. The apical third demonstrated higher means of push-out bond strength compared with middle and apical thirds. The most common failure mode was cohesive but showed no statistical difference compared to other types. Conclusions: Irrigation solution and final irrigation protocol affect the adhesion of calcium silicate-based sealers.

Push out bond strength of hydraulic cements used at different thicknesses

BACKGROUND

The aim of this study was to compare the pushout bond strength (POBS) of three hydraulic cements, when used at thicknesses of 3 and 5 mm.

METHODS

78 root slices of 3 and 5 mm of thickness were obtained from human teeth. Cylindrical cavities of 1.4 mm of diameter were drilled and filled with Biodentine (BD), Totalfill Root Repair paste (TF) or ProRoot MTA White (PMTA). Pushout tests were performed 21 days later. The fracture pattern of each sample was also analyzed. POBS data were analyzed with Welch and Brown-Forsythe and Tamhane's post hoc tests and a Weibull analysis was also performed.

RESULTS

In the 3 mm group, TF showed significantly lower bond strength than BD and PMTA. In the 5 mm group, BD showed significantly higher bond strength than TF. Both BD and TF showed higher bond strength when the thickness of the sample increased, while PMTA did not.

CONCLUSIONS

TF and BD achieve higher pushout bond strength resistance when used at a thickness of 5 mm than at 3 mm, while the mean resistance of PMTA is less influenced by the thickness. At 5 mm of thickness, BD and PMTA exhibit similar resistance to displacement. However, the behavior of BD is more predictable than that of its predecessor. BD is a reliable hydraulic cement for clinical situations where thick cavities need to be filled and displacement resistance plays an important role. Clinicians need to consider choosing specific hydraulic cements according to the thickness of material to be used.

Dislodgement pushout resistance of five bioceramic root-end filling materials

This study evaluated the dislodgement push-out resistance of five bioceramic materials. One hundred single-rooted teeth with one canal had the apical 3 mm and crown resected to create a 14 mm standardized length. The canals were instrumented to an apical size 80 with a 3 mm root-end preparation made with ultrasonic diamonds. The prepared roots were randomly divided into 5 root-end restorative groups (n=20). ProRoot MTA, Biodentine, EndoSequence Root Repair Material, EndoSequence Fast Set Putty, and EndoSequence BC Sealer with each material placed following manufacturer's instructions and stored at 100% humidity for 2 weeks. An apical-to-coronal static testing load with the identified dislodgement force converted into MPa with mean results analyzed with Kruskal-Wallis and Dunn's post hoc tests (α=0.05). ProRoot MTA and Biodentine displayed similar push-out stress resistance and exhibited significantly greater stress resistance than the similar Endosequence materials. However, all materials failed cohesively and were not dislodged from the root canal surface.

Effect of exposure to etidronic acid on the bond strength of calcium silicate-based cements after 1 and 21 days: an in vitro study

Background

After reparation of root perforations with calcium silicate-based cements (CSBC), the surface of the material is expected to be exposed to root canal irrigants (RCI) while resuming the root canal treatment.

Methods

The aim of this study was to compare the effect of exposure to a mixture of sodium hypochlorite (NaOCl) and etidronic acid (HEBP) or other irrigants on the Push Out Bond Strength (POBS) of CSBC after two different setting times. 240 root slices 1 mm thick were obtained from single-rooted human teeth. A 1.4 mm diameter perforation was performed on each slice and filled with Biodentine (BD) or ProRoot MTA (PMTA). After 1 or 21 days they were exposed to 17% ethylenediaminetetraacetic acid, 5.25% NaOCl, a mixture of 5.25% NaOCl and 9% HEBP (NaOCl + HEBP) or saline (n = 15) and submitted to a push-out test. POBS results were analysed with ANOVA and Tukey tests.

Results

BD showed higher POBS than PMTA after 1 day (p < .05). After 21 days no differences were found between materials. After 1 day exposure to NaOCl + HEBP resulted in higher POBS, compared to the other irrigants (p < .05).

Conclusion

POBS results are influenced by the cement, the setting time and the exposure to irrigants.

Effect of Sodium Hypochlorite Concentration in Continuous Chelation on Dislodgement Resistance of an Epoxy Resin and Hydraulic Calcium Silicate Sealer

The conditioning of the root canal wall during chemo-mechanical root canal treatment differentially affects the adhesion of root canal sealers. This investigation evaluated the impact of sodium hypochlorite (NaOCl) concentration as used in a root canal irrigation concept called continuous chelation, with 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) contained in the NaOCl solution that is applied. Fourier-transform infrared spectra of the dentinal wall were gathered. The consequential effects on push-out bond strength of an epoxy resin (AH Plus) versus a hydraulic CaSi sealer (BioRoot RCS) were assessed. Single-rooted extracted human teeth were used and irrigated with pure NaOCl at a concentration of 0% (physiological saline), 2.5%, or 5.25%. Dual Rinse HEDP (9%) was added to the solutions, or not added for further control. Pure NaOCl solutions caused a decrease in the amide III: phosphate ratios, which was counter-acted by the addition of HEDP. It was observed that the adhesion of the epoxy resin sealer under investigation was negatively affected by this NaOCl deproteinization of the canal wall in a dose-dependent manner, while the opposite was observed with the CaSi sealer. HEDP when used in conjunction with NaOCl was beneficial for the adhesion of both sealers.