Evaluation Of The Push-out Bond Strength Of The Bio-C Repair And Compare It With The Mineral Trioxide Aggregate And Amalgam When Used As Root-end Filling Material: An In Vitro Study
Fatimah R Hammadi, Zainab M Abdul-Ameer
Department of Restorative and Aesthetic Dentistry, College of Dentistry, University of Baghdad, Baghdad, Iraq
Correspondence Address:
Fatimah R Hammadi
Master student, Department of Restorative and Aesthetic Dentistry, College of Dentistry, University of Baghdad
Iraq
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/denthyp.denthyp_160_22
Introduction: We aimed to assess the push‐out bond strength of BIO-C REPAIR (a ready-to-use bioceramic material), and compare it with the mineral trioxide aggregate (MTA) and аmаlgаm. Methods: A total of 30 single-rooted, straight human maxillary central incisors were chosen. To keep the root canal length at 15 mm, the crown was resected. The teeth underwent endodontic treatment, along with the resection of their root ends and preparation of root-end cavities. The teeth were randomly allocated into three groups as follows: BIO-C REPAIR, MTА, and Zinc-free аmаlgаm. Utilizing a universal testing machine, the push-out test was done and the digital microscope was used to assess failure made. Data were analyzed by the one-way ANOVA and chi-square test using the Python software. Results: Statistically significant difference was found among study groups regarding push-out bond strength (p < 0.001) and mode of failure (p < 0.001). Post-hoc test showed MTA has significantly lower push-out bond strength than BIO-C REPAIR and amalgam (p < 0.001). Conclusion: Within the limitation of this study, the push‐out bond strength for BIO-C REPAIR was higher than the MTA and nearly similar to the amalgam.
Keywords: biocerаmic, endodontic surgery, endodontics, mineral trioxide aggregate (MTA), push‐out bond strength, retrograde obturation, root-end filling
Numerous studies had examined the surgical endodontic treatment’s clinical results and most of these studies showed that the choice of root-end materials had a significant impact on the clinical results of endodontic surgery.[1] The material used as root-end filling should be antibacterial, nontoxic, biocompatible with the periradicular tissue, radiopaque, nonresorbable, dimensionally stable, resist dissolution or breakdown by tissue fluids, possess good handling qualities, and have ability to adapt on the dentinal walls of root canal system.[2] The goal of endodontic therapy is to get a fluid-tight seal between the root canal system and the surrounding periodontium.[3]
Mineral trioxide aggregate (MTA), which is noncytotoxic and stimulates cementogenesis, is one of popular materials that have been clinically used as root-end filling materials.[4] Yet, MTA has some drawbacks, including difficult handling, a prolonged setting time, expensive cost, poor antibacterial properties, and discoloration.[5] Calcium sulphate is removed from MTA’s formulation to improve utilization and decrease the setting time.[6]
Bioceramic root repair materials, such as BIO-C REPAIR, are employed in root-end fillings. It is simple to use and placed into the cavity because it doesn’t need manipulation and is time saving.[7] BIO-C REPAIR had equivalent cytocompatibility in comparison with MTA and induces bio-mineralization.[8] It showed higher cell viability than MTA repair HP after 24 hours and 1 week.[9]
However, a biomaterial’s bond strength with dentin is essential for a sufficiently effective seal. Insufficient sealing could result in the bacteria and their products escaping.[10]
The aim of this study is to assess the push‐out bond strength of BIO-C REPAIR (a ready-to-use bioceramic material), and compare it with the MTA and аmаlgаm.
Materials and MethodsStudy protocol was approved by the research ethics committee of the College of Dentistry-University of Baghdad (Ref. number: 56, Date: April 20, 2022). Thirty single-rooted human maxillary central incisors which were extracted for periodontal reasons were selected according to the following criteria: single roots that completed the root formation without any anatomic variation, crack or, any resorption and no previous endodontic treatment. The sample was cleaned and disinfected with 2.5% NAOCL (Promida, Odunpazarı, Turkey) for 30 minutes and stored in normal saline.[11]
Periodontal tissue and calculus were removed and the crown was sectioned to standardize the root length (15 mm). Using a size 10 K-file and a barbed broach (DENTSPLY Maillefer, Ballaigues, Switzerland), the pulp tissue was removed, the file’s tip was 1 mm visible from the apical foramen. ProTaper rotary files (DENTSPLY Maillefer, Ballaigues, Switzerland) were used to prepare the root canals.
Gutta-percha points (DENTSPLY, Maillefer, and Ballaigues, Switzerland) and MTA-Fillapex sealer (Angelus Odonto, Londrina, Brazil) were used to fill the canals using lateral condensation technique. For complete setting of filling materials, the roots were stored in 100% humidity at 37 °C for 2 days.
The specimens were embedded in acrylic resin (New Stetic, Antioquia, Colombia). Three millimeter from the apical part of the root was eliminated to reduce the apical ramifications and lateral canals. The retrograde cavity (3 mm in depth and 1.5 mm in diameter) was prepared by fissure bur (FKG Dentaire, La Chaux-de-Fonds, Switzerland) using a high-speed headpiece.
The root-end cavities were irrigated by EDTA 17% (Dental Produits Dentaires SA, Vevey, Switzerland) for smear layer removal and rinsed with normal saline, after that the cavities were filled with the filling materials according to the manufacturer’s instruction. The teeth were randomly (using www.random.org) assigned to three groups: 1) BIO-C REPAIR (Angelus Odonto, Londrina, Brazil), 2) MTA (Angelus Odonto, Londrina, Brazil), and 3) Zinc-Free amalgam (NAIS, Sofia, Bulgaria). Radiographs were taken to confirm the proper filling of the material. All teeth were stored at 37 °C and 100% humidity for 7 days.
The push-out bond strength assessment was done by taking 2 mm thickness slice from the apical third of the root were retrograde filling positioned. The plunger used for this test was 1.3 mm in diameter to provide 0.2 mm clearance from the margin of dentinal wall to ensure contact was only with the filling material.[12] The cross-head speed was 1 mm/min using a universal testing machine (Z wick Roell, Donau, Germany). The maximum load applied to the root-end filling material was recorded blindly in Newton at the time of dislodgement. The bond strength in MPa was measured according to the following formula.[13] Push-out bond strength=force(Newton)/ 2πr × h, where π is the constant 3.14, r is the root canal radius, and h is the thickness of the slice in millimeters.
After that, the slices were examined under a digital microscope (OPTO-EDU, Beijing, China) at ×40 magnification to determine the mode of failure.
Push-out bond strength data were analyzed by the one-way ANOVA and Tukey post-hoc test. Mode of failure data were analyzed by chi-square test using the Python 3.10.4 (The Python Software Foundation, www.python.org).
ResultsStatistically significant difference was found among study groups regarding push-out bond strength (p < 0.001) and mode of failure (p < 0.001) [Figure 1] and [Figure 2]. Post-hoc test showed MTA has significantly lower push-out bond strength than BIO-C REPAIR and amalgam (p < 0.001). The difference between push-out bond strength of BIO-C REPAIR and amalgam was not significant (p = 0.99).
The optimum root-end filling material must be able to withstand forces that could dislodge it, such as the force of mastication or operative procedures. In this present in vitro study, push‐out bond strength for BIO-C REPAIR (8 MPa) was higher than the MTA (5 MPa) and nearly similar to the amalgam (8 MPa). The higher bond strength for BIO-C REPAIR material could be explained by dentin uptake to the calcium.
Vivan RR et al., reported push‐out bond strength of 19 MPa for MTA.[14] Amoroso-Silva PA et al., reported push‐out bond strength of 25 MPa for MTA.[15] However, the controversy between different studies maybe related to test methodology of such studies. Sirisha K et al., in a critical review stated that there is a lack of a standard method for documenting the bond strength tests which could lead to misunderstanding of the data and dental material binding capabilities.[16] Collares FM et al., conducted a meta-regression analysis to assess the effect of methodological variables on the push‐out bond strength of root filling materials. They reported factors such as sealer, core material, root filling technique, tooth type, tooth portion, slice thickness, storage time, and load velocity could affect the push‐out bond strength. They found deviation up to 4.73 MPa among different test centers.[17]However, the BIO-C REPAIR showed 70% occurrence of cohesive failure and 30% mixed mode of failure maybe due to chemical interaction between material and dentin which increases the material’s resistance to dislodgment. In contrast, regarding amalgam adhesive failure was observed. We found 10% occurrence of adhesive failure for MTA, whereas Vivan RR et al., reported 70% occurrence of adhesive failure and 30% mixed mode of failure for MTA.[14]
Nevertheless, readers must note the natural limitations of in vitro studies which could not simulate real oral environment. Limited sample size is another weakness of this study.
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Nil.
Conflicts of interest
There are no conflicts of interest.
References
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