An in vitro Investigation of the Sealing Ability of Biodentine and Mineral Trioxide Aggregate as Retrofilling Materials after the use of Various Irrigating Solutions.

Aim: The purpose of this study was to assess the sealing ability of Biodentine (BD) and mineral trioxide aggregate (MTA) as retrograde filling materials after irrigation with 17% ethylenediaminetetraacetic acid (EDTA) and QMix irrigating solutions. Materials and
Methods: Decoronation of 48 permanent maxillary central incisors was done. Root canal instrumentation was carried out in the samples. The apical root was resected for about 3 mm and retrocavities were prepared. Teeth were allocated into two groups (n = 24). MTA was used in Group 1. BD was used in Group 2. Depending on irrigation, the groups were subdivided A, B, and C subgroups. Group A - 0.9% saline; Group B - 17% EDTA; and Group C - QMix were used. The resected root end was irrigated with 5 ml of all irrigating solutions for 1 min. After final irrigation, cavities were filled with retrofilling materials in each group. Nail enamel was applied to the surfaces of the roots apart from the resected end. Roots were placed in India ink for 72 h. Teeth were sectioned longitudinally and microleakage was determined with a stereomicroscope. Statistical Analysis: Analysis was done using the one-way analysis of variance, Independent t-test, and post hoc test.
Results: Statistically significant difference in the degree of microleakage was observed between irrigating solutions and the retrofilling materials.
Conclusion: BD exhibits a better sealing ability compared to MTA as a retro filling material following QMix irrigation. Copyright:

INTRODUCTION

Endodontic therapy is considered to be successful when it provides a fluid tight seal between intraradicular space and periradicular tissues. Nonsurgical retreatment is preferred in cases where there is root canal treatment failure. When nonsurgical endodontic treatment fails to seal the root canal system, surgical endodontics becomes a viable alternative for saving the tooth.[1]

Smear layer is typically produced during periapical surgery when the root apex is prepared.[2] To eliminate the smear layer, several chemicals such as sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are utilized.[3] The elimination of the smear layer in the apical third of the root canal system using 17% EDTA has been reported to be ineffective.[4] Q-MIX™ 2 in 1 is an irrigant that can be helpful when used in the root canal's apical third for smear layer removal.[5]

Amalgam, glass ionomer cement (GIC), composite resin, carboxylate cement, zinc oxide eugenol cement (IRM, and super EBA), composite resins, and resin glass ionomer hybrids have all been employed as retro fillers. However, no substance exists that fits all of the requirements of an ideal root filling material.[67]

Mineral trioxide aggregate (MTA) has been identified as one of the best root end filling materials in several studies. It encourages tissue regeneration, is biocompatible, and prevents microleakage. When utilized as a retro filling material, it has a better apical sealing ability than IRM, EBA cement, and amalgam.[8]

Biodentine (BD) is a calcium silicate-based substance that was developed as a dentine replacement material.[9] It is biocompatible and according to studies, can be utilized for pulp capping, pulpotomy, apexification, internal and external resorption, root perforation repair, and as retrofilling material.[10]

However, research into the usefulness of BD as a retro filling material following the removal of smear layers is currently lacking. As a result, the purpose of this research was to see how irrigation with 17% EDTA and QMix influenced the sealing ability of BD and MTA when used as retrofilling materials.

MATERIALS AND METHODS

Selection of specimens

This study included 48 caries-free human permanent maxillary central incisors with straight roots. To eliminate organic material from the root surfaces, the teeth were submerged in a 5% NaOCl solution (VIP Vensons India) for around 15 min. The teeth were kept in sterile water until they were ready to be used. The Institutional Ethics Committee (Protocol no: 2018/089) granted ethical approval.

Preparation of the specimens

The teeth were de-coronated with a diamond disc, and the length was standardized at 15 mm. A #10 K file (Mani Inc, TochigiKen, Japan) was used to determine the working length. Rotary Protaper Universal files (Dentsply Maillefer, Ballaigues, Switzerland) were used to widen the canals up to size F3 (Dentsply Maillefer, Ballaigues, Switzerland). Between each instrument, 5 mL of 2.5% NaOCl was irrigated for 1 min. The canals were dried with paper points (Dentsply Maillefer, Ballaigues, Switzerland) after final irrigation with 5 mL of saline (BN Laboratory). All of the samples were sealed with AH Plus (Dentsply, Germany) and gutta-percha (Dentsply Maillefer, Ballaigues, Switzerland). Cavit (3M™ CAVIT™) was used to seal the access cavities. Using a carborundum disc and water as a coolant, 3 mm of the root apex were resected perpendicular to the long axis of the root. Ultrasonics was used to create a 3-mm deep apical chamber in each root (Dentsply Pro Ultra). The samples were then divided into two groups (n = 24) that were further subdivided into three groups (n = 8) as follows: A, B, and C.

For 1 min, 5 mL of the irrigating solutions was applied to the resected root end cavities. The root end cavities were dried with paper points after the final irrigation with 5 mL of distilled water for 1 min. MTA [Figure 1] and BD [Figure 2] were used to fill the root end cavities. The roots were then kept at 37°C in 100% humidity for 48 h.

Figure 1

Filling the root end with mineral trioxide aggregate (Dentsply Tulsa, Tulsa, OK, USA)-Group 1. (a) Root end cavities irrigation with 0.9% saline-Subgroup A (b) Root end cavities irrigation with 17% ethylenediaminetetraacetic acid (Prevest Denpro Limited, Jammu and Kashmir, India)-Subgroup B (c) Root end cavities irrigation with Q-MIX™ 2 in 1 (Dentsply Tulsa Dental Specialities, Tulsa, OK, USA)-Subgroup C

Figure 2

Filling the root end with BD (Septodont, France)-Group 2 (a) Root end cavities irrigation with 0.9% saline-Subgroup A (b) Root end cavities irrigation with 17% ethylenediaminetetraacetic acid-Subgroup B (c) Root end cavities irrigation with Q-MIX™ 2 in 1-Subgroup C

Dye penetration

Apart from the resected root end, which was immersed in India ink for 72 h, the external root surface received two coats of nail enamel. To assess microleakage, gutta-percha was removed after the teeth were cut longitudinally by making vertical grooves. A stereomicroscope with 0.1 mm accuracy was used to assess the degree of microleakage was by the linear measurement of dye penetration.

Statistical analysis

The irrigants were compared using the one-way analysis of variance (ANOVA), and the materials in each group were compared using an independent t-test. SPSS software version 22 (SPSS Inc., Chicago, Ill., USA) was used to analyze the data. P < 0.05 was deemed statistically significant.

RESULTS

After employing different irrigation solutions, an independent t-test Table 1 was used to see if there was any significant difference in the degree of microleakage between the groups MTA and BD. After irrigation with EDTA and QMix, there was a statistically significant difference in the degree of microleakage between MTA and BD, however after irrigating with saline, there was no change in the degree of microleakage.

Table 1

Independent t-test to compare between mineral trioxide aggregate and biodentine

Group	n	Mean	SD
Saline
MTA	8	7.1563	0.67076
BD	8	6.7063	0.80210
17% EDTA
MTA	8	6.1675	0.64233
BD	8	5.1112	0.40336
QMix
MTA	8	2.9588	0.24856
BD	8	2.2512	0.26134
		T-test for equality of means
		T	df
Saline
Equal variances assumed		1.217	14
Equal variances not assumed		1.217	13.575
17% EDTA
Equal variances assumed		3.939	14
Equal variances not assumed		3.939	11.778
QMix
Equal variances assumed		5.548	14
Equal variances not assumed		5.548	13.965

After irrigation with EDTA and QMix, there was a statistically significant difference in the degree of microleakage between MTA and BD, however after irrigating with saline, there was no difference in the degree of microleakage. n: Number of samples, df: Degree of freedom, MTA: Mineral trioxide aggregate, BD: Biodentine, SD: Standard deviation, EDTA: Ethylenediaminetetraacetic acid

A one-way ANOVA Table 2 was used to determine whether there was a significant difference in the degree of microleakage between the three irrigation solutions. The P value indicated that there was a significant difference in the degree of microleakage between the three solutions. According to the post hoc test, there were statistically significant differences between saline, EDTA, and QMix. According to the mean values, QMix is the best, followed by EDTA and saline.

Table 2

One-way ANOVA descriptive analysis to compare between the solutions

Group	n	Mean	SD	Minimum	Maximum
MTA
Saline	8	7.1563	0.67076	6.14	8.03
17% EDTA	8	6.1675	0.64233	5.55	7.65
Q mix	8	2.9588	0.24856	2.65	3.45
Total	24	5.4275	1.90557	2.65	8.03
BD
Saline	8	6.7063	0.80210	5.55	7.82
17% EDTA	8	5.1112	0.40336	4.35	5.64
Q mix	8	2.2512	0.26134	2.06	2.80
Total	24	4.6896	1.95206	2.06	7.82
Group	Sum of squares	df	Mean square	F	P
MTA
Between groups	77.047	2	38.524	125.038	0.000
Within groups	6.470	21	0.308
Total	83.517	23
BD
Between groups	81.522	2	40.761	139.853	0.000
Within groups	6.121	21	0.291
Total	87.642	23

From the P value obtained, it was clear that there was a significant difference in the degree of microleakage between the three different solutions. F: Variation within the samples, n: Number of samples, df: Degree of freedom, MTA: Mineral trioxide aggregate, BD: Biodentine, SD: Standard deviation, EDTA: Ethylenediaminetetraacetic acid

DISCUSSION

Endodontic success is dependent on the root canal system being completely obturated and having a fluid-tight closure. Endodontic failure occurs when the fluid impervious barrier is breached due to difficulties in the apical one-third of the root canal system and iatrogenic errors. In such cases, periapical surgery with retrograde filling is the preferred treatment. This method entails removing diseased tissues, gaining access to the affected root apex, preparing the root end, and placing a retrograde filling material to achieve an apical seal.[11]

Torabinejad introduced MTA in 1993,[1] and it has demonstrated high sealing ability, antimicrobial properties, and biocompatibility since then. It has been used for perforation repair, pulp capping, and retro filling.[12] BD, a bioactive calcium silicate-based cement, introduced recently has been used as a “dentin substitute” material.[9] As a result, in this investigation, MTA and BD were chosen as retro filling materials.

A carborundum disc with water cooling was used to execute root resections at 3 mm of the apex at 90° to the long axis of the root during the preparation of the samples following obturation. The number of open dentinal tubules is reduced as a result.[13] During periradicular surgery, root resection is carried out to eliminate pathological processes, soft-tissue lesions, anatomic variances, and errors in nonsurgical therapy. It also provides access to the canal system, forms an apical seal, reduces fenestrated root apices, and assesses aberrant canals and root fractures. Ultrasonics was used to create a 3-mm deep cavity on the resected root end. The use of an ultrasonic tip results in a deeper root-end cavity with less bevel for root end preparation and retrograde filling. It also follows the direction of the canal space when compared to bur preparations, even when no canal instrumentation or obturation is performed.[1415]

Apical preparation forms a 2–5 μm thick superficial smear layer packed into dentinal tubules up to 40 μm. It is made up of organic and inorganic debris, as well as microorganisms and endotoxins.[216] This interferes with the adhesion of filling materials to dentin walls and compromises the disinfection of dentinal tubules by preventing the penetration of disinfecting solutions.[1718]

Many irrigants have got smear layer removing ability, of which the commonly used irrigants is EDTA. It forms calcium chelates by acting as a chelating agent for inorganic divalent cations, including calcium ions.[19] Q-MIX, a chelating compound made of polyaminocarboxylic acid, a bisbiguanide antibacterial agent, a surfactant, and deionized water, has been shown to be as effective as EDTA.[5] Hence, after retropreparation, irrigation of the cavities was carried out with 0.9% saline, 17% EDTA, and QMix irrigating solutions.

In the appropriate groups, the root end preparations were subsequently restored with MTA and BD. To avoid microleakage through the lateral canals, the samples were covered with two coatings of nail enamel, with the exception of the excised apical root ends. Dye penetration, radioisotopes, bacterial leakage investigations, electrochemical techniques, scanning electron microscopy, and fluid filtration methods are all utilized to evaluate the sealing performance of retrofilling materials.

The dye penetration technique is one of the most common, with methylene blue and India ink as the most commonly used dyes. As a result, dye penetration was used in this study to assess the sealing ability of the retrofilling materials.[14] In the current study, India ink was used because 1% methylene blue dye solution may be decolored when in contact with alkaline materials such as MTA, resulting in unreliable results.[20]

In this study, saline had the highest microleakage, followed by 17% EDTA, and QMix had the lowest microleakage. The benefits of QMix as an irrigant can be attributed to its numerous effective components. The addition of a wetting agent reduces the physical phenomenon of solutions, which may increase wettability for better penetration into dentinal tubules. QMix is more biocompatible than many other irritants and has been shown to be as effective in removing the smear layer as EDTA.[5]

A good retrofilling material should be easy to work with, radiopaque, biocompatible, dimensionally stable, nonabsorbable, insoluble in tissue fluids, nontoxic, electrochemically active, noncorrosive, and not discolor the surrounding tissues. The periradicular tissues should tolerate it well, and it should encourage recovery.[6] When compared with MTA, BD had a better sealing ability when used as a retrofilling material.

BD is available in the form of a capsule with the optimum powder-to-liquid ratio. Zirconium oxide, dicalcium silicate, tricalcium silicate, calcium carbonate, and iron oxide are the primary ingredients in the powder. Calcium chloride, a hydrosoluble polymer, and water make up the liquid.[9] According to research, BD is biocompatible and can be used for pulp capping, pulpotomy, apexification, internal and external resorption, root perforation repair, and retro filling. It was created with MTA-based technology and claims a variety of physical properties, including use in endodontic repair and pulp capping in restorative dentistry. It enters the dentinal tubules and crystallises, interlocking with the dentin. It has the potential to induce mineralization and odontoblast differentiation in cultured pulp cells.[10]

The formation of apatite deposits, which form as a result of an interaction between the calcium silicate-based cement and the phosphate ions in saliva, improves the sealability of BD.[21] The release of calcium hydroxide increases the alkalinity of the surrounding media in BD. The biomineralization potential of BD was also demonstrated to be greater than MTA because to the wider calcium and silicon-rich layer at the material dentine contact. This could explain why BD outperformed MTA in terms of sealing ability.[2223] Research also claims BD exhibiting better sealing ability than MTA.[2425]

Hence, when root end cavities were irrigated with QMix irrigating solution, BD as a retrograde filling material demonstrated the best resistance to microleakage, according to this study.

CONCLUSION

Based on the study's limitations, it is possible to conclude that

BD has a superior sealing ability than MTA

QMix-irrigated retropreparations with BD restoration exhibited increased canal wall adaptability.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.