Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study)

Anan Medhat Mohamed, Angie Galal Ghoneim, Nehal Nabil Roshdy
2021 Acta Scientific Dental Scienecs  
Aim: This study was conducted to evaluate the effect of chitosan nanoparticles (CNPs), CNPs/EDTA (1:1) and EDTA as final irrigants on the push-out bond strength of different root canal sealers. Methodology: Thirty extracted human, single-rooted mandibular premolars were decoronated and prepared using ProTaper Next rotary system with 2.5% sodium hypochlorite (NaOCl) irrigation. The specimens were randomly distributed into three groups according to the final irrigation protocol; Group 1: 0.2%
more » ... ; Group 1: 0.2% CNPs, Group 2: 0.2% CNPs/17% EDTA (1:1), and Group 3: 17% EDTA. A standardized volume of 5 ml of each chelating solution was used for 3 min. Each group was further divided into two subgroups based on the root canal sealer used for obturation; AH Plus resin sealer and Sure-Seal Root bioceramic sealer. For assessment of the push-out bond strength, roots were sectioned horizontally to obtain 2 mm-thick discs from the coronal, middle and apical thirds, then discs were subjected to a compressive load via the universal testing machine followed by assessment of the failure pattern using stereomicroscope. Results : AH Plus showed a significantly higher push-out bond strength compared to Sure-Seal bioceramic sealer within the three experimental groups (p < 0.05). There was no significant difference in AH Plus bond strength among the three groups, while Sure-Seal bioceramic sealer showed a significantly higher bond strength in the CNPs group (p = 0.02). AH Plus showed a significantly higher bond strength at the coronal third compared to Sure-Seal bioceramic sealer (p ≤ 0.001), however there was no significant difference between them in the middle third. In the apical third, Sure-Seal recorded significantly higher bond strength (p < 0.05) except for the EDTA group. For AH Plus, the highest push-out bond strength values were recorded in the coronal third, while Sure-Seal bioceramic sealer showed significantly higher bond strength at the apical third. The failure mode was predominately cohesive for both sealers. Conclusion: Removal of the smear layer improves the bond strength of AH Plus to root dentin, but negatively affects that of Sure-Seal bioceramic sealer. CNPs had less adverse effects on the bond strength and adherence of Sure-Seal bioceramic sealer compared to EDTA. Citation: Anan Medhat Mohamed., et al. "Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study)". Acta Scientific Dental Sciences 5.4 (2021): 66-75. Citation: Anan Medhat Mohamed., et al. "Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study)". Acta Scientific Dental Sciences 5.4 (2021): 66-75. Introduction Successful root canal treatment depends on the combination of thorough chemo-mechanical debridement and three-dimensional obturation of the root canal system. The main objective of threedimensional obturation is to provide a gap-free interface between the canal walls and different root canal filling materials. The most accepted root canal obturation techniques involve the use of guttapercha cones and root canal sealers. Over the past century, various materials and techniques have been introduced aiming to improve the stability and sealing ability of the root canal filling materials [1]. The sealing ability of root canal filling materials depends mainly on the adhesion properties of root canal sealers and their ability to penetrate deeply into the dentinal tubules [2]. During chemo-mechanical preparation, the cutting action of hand or rotary files results in the formation of a smear layer on the instrumented surfaces of the canal walls. The smear layer is a thin layer of organic and inorganic remnants, which act as a barrier hindering penetration of antibacterial irrigants, intracanal medicaments and root canal sealers into the dentinal tubules [3]. EDTA is the most commonly used chelating agent for removal of the smear layer. However, prolonged exposure to EDTA results in dentin erosion and causes marked reduction in dentin microhardness [4]. Chitosan is a natural polysaccharide obtained by deacetylation of chitin, one of the most abundant natural biopolymers found in crustacean exoskeleton as crabs and shrimps [5]. Over the past few years, it has gained a great interest among researchers because of its biocompatibility, biodegradability, bio-adhesion and lack of toxicity. In addition, chitosan presents with high chelating capacity and antimicrobial activity against a wide range of gram-positive and gram-negative bacteria as well as fungi [6,7]. Furthermore, chitosan structure is similar to that of the extracellular matrix components which reinforces the collagen constructs and improves dentin resistance to degradation by collagenase [8]. Chitosan root canal irrigation was developed for removal of the smear layer after complete mechanical debridement of the root canals. Compared to EDTA, it can effectively remove the smear layer with less adverse effects on dentin structure [9]. Chitosan nanoparticles (CNPs) are biocompatible, polymeric nanoparticles with high antimicrobial activity. In the field of end-odontics, these nanoparticles were mainly used as antimicrobial agents and drug carriers. Kishen., et al. found that there was a significant decrease in the adherence of Enterococcus faecalis to dentin after treatment with chitosan nanoparticles [10]. Shrestha., et al. demonstrated the efficacy of chitosan nanoparticles in eliminating and disrupting E. faecalis biofilm [11]. Recently, it was reported that chitosan nanoparticles based irrigation can serve as an alternative chelating agent for EDTA as it removes the smear layer effectively when used as a final irrigant [12,13]. Many studies have assessed the smear layer removal efficacy of different chelating agents, however data regarding their effect on the adhesive potential of different root canal sealers to radicular dentin is still lacking in the literature. Therefore, the present study was conducted to evaluate the effect of chitosan nanoparticles and EDTA on the bond strength of epoxy-resin and bioceramic-based root canal sealers. Materials and Methods Sample size Based on the results of a previous study by Yap., et al. 2017 [14] and using power 80% and 5% significance level, a total sample size of 30 roots were included in the study. Thus, the samples were randomly distributed among 3 groups: each containing 10 samples. Sample selection Thirty human single-rooted mandibular premolar teeth extracted for periodontal reasons or due to orthodontic treatment, were collected from the outpatient clinic of Oral Surgery Department, Faculty of Dentistry, Cairo University. Criteria for teeth selection included straight roots with single root canals and completely formed apices. Teeth with open apices, visible cracks and root resorption were excluded. The selected teeth were thoroughly washed under running water and immersed in 5.25% NaOCl solution for 15 minutes to disinfect the teeth and remove any soft deposits on the root surface. The remaining hard deposits were removed from the root surface using curettes and finally teeth were stored in saline solution till the time of use. Sample preparation Teeth were decoronated at the cemento-enamel junction (CEJ) using a low-speed, water-cooled diamond disc to obtain a standardized root length of approximately 16 mm. The working length and Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study) Citation: Anan Medhat Mohamed., et al. "Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study)". Acta Scientific Dental Sciences 5.4 (2021): 66-75. test was proven to be better than the conventional shear test for evaluating the bond strength, since the sealer was placed in direct contact to the root canal dentinal walls instead of a flat coronal dentin surface which has a different tubular pattern [20] . Additionally, the push-out test allows the material to accommodate to the canal shape and penetrate into the dentinal tubules, which provides better simulation of the clinical conditions [21] . It also has the advantage of measuring the sealer bond strength at different root levels. Another benefit of this test is that it allows the sealers to be evaluated even when the bond strength is low [19] . Furthermore, the push-out bond strength test is less sensitive unlike the tensile test in which small alterations in the specimen or in stress distribution during load application have a major effect on the results [22] . Two root canal sealers with different adhesion properties were tested in this study. AH Plus root canal sealer belongs to the resinbased materials that has the ability to bond to radicular dentin and penetrate deeply into the dentinal tubules [23] . However, the polymerization shrinkage of resin-based sealers may affect the bonding quality to root canal dentin and different core materials [24] . While Sure-Seal bioceramic sealer is a premixed ready-to use, injectable calcium aluminosilicate paste which sets in the presence of moisture. Bioceramic sealers are composed mainly of calcium silicates, calcium phosphate monobasic, calcium hydroxide, zirconium oxide and thickening agents [25]. They have high dimensional sta-Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study) Citation: Anan Medhat Mohamed., et al. "Evaluation of the Effect of Final Rinse with Chitosan Nanoparticles and EDTA on the Push-out Bond Strength of Resin-based and Bioceramic-based Root Canal Sealers (A Comparative In Vitro Study)". Acta Scientific Dental Sciences 5.4 (2021): 66-75. addition, the smear layer removal efficacy of the chelating agents decrease from coronal to apical direction [13] . Therefore, Sure-Seal bioceramic sealer had a higher bond strength in the apical third compared to AH Plus except in the EDTA group, as it causes more erosion in dentin affecting the bond strength of calcium silicatebased sealers [43]. Moreover, the higher bond strength of Sure-Seal bioceramic sealer in the apical region may be due to its higher flowability and smaller particle size compared to AH Plus, which enhances sealer penetration into the dentinal tubules and allows the sealer to fill radicular dentin irregularities and minor spaces of difficult access [49]. At different root levels, the highest push-out bond strength values for AH Plus were recorded in the coronal third with a statistically significant difference from the middle and apical thirds, as the number of the dentinal tubules and the tubular diameter decreases from coronal to apical direction [48]. No significant difference was found between the middle and apical thirds because of the circular cross section of the root canal at the apical third, which provides a high resistance to dislodgment during the push-out test [50]. For Sure-Seal bioceramic sealer, the apical third showed significantly higher push-out bond strength values followed by the middle and coronal thirds. This may be attributed to the canal circular cross section in the apical areas and limited accessibility of the chelating agents to these areas [13, 50], which decrease the smear layer removal efficacy and minimize changes in the Ca:P proportion of root dentin. Regarding the failure mode, the present results obtained for AH Plus and Sure-Seal bioceramic sealer are in accordance with previously reported findings [39,47]. AH Plus and Sure-Seal bioceramic sealer predominantly showed cohesive failure modes. This is likely due to the stronger link formed between these sealers and radicular dentin compared to their link with gutta-percha [39]. Conclusion Within the limitations of this study, it could be concluded that: • The push-out bond strength of resin-based and bioceramicbased root canal sealers was influenced by the use of different chelating agents. • Removing the smear layer improves the bond strength of AH Plus to root dentin, but negatively affects that of Sure-Seal bioceramic sealer. • CNPs had less adverse effects on the bond strength and adherence of Sure-Seal bioceramic sealer compared to EDTA. • The combined use of CNPs/EDTA (1:1) showed the same effect on the bond strength of both sealers compared to each individual irrigant.
doi:10.31080/asds.2021.05.1066 fatcat:ihqdeje3xngc3ayf3z372d4xke